EFFICACY OF A LIPID-LOWERING DIET ON KEY FATTY ACID RATIOS AND OMEGA-3 INDEX IN HYPERLIPIDEMIC SUBJECTS

Polyunsaturated fatty acid (PUFA) dietary intake, status and serum key fatty acid (FA) ratios may aid in cardiovascular disease-related risk assessment. The aim of this study was to investigate the effects of lipid-lowering diet on key FA ratios in serum phospholipids and omega-3 index in erythrocyte phospholipids in moderately hyperlipidemic subjects. The study included 41 subjects, mean age 56±6 years. Nutritional habits were evaluated by food frequency questionnaire. Participants followed lipid lowering diet for 12 weeks. Energy intake of omega-6 and omega-3 FA was changed from 7.6% and 0.6% to 5.7% and 1.2%, respectively. Marked decrease in four FA ratios in serum phospholipids, i.e., omega-6/omega-3, arachidonic acid (AA)/eicosapentaenoic acid (EPA), AA/docosahexaenoic acid (DHA), AA/(EPA+DHA) and omega-3 index (EPA+DHA) was found in study subjects after lipid-lowering diet. Total cholesterol/high-density lipoprotein (HDL), low-density lipoprotein (LDL)/HDL and triacylglycerol/HDL-cholesterol ratios positively correlated with all FA ratios, and negatively correlated with total omega-3 levels in serum phospholipids and omega-3 index in erythrocytes. Total serum omega-3 levels showed strongest association with lipoprotein ratios and positive correlation with homeostatic model assessment (HOMA) index. In conclusion, lipid-lowering diet resulted in decreased serum key FA ratios, increased omega-3 levels, and improved insulin sensitivity that may lead to a lower risk of cardiovascular disease in subjects with moderate hyperlipidemia.

Circulatory Imbalance of Essential and Toxic Trace Elements in Pre-dialysis and Hemodialysis Patients

The status of essential and toxic trace elements in patients with different stages of chronic kidney disease (CKD) is still unclear and not well characterized. The present study examined the circulatory levels of a wide panel of trace elements (Al, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Cd, Pb, and U) in hemodialysis patients (HD group) and pre-dialysis patients with stage 3 CKD (PD group). Comparisons were made between groups of patients and healthy individuals from the control group (CG). The levels of Al, Mn, Co, Ni, Cu, As, Se, Sr, and Pb were higher, while the levels of Cr, Zn, Rb, Cd, and U were lower in HD patients than in our CG. Higher levels of Al and Se, as well as lower levels of As, Sr, Zn, Rb, and U were significant and distinguished HD from PD. Among other analyzed elements, Co, Se, and U are the only trace elements that did not distinguish PD from CG at a statistically significant level. The HD group had lower serum U levels than the PD group, and this could be a result of hemodialysis. This study also revealed that the Cu/Zn ratio could be used as a marker for early and late detection of renal failure. Marked changes of essential and toxic trace element levels in sera indicate additional pathophysiological events in CKD, which could additionally contribute to the preexisting increased morbidity of HD patients. Measurement of trace elements in HD patients should be performed routinely.

Trans fatty acids in frequently consumed products from Serbian and Slovenian market

OBJECTIVES

Industrially produced trans fatty acid (iTFA) have adverse health effects and thus their consumption should be limited. The aim of this study was to determine and compare the iTFA content in frequently consumed food products by young adults from the Serbian and Slovenian market with supposedly elevated iTFA content in 2015. At the time of this study, there was no recommended limit of iTFA in both countries, and reduction of iTFA in foods was on voluntary basis.

METHODS

We determined iTFA content in food products, 19 from the Serbian and 22 from the Slovenian market, blinded and analysed in the same analytical run. Contents of fatty acids (FA) methyl esters were analysed by capillary gas chromatography with a flame ionisation detector. Heptadecanoic acid was used as internal standard. Individual FA along with TFA were expressed as percentages of total measured FA. The amount of each FA in the sample was then calculated from the response factor and the transformation factor of the FA from the FA methyl ester content.

RESULTS

Elaidic acid (C18:1t) was found as the most abundant TFA in analysed products, ranging from 0.52 g/100 g of total FA in chocolate candy up to 60.4 g/100 g in a salami from Serbian market. In Slovenian products, the values for elaidic acid were lower, 0.04-3.95 g/100 g of total FA, except in one type of wafers (24.3 g/100 g).

CONCLUSIONS

The majority of analysed products from the Serbian and three from Slovenian market exceeded the recommended WHO and EU limit of 2% iTFA of total fat in foods. Samples of frequently consumed salami, wafers, tea biscuits, and snacks were identified as products with potentially higher burden of iTFA in diets of young adults in Serbia.

Systematic Review of Observational Studies with Dose-Response Meta-Analysis between Folate Intake and Status Biomarkers in Adults and the Elderly

BACKGROUND

Dietary reference values for folate intake vary widely across Europe.

METHODS

MEDLINE and Embase through November 2016 were searched for data on the association between folate intake and biomarkers (serum/plasma folate, red blood cell [RBC] folate, plasma homocysteine) from observational studies in healthy adults and elderly. The regression coefficient of biomarkers on intake (β) was extracted from each study, and the overall and stratified pooled β and SE (β) were obtained by random effects meta-analysis on a double log scale. These dose-response estimates may be used to derive folate intake reference values.

RESULTS

For every doubling in folate intake, the changes in serum/plasma folate, RBC folate and plasma homocysteine were +22, +21, and -16% respectively. The overall pooled regression coefficients were β = 0.29 (95% CI 0.21-0.37) for serum/plasma folate (26 estimates from 17 studies), β = 0.28 (95% CI 0.21-0.36) for RBC (13 estimates from 11 studies), and β = -0.21 (95% CI -0.31 to -0.11) for plasma homocysteine (10 estimates from 6 studies).

CONCLUSION

These estimates along with those from randomized controlled trials can be used for underpinning dietary recommendations for folate in adults and elderly.

Systematic review using meta-analyses to estimate dose-response relationships between iodine intake and biomarkers of iodine status in different population groups

The objective of this systematic review was to identify studies investigating iodine intake and biomarkers of iodine status, to assess the data of the selected studies, and to estimate dose-response relationships using meta-analysis. All randomized controlled trials, prospective cohort studies, nested case-control studies, and cross-sectional studies that supplied or measured dietary iodine and measured iodine biomarkers were included. The overall pooled regression coefficient (β) and the standard error of β were calculated by random-effects meta-analysis on a double-log scale, using the calculated intake-status regression coefficient (β) for each individual study. The results of pooled randomized controlled trials indicated that the doubling of dietary iodine intake increased urinary iodine concentrations by 14% in children and adolescents, by 57% in adults and the elderly, and by 81% in pregnant women. The dose-response relationship between iodine intake and biomarkers of iodine status indicated a 12% decrease in thyroid-stimulating hormone and a 31% decrease in thyroglobulin in pregnant women. The model of dose-response quantification used to describe the relationship between iodine intake and biomarkers of iodine status may be useful for providing complementary evidence to support recommendations for iodine intake in different population groups.

Abnormalities in the serum phospholipids fatty acid profile in patients with alcoholic liver cirrhosis - a pilot study

The fatty acid composition of serum phospholipids were analyzed in 20 patients with alcoholic liver cirrhosis (11 with malnutrition and 9 with acceptable nutritional status); 25 healthy age and sex-matched adults were used as controls. Cirrhotic patients showed higher levels of palmitic acid and total saturated fatty acids than healthy subjects. Total n-6 and n-3 polyunsaturated fatty acids (PUFA), and levels of linoleic, dihomo-gama linolenic, arachidonic, and docosahexaenoic acid were significantly lower (p<0.001) in patients with alcoholic cirrhosis compared to healthy controls. Significant changes were also found between patients stratified according to nutritional status. In particular, the sum of n-3 PUFA was significantly lower (p<0.001) and ratio of n-6/n-3 fatty acids was higher (p<0.01) in malnourished patients when compared to the patients with acceptable nutritional status. Furthermore, important changes in the levels of saturated fatty acids, palmitoleic and oleic acid and long-chain PUFA were found in well-nourished patients with alcoholic cirrhosis as well. Our present data confirmed evidence that malnutrition is one of the factors that led to lower levels of polyunsaturated fatty acids in patients with alcoholic liver cirrhosis. PUFA supplementation in the latter needs further investigation.

Different fatty acid composition of serum phospholipids of small and appropriate for gestational age preterm infants and of milk from their mothers

BACKGROUND

Placental supply of fatty acids (FA) is essential for normal foetal development but in premature infants this supply is interrupted. To investigate the association of intrautrine growth restriction with serum phospholipid and breast milk FA composition, we compared preterm infants small for gestational age (SGA) and matched appropriate for gestational age (AGA), and their mothers' milk during the first 4 weeks of postnatal life.

METHODS

Sera from 11 SGA and 12 AGA infants born 34-36 weeks of gestation were collected at birth, 14(th) and 28(th) day, and breast milk on 14(th) and 28(th) day after birth. FA composition was analyzed by gas chromatography.

RESULTS

Preterm SGA infants had significantly lower oleic, total monounsaturated FA (MUFA), docosahexaenoic acid (DHA) and n-3 polyunsaturated FA (PUFA) and higher levels of stearic and linoleic acid at birth than AGA infants (p<0.05). DHA was significantly lower, whereas docosatetraenoic and docosapentaenoic acids were higher in SGA infants after 28 days. Mothers of AGA infants had markedly lower levels of MUFA and higher levels of total and n-6 PUFA in their breast milk.

CONCLUSION

SGA infants have altered serum phospholipid FA composition at birth and during their first month of life, probably due to inadequate transplacental supply and activity of desaturase system. RESULTS on human milk suggest that pregnancies with AGA or SGA would later influence breast milk FA composition.

Insulin resistance and chronic inflammation are associated with muscle wasting in end-stage renal disease patients on hemodialysis

Muscle wasting is independent predictor of mortality in end-stage renal disease (ESRD) patients on maintenance hemodialysis (MHD). We investigated the effect of insulin resistance on lean body mass (LBM), and association between insulin resistance, chronic inflammation, and body composition in these patients. We analyzed cross-sectionally body composition, nutritional status and biochemical parameters in 35 non-diabetic ESRD patients who were on MHD. Bioelectrical impedance analysis was performed to quantify body fat, lean body mass and total body water (FAT (%), FAT (kg), LBM (%), LBM (kg) and TBW(%)). The association between LBM (kg) and gender, FAT (kg), high sensitivity C-reactive protein (hs-CRP), and homeostatic model assessment score (HOMA-IR) was recorded. Multiple linear regression analysis using LBM (kg) as dependent variable showed that FAT (kg) (beta = 0.563, p = 0.05), HOMA-IR (beta = 0.619, p = 0.03), and hs-CRP (beta = 0.488, p = 0.04) were independently associated with LBM in males. In females, only FAT (kg) (beta = 0.648, p = 0.001) significantly predicted LBM. Those variables explained 37% of variance of LBM (kg) in males, and 44% in females. It seems that insulin resistance participates independently in the pathogenesis of muscle wasting in both sexes, particularly in males. The effect of chronic inflammation was not so strong in females, and this point out that regulation of muscle wasting in female patients probably differs from that in males.

[Alpha-linolenic acid and cardiovascular diseases]

IMPORTANCE AND METABOLISM OF ALPHA-LINOLENIC ACID: Alpha-linolenic acid is an essential fatty acid which cannot be produced in the body and must be taken by food. Both in animals and humans, alpha-linolenic acid is desaturated and elongated into eicosapentaenoic and docosahexaenoic acid. It is also incorporated into plasma and tissue lipids and its conversion is affected by levels of linoleic acid. POTENTIAL ROLE IN PATHOGENESIS OF CARDIOVASCULAR DISEASES: Diet enriched in n-3 fatty acids, especially alpha-linolenic acid, reduces the incidence of cardiac death. Studies have shown that alpha linolenic acid prevents ventricular fibrillation which is the main cause of cardiac death. Studies in rats suggest that alpha-linolenic acid may be more effective in preventing ventricular fibrillations than eicosapentaenoic and docosahexaenoic acid. Furthermore, alpha-linolenic acid is the main fatty acid decreasing platalet aggregation which is an important step in thrombosis i.e. non-fatal myocardial infarction and stroke. DIETARY SOURCES AND NUTRITION RECOMMENDATIONS: Dietary sources include flaxseed and flaxseed oil, canola oil, soybean and soybean oil, pumpkin seed and pumpkin oil, walnuts and walnut oil. Strong evidence supports beneficial effects of alpha-linolenic acid and its dietary sources should be incorporated into balanced diet for prevention of cardiovascular diseases. The recommended daily intake is 2 g with a ratio of 5/1 for linoleic/alpha-linolenic acid.

Effects of different quantities of fat on serum and liver lipids, phospholipid class distribution and fatty acid composition in alcohol-treated rats

The present study investigated the quantitative effect of dietary fats and ingestion of alcohol on serum and liver lipids, fatty acid bound to phospholipids and their class distribution of male Wistar rats. The rats in C (control) and A (alcohol) groups were fed a standard laboratory diet, HFC (high fat-control) and HFA (high fat-alcohol) groups were fed a high fat diet (standard diet supplemented with 20 g%w/w, sunflower oil: lard mixture 1: 1) for 6 wk. Alcohol-treated rats consumed alcohol at the rate of 9 g/kgbw/d (15-20% energy). Liver phospholipid (PL) content was decreased, and phospholipid/cholesterol liver molar ratio increased in the alcohol treated rats. The proportion of serum sphingophospholipid (Sph) was significantly lower and proportion of phosphatidylcholin (PC) significantly higher in serum PL in alcohol-treated rats. Phospholipid class distribution was unaffected by alcohol feeding in liver. Significantly lower levels of 16:1n-7 and higher levels of 20:5n-3 and 22:4n-6 in the serum PL were observed in the alcohol-treated rats. The groups on the HF diet increased levels of 20:4n-6, 22:4n-6 and total n-6, polyunsaturated fatty acid (PUFA) and decreased levels of 18:1n-9 and total monounsaturated fatty acids (MUFA)in both liver and serum PL, but n-3 fatty acid increased in serum PL and decreased in liver PL compared to groups on the standard diet. Alcohol fat interaction was evident in MUFA and PUFA/SFA in serum PL and n-6, MUFA, PUFA and polyunsaturated/saturated fatty acid ratios (PUFA/SFA) in liver PL. This study showed that the high fat intake in alcohol-treated rats increased levels of 20:4n-6, 22:4n-6 and 20:4/18:2 ratio, and decreased level of 18:1n-9 in liver and serum phospholipids.