Consumption of long-chain n-3 PUFA, α-linolenic acid and fish is associated with the prevalence of chronic kidney disease

Plasma Levels of Polyunsaturated Fatty Acids and Adverse Kidney Outcomes

RATIONALE & OBJECTIVE

Many studies have reported polyunsaturated fatty acids (PUFA) as significant predictors of cardiovascular disease, but little is known about the relationship between PUFA levels and chronic kidney disease (CKD). This study explored this relationship among individuals with and without CKD.

STUDY DESIGN

Prospective observational cohort study.

SETTING & PARTICIPANTS

73,419 participants without CKD (cohort 1) and 6,735 participants with CKD (cohort 2) in the UK Biobank Study, with PUFA levels measured between 2007 and 2010.

EXPOSURE

Percentage of plasma PUFA, omega-3 fatty acid (FA), omega-6 FA, docosahexaenoic acid (DHA), and linoleic acid relative to total FA.

OUTCOME

Incident CKD for cohort 1 and incident kidney failure requiring replacement therapy (KFRT) for cohort 2.

ANALYTICAL APPROACH

Cox proportional hazards regression analyses, including a cause-specific competing risk model.

RESULTS

In cohort 1, individuals with higher quartiles of plasma PUFA levels had healthier lifestyles and fewer comorbidities. During 841,007 person-years of follow-up (median 11.9 years), incident CKD occurred in 4.5% of participants (incidence rate, 39.1 per 10,000 person-years). For incident CKD in cohort 1, the adjusted cause-specific hazard ratios for quartiles 2, 3, and 4 were 0.83 (95% CI, 0.75-0.92), 0.85 (95% CI, 0.76-0.96), 0.71 (95% CI, 0.62-0.82), respectively, compared with quartile 1. This inverse relationship was consistently observed for all PUFA types. In cohort 2, although total PUFA levels were not associated with KFRT, higher PUFA subtype levels of DHA were associated with a lower risk of KFRT.

LIMITATIONS

Observational design and limited generalizability to individuals with higher disease severity; no data on eicosapentaenoic acid.

CONCLUSIONS

Among individuals without CKD, higher plasma PUFA levels and all 4 PUFA components were associated with a lower risk of incident CKD. In individuals with CKD, only the omega-3 component of PUFA, DHA, was associated with a lower risk of KFRT.

PLAIN-LANGUAGE SUMMARY

Low amounts of polyunsaturated fatty acids (PUFA) in the blood are suspected of increasing the chances of heart disease, but it is not known whether the PUFA relates to kidney disease occurrence. In a large group without kidney disease in the United Kingdom, people with higher levels of PUFA in their blood tended to have a lower risk of developing kidney disease compared to those with lower PUFA levels. This relationship was consistently observed for all PUFA types. However, in the group with kidney disease, only higher levels of docosahexaenoic acid, a subtype of PUFAs, were associated with a lower risk of developing severe kidney problems that required kidney replacement therapy. These findings suggest that higher levels of PUFA, found in certain healthy fats, might protect against the development of kidney disease in the general population. As kidney function declines, only the docosahexaenoic acid, a subtype of PUFA, appears to be associated with preserved kidney function.

The impacts of dietary inclusion of soybean oil and linseed oil on growth performance, carcass yield, and health status of growing Japanese quail

Polyunsaturated fatty acids (PUFA), including n-6 and n-3 fatty acids, are essential for enhancing the performance and health of poultry. Avian species lack desaturase enzymes for endogenous synthesis of n-6 and n-3 fatty acids. This work aimed to determine the impacts of including soybean oil (SO) and linseed oil (LO) in quail diets on growth, lipid profile, hepatic and renal functions, immunity, and antioxidant status. A total of 350 Japanese quail chicks (1-wk-old) were randomly arranged into 7 dietary treatment groups. Seven isocaloric and isonitrogenous experimental basal diets were formed based on the nutritional requirements of growing Japanese quail. Group 1, the control, received a basal with no oils, while groups 2 to 7 received a basal diet containing either 1% SO, 1.5% SO, 2% SO, 1% LO, 1.5% LO, or 2% LO, respectively. Quail groups that consumed diets containing LO at all levels showed significantly greater live body weight (LBW) at 5th wk of age than other experimental groups. The dietary incorporation of 1.5 or 2% SO or LO at all levels yielded significant improvements in body weight gain (BWG) and feed conversion ratio (FCR) through 3 to 5 and 1 to 5 wk of age. Different dietary oil sources and levels have no significant impacts on feed intake (FI) and carcass yield parameters. Lipid profile parameters were improved by adding SO and LO in quail diets, with LO having a higher effect than SO. The hepatic and renal functionality were improved by adding SO and LO in quail diets. The lowest uric acid (UA) bloodstream concentrations were recorded in the quail group fed a diet with 2% LO. Values of Gamma globulins (G-GLO) and immunoglobulins (G, M, and A) were increased by adding SO or LO to quail diets. Blood levels of MDA and TAC were improved significantly by including LO in quail diets. The activity of the superoxide dismutase (SOD) enzyme was significantly increased by adding SO or LO to quail diets. Generally, adding SO or LO to growing quail diets up to 2% could yield favorable effects on growth performance, blood lipids, hepatic and renal functions, immunity, and antioxidant status; however, LO seems to have better effects than SO.

Association between dietary protein intake and risk of chronic kidney disease: a systematic review and meta-analysis

Objective

There is suggestive data indicating a correlation among dietary protein intake and the progression of chronic kidney disease (CKD). Nonetheless, the exact associations between dietary protein intake and the incidence of CKD have remained uncertain. We performed the first meta-analysis to explore the correlation among total protein, plant protein, animal protein intake and CKD risk.

Methods

The study conformed the PRISMA statement guidelines. We comprehensively searched PubMed, Web of Science, and Embase until to December 2023. The retrieved studies underwent rigorous evaluation for eligibility, and relevant data were meticulously extracted. The Newcastle-Ottawa Scale (NOS) tool was applied to evaluate the risk of bias. Subsequently, relevant data were extracted and pooled to evaluate the relations among dietary protein intake and CKD incidence.

Results

Totally, 6,191 articles were identified, six studies were eligible. A total of 148,051 participants with 8,746 CKD cases were included. All studies had a low overall risk of bias. Higher total, plant and animal protein intake were all correlated with decreased CKD incidence, pooled risk ratios (RRs) and 95% confidence intervals (CIs) were as follows: (RR = 0.82, 95% CI = 0.71-0.94, p = 0.005; I2 = 38%, p = 0.17); (RR = 0.77, 95% CI = 0.61-0.97, p = 0.03; I2 = 77%, p = 0.001); (RR = 0.86, 95% CI = 0.76-0.97, p = 0.02; I2 = 0%, p = 0.59), respectively. For fish and seafood within animal protein: RR = 0.84, 95% CI = 0.74-0.94. Subgroup analysis showed that geographical region, sample size, follow-up time, not assessing protein by food frequency questionnaire, using %energy as the measurement index, not adjusting for several covariates may be the sources of heterogeneity for plant protein. A significant non-linear relation among plant protein and incident CKD was observed by dose-response analysis.

Conclusion

The data showed a lower CKD risk significantly associated higher-level dietary total, plant or animal protein (especially for fish and seafood) intake. Further prospective studies demonstrating the correlations of precise sources, intake and duration of dietary protein and incident CKD are warranted.

Consumption of red, white, and processed meat and odds of developing kidney damage and diabetic nephropathy (DN) in women: a case control study

Diabetic nephropathy (DN) is one of the most prevalent and severe complications of diabetes mellitus (DM) and is associated with increased morbidity and mortality. We aimed to investigate the associations between red, processed, and white meat consumption and the odds of developing kidney damage and DN in women. We enrolled 105 eligible women with DN and 105 controls (30-65 years). A validated and reliable food frequency questionnaire (FFQ) was used to evaluate the consumption of red, processed, and white meat. Biochemical variables and anthropometric measurements were assessed for all patients using pre-defined protocols. Binary logistic regression was conducted to examine possible associations. The results of the present study showed that there was a direct significant association between high consumption of red meat and processed meats and odds of microalbuminuria (red meat 2.30, 95% CI 1.25, 4.22; P-value = 0.007, processed meat: OR 2.16, 95% CI 1.18, 3.95; P-value = 0.01), severe albuminuria (red meat OR 3.25, 95% CI 1.38, 7.46; P-value = 0.007, processed meat: OR 2.35, 95% CI 1.01, 5.49; P-value = 0.04), BUN levels (red meat: OR 2.56, 95% CI 1.10, 5.93; P-value = 0.02, processed meat: OR 2.42, 95% CI 1.04, 5.62; P-value = 0.03), and DN (red meat 2.53, 95% CI 1.45, 4.42; P-value = 0.001, processed meat: OR 2.21; 95% CI 1.27, 3.85; P-value = 0.005). In summary, our study suggests that higher consumption of red and processed meat sources may be associated with microalbuminuria, severe albuminuria, higher BUN level, and higher odds of DN.

Associations of dietary inflammatory index with low estimated glomerular filtration rate, albuminuria and chronic kidney disease in U.S adults: Results from the NHANES 2011-2018

BACKGROUND AND AIMS

Chronic Kidney Disease (CKD) is characterized by a high inflammation status with ever-increasing prevalence, and defined as low estimated glomerular filtration rate (eGFR) or albuminuria. Both low eGFR and albuminuria can have independent effects on the body. The dietary inflammatory index (DII) is a validated tool used to assess the inflammatory potential of the diet. We aim to explore not only the association between DII and CKD, but also the associations of DII with low eGFR and albuminuria, respectively. In addition, their associations in different subgroups remain to be explored.

METHODS AND RESULTS

18,070 participants from the 2011-2018 NHANES with complete data of dietary intake and laboratory data were involved in our study. The data of 24-hour dietary recall interview was used to calculate DII, CKD could be reflected by laboratory data of creatinine and albumin. Then weighted multivariate logistic regression models and subgroup analyses were performed. The prevalence of low eGFR, albuminuria and CKD were 6.8%, 9.8% and 14.5%, respectively. A positive association between DII and low eGFR was observed (OR=1.12, 95%CI: 1.05-1.21), Q2, Q3 and Q4 are positively associated with a significant 39%, 65% and 71% increased risk of low eGFR compared with Q1 (P for trend<0.05). DII was also associated with CKD (OR=1.06, 95%CI: 1.01-1.11).

CONCLUSION

Significant positive associations of DII with CKD and low eGFR were observed. But we didn't find such association between DII and albuminuria.

A diet containing cod backbone proteins attenuated the development of mesangial sclerosis and tubular dysfunction in male obese BTBR ob/ob mice

PURPOSE

The obese black and tan, brachyuric (BTBR) ob/ob mouse spontaneously develops features comparable to human diabetic nephropathy. The primary aim of the present study was to investigate if a diet containing fish proteins would attenuate or delay the development of glomerular hypertrophy (glomerulomegaly), mesangial sclerosis and albuminuria in obese BTBR ob/ob mice.

METHODS

Obese BTBR.CgLepob/WiscJ male mice were fed diets containing 25% of protein from Atlantic cod backbones and 75% of protein from casein (Cod-BB group), or casein as the sole protein source (control group). Kidneys were analysed morphologically, and markers for renal dysfunction were analysed biochemically in urine and serum.

RESULTS

The Cod-BB diet attenuated the development of mesangial sclerosis (P 0.040) without affecting the development of glomerular hypertrophy and albuminuria. The urine concentration of cystatin C (relative to creatinine) was lower in mice fed the Cod-BB diet (P 0.0044).

CONCLUSION

A diet containing cod backbone protein powder attenuated the development of mesangial sclerosis and tubular dysfunction in obese BTBR ob/ob mice, but did not prevent the development of glomerular hypertrophy and albuminuria in these mice.

Associations of meat, fish and seafood consumption with kidney function in middle-aged to older Chinese: a cross-sectional study based on the Guangzhou Biobank Cohort Study

OBJECTIVE

To examine the associations of red meat, poultry, fish and seafood and processed meat consumption with kidney function in middle-aged to older Chinese.

DESIGN

A cross-sectional study based on the Guangzhou Biobank Cohort Study.

SETTING

Community-based sample.

PARTICIPANTS

9768 participants (2743 men and 7025 women) aged 50+ years.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome was estimated glomerular filtration rate (eGFR) derived from the Chinese-specific equation based on the Modification of Diet in Renal Disease (MDRD) equation (c-aGFR). eGFR derived from the original isotope-dilution mass spectrometry-traceable MDRD study equation, and prevalent chronic kidney disease (CKD) defined as c-aGFR<60 mL/min/1.73 m2 were considered the secondary outcomes.

RESULTS

After adjusting for sex, age, body mass index, education, occupation, family income, smoking status, alcohol use, physical activity, daily energy intake, self-rated health and chronic disease history (diabetes, hypertension and dyslipidaemia), compared with processed meat consumption of 0-1 portion/week, those who consumed ≥3 portions/week had lower c-aGFR (β=-2.74 mL/min/1.73 m2, 95% CI=-4.28 to -1.20) and higher risk of prevalent CKD (OR=1.40, 95% CI=1.09 to 1.80, p<0.0125). Regarding fish and seafood consumption, the associations varied by diabetes (p for interaction=0.02). Fish and seafood consumption of ≥11 portions/week, versus 0-3 portions/week, was non-significantly associated with higher c-aGFR (β=3.62 mL/min/1.73 m2, 95% CI=-0.06 to 7.30) in participants with diabetes, but was associated with lower c-aGFR in normoglycaemic participants (β=-1.51 mL/min/1.73 m2, 95% CI=-2.81 to -0.20). No significant associations of red meat or poultry consumption with c-aGFR nor prevalent CKD were found. Similar results were found for meat, fish and seafood consumption with eGFR.

CONCLUSIONS

Higher processed meat, fish and seafood consumption was associated with lower kidney function in normoglycaemic participants. However, the associations in participants with diabetes warrant further investigation.

Phytochemical analysis and nephroprotective potential of Ajwa date in doxorubicin-induced nephrotoxicity rats: Biochemical and molecular docking approaches

The purpose of this study is to evaluate the likely defensive impact of Ajwa date aqueous extract (AJDAE) in alleviating the nephrotoxicity generated by doxorubicin (DOX) injection in rats. Sixty male Wister albino rats were randomly and equally separated into six groups (n = 10), and they were treated as follows: untreated control group, extract groups administered with 0.75 and 1.5 mg kg bw of AJDAE, toxicant control group administered with DOX, and prophylactic groups were treated with 0.75 and 1.5 mg/kg of AJDAE and 15 mg/kg DOX. Biochemical parameters, antioxidant enzymes, renal functions, DNA integrity, and histopathology were studied to evaluate the nephroprotective activity of AJDAE. Furthermore, bioactive compounds were utilized for in silico molecular docking. AJDAE treatment resulted in significant improvements in the amended renal biomarkers (urea, creatinine, calcium, phosphorous, and uric acid), antioxidative markers, and MDA. Noticeable histopathological improvements supported this result. Results of in silico studies revealed that d-Mannitol, 6TMS derivative, palmitic acid, and TMS derivative had a higher docking score with human soluble epoxide hydrolase (-10.9 kcal/mol) and NF-κB-DNA (-7 kcal/mol). The present findings indicated that AJDAE could decrease ROS generation and lipid peroxidation (LPO) and repair the DOX injection-related DNA damage.

Association of omega 3 polyunsaturated fatty acids with incident chronic kidney disease: pooled analysis of 19 cohorts

OBJECTIVE

To assess the prospective associations of circulating levels of omega 3 polyunsaturated fatty acid (n-3 PUFA) biomarkers (including plant derived α linolenic acid and seafood derived eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid) with incident chronic kidney disease (CKD).

DESIGN

Pooled analysis.

DATA SOURCES

A consortium of 19 studies from 12 countries identified up to May 2020.

STUDY SELECTION

Prospective studies with measured n-3 PUFA biomarker data and incident CKD based on estimated glomerular filtration rate.

DATA EXTRACTION AND SYNTHESIS

Each participating cohort conducted de novo analysis with prespecified and consistent exposures, outcomes, covariates, and models. The results were pooled across cohorts using inverse variance weighted meta-analysis.

MAIN OUTCOME MEASURES

Primary outcome of incident CKD was defined as new onset estimated glomerular filtration rate <60 mL/min/1.73 m2. In a sensitivity analysis, incident CKD was defined as new onset estimated glomerular filtration rate <60 mL/min/1.73 m2 and <75% of baseline rate.

RESULTS

25 570 participants were included in the primary outcome analysis and 4944 (19.3%) developed incident CKD during follow-up (weighted median 11.3 years). In multivariable adjusted models, higher levels of total seafood n-3 PUFAs were associated with a lower incident CKD risk (relative risk per interquintile range 0.92, 95% confidence interval 0.86 to 0.98; P=0.009, I2=9.9%). In categorical analyses, participants with total seafood n-3 PUFA level in the highest fifth had 13% lower risk of incident CKD compared with those in the lowest fifth (0.87, 0.80 to 0.96; P=0.005, I2=0.0%). Plant derived α linolenic acid levels were not associated with incident CKD (1.00, 0.94 to 1.06; P=0.94, I2=5.8%). Similar results were obtained in the sensitivity analysis. The association appeared consistent across subgroups by age (≥60 v <60 years), estimated glomerular filtration rate (60-89 v ≥90 mL/min/1.73 m2), hypertension, diabetes, and coronary heart disease at baseline.

CONCLUSIONS

Higher seafood derived n-3 PUFA levels were associated with lower risk of incident CKD, although this association was not found for plant derived n-3 PUFAs. These results support a favourable role for seafood derived n-3 PUFAs in preventing CKD.

Total protein intake and subsequent risk of chronic kidney disease: the Circulatory Risk in Communities Study

BACKGROUND

Whether dietary protein intake worsens renal function in the general population has been discussed but not yet determined. We aimed to examine the longitudinal association between dietary protein intake and risk of incident chronic kidney disease (CKD).

METHODS

We conducted a 12-year follow-up study with 3,277 Japanese adults (1,150 men and 2,127 women) aged 40-74 years, initially free from CKD, who participated in cardiovascular risk surveys from two Japanese communities under the Circulatory Risk in Communities Study. The development of CKD was defined by the estimated glomerular filtration rate (eGFR) during the follow-up period. Protein intake was measured at baseline by using the brief-type self-administered diet history questionnaire. We estimated sex-, age-, community- and multivariate-adjusted hazard ratios (HR) for incident CKD were calculated using the Cox proportional hazards regression models according to quartiles of percentage of energy (%energy) from protein intake.

RESULTS

During 26,422 person-years of follow-up, 300 participants developed CKD (137 men and 163 women). The sex-, age-, and community-adjusted HR (95% confidence interval, CI) for the highest (≥16.9%energy) versus lowest (≤13.4%energy) quartiles of total protein intake was 0.66 (0.48-0.90), p for trend = 0.007. The multivariable HR (95%CI) was 0.72 (0.52-0.99), p for trend = 0.016 after further adjustment for body mass index, smoking status, alcohol drinking status, diastolic blood pressure, antihypertensive medication use, diabetes mellitus, serum total cholesterol levels, cholesterol-lowering medication use, total energy intake, and baseline eGFR. The association did not vary by sex, age, and baseline eGFR. When examining animal and vegetable protein intake separately, the respective multivariable HRs (95%CIs) were 0.77 (0.56-1.08), p for trend = 0.036, and 1.24 (0.89-1.75), p for trend = 0.270.

CONCLUSIONS

Higher protein intake, more specifically animal protein intake was associated with a lower risk of CKD.

Causal associations between polyunsaturated fatty acids and kidney function: A bidirectional Mendelian randomization study

BACKGROUND

PUFAs were suggested to be beneficial for kidney function in observational studies. However, whether these associations are causal remains unclear.

OBJECTIVES

This study explores the causality between PUFAs and chronic kidney disease (CKD) or estimated glomerular filtration rate (eGFR) using bidirectional 2-sample Mendelian randomization (MR).

METHODS

Single nucleotide polymorphisms associated with PUFAs and kidney function were obtained from the largest and most recent genome-wide association studies with sample sizes of 13,544, 13,506, 13,499, 13,527, and 13,549 for omega-3 fatty acids, omega-6 fatty acids, DHA, LA, and other PUFAs than 18:2 (otPUFA), and 480,698 and 1,201,909 for CKD and eGFR, respectively. MR inverse-variance weighted (IVW) and pleiotropy residual sum and outlier test (MR-PRESSO) were used for data analysis, supplemented with a weighted median estimator, MR-Egger regression, and multivariable MR, giving β or OR and their 95% CIs.

RESULTS

There was suggestive evidence that higher omega-6 fatty acids were associated with increased eGFR using MR-PRESSO [β: 0.005 log(mL/min/1.73 m²) per SD increase in omega-6 fatty acids; 95% CI: 0.002, 0.008; P = 0.008]. Higher LA level was also associated with higher eGFR [β: 0.005 log(mL/min/1.73 m²) per SD increase in LA; 95% CI: 0.003, 0.007; P = 0.0007] using MR-PRESSO. Neither association of the other PUFAs, i.e., omega-3 fatty acids, DHA, and otPUFA, with CKD or eGFR nor the association of CKD and eGFR with PUFAs was found. Similar results were found in sensitivity analyses.

CONCLUSIONS

Our results suggest that higher omega-6 fatty acids and LA may increase eGFR levels. Although the estimated effects were relatively small, the results provide public health and research relevance, indicating the need for further longitudinal cohorts or randomized controlled trials on omega-6 fatty acids in improving kidney function.

Associations between dietary patterns and stages of chronic kidney disease

BACKGROUND

Studies have revealed that patients with chronic kidney disease (CKD) have dietary patterns different from those of the general population. However, no studies have compared the dietary patterns of between patients with early-stages (stages 1-3a) and late-stages (stages 3b-5) of CKD. Our objective was to investigate the associations between dietary patterns in early and late-stage CKD.

METHODS

We analyzed 4480 participants with CKD at various stages based on the data recorded between 2007 and 2016 from the database of the American National Health and Nutrition Examination Survey.

RESULTS

In total, 3683 and 797 participants had early and late-stage CKD, respectively. Through principal components analysis, the dietary intake dimension was reduced from 63 variables to 3 dietary patterns. We adopted logistic regression for analysis. The three dietary patterns are as follows: (1) saturated fatty acids and mono-unsaturated fatty acids (MUFA); (2) vitamins and minerals; and (3) cholesterols and polyunsaturated fatty acids (PUFA). These 3 patterns explained > 50% of dietary nutrient intake. Results indicated that among participants with dietary patterns 2 (vitamins and minerals) and 3 (cholesterols and PUFA), those with low intakes were more likely to have late-stage CKD. The odds ratios for patterns 2 and 3 were 1.74 (95% CI: 1.21-2.50) and 1.66 (95% CI: 1.13-2.43), respectively.

CONCLUSIONS

This study revealed that intakes of vitamins and minerals and cholesterols and PUFA were associated with the stages of CKD.

Pulicaria crispa mitigates nephrotoxicity induced by carbon tetrachloride in rats via regulation oxidative, inflammatory, tubular and glomerular indices

CONTEXT

Carbon tetrachloride (CCl₄) induces oxidative stress in various tissues by altering antioxidants defense system. Recently, there has been a substantial use of phytotherapy to treat different diseases.

OBJECTIVE

This study was designed to evaluate the curative effect of Pulicaria crispa (Forssk.) Benth et Hook (Family Asteraceae) aerial parts ethanol extract against CCl₄ induced toxicity in rats kidneys.

MATERIALS AND METHODS

Nephrotoxicity was induced by intraperitoneal injection with CCl₄ in a dose of 0.5 mL/kg b.wt./twice a week for six consecutive weeks. Serum kidney function tests, oxidative stress markers, inflammatory cytokines, nephrotoxicity biomarkers and histopathological observation were evaluated.

RESULTS

CCl₄ increased serum kidney function parameters, malondialdehyde level, inflammatory cytokines, and nephrotoxicity markers, while decreased certain oxidative stress indices as superoxide dismutase and glutathione refereeing to the control group (p < 0.0001). Administration of P. crispa ethanol extract to CCl₄ injured rats attenuated these changes with variable degrees. The results were confirmed through the observed amelioration of the renal histological architectures.

CONCLUSION

P. crispa ethanol extract possesses potent curative effect against CCl₄-induced nephropathy through improvement of kidney function, oxidative stress, inflammatory and nephrotoxicity index and the renal histopathological features. To establish the therapeutic and pharmacological applications of the plant, additional researches are required.

A chemometrics approach comparing characteristics and free radical scavenging capacity of flax (Linum usitatissimum L.) oils obtained from seeds and cakes with different extraction methods

BACKGROUND

Flax oil, a nutritive vegetable oil, is a rich natural source of the essential C18:3 α-linolenic acid and trace nutrients (tocopherol, phytosterol, polyphenol, flavonoid, etc.). In most small- and medium-sized facilities, the oil content in pressed cake is as high as 10%, which is not fully extracted and utilized. These cannot be neglected since they account for a considerable proportion. Characteristics and free radical scavenging capacity of flax (Linum usitatissimum L.) oil obtained from seeds and cakes with different extraction methods - cold-pressing, hot-pressing (120 and 160 °C) and solvent extraction (oil extracted with solvent from flaxseed, cold-pressed cake, and hot-pressed cake) - were evaluated and analyzed using chemometrics methods.

RESULTS

The composition of C18:3 α-linolenic acid of flax oil was not affected by the extraction methods in this work. Flax oils extracted with solvent from pressed cakes had lower content of bioactive minor components (tocopherols and phytosterols) compared with pressed and solvent-extracted seed oils. The former also showed poorer oxidative stability and free radical scavenging capacity (polar fraction) when compared with the latter. Flax oils could be distinguished with principal component analysis and hierarchical cluster analysis. Tocopherols and phytosterols exhibited significant contributions to the antioxidant capacity of flax oils via correlation analysis and multiple linear regression analysis.

CONCLUSION

Tocopherols and phytosterols were appropriate and potent indicators for evaluating the antioxidant capacity of flax oil. Results have important implications for the industrial production and nutritional value of flax oil, especially for flax oils from the cakes after pressing. © 2021 Society of Chemical Industry.

Dietary Lipids and Dyslipidemia in Chronic Kidney Disease

The progression of chronic kidney disease (CKD) leads to altered lipid metabolism. CKD patients exhibit high blood triglyceride (TG) levels, reduced concentrations and functionality of high-density lipoproteins (HDL), and elevated levels of atherogenic small, dense, low-density lipoproteins (sdLDL). Disorders of lipid metabolism and other metabolic disturbances place CKD patients at high risk for cardiovascular disease (CVD). Extensive evidence supports the cardioprotective effects of unsaturated fatty acids, including their beneficial effect on serum cholesterol and TG levels. Dietary lipids might therefore be especially important in the nutritional management of CKD. We review current dietary recommendations for fat intake by CKD patients and suggest potential nutritional interventions by emphasizing dietary lipids that might improve the blood lipid profile and reduce cardiovascular risk in CKD.

Baked cod consumption delayed the development of kidney and liver dysfunction and affected plasma amino acid concentrations, but did not affect blood pressure, blood glucose or liver triacylglycerol concentrations in obese fa/fa Zucker rats

Obesity is associated with changes in amino acid metabolism, and studies show that ingestion of fish proteins influence amino acid composition in plasma and urine, in addition to affecting risk factors for metabolic syndrome. Since the majority of fish proteins consumed by humans are as fish fillet, it is of interest to investigate if cod fillet intake affects amino acid composition and metabolic disorders. We hypothesized that a modified AIN-93G diet containing cod fillet would affect amino acid compositions in plasma and urine in obese rats, and also affect risk factors for metabolic syndrome when compared to rats fed a regular AIN-93G diet with casein as the protein source. Obese Zucker fa/fa rats, a rat model of metabolic syndrome, received diets containing 25% protein from lyophilized baked cod fillet and 75% protein from casein (Baked cod diet), or a Control diet with casein for four weeks. The Baked cod diet affected the amino acid composition in plasma, with e.g., lower glycine, histidine, homoarginine, homocysteine, methionine, proline and tyrosine concentrations, but did not affect amino acid concentrations in urine. The concentrations of markers for kidney and liver dysfunction were lower in the Baked cod group, however blood pressure development, fasting and postprandial glucose, and hepatic triacylglycerol concentrations were similar to the Control group. To conclude, substituting 25% of dietary protein with baked cod fillet affected concentrations of some amino acids in plasma and delayed development of kidney and liver dysfunction, but did not affect blood pressure, glucose concentration or fatty liver.

Lipidomics reveals association of circulating lipids with body mass index and outcomes in IgA nephropathy patients

IgA nephropathy (IgAN) is a leading cause of chronic kidney disease (CKD), which are commonly accompanied by dyslipidemia. Obesity is also associated with dyslipidemia and risk of CKD, but the relation of the dyslipidemia patterns with obesity and disease progression in IgAN patients remains unknown. Traditional Chinese medicine (TCM) and the combined treatment with corticosteroids and TCM have been shown to be of benefit for IgAN patients, but predictive markers for guiding these treatments are lacking. Here, we quantified 545 lipid species in the plasma from 196 participants, including 140 IgAN patients and 56 healthy volunteers, and revealed an altered plasma lipidome in IgAN patients as compared to healthy participants. Association analysis showed that a sub-group of glycerides, particularly triacylglycerols (TGs) containing docosahexaenoic acid, were positively associated with high body mass index (BMI) in under- or normal weight IgAN patients, while several free fatty acids and sphingomyelins were positively associated with high BMI in overweight or obese IgAN patients. Further, our study suggested that elevated levels of eight lipids, mainly TG species containing linolenic acid, were independent risk factors for IgAN progression and also reported the prospective association of circulating lipids with treatment outcomes in IgAN. Taken together, our findings may not only help to achieve precision medicine but also provide a knowledge base for dietary intervention in the treatment of IgAN.

Effect of pravastatin on erythrocyte membrane fatty acid contents in patients with chronic kidney disease

Background

Statin treatment has decreased the risk of cardiovascular events in patients with chronic kidney disease (CKD). Erythrocyte membrane oleic acid level is higher in patients with acute coronary syndrome. This study aimed to evaluate the effect of pravastatin on the erythrocyte membrane fatty acid (FA) contents in patients with CKD.

Methods

Sixty-two patients were enrolled from January 2017 to March 2019 (NCT02992548). Pravastatin was initially administered at a dose of 20 mg for 24 weeks. The pravastatin dose was increased to 40 mg after 12 weeks if it was necessary to control dyslipidemia. The primary outcome was change in erythrocyte membrane FA, including oleic acid, after pravastatin treatment for 24 weeks.

Results

Forty-five patients finished this study, and there was no adverse effect related to pravastatin. Compared with baseline, total cholesterol and low-density lipoprotein cholesterol levels were significantly decreased after pravastatin treatment. Compared with baseline, saturated FA, oleic acid, and arachidonic acid levels were significantly increased and polyunsaturated FA and linoleic acid (LA) levels were significantly decreased after pravastatin treatment. There was also a decrease in eicosapentaenoic acid after pravastatin treatment in CKD patients with estimated glomerular filtration rate < 60 mL/min/1.73 m².

Conclusion

Administration of pravastatin in patients with CKD leads to a decrease in FA known to be protective against the risk of CVD. Omega-3 FA or LA supplementation might be necessary to recover changes in erythrocyte membrane FA contents when pravastatin is used for treating dyslipidemia in patients with CKD.

The effect of omega-3 fatty acid supplementation on clinical and biochemical parameters of critically ill patients with COVID-19: a randomized clinical trial

BACKGROUND

Omega-3 polyunsaturated fatty acids (n3-PUFAs) may exert beneficial effects on the immune system of patients with viral infections. This paper aimed to examine the effect of n3-PUFA supplementation on inflammatory and biochemical markers in critically ill patients with COVID-19.

METHODS

A double-blind, randomized clinical trial study was conducted on 128 critically ill patients infected with COVID-19 who were randomly assigned to the intervention (fortified formula with n3-PUFA) (n = 42) and control (n = 86) groups. Data on 1 month survival rate, blood glucose, sodium (Na), potassium (K), blood urea nitrogen (BUN), creatinine (Cr), albumin, hematocrit (HCT), calcium (Ca), phosphorus (P), mean arterial pressure (MAP), O2 saturation (O2sat), arterial pH, partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), bicarbonate (HCO3), base excess (Be), white blood cells (WBCs), Glasgow Coma Scale (GCS), hemoglobin (Hb), platelet (Plt), and the partial thromboplastin time (PTT) were collected at baseline and after 14 days of the intervention.

RESULTS

The intervention group had significantly higher 1-month survival rate and higher levels of arterial pH, HCO3, and Be and lower levels of BUN, Cr, and K compared with the control group after intervention (all P < 0.05). There were no significant differences between blood glucose, Na, HCT, Ca, P, MAP, O2sat, PO2, PCO2, WBCs, GCS, Hb, Plt, PTT, and albumin between two groups.

CONCLUSION

Omega-3 supplementation improved the levels of several parameters of respiratory and renal function in critically ill patients with COVID-19. Further clinical studies are warranted. Trial registry Name of the registry: This study was registered in the Iranian Registry of Clinical Trials (IRCT); Trial registration number: IRCT20151226025699N3; Date of registration: 2020.5.20; URL of trial registry record: https://en.irct.ir/trial/48213.

Dietary Assessment of Korean Non-dialysis Chronic Kidney Disease Patients with or without Diabetes

BACKGROUND

Dietary intervention at the early stage of chronic kidney disease (CKD) is important for preventing progression to the end-stage renal disease (ESRD). However, few studies have investigated dietary intake of CKD patients in non-dialysis stage. Therefore, we investigated the dietary intake of Korean non-dialysis CKD patients and aimed to establish baseline data for the development of dietary education and intervention strategies for CKD patients.

METHODS

Three hundred fifty CKD patients who visited Seoul National University Hospital outpatient clinic from February 2016 to January 2017 were recruited for this cross-sectional study. Subjects on dialysis and those who had undergone kidney transplantation were excluded. Dietary intake, demographic information, and biochemical characteristics of 256 subjects who completed three-day dietary records were analyzed. Subjects were divided into four groups based on diabetes mellitus (DM) (DM-CKD and Non-DM-CKD groups) and kidney function (Early-CKD and Late-CKD groups).

RESULTS

Total energy intake was lower in the Late-CKD group compared with the Early-CKD group. In men, carbohydrate intake was higher and protein and fat intakes tended to be lower in the Late-CKD group compared with the Early-CKD group. In women, carbohydrate intake tended to be lower in the DM-CKD group than the Non-DM-CKD group. Protein intake tended to be higher in the DM-CKD groups. Phosphorus and sodium intakes were higher in the DM-CKD groups compared with the Non-DM-CKD groups in women, and tended to be higher in the DM-CKD groups in men.

CONCLUSION

DM and kidney function affected energy and nutrient intakes. Subjects in the Late-CKD group consumed less energy than those in the Early-CKD group. Non-DM subjects seemed to restrict protein intake starting from the Early-CKD stage than subjects with DM. Subjects in this study had low energy and high sodium intakes compared with recommended levels. Protein intake was lower in advanced CKD patients, but their intake level was still higher than the recommendation. Dietary intervention strategies for non-dialysis CKD patients need to be customized depending on the presence of DM and kidney function.

Intakes of long-chain omega-3 polyunsaturated fatty acids and non-fried fish in relation to incidence of chronic kidney disease in young adults: a 25-year follow-up

PURPOSE

The prevalence of chronic kidney disease (CKD) is increasing rapidly in many countries and has become a major public health concern. Although intakes of long-chain omega-3 polyunsaturated fatty acids (LCω3PUFA) and its food source-fish-may have renal protective effects, little is known about the longitudinal association between these dietary factors and CKD incidence.

METHODS

A total of 4133 healthy individuals of black and white race aged 18-30 at baseline (1985-1986) from the Coronary Artery Risk Development in Young Adults study were enrolled and followed up over 25 years. LCω3PUFA and fish intake were assessed by an interview-based dietary history questionnaire at baseline, year 7 (1992-1993) and 20 (2005-2006).

RESULTS

Four hundred and eighty-nine incident cases of CKD were identified. After adjustment for potential confounders, LCω3PUFA intake was inversely associated with CKD incidence [HR = 0.73 (95% CI 0.60-0.89), P = 0.002, with one standard division (0.19 g/day) increment in LCω3PUFA]. This inverse association was persisted among females [0.64 (95% CI 0.48, 0.84; P = 0.002], but not males (Pinteraction = 0.070). A marginal significant inverse association was also found between non-fried fish consumption and CKD incidence (HR = 0.86, 95% CI 0.73, 1.01; P = 0.073).

CONCLUSIONS

Dietary LCω3PUFA intake was inversely associated with incidence of CKD among American young adults over 25 years of follow-up. The suggestive evidence of the inverse association between non-fried fish consumption with CKD incidence needs further confirmation.

Nut Consumption and Renal Function Among Women With a History of Gestational Diabetes

OBJECTIVE

Nut intake has been associated with reduced cardiometabolic risk, but few studies have examined its association with renal function. We examined associations between nut intake and renal function among women with previous gestational diabetes mellitus (GDM), a population with an increased risk for renal dysfunction.

DESIGN AND METHODS

This study included 607 women with a history of GDM who participated in the Diabetes & Women's Health Study (2012-2014) follow-up clinical examination in Denmark. At the clinic, biospecimens were collected, and habitual intake of nuts (9 types) in the past year was assessed using a food frequency questionnaire. A total of 330 women free of major chronic diseases were included in the analysis. Total nut intake was classified as none (≤1 serving/month), monthly (2-3 servings/month), weekly (1-6 servings/week), and daily (≥1 serving/day). One serving was defined as 28 g. Renal function markers included estimated glomerular rate (eGFR) and urinary albumin-to-creatinine ratio (UACR), calculated based on plasma creatinine (mg/dL), and urinary albumin (mg/L), and creatinine (mg/dL) measurements, respectively. We estimated percent differences with 95% confidence intervals for each outcome by nut intake, adjusted for current body mass index, age, physical activity, energy intake, alcohol consumption, and vegetables intake.

RESULTS

We observed a nonlinear association between total nut intake and UACR with lowest UACR values among women with weekly intake. Compared to women with weekly intake (n = 222), the adjusted UACR values were higher by 86% [95% confidence interval: 15%, 202%], 24% [-1%, 54%], and 117% [22%, 288%] among women with no (n = 13), monthly (n = 86), and daily (n = 9) intake, respectively. Compared to weekly consumers, daily nut consumers also had 9% [0%, 19%] significantly higher eGFR values, but eGFR values were similar among women with no and monthly intake.

CONCLUSION

Moderate nut consumption may be beneficial to kidney health among women with prior GDM.

Association Between Dietary Patterns and Kidney Function in Patients With Chronic Kidney Disease: A Cross-Sectional Analysis of the German Chronic Kidney Disease Study

OBJECTIVE

In the general population, "healthy" dietary patterns are associated with improved health outcomes, but data on associations between observance of specific dietary patterns and kidney function in patients with chronic kidney disease (CKD) are sparse.

METHODS

Dietary intake was evaluated using food frequency questionnaires in patients with moderately severe CKD under nephrology care enrolled into the observational multicenter German CKD study. The Dietary Approaches to Stop Hypertension (DASH) diet score, Mediterranean diet score, and German Food Pyramid Index (GFPI) were calculated and their association with estimated glomerular filtration rate (eGFR) and albuminuria was assessed by multivariable linear regression analysis, adjusted for gender, age, body mass index, energy intake, smoking status, alcohol intake, education, high-density lipoprotein-cholesterol (HDL- cholesterol), low-density lipoprotein-cholesterol (LDL-cholesterol), hypertension, and diabetes mellitus.

RESULTS

A total of 2,813 patients (41% women; age 60.1 ± 11.6 years) were included in the analysis. High DASH diet score and GFPI were associated with lower systolic blood pressure and lower intake of antihypertensive medication, higher HDL, and lower uric acid levels. Mediterranean-style diet was associated with lower prevalence of diabetes mellitus. Higher DASH and Mediterranean diet scores were associated with higher eGFR (β-coefficient = 1.226, P < .001; β-coefficient = 0.932, P = .007, respectively). In contrast, GFPI was not associated with eGFR. For the individual components of the dietary patterns, higher intake of nuts and legumes, cereals, fish, and polyunsaturated fats was associated with higher eGFR and higher intake of dairy, composed of low- and whole-fat dairy, was associated with lower eGFR. No association was found between dietary patterns and albuminuria.

CONCLUSION

Higher observance of the DASH or Mediterranean diet, but not German food pyramid recommendations, was associated with higher eGFR among patients with CKD. Improving dietary habits may offer an opportunity to better control comorbidities and kidney function decline in patients with CKD.

Linseed Essential Oil - Source of Lipids as Active Ingredients for Pharmaceuticals and Nutraceuticals

Linseed - also known as flaxseed - is known for its beneficial effects on animal health attributed to its composition. Linseed comprises linoleic and α-linolenic fatty acids, various dietary fibers and lignans, which are beneficial to health because they reduce the risk of cardiovascular diseases, as well as cancer, decreasing the levels of cholesterol and relaxing the smooth muscle cells in arteries increasing the blood flow. Essential fatty acids from flax participate in several metabolic processes of the cell, not only as structuring components of the cell membrane but also as storage lipids. Flax, being considered a functional food, can be consumed in a variety of ways, including seeds, oil or flour, contributing to basic nutrition. Several formulations containing flax are available on the market in the form of e.g. capsules and microencapsulated powders having potential as nutraceuticals. This paper revises the different lipid classes found in flaxseeds and their genomics. It also discusses the beneficial effects of flax and flaxseed oil and their biological advantages as ingredients in pharmaceuticals and in nutraceuticals products.

Dietary omega-3 PUFA improved tubular function after ischemia induced acute kidney injury in mice but did not attenuate impairment of renal function

BACKGROUND

Acute kidney injury (AKI) is an important complication after major surgery and solid organ transplantation. Here, we present a dietary omega-3 polyunsaturated fatty acid (n3-PUFA) supplementation study to investigate whether pre-treatment can reduce ischemia induced AKI in mice.

METHODS

Male 12-14 week old C57BL/6 J mice received a linoleic acid rich sunflower oil based standard diet containing 10 % fat (STD) or the same diet enriched with n3-PUFA (containing 1 % EPA and 1 % DHA) (STD + n3). After 14 days of feeding bilateral 30 min renal ischemia reperfusion injury (IRI) was conducted to induce AKI and mice were sacrificed at 24 h. Serum creatinine and blood urea nitrogen (BUN) as well as liver enzyme elevation were measured. Kidney damage was analyzed by histology and immunohistochemistry. Furthermore, pro-inflammatory cytokines (IL-6, MCP-1) were determined by qPCR. FA and oxylipin pattern were quantified in blood and kidneys by GC-FID and LC-MS/MS, respectively.

RESULTS

n3-PUFA supplementation prior to renal IRI increased systemic and renal levels of n3-PUFA. Consistently, eicosanoids and other oxylipins derived from n3-PUFA including precursors of specialized pro-resolving mediators were elevated while n6-PUFA derived mediators such as pro-inflammatory prostaglandins were decreased. Feeding of n3-PUFA did not attenuate renal function impairment, morphological renal damage and inflammation characterized by IL-6 and MCP-1 elevation or neutrophil infiltration. However, the tubular transport marker alpha-1 microglobulin (A1M) was significantly higher expressed in proximal tubular epithelial cells of STD + n3 compared to STD fed mice. This indicates a better integrity of proximal tubular epithelial cells and thus significant protection of tubular function. In addition, heme oxygenase-1 (HO-1) which protects tubular function was also up-regulated in the treatment group receiving n3-PUFA supplemented chow.

DISCUSSION

We showed that n3-PUFA pre-treatment did not affect overall renal function or renal inflammation in a mouse model of moderate ischemia induced AKI, but tubular transport was improved. In conclusion, dietary n3-PUFA supplementation altered the oxylipin levels significantly but did not protect from renal function deterioration or attenuate ischemia induced renal inflammation.

Obesity and synergistic risk factors for chronic kidney disease in African American adults: the Jackson Heart Study

Background

African Americans are at high risk for chronic kidney disease (CKD). Obesity may increase the risk for CKD by exacerbating features of the metabolic syndrome and promoting glomerular hyperfiltration. Whether other factors also affecting these pathways may amplify or mitigate obesity-CKD associations has not been investigated.

Methods

We studied interactions between obesity and these candidate factors in 2043 African Americans without baseline kidney disease enrolled in the Jackson Heart Study. We quantified obesity as body mass index (BMI), sex-normalized waist circumference and visceral adipose volume measured by abdominal computed tomography at an interim study visit. Interactions were hypothesized with (i) metabolic risk factors (dietary quality and physical activity, both quantified by concordance with American Heart Association guidelines) and (ii) factors exacerbating or mitigating hyperfiltration (dietary protein intake, APOL1 risk status and use of renin-angiotensin system blocking medications). Using multivariable regression, we evaluated associations between obesity measures and incident CKD over the follow-up period, as well as interactions with metabolic and hyperfiltration factors.

Results

Assessed after a median of 8 years (range 6-11 years), baseline BMI and waist circumference were not associated with incident CKD. Higher visceral adipose volume was independently associated with incident CKD (P = 0.008) in a nonlinear fashion, but this effect was limited to those with lower dietary quality (P = 0.001; P-interaction = 0.04). In additional interaction models, higher waist circumference was associated with greater risk of incident CKD among those with the low-risk APOL1 genotype (P = 0.04) but not those with a high-risk genotype (P-interaction = 0.02). Other proposed factors did not modify obesity-CKD associations. Conclusions. Higher risks associated with metabolically active visceral adipose volume and interactions with dietary quality suggest that metabolic factors may be key determinants of obesity-associated CKD risk. Interactions between obesity and APOL1 genotype should be considered in studies of African Americans.

Urine and plasma concentrations of amino acids and plasma vitamin status differ, and are differently affected by salmon intake, in obese Zucker fa/fa rats with impaired kidney function and in Long-Evans rats with healthy kidneys

Kidney function affects amino acid metabolism and vitamin status. The aims of the present study were to investigate urine and plasma concentrations of amino acids as well as plasma vitamin status in rats with impaired renal function (Zucker fa/fa rats) and in rats with normal kidney function (Long-Evans rats), and to explore the effects of salmon intake on these parameters and potential biomarkers of salmon intake in both rat strains. Male rats were fed diets with casein as sole protein source (control diet) or 25 % protein from baked salmon and 75 % casein for 4 weeks. Urine concentrations of markers of renal function and most amino acids and plasma concentrations of most vitamins were higher, and plasma concentrations of several amino acids including arginine, total glutathione and most tryptophan metabolites were lower in Zucker fa/fa rats compared with Long-Evans rats fed the control diet. Concentrations of kidney function markers were lower after salmon intake only in Zucker fa/fa rats. A trend towards lower urine concentrations of amino acids was seen in both rat strains fed the salmon diet, but this was more pronounced in Long-Evans rats and did not reflect the dietary amino acid content. Urine 1-methylhistidine, 3-methylhistidine, trimethylamineoxide and creatine concentrations, and plasma 1-methylhistidine and creatine concentrations were higher after salmon intake in both rat strains. To conclude, concentrations of amino acids in urine and plasma as well as vitamin status were different in Zucker fa/fa and Long-Evans rats, and the effects of salmon intake differed by rat strain for some of these parameters.

Evaluation of serum free fatty acids in chronic renal failure: evidence from a rare case with undetectable serum free fatty acids and population data

Background

Free fatty acid (FFA) accumulation in proximal tubules plays a fundamental role in the progress of kidney disease. Here, we reported a rare case with undetectable serum FFAs and further evaluated the changes of serum FFAs in patients with chronic renal failure (CRF).

Methods

We analyzed the clinical data of a rare case and 574 CRF patients. The mRNA expression of lipoprotein lipase (LPL), hepatic lipase (HL) and fatty acid synthase (FASN) were determined in the rare case and 30 age-matched healthy males with qPCR.

Results

This rare case had serious proteinuria, hyperglycemia, lipid disorders and bilateral renal glomerular filtration dysfunction. Compared with healthy males, this case showed a 1.49-fold increase of LPL expression (P < 0.01), a 3.38-fold reduction of HL expression (P < 0.001), and no significant change of FASN expression (P > 0.05). In total, 21.6% of CRF patients showed abnormal FFAs. Biochemical parameters such as blood urea nitrogen (BUN) and creatinine (CREA) significantly differed among groups with low-, normal- or high-level-FFAs. Moreover, serum FFAs was found to be associated with BUN. FFAs decreased in the group with higher BUN (> 17.4 mmol/L) and in the group with lower estimated glomerular filtration rate (eGFR) (< 15 mL/min/1.73m²).

Conclusions

The proteinuria, HL low expression and renal function failure may contribute to the FFA reduction, which might imply that the renal function is severely damaged.

Electronic supplementary material

The online version of this article (10.1186/s12944-019-1093-5) contains supplementary material, which is available to authorized users.

Plasma marine n-3 polyunsaturated fatty acids and cardiovascular risk factors: data from the ACE 1950 study

PURPOSE

A high intake of marine n-3 polyunsaturated fatty acids (PUFAs) might improve cardiovascular (CV) health. We conducted a cross-sectional study to investigate associations between plasma phospholipid levels of marine n-3 PUFAs and CV risk factors, educational level, physical activity and smoking habits.

METHODS

A total of 3706 individuals from a general population, all born in 1950 and residing in Akershus County, Norway, were included in this study. The main statistical approach was multivariable adjusted linear regression.

RESULTS

Plasma marine n-3 PUFA levels ranged from 2.7 to 20.3 wt%, with a median level of 7.7 wt% (interquartile range 4.3-11.1 wt%). High levels of plasma marine n-3 PUFAs were associated with lower serum triglycerides [Standardized regression coefficient (Std.β-coeff.) - 0.14, p < 0.001], body mass index (Std. β-coeff. -0.08, p < 0.001), serum creatinine (Std. β-coeff. -0.03, p = 0.05), C-reactive protein levels (Std. β-coeff. - 0.03, p = 0.04), higher levels of serum high-density lipoprotein cholesterol (Std. β-coeff. 0.08, p < 0.001) and low-density lipoprotein cholesterol (Std. β-coeff. 0.04, p = 0.003). High levels of plasma marine n-3 PUFAs were also associated with lower glycated hemoglobin (Std. β-coeff. - 0.04, p = 0.01), however, only in individuals without diabetes. We found no associations between plasma marine n-3 PUFA levels and fasting plasma glucose or carotid intima-media thickness. High levels of plasma marine n-3 PUFAs were associated with higher educational level, more physical activity and lower prevalence of smoking.

CONCLUSION

In this cross-sectional study of Norwegian individuals born in 1950, high levels of plasma marine n-3 PUFAs were favourably associated with several CV risk factors, suggesting that fish consumption might improve CV health.

Heart Rate Variability: A Potential Tool for Monitoring Immunomodulatory Effects of Parenteral Fish Oil Feeding in Patients With Sepsis

Fish oil, rich in the very-long chain omega (ω)-3 polyunsaturated fatty acids (PUFAs), has been found to have immunomodulatory effects in different groups of critically ill patients. In addition, its parenteral administration seems to attenuate the inflammatory response within 2 to 3 days. The activation of the cholinergic anti-inflammatory pathway has been suggested to mediate such immunoregulatory effects. As different experimental studies have convincingly illustrated that enhanced vagal tone can decrease pro-inflammatory cytokine secretion, novel monitoring tools of its activity at the bedside could be developed, to evaluate nutritional manipulation of immune response in the critically ill. Heart rate variability (HRV) is the variability of R-R series in the electrocardiogram and could be a promising surrogate marker of immune response and its modulation during fish oil feeding, rich in ω-3 PUFAs. Heart rate variability is an indirect measure of autonomic nervous system (ANS) output, reflecting mainly fluctuations in ANS activity. Through HRV analysis, different "physiomarkers" can be estimated that could be used as early and more accurate "smart alarms" because they are based on high-frequency measurements and are much more easy to get at the bedside. On the contrary, various "biomarkers" such as cytokines exhibit marked interdependence, pleiotropy, and their plasma concentrations fluctuate from day to day in patients with sepsis. In this respect, an inverse relation between different HRV components and inflammatory biomarkers has been observed in patients with severe sepsis and septic shock, whereas a beneficial effect of ω-3 PUFAs on HRV has been demonstrated in patients with cardiovascular diseases. Consequently, in this article, we suggest that a beneficial effect of ω-3 PUFAs on HRV and clinical outcome in patients with sepsis merits further investigation and could be tested in future clinical trials as a real-time monitoring tool of nutritional manipulation of the inflammatory response in the critically ill.

Poor accordance to a DASH dietary pattern is associated with higher risk of ESRD among adults with moderate chronic kidney disease and hypertension

The Dietary Approaches to Stop Hypertension (DASH) diet lowers blood pressure, an important risk factor for chronic kidney disease (CKD) and end-stage renal disease (ESRD). However, it is unclear whether adherence to a DASH diet confers protection against future ESRD, especially among those with pre-existing CKD and hypertension. We examined whether a DASH diet is associated with lower risk of ESRD among 1,110 adults aged ≥ 20 years with hypertension and CKD (estimated glomerular filtration rate, eGFR 30-59 ml/min/1.73 m²) enrolled in the National Health and Nutrition Examination Survey (1988-1994). Baseline DASH diet accordance score was assessed using a 24-hour dietary recall questionnaire. ESRD was ascertained by linkage to the U.S. Renal Data System registry. We used the Fine-Gray competing risks method to estimate the relative hazard (RH) for ESRD after adjusting for sociodemographics, clinical and nutritional factors, eGFR, and albuminuria. Over a median follow-up of 7.8 years, 18.4% of subjects developed ESRD. Compared to the highest quintile of DASH diet accordance, there was a greater risk of ESRD among subjects in quintiles 1 (RH=1.7; 95% CI 1.1-2.7) and 2 (RH 2.2; 95% CI 1.1-4.1). Significant interactions were observed with diabetes status and race/ethnicity, with the strongest association between DASH diet adherence and ESRD risk observed in individuals with diabetes and in non-Hispanic blacks. Low accordance to a DASH diet is associated with greater risk of ESRD in adults with moderate CKD and hypertension, particularly in non-Hispanic blacks and persons with diabetes.

Impact of Blood or Erythrocyte Membrane Fatty Acids for Disease Risk Prediction: Focusing on Cardiovascular Disease and Chronic Kidney Disease

Fatty acids (FAs) are essential nutrients and main constituents of cell membranes that are involved in the signaling pathway and associated with health conditions. We investigated if blood or erythrocyte membrane FAs can predict the risk of cardiovascular disease (CVD), chronic kidney disease (CKD), and related complications. Omega-3 (n-3) FAs are important predictors for metabolic syndrome, diabetes, CVD, and CKD risks, and the n-3 index is also a good biomarker for sudden cardiac death in coronary artery disease. Linoleic acid, which is one of the major n-6 FAs reflecting recent dietary FA intake, may predict CVD risk and mortality in the general population and patients with CKD. Monounsaturated FAs (MUFAs) are also related to diabetes or diabetic nephropathy. Oleic acid, a major MUFA, is an emerging marker that is related to acute coronary syndrome, low glomerular filtration rate, and vascular calcification in patients with CKD, and can be modified by n-3 FA supplementation. Saturated FAs, trans-FAs, and FA desaturation/elongation are associated with CVD risk; however, few studies have been conducted on patients with CKD. In summary, blood or erythrocyte membrane FA measurements are important for CVD and CKD risk prediction and management. Further studies are needed to elucidate the FAs for their risk predictions.

Dietary intake of cod protein beneficially affects concentrations of urinary markers of kidney function and results in lower urinary loss of amino acids in obese Zucker fa/fa rats

Obesity increases the risk for developing kidney disease, and protection of kidneys through changes in diet should be investigated. Fish intake has been associated with reduced risk of developing kidney disease; therefore, we wanted to investigate whether cod protein intake could prevent or delay the development of kidney damage in an obese rat model that spontaneously develops proteinuria and focal segmental glomerulosclerosis. The aim of the study was to investigate any effects of cod protein intake on established markers of kidney function, amino acid composition, protein utilisation and growth in obese Zucker fa/fa rats in the early stage of decreased renal function. Male obese Zucker fa/fa rats (HsdOla:Zucker-Lepr) were fed cod muscle proteins in an amount corresponding to 25 % of dietary protein, with the remaining protein from a casein/whey mixture (COD diet). A control group was fed a diet with a casein/whey mixture as the only protein source (CAS diet). The intervention started when rats were 9–10 weeks old, and the rats were fed these diets for 4 weeks. At the end of the study, rats fed the COD diet had lower urine concentration of cystatin C, T-cell immunoglobulin mucin-1 (TIM-1), amino acids, carbamide, uric acid and ammonium and higher concentrations of creatine, trimethylamine N-oxide, 1-methylhistidine and 3-methylhistidine, lower kidney concentration of TIM-1 and showed better growth when compared with the CAS group. To conclude, cod protein may have the potential to delay the development of kidney damage in young obese Zucker rats and to improve protein utilisation and growth.

Low linolenic and linoleic acid consumption are associated with chronic kidney disease in patients with type 2 diabetes

Aim

This cross-sectional study aimed to assess the association of the fat content in the diet with Diabetic Kidney Disease (DKD) in patients with type 2 diabetes.

Methodology

Patients from the Diabetes research clinic at Hospital de Clínicas de Porto Alegre (Brazil) were consecutively recruited. The inclusion criterion was the diagnosis of type 2 diabetes. The exclusion criteria were as follows: body mass index >40 kg/m², heart failure, gastroparesis, diabetic diarrhea, dietary counseling by a registered dietitian during the previous 12 months, and inability to perform the weighed diet records (WDR). The dietary fatty acids (saturated, monounsaturated and polyunsaturated) consumption was estimated by 3-day WDR. Compliance with the WDR technique was assessed by comparison of protein intake estimated from the 3-day WDR and from the 24-h urinary nitrogen output performed on the third day of the WDR period. The presence of DKD was defined as urinary albumin excretion (UAE) ≥ 30 mg / 24 h or/and glomerular filtration rate (eGFR) <60 ml/min/1.73 m². Urinary albumin was measured twice and eGFR was estimated by using the CKD-EPI equation.

Results

A total of 366 patients were evaluated; of these, 33% (n = 121) had DKD. Multivariate analysis showed that the intake of linolenic acid was negatively associated with DKD (OR = 0.57; 95% CI 0.35–0.93; P = 0.024), adjusted for gender, smoking, cardiovascular disease, ACE inhibitors and/or angiotensin receptor blocker use, systolic blood pressure, fasting plasma glucose and HDL cholesterol. In a separate model, similar results were observed for linoleic acid, adjusting to the same co-variables (OR = 0.95; 95% CI 0.91–0.99; P = 0.006).

Conclusion

The lower intake of polyunsaturated fatty acids, especially linolenic and linoleic acid, is associated with chronic kidney disease in patients with type 2 diabetes.

Association of non-allopathic drugs and dietary factors with chronic kidney disease: A matched case-control study in South India

Background:

The multifactorial etiology of chronic kidney disease (CKD) is known to vary with geographical region. Although diabetes and hypertension are the major known contributors for CKD, the role of other risk factors relevant to India needs to be explored. This study was done to find out the role of dietary factors and nonallopathic drugs in CKD.

Materials and Methods:

A hospital-based individual pair-matched case–control study was conducted in a tertiary care center in South India. The sample included 80 incident cases of CKD matched with 80 controls. Factors assessed in the study include sociodemographic factors, medical history, dietary factors, nonallopathic drugs, substance use, and other possible confounders. Univariate analysis was performed using McNemar's test and multivariate analysis was done using conditional logistic regression.

Results:

On multivariate analysis, lifetime exposure to nonallopathic drugs increased risk of CKD by approximately five times [odds ratio (OR): 5.15, confidence interval (CI): 1.27–20.87] and chicken intake (two to three times a month to once a week) had an increased risk by approximately four times (OR = 4.23, CI: 1.13–15.80). Fish intake at a frequency of two to three times or more reduced the risk of CKD by 94% (OR = 0.06, CI: 0.01–0.43).

Conclusion:

Chicken intake and lifetime exposure to nonallopathic drugs could increase risk for CKD in South India. Increased fish intake was found to be protective for CKD.

Fatty Acids in Nephrotic Syndrome and Chronic Kidney Disease

The role of fatty acids (FAs) in inflammation and in the related chronic diseases has been demonstrated. However, there is a lack of consistent and agreed knowledge about the role of FA profile and renal physiology and pathology, most articles focusing on the effect of polyunsaturated FAs supplementation, without considering the impact of basal FA metabolism on the efficacy of the supplementation. Here, we have summarized the specific literature concerning the assessment of circulating FA in 2 renal diseases, namely nephrotic syndrome and chronic kidney disease, also under hemodialytic treatment, and have received the most significant contributions in the last years. The effects of changes of FA profile and metabolism and the possible involvement of polyunsaturated FA metabolites in raising and modulating inflammation are discussed.

Diet and enteral nutrition in patients with chronic kidney disease not on dialysis: a review focusing on fat, fiber and protein intake

The clinical data available on dietary requirements of patients with chronic kidney disease (CKD) not on dialysis are limited and largely inconclusive in terms of the renal, cardiovascular and nutritional outcomes achievable through dietary modifications. Restriction of protein intake during the early stages of CKD may in fact slow its progression, but at the same time this approach may also lead to protein-energy wasting, if energy intake is not adequate and properly monitored. Unfortunately, compliance to dietary recommendations is traditionally low in this patient population. A switch from saturated to mono- and polyunsaturated fats is generally recognized as advantageous for cardiac health; however, the benefits in term of renal function are largely unknown. Similarly, the association between dietary fiber intake and kidney disease is largely unknown. In fact, while there is evidence on the positive health effects of dietary fibers in the general population, nutritional guidelines for CKD lack formal recommendations concerning fiber intake. This paper reviews data and evidence from clinical trials and meta-analyses on renal and cardiovascular outcomes related to modifications in protein, fat and fiber intake. Suggestions for maintaining nutritional status through patient-oriented dietary patterns and enteral supplementation in CKD patients on conservative therapy are also presented.

Associations between dairy food consumption and chronic kidney disease in older adults

We aimed to assess the association between dairy product consumption and calcium intake with the prevalence and 10-year incidence of chronic kidney disease (CKD). 1185 participants aged ≥50 years at baseline were examined between 1992–4 and 2002–4. Dietary data were collected using a food frequency questionnaire, and servings of dairy food consumption were calculated. Baseline biochemistry including serum creatinine was measured. CKD was defined as Modification of Diet in Renal Disease Study estimated glomerular filtration rate <60 mL·min^−1.1.73 m⁻². Cross-sectional analysis showed that older adults in the highest quintile compared to the lowest quintile (reference group) of low/reduced fat dairy food consumption had reduced odds of CKD, multivariable-adjusted odds ratio, OR, 0.64 (95% confidence intervals, CI, 0.43–0.96). Increasing total intake of dietary calcium was associated with reduced odds of CKD (P-trend = 0.02); comparing highest versus lowest quintile: OR 0.62 (95% CI 0.42–0.92). Participants in the second versus first quintile of low/reduced fat dairy food consumption at baseline had 49% reduced risk of CKD 10 years later, OR 0.51 (95% CI 0.29–0.89). Higher consumption of low/reduced fat dairy foods was independently associated with lower risk of CKD. Additional population-based studies are warranted to confirm these findings.

Lipophilic index, kidney function, and kidney function decline

BACKGROUND AND AIMS

Unhealthy dietary fats are associated with faster kidney function decline. The cell membrane composition of phospholipid fatty acids (FAs) is a determinant of membrane fluidity and rheological properties. These properties, which have been linked to kidney damage, are thought to be reflected by the lipophilic index (LI). We prospectively investigated the associations of LI with kidney function and its decline.

METHODS AND RESULTS

Observational study from the Prospective Investigation of Vasculature in Uppsala Seniors including 975 men and women with plasma phospholipid FAs composition and cystatin-C estimate glomerular filtration rate (eGFR). Of these, 780 attended re-examination after 5 years, and eGFR changes were assessed. Participants with a 5-year eGFR reduction ≥30% were considered chronic kidney disease (CKD) progressors (n = 198). LI was calculated as the sum of the products of the FA proportions with the respective FAs melting points. Blood rheology/viscosity measurements were performed in a random subsample of 559 subjects at baseline. Increased LI showed a statistically significant but overall weak association with blood, plasma viscosity (both Spearman rho = 0.16, p < 0.01), and erythrocyte deformability (rho = -0.09, p < 0.05). In cross-sectional analyses, LI associated with lower eGFR (regression coefficient 3.00 ml/min/1.73 m² 1-standard deviation (SD) increment in LI, 95% CI: -4.31, -1.69, p < 0.001). In longitudinal analyses, LI associated with a faster eGFR decline (-2.13 [95% CI -3.58, -0.69] ml/min/1.73 m², p < 0.01) and with 32% increased odds of CKD progression (adjusted OR 1.32 [95%, CI 1.05-1.65]).

CONCLUSIONS

A high LI was associated with lower kidney function, kidney function decline, and CKD progression.

Dietary polyunsaturated fatty acids and incidence of end-stage renal disease in the Southern Community Cohort Study

BACKGROUND

Whether polyunsaturated fatty acids (PUFA) are associated with end-stage renal disease (ESRD) in populations with a high burden of risk factors for kidney disease is unknown. We sought to determine whether PUFA intake is associated with ESRD.

METHODS

We conducted a nested case-control study of ESRD within the Southern Community Cohort Study (SCCS), a prospective cohort of low-income blacks and whites in the southeastern US (2002-2009). Through 2012, 1,074 incident ESRD cases were identified by linkage with the United States Renal Data System and matched to 3,230 controls by age, sex and race. Dietary intake of total, n-3 or n-6 PUFA was assessed from a validated food frequency questionnaire administered at baseline. Odds ratios (ORs) and 95 % confidence intervals (CIs) were computed from logistic regression models that included matching variables, body mass index, smoking, diabetes, hypertension, education, income, total energy intake and percent energy from protein and saturated fat.

RESULTS

The mean (SD) age of participants was 55 (9) years. Most participants were women (55 %), black (87 %), with hypertension (67 %) and on average obtained 8 % of their energy from PUFA. Higher PUFA intake was marginally associated with a lower risk of ESRD in adjusted analyses. The adjusted odds ratios (95 % confidence intervals) for ESRD for the 5th vs. 1st quintile of PUFA were 0.79 (0.60-1.05; P trend = 0.06) for total PUFA, 0.81 (0.61-1.06; P trend = 0.04) for n-6 PUFA and 0.93 (0.71-1.21; P trend = 0.45) for n-3 PUFA.

CONCLUSIONS

We observed a marginally significant inverse trend between dietary PUFA intake and ESRD incidence, mainly driven by n-6 fatty acid intake. Our findings require replication but suggest that a diet rich in n-6 PUFA may prevent ESRD development in a population with a high burden of kidney disease risk factors.

Effects of Omega-3 Fatty Acid Supplementation on Diabetic Nephropathy Progression in Patients with Diabetes and Hypertriglyceridemia

Beneficial effects of omega-3 fatty acid (O3FA) supplementation in a wide range of disease condition have been well studied. However, there is limited information regarding the effects of O3FAs on chronic kidney disease (CKD), especially in diabetic nephropathy (DN) with hypertriglyceridemia. We investigate whether O3FA supplementation could help maintain renal function in patients with diabetes and hypertriglyceridemia. Total 344 type 2 diabetic patients with a history of O3FA supplementation for managing hypertriglyceridemia were included. Reduction in urine albumin to creatinine ratio (ACR) and glomerular filtrate rate (GFR) were examined. Subgroup analyses were stratified according to the daily O3FA doses. Serum total cholesterol, triglyceride, and urine ACR significantly reduced after O3FA supplementation. Overall, 172 (50.0%) patients did not experience renal function loss, and 125 (36.3%) patients had a GFR with a positive slope. The patients treated with O3FAs at 4g/day showed greater maintenance in renal function than those treated with lower dosages (p < 0.001). This dose dependent effect remains significant after adjustment for multiple variables. O3FA supplementation in diabetic patients with hypertriglyceridemia shows benefits of reducing albuminuria and maintaining renal function. The effects are dependent on the dose of daily O3FA supplementation.

Lifestyle factors and indices of kidney function in the Framingham Heart Study

BACKGROUND AND OBJECTIVES

Lifestyle characteristics are modifiable factors that could be targeted as part of chronic kidney disease (CKD) prevention. We sought to determine the association of lifestyle characteristics with incident estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2) and rapid eGFR decline in older adults in the United States.

METHODS

Prospective cohort study of Framingham Offspring participants with baseline eGFR <60 ml/min/1.73 m(2) (n = 1,802) who attended the seventh (1998-2001; baseline) and eighth (2005-2008; follow-up) examinations (mean age = 59 years, 54.8% women). Predictors included measures of diet quality, physical activity, alcohol intake, and current smoking status assessed during baseline. Outcomes were based on creatinine-based eGFR at baseline and follow-up and included incident eGFR <60 ml/min/1.73 m(2) (at follow-up) and rapid eGFR decline (annual eGFR decrease ≥3 ml/min/1.73 m(2)).

RESULTS

Over an average follow-up of 6.6 years, 9.5% (n = 171) of participants developed incident eGFR <60. A trend was observed across quartiles of diet quality, with higher levels of diet quality associated with a decreased odds ratio (OR) of incident eGFR <60 (p trend = 0.045). Higher diet quality was associated with decreased odds of rapid eGFR decline (p trend = 0.03) and was attenuated with additional adjustment (p trend = 0.07). In sensitivity analysis for rapid eGFR decline using a secondary definition (annual eGFR decrease ≥3 and incident eGFR <60), diet associations remained significant with additional adjustment (p trend = 0.04). No associations were observed with physical activity, smoking status, or alcohol intake with incident eGFR <60 or rapid eGFR decline (all p > 0.19).

CONCLUSIONS

Higher diet quality may be associated with a decreased risk of incident eGFR <60 ml/min/1.73 m(2), and rapid eGFR decline. Whether adherence to a healthy diet can prevent reduction in kidney function warrants further study.

Omega-3 dietary Fatty Acid status of healthy older adults in Tasmania, Australia: an observational study

OBJECTIVES

To determine the dietary and supplement intake of omega-3 (n-3) polyunsaturated fatty acids (PUFA) of older Tasmanian adults; their plasma n-3 PUFA status and the relationship between n-3 PUFA intake and plasma status.

DESIGN

Cross-sectional study.

SETTING

Launceston and surrounding regions, Tasmania, Australia.

PARTICIPANTS

Seventy-three community-dwelling older adults: 23 men aged 70 ± 6.1 years and 50 women aged 70 ± 6.7 years.

MEASUREMENTS

A validated, semi-quantitative food frequency questionnaire estimated dietary PUFA intake. The plasma phospholipid fraction of venous blood samples was analysed for fatty acid content. Anthropometric data was recorded.

RESULTS

Thirty-five participants (48%) regularly ingested a fish oil supplement. Their plasma n-3 PUFA profile contained significantly more eicosapentaenoic acid (EPA) (odds ratio 3.14; 95% CI 1.37% to 7.30%; p<0.05) and docosahexaenoic acid (DHA) (odds ratio 2.64; 95% CI 1.16% to 6.01%; p<0.05) than non-supplement users. Fish and meat were the main dietary sources of n-3 PUFAs. Participants most commonly consumed fish 3-4 times per week. Significant associations of dietary α-linolenic acid (ALA), EPA, docosapentaenoic acid (DPA) and DHA with plasma n-3 PUFAs were noted but not always between dietary and plasma counterparts.

CONCLUSION

Without the use of fish oil supplements, most study participants were unable to meet the recommended daily intake of 0.5g EPA and DHA combined; however, the plasma n-3 PUFA profile of non-supplement-users was still robust compared to other Australian and overseas studies.

Association between serum long-chain n-3 and n-6 polyunsaturated fatty acid profiles and glomerular filtration rate assessed by serum creatinine and cystatin C levels in Japanese community-dwellers

Background

Plasma concentration of n-3 polyunsaturated fatty acids (PUFAs) has been reported to be associated with renal function in Western populations. However, few studies have investigated the association between serum long-chain n-3 and n-6 PUFA profiles and renal function in a Japanese population with high marine-derived long-chain n-3 PUFA intake.

Methods

A cross-sectional study was performed in 549 Japanese rural community-dwellers aged 40 to 64 years. In adjusted analysis of covariance, we assessed the relationship between estimated glomerular filtration rate (eGFR) and tertiles of serum long-chain n-3 and n-6 PUFA profiles ([eicosapentaenoic acid {EPA} + docosahexaenoic acid {DHA}]:arachidonic acid [AA]). GFR was estimated by Japanese specific equations using serum creatinine and cystatin C (eGFR_cre and eGFR_cys). Using multivariate-adjusted linear regression models, we also assessed the relationships between eGFRs and several n-3 and n-6 PUFAs, which have been suggested to be associated with renal function.

Results

In all participants, higher dietary fish intake as assessed by a semi-quantitative questionnaire was associated with higher serum value of (EPA+DHA):AA. Participants in the higher (EPA+DHA):AA tertiles had non-significantly higher eGFR_cre and significantly higher eGFR_cys (P = 0.016). In addition, eGFR_cys in T₂+T₃ of (EPA+DHA):AA was significantly higher than that in T₁ (adjusted mean eGFR_cys, T₁: 87 ml/min/1.73 m², T₂+T₃: 91 ml/min/1.73 m²; P < 0.01). Among the PUFAs, only (EPA+DHA) was significantly associated with eGFR_cys.

Conclusions

Serum (EPA+DHA):AA, which reflects an individual’s fish intake, might be associated with eGFR_cys in Japanese community-dwellers.

Flax and flaxseed oil: an ancient medicine & modern functional food

Flaxseed is emerging as an important functional food ingredient because of its rich contents of α-linolenic acid (ALA, omega-3 fatty acid), lignans, and fiber. Flaxseed oil, fibers and flax lignans have potential health benefits such as in reduction of cardiovascular disease, atherosclerosis, diabetes, cancer, arthritis, osteoporosis, autoimmune and neurological disorders. Flax protein helps in the prevention and treatment of heart disease and in supporting the immune system. As a functional food ingredient, flax or flaxseed oil has been incorporated into baked foods, juices, milk and dairy products, muffins, dry pasta products, macaroni and meat products. The present review focuses on the evidences of the potential health benefits of flaxseed through human and animals' recent studies and commercial use in various food products.

Effect of omega-3 fatty acids on kidney function after myocardial infarction: the Alpha Omega Trial

BACKGROUND AND OBJECTIVES

Kidney function gradually decreases with age, and myocardial infarction accelerates this deterioration. Omega-3 (n-3) fatty acids may slow down the decline of kidney function. The effect of marine and plant-derived n-3 fatty acids on kidney function in patients after myocardial infarction was examined.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In the Alpha Omega Trial, 2344 patients with history of myocardial infarction ages 60-80 years old (81% men) were randomized to one of four trial margarines. The patients received an additional targeted amount of 400 mg/d eicosapentaenoic acid and docosahexaenoic acid, 2 g/d α-linolenic acid, eicosapentaenoic acid-docosahexaenoic acid plus α-linolenic acid, or placebo for 40 months. Serum cystatin C and serum creatinine were assessed at baseline and after 40 months. Creatinine-cystatin C-based GFR was estimated with the Chronic Kidney Disease Epidemiology Collaboration equation.

RESULTS

Patients consumed 19.9 g margarine/d, providing an additional 239 mg/d eicosapentaenoic acid with 159 mg/d docosahexaenoic acid, 1.99 g/d α-linolenic acid, or both in the active treatment groups. After 40 months, compared with baseline, mean (±SD) creatinine-cystatin C-based GFR was -6.9 (±12.6), -4.8 (±13.4), -6.2 (±12.8), and -6.0 (±13.0) ml/min per 1.73 m(2) in the placebo, eicosapentaenoic acid-docosahexaenoic acid, α-linolenic acid, and eicosapentaenoic acid-docosahexaenoic acid plus α-linolenic acid groups, respectively. After 40 months, in patients receiving eicosapentaenoic acid-docosahexaenoic acid compared with placebo, the decline in creatinine-cystatin C-based GFR was 2.1 less (95% confidence interval, 0.6 to 3.6; P<0.01) ml/min per 1.73 m(2); other comparisons were not statistical significant. Odds ratios (95% confidence intervals) of incident CKD (<60 ml/min per 1.73 m(2)) and rapid decline of kidney function (≥3 ml/min per year) for eicosapentaenoic acid-docosahexaenoic acid compared with placebo were 0.83 (0.58 to 1.18) and 0.85 (0.67 to 1.08), respectively.

CONCLUSIONS

Long-term supplementation with 400 mg/d eicosapentaenoic acid-docosahexaenoic acid provides a small beneficial effect on kidney function in patients with a history of myocardial infarction.

Effect of six different cooking techniques in the nutritional composition of two fish species previously selected as optimal for renal patient's diet

Benefits of fish consumption are widely known, but there is little information about nutrient values of raw and cooked fish. The aim was to study the impact that six cooking techniques have on the nutritional composition of two fish species with low content of adverse nutrients in renal diet. Raw and steamed, foiled with aluminum, foiled with banana leaf, gas oven-baked, microwave oven-coked and fried lightly samples were chemically analyzed to determine their protein, phosphorus and lipid content. Crevalle jack: all methods increased lipid and protein content and fatty acids (FA) varied in all cooking methods. Phosphorus decreased in the steamed and microwave oven-cooked samples. Red drum: foiled and fried lightly increased lipid content compared to the raw sample. FA concentration changed in all cooking methods. Protein increased with every technique and phosphorus decreased in the steamed and gas oven-baked samples. Renal patients should preferably consume crevalle jack steamed or microwave oven-cooked and red drum steamed or gas oven-baked.