The role of reducing intakes of saturated fat in the prevention of cardiovascular disease: where does the evidence stand in 2010?

A high-fat diet differentially affects the gut metabolism and blood lipids of rats depending on the type of dietary fat and carbohydrate

The aim of this model study was to investigate how selected gut functions and serum lipid profile in rats on high-fat diets differed according to the type of fat (saturated vs. unsaturated) and carbohydrate (simple vs. complex). The experiment was conducted using 32 male Wistar rats distributed into 4 groups of 8 animals each. For 4 weeks, the animals were fed group-specific diets that were either rich in lard or soybean oil (16% of the diet) as the source of saturated or unsaturated fatty acids, respectively; further, each lard- and soybean oil-rich diet contained either fructose or corn starch (45.3% of the diet) as the source of simple or complex carbohydrates, respectively. Both dietary factors contributed to changes in the caecal short-chain fatty acid concentrations, especially to the butyrate concentration, which was higher in rats fed lard- and corn starch-rich diets compared to soybean oil- and fructose-rich diets, respectively. The lowest butyrate concentration was observed in rats fed the soybean oil- and fructose-rich diet. On the other hand, the lard- and fructose-rich diet vs. the other dietary combinations significantly increased serum total cholesterol concentration, to more than two times serum triglyceride concentration and to more than five times the atherogenic index. In conclusion, a high-fat diet rich in fructose can unfavorably affect gut metabolism when unsaturated fats are predominant in the diet or the blood lipids when a diet is rich in saturated fats.

Relationships of neophobia and pickiness with dietary variety, dietary quality and diabetes management adherence in youth with type 1 diabetes

BACKGROUND/OBJECTIVES

Neophobia, pickiness and diet variety are associated with diet quality and health outcomes in young children. Limited research has examined these associations among youth with type 1 diabetes (T1D), a population at risk for poor health outcomes when dietary quality is inadequate.

SUBJECTS/METHODS

Youth (n=252, age 13.2 ± 2.8 years, 92% white, diabetes duration 6.3 ± 3.4 years) with T1D and their parents completed 3-day youth diet records; parents completed questionnaires regarding youth neophobia, pickiness and diabetes management adherence. Medical records provided biomedical data. Dietary quality indicators included Nutrient-Rich Foods Index 9.3 (NRF9.3), Healthy Eating Index-2005 (HEI-2005), Whole Plant Food Density (WPFD) and key single nutrients. Dietary variety was operationalized as a count of 20 recommended food groups consumed. Relationships of dietary quality and diabetes management adherence with neophobia, pickiness and dietary variety as independent variables were examined using multiple linear regression analyses adjusted for total energy intake, age, height and weight.

RESULTS

In multiple linear regression analyses, NRF9.3 and HEI-2005 were each inversely associated with neophobia and pickiness, and positively associated with dietary variety. WPF and potassium were each positively associated and saturated fat was inversely associated with dietary variety. However, in models simultaneously including neophobia, pickiness and dietary variety as independent correlates of dietary quality, only relationships with dietary variety remained significant. Diabetes management adherence was negatively associated with both neophobia and pickiness and positively associated with dietary variety.

CONCLUSIONS

Findings suggest that increasing dietary variety may contribute toward improved dietary quality among youth with T1D, despite potentially adverse influences of neophobia and pickiness.

Effect of diet on vascular health

Cardiovascular disease (CVD) is a major cause of morbidity and mortality in the Western world in older people. Diet and lifestyle change can reduce CVD risk in older people, and this evidence base is reviewed. For example, diets low in trans fats can reduce CVD risk, while for saturated fats the CVD-lowering effect depends on what is substituted for the saturated fat. Diets rich in fish reduce CVD risk, although n-3 supplements have not been shown to have a consistent effect on CVD end-points. Antioxidant and B-group vitamin supplementation are unlikely to reduce CVD risk, but diets rich in these micronutrients (e.g. rich in fruits and vegetables and the Mediterranean diet) are associated with lower CVD risk, while, for the Mediterranean diet, this has been supported by randomized controlled trials. Maintaining a healthy weight and being physically active reduce CVD risk factors and CVD incidence and mortality.

[Nutritional education of the coronary patient in practice]

BACKGROUND

The Mediterranean diet is one of the food models which showed its ability at the patient at high cardiovascular risk in numerous cohort studies and two major interventional studies: Lyon Heart Study in 1999 and PREDIMED in 2013.

AIM OF THE STUDY

Propose a practical assistance in the analysis of the dietary habits of the coronary patient with a simplified food frequency questionnaire.

PATIENTS AND METHODS

Hundred coronary patients followed a program of cardiac rehabilitation and benefited from a nutritional education. The analysis of their dietary habits was made with the questionnaire of frequency of consumption of Rennes upon their arrival and 6months later. We have coded again these data by means of a simplified questionnaire with 15 items and compared the results and their evolution in 6months.

RESULTS

On studied 200 questionnaires, the score of Rennes was 10.6±4.5 and the simplified score 8.2±3.4 with a coefficient of correlation of Pearson r=0.94 (0.91-0.95) at risk P<0.0001. Initial scores were respectively 8.0±4.4 and 6.3±3.4 (r=0.93) and the scores at 6months 13.1±2.9 and 10.1±2.2 (r=0.86). The evolution of the scores of 100 patients were respectively 14.2±11.7% and 12.6±11% (P<0.26).

CONCLUSION

The use of a simplified questionnaire allows to analyze the dietary habits of the coronary patient and to estimate their evolution during a therapeutic educational program.

Increasing the percentage of energy from dietary sugar, fats, and alcohol in adults is associated with increased energy intake but has minimal association with biomarkers of cardiovascular risk

The optimal diet composition to prevent obesity and its complications is unknown. Study aims were to determine the association of diet composition with energy intake, homeostatic model assessment-insulin resistance (HOMA-IR), and C-reactive protein (CRP). Data were from the NHANES for eligible adults aged 20-74 y from 2005 to 2006 (n = 3073). Energy intake and diet composition were obtained by dietary recall. HOMA-IR was calculated from fasting insulin and glucose concentrations, and CRP was measured directly. Changes for a 1-point increase in percentage of sugar, saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), and alcohol were determined across their means in exchange for a 1-point decrease in percentage of nonsugar carbohydrates. Regression analyses were performed, and means ± SEs were estimated. Increasing the percentage of sugar was associated with increased energy intake in men (23 ± 5 kcal; P < 0.001) and women (12 ± 3 kcal; P = 0.002). In men, increasing percentages of SFAs (58 ± 13 kcal; P = 0.001) and PUFAs (66 ± 19 kcal; P < 0.001) were associated with increased energy intake. In women, increasing percentages of SFAs (27 ± 10 kcal; P = 0.02), PUFAs (43 ± 6 kcal; P < 0.001), and MUFAs (36 ± 13 kcal; P = 0.01) were associated with increased energy intake. Increasing the percentage of alcohol was associated with increased energy intake in men (38 ± 7 kcal; P < 0.001) and women (25 ± 8 kcal; P = 0.001). Obesity was associated with increased HOMA-IR and CRP in both genders (all P ≤ 0.001). Increasing PUFAs was associated with decreasing CRP in men (P = 0.02). In conclusion, increasing the percentage of calories from sugar, fats, and alcohol was associated with substantially increased energy intake but had minimal association with HOMA-IR and CRP.

Reappraisal of SFA and cardiovascular risk

This review reappraises dietary advice to reduce and replace SFA for the prevention of CVD. In the 1970s, SFA accounted for about 18% UK food energy, by 2001 it had fallen to 13% and continues to be above the <11% target. Compared with carbohydrates, C12–C16 SFA raise serum total cholesterol (TC), LDL-cholesterol (LDL-C) and HDL-cholesterol (HDL-C) without affecting the TC:HDL-C ratio; other SFA have neutral effects on the fasting lipid profile. Replacing 3% dietary SFA with MUFA or PUFA lowers LDL-C by 2% and TC:HDL-C ratio by 0·03. No other specific adverse effects of SFA compared with MUFA on risk CVD factors have been proven. Meta-analyses of prospective cohort studies report the relative risks (95% CI) of high v. low intakes of SFA to be 1·07 (0·96, 1·19) for CHD, 0·81 (0·62, 1·05) for stroke and 1·00 (0·89, 1·11) for CVD mortality and were not statistically significant. Exchanging 5% energy SFA for PUFA or carbohydrates found hazard ratios (95% CI) for CHD death to be 26% (−23, −3) and 4% (−18, 12; NS) lower, respectively. Meta-analysis of randomised controlled trials with clinical endpoints reports mean reductions (95% CI) of 14% (4, 23) in CHD incidence and 6% (−25, 4; NS) in mortality in trials, where SFA was lowered by decreasing and/or modifying dietary fat. In conclusion, SFA intakes are now close to guideline amounts and further reductions may only have a minor impact on CVD.

Fatty acids as determinants of in-vivo lipid peroxidation: the EFFGE study in Eastern Finnish hypertensive and non-hypertensive subjects

BACKGROUND

The degree of fatty acid (FA) unsaturation as a determinant of lipid peroxidation has been inadequately studied.

METHODS

We examined associations of plasma free F2α-isoprostanes (F2-IsoPs), an indicator of in-vivo lipid peroxidation, with the levels/intake of FAs, adjusted for the risk factors of cardiovascular disease (CVD) in 1211 Finnish men and women, of whom 50% were hypertensive, aged 59.3 ± 8.3 years, mean ± SD.

RESULTS

Elevated age- and sex-adjusted plasma free levels of omega-6 and omega-3 polyunsaturated Fas (PUFAs), saturated FAs (SFAs), and the PUFA/SFA and the omega-6/omega-3 PUFA ratios were all associated with decreased F2-IsoPs. High dietary SFA intake was associated with elevated F2-IsoP concentrations. In a multivariable regression (with clinical, nutritional, and behavioral CVD risk factors), female gender, body mass index (BMI), serum apolipoprotein A1, and NT-proBNP (natriuretic peptide) were positively associated with the F2-IsoPs, whereas the dietary PUFA/SFA ratio, plasma β-carotene, the omega-6/omega-3 PUFA ratio, and protein intake showed inverse associations.

CONCLUSIONS

We propose that elevated lipid peroxidation is associated with several risk factors of CVD, such as a low PUFA/SFA ratio, whereas the FA precursors of lipid peroxidation, i.e. omega-3 and omega-6 PUFAs are associated with attenuated F2-IsoP levels. These findings provide mechanistic support for earlier observations linking PUFA to improved cardiovascular health.

Food sources of saturated fat and the association with mortality: a meta-analysis

We summarized the data related to foods high in saturated fat and risk of mortality. We searched Cochrane Library, MEDLINE, EMBASE, and ProQuest for studies from January 1952 to May 2012. We identified 26 publications with individual dietary data and all-cause, total cancer, or cardiovascular mortality as endpoints. Pooled relative risk estimates demonstrated that high intakes of milk, cheese, yogurt, and butter were not associated with a significantly increased risk of mortality compared with low intakes. High intakes of meat and processed meat were significantly associated with an increased risk of mortality but were associated with a decreased risk in a subanalysis of Asian studies. The overall quality of studies was variable. Associations varied by food group and population. This may be because of factors outside saturated fat content of individual foods. There is an ongoing need for improvement in assessment tools and methods that investigate food sources of saturated fat and mortality to inform dietary guidelines.

SFAs do not impair endothelial function and arterial stiffness

BACKGROUND

It is uncertain whether saturated fatty acids (SFAs) impair endothelial function and contribute to arterial stiffening.

OBJECTIVE

We tested the effects of replacing SFAs with monounsaturated fatty acids (MUFAs) or carbohydrates on endothelial function and arterial stiffness.

DESIGN

With the use of a parallel-designed randomized controlled trial in 121 insulin-resistant men and women, we measured vascular function after 1 mo of consumption of a high-SFA (HS) diet and after 24 wk after random assignment to the HS diet or diets that contained <10% SFAs and were high in either MUFAs or carbohydrates. The primary outcome was a change in flow-mediated dilation (FMD), and secondary outcomes were changes in carotid to femoral pulse wave velocity (PWV) and plasma 8-isoprostane F2α-III concentrations.

RESULTS

For 112 participants with data available for analysis on the specified outcomes, no significant differences were shown. FMD with the HS reference diet was 6.7 ± 2.2%, and changes (95% CIs) after 6 mo of intervention were +0.3 (-0.4, 1.1), -0.2 (-0.8, 0.5), and -0.1 (-0.6, 0.7) with HS, high-MUFA (HM), and high-carbohydrate (HC) diets, respectively. After consumption of the HS reference diet, the geometric mean (±SD) PWV was 7.67 ± 1.62 m/s, and mean percentages of changes (95% CIs) were -1.0 (-6.2, 4.3) with the HS diet, 2.7 (-1.4, 6.9) with the HM diet, and -1.0 (-5.5, 3.4) with the HC diet. With the HS reference diet, the geometric mean (±SD) plasma 8-isoprostane F2α-III concentration was 176 ± 85 pmol/L, and mean percentage of changes (95% CIs) were 1 (-12, 14) with the HS diet, 6 (-5, 16) with the HM diet, and 4 (-7, 16) with the HC diet.

CONCLUSION

The replacement of SFAs with MUFAs or carbohydrates in healthy subjects does not affect vascular function. This trial was registered at Current Controlled Trials (http://www.controlled-trials.com/ISRCTN) as ISRCTN 29111298.

Modulation of human postprandial lipemia by changing ratios of polyunsaturated to saturated (P/S) fatty acid content of blended dietary fats: a cross-over design with repeated measures

BACKGROUND

Postprandial lipemia (PL) contributes to coronary artery disease. The fatty acid composition of dietary fats is potentially a modifiable factor in modulating PL response.

METHODS

This human postprandial study evaluated 3 edible fat blends with differing polyunsaturated to saturated fatty acids (P/S) ratios (POL = 0.27, AHA = 1.00, PCAN = 1.32). A cross-over design included mildly hypercholestrolemic subjects (9 men and 6 women) preconditioned on test diets fats at 31% energy for 7 days prior to the postprandial challenge on the 8th day with 50 g test fat. Plasma lipids and lipoproteins were monitored at 0, 1.5, 3.5, 5.5 and 7 hr.

RESULTS

Plasma triacylglycerol (TAG) concentrations in response to POL, AHA or PCAN meals were not significant for time x test meal interactions (P > 0.05) despite an observed trend (POL > AHA > PCAN). TAG area-under-the-curve (AUC) increased by 22.58% after POL and 7.63% after PCAN compared to AHA treatments (P > 0.05). Plasma total cholesterol (TC) response was not significant between meals (P > 0.05). Varying P/S ratios of test meals significantly altered prandial high density lipoprotein-cholesterol (HDL-C) concentrations (P < 0.001) which increased with decreasing P/S ratio (POL > AHA > PCAN). Paired comparisons was significant between POL vs PCAN (P = 0.009) but not with AHA or between AHA vs PCAN (P > 0.05). A significantly higher HDL-C AUC for POL vs AHA (P = 0.015) and PCAN (P = 0.001) was observed. HDL-C AUC increased for POL by 25.38% and 16.0% compared to PCAN and AHA respectively. Plasma low density lipoprotein-cholesterol (LDL-C) concentrations was significant (P = 0.005) between meals and significantly lowest after POL meal compared to PCAN (P = 0.004) and AHA (P > 0.05) but not between AHA vs PCAN (P > 0.05). AUC for LDL-C was not significant between diets (P > 0.05). Palmitic (C16:0), oleic (C18:1), linoleic (C18:2) and linolenic (C18:3) acids in TAGs and cholesteryl esters were significantly modulated by meal source (P < 0.05).

CONCLUSIONS

P/S ratio of dietary fats significantly affected prandial HDL-C levels without affecting lipemia.

Sugar restriction: the evidence for a drug-free intervention to reduce cardiovascular disease risk

BACKGROUND/AIM

Uncertainty exists about what dietary component is most likely to cause coronary heart disease. Over the last thirty years, attention has focused on saturated fat and salt as guilty parties. More recently, evidence suggests that excess sugar intake is more likely than either traditional factor to lead to atherosclerotic disease. Some researchers have also speculated that sugar is addictive, in a similar manner to caffeine and established drugs of abuse.

METHODS

Here we review the epidemiological, biochemical and psychological evidence that implicates excess sugar intake as an important cause of ill-health.

RESULTS

We found relatively consistent evidence of association between markers of sugar intake and risk factors for cardiovascular disease, or the disease itself. This evidence contrasted with rather weaker evidence which linked either saturated fat or salt with cardiovascular disease endpoints. We also found some evidence of a sugar addiction syndrome.

CONCLUSION

We suggest that advice to restrict sugar intake should be a routine part of clinical care, particularly when patients are being counselled about cardiovascular risk.

Dietary saturated fat and docosahexaenoic acid differentially effect cardiac mitochondrial phospholipid fatty acyl composition and Ca(2+) uptake, without altering permeability transition or left ventricular function

High saturated fat diets improve cardiac function and survival in rodent models of heart failure, which may be mediated by changes in mitochondrial function. Dietary supplementation with the n3-polyunsaturated fatty acid docosahexaenoic acid (DHA, 22:6n3) is also beneficial in heart failure and can affect mitochondrial function. Saturated fatty acids and DHA likely have opposing effects on mitochondrial phospholipid fatty acyl side chain composition and mitochondrial membrane function, though a direct comparison has not been previously reported. We fed healthy adult rats a standard low-fat diet (11% of energy intake from fat), a low-fat diet supplemented with DHA (2.3% of energy intake) or a high-fat diet comprised of long chain saturated fatty acids (45% fat) for 6 weeks. There were no differences among the three diets in cardiac mass or function, mitochondrial respiration, or Ca²⁺-induced mitochondrial permeability transition. On the other hand, there were dramatic differences in mitochondrial phospholipid fatty acyl side chains. Dietary supplementation with DHA increased DHA from 7% to ∼25% of total phospholipid fatty acids in mitochondrial membranes, and caused a proportional depletion of arachidonic acid (20:4n6). The saturated fat diet increased saturated fat and DHA in mitochondria and decreased linoleate (18:2n6), which corresponded to a decrease in Ca²⁺ uptake by isolated mitochondria compared to the other diet groups. In conclusion, despite dramatic changes in mitochondrial phospholipid fatty acyl side chain composition by both the DHA and high saturated fat diets, there were no effects on mitochondrial respiration, permeability transition, or cardiac function.

Diet and physical activity for the prevention of noncommunicable diseases in low- and middle-income countries: a systematic policy review

BACKGROUND

Diet-related noncommunicable diseases (NCDs) are increasing rapidly in low- and middle-income countries (LMICs) and constitute a leading cause of mortality. Although a call for global action has been resonating for years, the progress in national policy development in LMICs has not been assessed. This review of strategies to prevent NCDs in LMICs provides a benchmark against which policy response can be tracked over time.

METHODS AND FINDINGS

We reviewed how government policies in LMICs outline actions that address salt consumption, fat consumption, fruit and vegetable intake, or physical activity. A structured content analysis of national nutrition, NCDs, and health policies published between 1 January 2004 and 1 January 2013 by 140 LMIC members of the World Health Organization (WHO) was carried out. We assessed availability of policies in 83% (116/140) of the countries. NCD strategies were found in 47% (54/116) of LMICs reviewed, but only a minority proposed actions to promote healthier diets and physical activity. The coverage of policies that specifically targeted at least one of the risk factors reviewed was lower in Africa, Europe, the Americas, and the Eastern Mediterranean compared to the other two World Health Organization regions, South-East Asia and Western Pacific. Of the countries reviewed, only 12% (14/116) proposed a policy that addressed all four risk factors, and 25% (29/116) addressed only one of the risk factors reviewed. Strategies targeting the private sector were less frequently encountered than strategies targeting the general public or policy makers.

CONCLUSIONS

This review indicates the disconnection between the burden of NCDs and national policy responses in LMICs. Policy makers urgently need to develop comprehensive and multi-stakeholder policies to improve dietary quality and physical activity.

Lean red meat consumption and lipid profiles in adolescent girls

BACKGROUND

Epidemiological studies of red meat consumption often fail to distinguish between leaner and fattier or processed cuts of meat. Red meat has also been frequently linked with less healthy diet patterns. Data exploring the health effects of lean red meat in younger individuals are scarce, particularly in the context of a healthy diet. The present study examined the effects of lean red meat in combination with higher intakes of fruit/nonstarchy vegetables on lipid profiles in older adolescent girls.

METHODS

Data from 1461 girls who were followed for 10 years, starting at 9-10 years of age, in the National Heart Lung and Blood Institute Growth and Health Study were used. Diet was assessed using multiple sets of 3-day records collected over eight examination cycles. Outcome measures included fasting levels of low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), non-HDL-C and triglycerides at age 18-20 years.

RESULTS

After adjusting for age, race, socioeconomic status, height, activity level, hours of television per day, and intakes of whole grains and dairy foods using multivariable modelling, girls consuming ≥6 oz lean red meat per week combined with two or more servings of fruit/nonstarchy vegetables per day had LDL-C levels approximately 6-7 mg dL(-1) lower (P < 0.05) than girls with lower intakes of lean red meat and fruit/nonstarchy vegetables. In addition, girls with higher intakes of both were 33% less likely (odds ratio = 0.67, 95% confidence interval = 0.48-0.94) to have an LDL-C ≥110 mg dL(-1) and 41% less likely (odds ratio = 0.59, 95% confidence interval = 0.42-0.83) to have an elevated LDL : HDL ratio (≥2.2) at the end of adolescence.

CONCLUSIONS

These analyses suggest that lean red meat may be included in a healthy adolescent diet without unfavourable effects on lipid values.

Dietary fats and health: dietary recommendations in the context of scientific evidence

Although early studies showed that saturated fat diets with very low levels of PUFAs increase serum cholesterol, whereas other studies showed high serum cholesterol increased the risk of coronary artery disease (CAD), the evidence of dietary saturated fats increasing CAD or causing premature death was weak. Over the years, data revealed that dietary saturated fatty acids (SFAs) are not associated with CAD and other adverse health effects or at worst are weakly associated in some analyses when other contributing factors may be overlooked. Several recent analyses indicate that SFAs, particularly in dairy products and coconut oil, can improve health. The evidence of ω6 polyunsaturated fatty acids (PUFAs) promoting inflammation and augmenting many diseases continues to grow, whereas ω3 PUFAs seem to counter these adverse effects. The replacement of saturated fats in the diet with carbohydrates, especially sugars, has resulted in increased obesity and its associated health complications. Well-established mechanisms have been proposed for the adverse health effects of some alternative or replacement nutrients, such as simple carbohydrates and PUFAs. The focus on dietary manipulation of serum cholesterol may be moot in view of numerous other factors that increase the risk of heart disease. The adverse health effects that have been associated with saturated fats in the past are most likely due to factors other than SFAs, which are discussed here. This review calls for a rational reevaluation of existing dietary recommendations that focus on minimizing dietary SFAs, for which mechanisms for adverse health effects are lacking.

Diet and cardiovascular disease

This paper describes the importance of diet in cardiovascular disease prevention. Different aspects of diet are discussed: nutrients, single foods/food groups and dietary patterns. The evidence regarding the impact of diet on intermediate risk factors (such as blood pressure and cholesterol levels) and the impact on cardiovascular endpoints are discussed.

Childhood serum fatty acid quality is associated with adult carotid artery intima media thickness in women but not in men

Childhood nutrition may play a role in the development of cardiovascular disease risk in adulthood. We examined the links between childhood dietary fatty acid quality and adult subclinical atherosclerosis in a cohort of 374 males and 449 females, aged 3-18 y at baseline in 1980, followed for 27 y. Serum cholesterol ester fatty acid (CEFA) percentages were analyzed as markers of dietary fatty acid intake. Adulthood carotid artery intima media thickness (cIMT, μm), adjusted for childhood and adulthood lipid and nonlipid risk markers, was used as the outcome. In women, after adjustment for age and childhood nonlipid risk markers, the childhood saturated CEFA (B = 11.3; P = 0.011), monounsaturated CEFA (B = 2.5; P = 0.025), and n3 (ω3) polyunsaturated CEFA (B = 16.2; P = 0.035) percentages were directly associated with adult cIMT. In contrast, the n6 (ω6) polyunsaturated CEFA percentage was negatively associated with cIMT (B = -2.3; P = 0.008). Similar relationships were observed between childhood dietary intake data and adult cIMT. In men, these associations were generally weak and nonsignificant (P > 0.05) after controlling for confounders. These longitudinal data suggest that fat quality as reflected in the serum cholesterol ester fraction in childhood is associated with adult cIMT in women.

A lipidomics analysis of the relationship between dietary fatty acid composition and insulin sensitivity in young adults

Relative to diets enriched in palmitic acid (PA), diets rich in oleic acid (OA) are associated with reduced risk of type 2 diabetes. To gain insight into mechanisms underlying these observations, we applied comprehensive lipidomic profiling to specimens collected from healthy adults enrolled in a randomized, crossover trial comparing a high-PA diet to a low-PA/high-OA (HOA) diet. Effects on insulin sensitivity (SI) and disposition index (DI) were assessed by intravenous glucose tolerance testing. In women, but not men, SI and DI were higher during HOA. The effect of HOA on SI correlated positively with physical fitness upon enrollment. Principal components analysis of either fasted or fed-state metabolites identified one factor affected by diet and heavily weighted by the PA/OA ratio of serum and muscle lipids. In women, this factor correlated inversely with SI in the fasted and fed states. Medium-chain acylcarnitines emerged as strong negative correlates of SI, and the HOA diet was accompanied by lower serum and muscle ceramide concentrations and reductions in molecular biomarkers of inflammatory and oxidative stress. This study provides evidence that the dietary PA/OA ratio impacts diabetes risk in women.

Substituting dietary monounsaturated fat for saturated fat is associated with increased daily physical activity and resting energy expenditure and with changes in mood

BACKGROUND

The Western diet increases risk of metabolic disease.

OBJECTIVE

We determined whether lowering the ratio of saturated fatty acids to monounsaturated fatty acids in the Western diet would affect physical activity and energy expenditure.

DESIGN

With the use of a balanced design, 2 cohorts of 18 and 14 young adults were enrolled in separate randomized, double-masked, crossover trials that compared a 3-wk high-palmitic acid diet (HPA; similar to the Western diet fat composition) to a low-palmitic acid and high-oleic acid diet (HOA; similar to the Mediterranean diet fat composition). All foods were provided by the investigators, and the palmitic acid (PA):oleic acid (OA) ratio was manipulated by adding different oil blends to the same foods. In both cohorts, we assessed physical activity (monitored continuously by using accelerometry) and resting energy expenditure (REE). To gain insight into a possible mood disturbance that might explain changes in physical activity, the Profile of Mood States (POMS) was administered in cohort 2.

RESULTS

Physical activity was higher during the HOA than during the HPA in 15 of 17 subjects in cohort 1 (P = 0.008) (mean: 12% higher; P = 0.003) and in 12 of 12 subjects in the second, confirmatory cohort (P = 0.005) (mean: 15% higher; P = 0.003). When the HOA was compared with the HPA, REE measured during the fed state was 3% higher for cohort 1 (P < 0.01), and REE was 4.5% higher in the fasted state for cohort 2 (P = 0.04). POMS testing showed that the anger-hostility score was significantly higher during the HPA (P = 0.007).

CONCLUSIONS

The replacement of dietary PA with OA was associated with increased physical activity and REE and less anger. Besides presumed effects on mitochondrial function (increased REE), the dietary PA:OA ratio appears to affect behavior. The second cohort was derived from a study that was registered at clinicaltrials.gov as R01DK082803.

Clinical determinants and mortality predictability of stearoyl-CoA desaturase-1 activity indices in dialysis patients

BACKGROUND

Stearoyl-CoA desaturase-1 (SCD-1) converts dietary saturated fatty acids to monounsaturated fatty acids. Elevated SCD-1 activity thus signifies impaired fatty acid metabolism and excess saturated fat intake. In the general population, increased SCD-1 activity is associated with cardiovascular disease and mortality. The determinants and implications of SCD-1 activity in dialysis patients are unknown.

SUBJECTS

A total of 222 dialysis patients (39% women) with prospective follow-up, median age of 57 years and an average of 12 months of dialysis.

DESIGN

Fatty acid compositions in plasma phospholipids and free fatty acids (FFAs) were assessed by gas-liquid chromatography. SCD-1 activity indices were calculated as the product-to-precursor fatty acid ratio (palmitoleic acid/palmitic acid) in each fraction to reflect SCD-1 activities in the liver and adipose tissue.

RESULTS

Median hepatic and adipose tissue SCD-1 activity indices were 0.016 and 0.150, respectively. In multivariate analyses, SCD-1 was positively associated with age, female sex and serum interleukin-6 level. During 18.4 (interquartile range 5.5-37.3) months of follow-up, there were 61 deaths and 115 kidney transplants. The cut-off level for high SCD-1 indices was determined by receiver operating characteristic curve analyses. In fully adjusted competing risk models, patients with high SCD-1 indices in both phospholipids and FFAs had more than twofold increased mortality risk before kidney transplantation [hazard ratio (HR) 2.29, 95% confidence interval (CI) 1.28-4.11 and HR 2.36, 95% CI 1.38-4.03, respectively], compared with patients with low SCD-1 indices.

CONCLUSIONS

Both hepatic and adipose tissue SCD-1 activity indices independently predict mortality in dialysis patients. Further studies are warranted to determine whether reducing SCD-1 activity by dietary intervention (limiting saturated fat) could improve survival in dialysis patients.

Incremental cost-effectiveness of guideline-directed medical therapies for heart failure

OBJECTIVES

This study sought to quantify the incremental cost-effectiveness ratios (ICER) of angiotensin-converting enzyme inhibitor (ACEI), beta-blocker (BB), and aldosterone antagonist (AldA) therapies for patients with heart failure with reduced ejection fraction (HFrEF).

BACKGROUND

There are evidence-based, guideline-directed medical therapies for patients with HFrEF, but the incremental cost-effectiveness of these therapies has not been well studied using contemporary data.

METHODS

A Markov model with lifetime horizon and two states, dead or alive, was created. We compared HFrEF patients treated with diuretic agents alone to three treatment arms: 1) ACEI therapy alone; 2) ACEI+BB; and 3) ACEI+BB+AldA. Sequential therapy was also analyzed. HF hospitalizations and mortality rates were based on representative studies. Costs of medications and inpatient and outpatient care were accounted for.

RESULTS

Treatment with ACEI and ACEI+BB strictly dominated treatment with diuretics only (cost-saving). The greatest gains in quality-adjusted life-years occurred when all 3 guideline-directed medications were provided. The incremental cost-effectiveness ratio (ICER) of ACEI+BB+AldA versus ACEI+BB and ACEI+BB versus ACEI was <$1,500 per quality-adjusted life-year. The cost-savings in the ACEI and ACEI+BB cohorts compared to that with diuretics alone were $444 and $33, respectively. Assuming lower treatment costs and lower hospitalization rates in the ACEI+BB+AldA arm resulted in greater cost-savings. Even in the most unfavorable situations, the ICER was <$10,000 per life-year gained.

CONCLUSIONS

Our analysis demonstrates that medical treatment of HFrEF is highly cost-effective and may even result in cost-savings. Greater efforts to ensure optimal adherence to guideline-directed medical therapy for HFrEF are warranted.

Quantitative determination of fatty acid chain composition in pork meat products by high resolution 1H NMR spectroscopy

High resolution (1)H NMR spectroscopy was proposed for the determination of the fatty acid chain profile of lipids in pork meat products during ripening. Two typical Mediterranean PDO salami produced in Calabria, a region in the Southern Italy, were chosen as a case of study. Quantitative NMR analysis provided the fatty acid chain profiles of total lipid extracts. The transesterification of total lipid extracts furnished FAME mixtures that enabled quantitation of fatty acid acyl chains in the acylglycerol and FFA portions. In all cases, oleyl chains were predominant, and high amounts of polyunsaturated fatty acid chains were observed. The proposed spectroscopic method allowed also the estimation of the most important nutritional parameters of dry fermented meat products.

Can breast cancer patients use soyafoods to help reduce risk of CHD?

Over the past 20 years, the popularity of soyafoods has increased in part because of research suggesting that these foods convey health benefits independent of their nutrient content. For example, in 1999, the US Food and Drug Administration approved a health-claim for soyafoods and CHD based on the hypocholesterolaemic effects of soya protein. However, soyafoods have become controversial in recent years because of concerns that their uniquely rich phyto-oestrogen (isoflavone) content may cause untoward effects in some individuals. Most notable in this regard is the concern that soyafoods are contraindicated for breast cancer patients and women at high risk of developing this disease. Furthermore, the hypocholesterolaemic effects of soya protein have been challenged. However, the results of recently published meta-analyses indicate that soya protein directly lowers circulating LDL-cholesterol levels by approximately 4 %. There is also intriguing evidence that soyafoods reduce CHD risk independent of their effects on lipid levels. In regard to the breast cancer controversy, recently published clinical and epidemiological data do not support observations in rodents that soyabean isoflavones increase breast cancer risk. In postmenopausal women, isoflavone exposure does not adversely affect breast tissue density or breast cell proliferation. Furthermore, both US and Chinese prospective epidemiological studies show that post-diagnosis soya consumption is associated with an improved prognosis. Therefore, soyafoods should be considered by women as healthy foods to include in diets aimed at reducing the risk of CHD regardless of their breast cancer status.

Diet and fatty acid pattern among patients with SLE: associations with disease activity, blood lipids and atherosclerosis

OBJECTIVE

As atherosclerosis is increased in systemic lupus erythematosus (SLE) we compared dietary habits in patients with SLE with controls, and in the patients studied associations of diet components, especially fatty acids (FAs), with disease activity, serum lipids and carotid plaque presence.

METHODS

In all 114 patients with SLE and 122 age- and sex-matched population-based controls answered a food frequency questionnaire (FFQ). Subcutaneous abdominal fat cell aspiration was analysed as to FA content and plaque occurrence was determined by B-mode ultrasound.

RESULTS

The total diet energy intake did not differ between patients and controls. However, the patients with SLE reported a higher intake of carbohydrate, lower fibre intake and lower intake of omega-3 and omega-6, than controls (p < 0.05). In the patients, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in adipose tissue (AT) correlated negatively with disease activity (SLEDAI), r = -0.36, p = < 0.001 and r = -0.33, p = < 0.001, respectively. AT omega-3 was further positively associated with serum apoA1, r = 0.29, p = 0.004, whereas AT omega-6 showed a negative association, r = -0.21, p = 0.040. These FAs also had opposite associations with plaque presence, EPA and were DHA negative, r = -0.32, p = 0.002 and r = -0.33, p = 0.001, respectively, and omega-6 positive, r = 0.22, p = 0.027. The carbohydrate intake was positively correlated to AT omega-6, r = 0.38, p < 0.001, and negatively with serum apoA1, r = -0.27, p = 0.005.

CONCLUSION

The macronutrient dietary pattern is different in SLE as compared with controls. The low intake of omega-3 and high intake of carbohydrate among patients with SLE appear to be associated with worse disease activity, adverse serum lipids and plaque presence.

The impact of substituting SFA in dairy products with MUFA or PUFA on CVD risk: evidence from human intervention studies

With the substantial economic and social burden of CVD, the need to modify diet and lifestyle factors to reduce risk has become increasingly important. Milk and dairy products, being one of the main contributors to SFA intake in the UK, are a potential target for dietary SFA reduction. Supplementation of the dairy cow's diet with a source of MUFA or PUFA may have beneficial effects on consumers' CVD risk by partially replacing milk SFA, thus reducing entry of SFA into the food chain. A total of nine chronic human intervention studies have used dairy products, modified through bovine feeding, to establish their effect on CVD risk markers. Of these studies, the majority utilised modified butter as their primary test product and used changes in blood cholesterol concentrations as their main risk marker. Of the eight studies that measured blood cholesterol, four reported a significant reduction in total and LDL-cholesterol (LDL-C) following chronic consumption of modified milk and dairy products. Data from one study suggested that a significant reduction in LDL-C could be achieved in both the healthy and hypercholesterolaemic population. Thus, evidence from these studies suggests that consumption of milk and dairy products with modified fatty acid composition, compared with milk and dairy products of typical milk fat composition, may be beneficial to CVD risk in healthy and hypercholesterolaemic individuals. However, current evidence is insufficient and further work is needed to investigate the complex role of milk and cheese in CVD risk and explore the use of novel markers of CVD risk.

Dietary protein requirements and adaptive advantages in athletes

Dietary guidelines from a variety of sources are generally congruent that an adequate dietary protein intake for persons over the age of 19 is between 0·8–0·9 g protein/kg body weight/d. According to the US/Canadian Dietary Reference Intakes, the RDA for protein of 0·8 g protein/kg/d is “…the average daily intake level that is sufficient to meet the nutrient requirement of nearly all [~98 %]… healthy individuals…” The panel also states that “…no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise.” These recommendations are in contrast to recommendations from the US and Canadian Dietetic Association: “Protein recommendations for endurance and strength trained athletes range from 1·2 to 1·7 g/kg/d.” The disparity between those setting dietary protein requirements and those who might be considered to be making practical recommendations for athletes is substantial. This may reflect a situation where an adaptive advantage of protein intakes higher than recommended protein requirements exists. That population protein requirements are still based on nitrogen balance may also be a point of contention since achieving balanced nitrogen intake and excretion likely means little to an athlete who has the primary goal of exercise performance. The goal of the present review is to critically analyse evidence from both acute and chronic dietary protein-based studies in which athletic performance, or correlates thereof, have been measured. An attempt will be made to distinguish between protein requirements set by data from nitrogen balance studies, and a potential adaptive ‘advantage’ for athletes of dietary protein in excess of the RDA.

The association between dairy product consumption and cognitive function in the National Health and Nutrition Examination Survey

The present cross-sectional study sought to determine the potential relationships between the intake of dairy foods (total dairy products, milk and cheese) and cognitive function through information garnered in the National Health and Nutrition Examination Surveys (1988-94 and 1999-2002). Cognitive measures of vasomotor speed, coding speed and immediate memory recall were assessed from a simple reaction time task (SRTT), symbol-digit substitution test (SDST) and serial digit learning task, respectively, in adults 20-59 years of age. A summation of the percentile rank scores on each of the three tests provided a measure of overall cognitive function. In adults 60 years of age and above, a story recall test and a digit-symbol substitution test (DSST) were utilised to determine cognitive function in an elderly population. The results indicated that cognitive scores for the SRTT were not different between consumers and non-consumers of dairy foods. However, there were associations observed between 20- and 59-year-old consumers of total dairy foods and a higher SDST percentile score (53.2 (SE 1.3) to 49.4 (SE 2.0)) and a calculated global cognitive percentile score (53.3 (SE 1.1) to 50.2 (SE 1.4)) compared with non-consumers. A similar significant association was observed with cheese consumers. In adults over 60 years of age, an association between total dairy product consumption and higher DSST percentile scores (51.5 (SE 1.9) to 46.2 (se 3.0)) was also observed. These findings highlight the need for additional research on how dairy products may affect cognition and by what mechanisms, through its nutrients or other components.

Adherence to a Mediterranean diet and energy, macro-, and micronutrient intakes in older persons

The Mediterranean-type diet combines several foods and nutrients already individually proposed as potential protective factors against adverse health outcomes, such as cardiovascular diseases. The aim of the present study was to describe the association between adherence to a Mediterranean diet (MeDi) and intake of energy, macronutrients, and micronutrients. The study sample consisted of 1,595 individuals from Bordeaux, France, included in 2001-2002 in the Three-City Study. Adherence to a MeDi (scored as 0 to 9) was computed from a food frequency questionnaire (FFQ). Total energy intake (EI) and nutrient intake were evaluated on a 24 h recall. Statistical analyses were stratified by gender. Both in men and women, greater MeDi adherence was associated with higher total vegetal protein, polyunsaturated fatty acids (PUFA), notably n - 6 PUFA, and lower total saturated fat intakes, as expressed in percentage of EI. Higher total monounsaturated fat and oleic acid intakes (% EI) were observed with greater MeDi adherence in men. Women with the highest MeDi adherence exhibited a higher mean carbohydrate, polysaccharide, and total n - 3 PUFA intakes (% EI). The consumption of fibers; vitamins B6, C, and E; folate; magnesium; potassium; and iron increased with greater MeDi adherence, both in men and women. However, consumption of calcium significantly decreased with greater MeDi adherence in women, while the ratio of n - 6/n - 3 PUFA precursors increased. This cross-sectional study provides the nutrient-related basis of the Mediterranean-type diet of French elderly community dwellers, which might participate to its well-documented beneficial effects on health.

Dietary fats and coronary heart disease

The relation of dietary fat to risk of coronary heart disease (CHD) has been studied extensively using many approaches, including controlled feeding studies with surrogate end-points such as plasma lipids, limited randomized trials and large cohort studies. All lines of evidence indicate that specific dietary fatty acids play important roles in the cause and the prevention of CHD, but total fat as a percent of energy is unimportant. Trans fatty acids from partially hydrogenated vegetable oils have clear adverse effects and should be eliminated. Modest reductions in CHD rates by further decreases in saturated fat are possible if saturated fat is replaced by a combination of poly- and mono-unsaturated fat, and the benefits of polyunsaturated fat appear strongest. However, little or no benefit is likely if saturated fat is replaced by carbohydrate, but this will in part depend on the form of carbohydrate. Because both N-6 and N-3 polyunsaturated fatty acids are essential and reduce risk of heart disease, the ratio of N-6 to N-3 is not useful and can be misleading. In practice, reducing red meat and dairy products in a food supply and increasing intakes of nuts, fish, soy products and nonhydrogenated vegetable oils will improve the mix of fatty acids and have a markedly beneficial effect on rates of CHD.