Fats in Foods: Current Evidence for Dietary Advice.

Current discussion of the importance of food fats in the risk of coronary heart disease (CHD) often suffers from preconceptions, misunderstandings, insufficient knowledge, and selective reasoning. As a result, the sustained controversy about dietary fat recommendations can be contradictory and confusing. To clarify some of these issues, the International Expert Movement to Improve Dietary Fat Quality in cooperation with the International Union of Nutritional Sciences (IUNS) organized a symposium at the 21st meeting of the IUNS, October 17, 2017, Buenos Aires, Argentina, to summarize the key scientific evidence underlying the controversy on the relationship between the saturated and unsaturated fat consumption and CHD risk. Presenters also discussed, using examples, the rationale for and implications of the partial replacement of foods rich in saturated fats by those rich in unsaturated fats. Presentations included strategies to fit healthier fats into meals. This report summarizes the symposium presentations.

Progressing Insights into the Role of Dietary Fats in the Prevention of Cardiovascular Disease.

Dietary fats have important effects on the risk of cardiovascular disease (CVD). Abundant evidence shows that partial replacement of saturated fatty acids (SAFA) with unsaturated fatty acids improves the blood lipid and lipoprotein profile and reduces the risk of coronary heart disease (CHD). Low-fat diets high in refined carbohydrates and sugar are not effective. Very long-chain polyunsaturated n-3 or omega-3 fatty acids (n-3 VLCPUFA) present in fish have multiple beneficial metabolic effects, and regular intake of fatty fish is associated with lower risks of fatal CHD and stroke. Food-based guidelines on dietary fats recommend limiting the consumption of animal fats high in SAFA, using vegetable oils high in monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA), and eating fatty fish. These recommendations are part of a healthy eating pattern that also includes ample intake of plant-based foods rich in fiber and limited sugar and salt.

ISSFAL 2010 dinner debate: healthy fats for healthy hearts - annotated report of a scientific discussion.

BACKGROUND/AIMS: The importance of reducing saturated fatty acid intake to prevent cardiovascular disease and recommended intakes for omega-6 polyunsaturated fatty acids (PUFAs) are controversial. Therefore, experts debated these topics at the biennial meeting of the International Society for the Study of Fatty Acids and Lipids (ISSFAL), in May 2010. METHODS: Debate transcripts, debaters' and discussants' reviews and literature citations were the basis of this report. RESULTS: Participants agreed that saturates per se are not 'bad', but that dietary recommendations should emphasize the substitution of unsaturates for part of the saturates. Evidence supporting omega-6 PUFA intakes of 5 to 10% is mixed; some interpret the overall data from diverse studies as consistent with a reduction in the risk of cardiovascular mortality and events. Others assert that randomized controlled trial data suggest that higher intakes of omega-6 PUFAs are not associated with lower risk of heart disease, or may even increase it. CONCLUSIONS: All agreed that a 5-year randomized controlled trial comparing the effects of historically low (2%) with currently high (7.5%) linoleic acid intakes on cardiac endpoints would address the knowledge gap about the effects of different omega-6 PUFA intakes on the risk of heart disease.

Dietary arachidonic acid dose-dependently increases the arachidonic acid concentration in human milk.

Lactation hampers normalization of the maternal arachidonic acid (AA) status, which is reduced after pregnancy and can further decline by the presently recommended increased consumption of (n-3) long-chain PUFA [(n-3) LCPUFA]. This may be unfavorable for breast-fed infants, because they also require an optimum supply of (n-6) LCPUFA. We therefore investigated the LCPUFA responses in nursing mothers upon increased consumption of AA and (n-3) LCPUFA. In a parallel, double-blind, controlled trial, lactating women received for 8 wk no extra LCPUFA (control group, n = 8), 200 (low AA group, n = 9), or 400 (high AA group, n = 8) mg/d AA in combination with (n-3) LCPUFA [320 mg/d docosahexaenoic acid (DHA), 80 mg/d eicosapentaenoic acid, and 80 mg/d other (n-3) fatty acids], or this dose of (n-3) LCPUFA alone [DHA + eicosapentaenoic acid group, n = 8]. Relative concentrations of AA, DHA, and sums of (n-6) and (n-3) LCPUFA were measured in milk total lipids (TL) and erythrocyte phospholipids (PL) after 2 and 8 wk and changes were compared by ANCOVA. The combined consumption of AA and (n-3) LCPUFA caused dose-dependent elevations of AA and total (n-6) LCPUFA concentrations in milk TL and did not significantly affect the DHA and total (n-3) LCPUFA increases caused by (n-3) LCPUFA supplementation only. This latter treatment did not significantly affect breast milk AA and total (n-6) LCPUFA concentrations. AA and DHA concentrations in milk TL and their changes were strongly and positively correlated with their corresponding values in erythrocyte PL (r(2) = 0.27-0.50; P

Maternal n-3, n-6, and trans fatty acid profile early in pregnancy and term birth weight: a prospective cohort study.

BACKGROUND: Maternal n-3, n-6, and trans fatty acids are claimed to affect fetal growth, yet evidence is limited. OBJECTIVE: We investigated the association between maternal n-3, n-6, and trans fatty acids measured early in pregnancy and fetal growth. DESIGN: Amsterdam pregnant women (n = 12 373) were invited to complete a questionnaire (response 67%) and donate blood around the 12th pregnancy week for nutrient analysis. For 4336 women, fatty acid concentrations were measured in plasma phospholipids (gas-liquid chromatography). Associations of these concentrations with birth weight and small-for-gestational-age (SGA) risk were analyzed (liveborn singleton term deliveries, n = 3704). RESULTS: Low concentrations of individual n-3 fatty acids and 20:3n-6, the precursor of arachidonic acid (20:4n-6), but high concentrations of the other n-6 fatty acids and the main dietary trans fatty acid (18:1n-9t) were associated with lower birth weight (estimated difference in univariate analysis -52 to -172 g for extreme quintile compared with middle quintile). In general, SGA risk increased accordingly. After adjustment for physiologic, lifestyle-related and sociodemographic factors, low concentrations of most n-3 fatty acids and 20:3n-6 and high concentrations of 20:4n-6 remained associated with lower birth weight (-52 to -57 g), higher SGA risk, or both (odds ratios: 1.38-1.50). Infants of the 7% of women with the most adverse fatty acid profile were on average 125 g lighter and twice as likely to be small for gestational age. CONCLUSION: An adverse maternal fatty acid profile early in pregnancy is associated with reduced fetal growth, which, if confirmed, gives perspective for the dietary prevention of lower birth weight.

Co-supplementation of healthy women with fish oil and evening primrose oil increases plasma docosahexaenoic acid, gamma-linolenic acid and dihomo-gamma-linolenic acid levels without reducing arachidonic acid concentrations.

Fish oil supplementation during pregnancy not only improves maternal and neonatal DHA status, but often reduces gamma-linolenic acid (GLA), dihomo-GLA (DGLA), and arachidonic acid (ARA) levels also, which may compromise foetal and infant development. The present study investigated the effects of a fish oil/evening primrose oil (FSO/EPO) blend (456 mg DHA/d and 353 mg GLA/d) compared to a placebo (mixture of habitual dietary fatty acids) on the plasma fatty acid (FA) composition in two groups of twenty non-pregnant women using a randomised, double-blind, placebo-controlled parallel design. FA were quantified in plasma total lipids, phospholipids, cholesterol esters, and TAG at weeks 0, 4, 6 and 8. After 8 weeks of intervention, percentage changes from baseline values of plasma total lipid FA were significantly different between FSO/EPO and placebo for GLA (+49.9 % v. +2.1 %, means), DGLA (+13.8 % v. +0.7 %) and DHA (+59.6 % v. +5.5 %), while there was no significant difference for ARA ( - 2.2 % v. - 5.9 %). FA changes were largely comparable between plasma lipid fractions. In both groups three subjects reported mild adverse effects. As compared with placebo, FSO/EPO supplementation did not result in any physiologically relevant changes of safety parameters (blood cell count, liver enzymes). In women of childbearing age the tested FSO/EPO blend was well tolerated and appears safe. It increases plasma GLA, DGLA, and DHA levels without impairing ARA status. These data provide a basis for testing this FSO/EPO blend in pregnant women for its effects on maternal and neonatal FA status and infant development.

Effect of alpha-linolenic acid supplementation during pregnancy on maternal and neonatal polyunsaturated fatty acid status and pregnancy outcome.

BACKGROUND: Maternal essential fatty acid status declines during pregnancy, and as a result, neonatal concentrations of docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6) may not be optimal. OBJECTIVE: Our objective was to improve maternal and neonatal fatty acid status by supplementing pregnant women with a combination of alpha-linolenic acid (ALA, 18:3n-3) and linoleic acid (LA, 18:2n-6), the ultimate dietary precursors of DHA and AA, respectively. DESIGN: From week 14 of gestation until delivery, pregnant women consumed daily 25 g margarine supplying either 2.8 g ALA + 9.0 g LA (n = 29) or 10.9 g LA (n = 29). Venous blood was collected for plasma phospholipid fatty acid analyses at weeks 14, 26, and 36 of pregnancy, at delivery, and at 32 wk postpartum. Umbilical cord blood and vascular tissue samples were collected to study neonatal fatty acid status also. Pregnancy outcome variables were assessed. RESULTS: ALA+LA supplementation did not prevent decreases in maternal DHA and AA concentrations during pregnancy and, compared with LA supplementation, did not increase maternal and neonatal DHA concentrations but significantly increased eicosapentaenoic acid (20:5n-3) and docosapentaenoic acid (22:5n-3) concentrations. In addition, ALA+LA supplementation lowered neonatal AA status. No significant differences in pregnancy outcome variables were found. CONCLUSIONS: Maternal ALA+LA supplementation did not promote neonatal DHA+AA status. The lower concentrations of Osbond acid (22:5n-6) in maternal plasma phospholipids and umbilical arterial wall phospholipids with ALA+LA supplementation than with LA supplementation suggest only that functional DHA status improves with ALA+LA supplementation.

Cholesterol-lowering effect of beta-glucan from oat bran in mildly hypercholesterolemic subjects may decrease when beta-glucan is incorporated into bread and cookies.

BACKGROUND: Findings about the effects of beta-glucan on serum lipoproteins are conflicting. OBJECTIVE: The study investigated the effects of beta-glucan from oat bran in bread and cookies (study 1) and in orange juice (study 2) on serum lipoproteins in mildly hypercholesterolemic subjects. DESIGN: In study 1, 48 subjects (21 men, 27 women) received for 3 wk control bread and cookies rich in wheat fiber. For the next 4 wk, by random assignment, 23 subjects continued to consume the control products, and 25 received bread and cookies rich in beta-glucan. Mean daily intake of beta-glucan was 5.9 g. Total dietary fiber intake did not differ significantly between the groups. In study 2, the same sources of control fiber and beta-glucan (5 g/d) as in study 1 were provided. For 2 wk, 25 of the original 48 subjects (10 men, 15 women) were randomly assigned to consume orange juice containing either wheat fiber (n = 13) or beta-glucan from oat bran (n = 12). After a washout period of 1 wk, dietary regimens were crossed over. RESULTS: In study 1, the change in LDL cholesterol did not differ significantly (-0.12 mmol/L; P = 0.173) between the 2 groups. In study 2, the drink rich in beta-glucan decreased LDL cholesterol by 0.26 +/- 0.07 mmol/L (6.7 +/- 1.8%; P = 0.001) and the ratio of total to HDL cholesterol by 0.26 +/- 0.11 (5.4 +/- 2.1%; P = 0.029) compared with the other drink. HDL-cholesterol and triacylglycerol concentrations did not change significantly. CONCLUSIONS: The food matrix or the food processing, or both, could have adverse effects on the hypocholesterolemic properties of oat beta-glucan.

Effects on the human serum lipoprotein profile of beta-glucan, soy protein and isoflavones, plant sterols and stanols, garlic and tocotrienols.

The effects of beta-glucan, soy protein, isoflavones, plant sterols and stanols, garlic and tocotrienols on serum lipoproteins have been of great interest the last decade. From a critical review of the literature, it appeared that recent studies found positive as well as no effects of beta-glucan from oats on serum LDL cholesterol concentrations. These conflicting results may suggest that the cholesterol-lowering activity of products rich in oat beta-glucan depends on factors, such as its viscosity in the gastrointestinal tract, the food matrix and/or food processing. The effects of beta-glucan from barley or yeast on the lipoprotein profile are promising, but more human trials are needed to further substantiate these effects. It is still not clear whether the claimed hypocholesterolemic effects of soy can be attributed solely to the isoflavones. Several studies found no changes in serum LDL cholesterol concentrations after consumption of isolated soy isoflavones (without soy protein), indicating that a combination of soy protein and isoflavones may be needed for eliciting a cholesterol-lowering effect of soy. Therefore, the exact (combination of) active ingredients in soy products need to be identified. The daily consumption of 2-3 g of plant sterols or stanols reduces LDL cholesterol concentrations by 9-14%. It has been demonstrated that functional foods enriched with plant sterols and stanols are effective in various population groups, and in combination with cholesterol-lowering diets or drugs. Whether garlic or garlic preparations can be used as a lipid-lowering agent is still uncertain. It is important to characterize the active components in garlic and their bioavailability after ingestion. It is not very likely that tocotrienols from palm oil or rice bran oil have favorable effects on the human serum lipoprotein profile.

The n-3 and n-6 polyunsaturated fatty acid composition of plasma phospholipids in pregnant women and their infants. relationship with maternal linoleic acid intake.

The availability of long-chain polyunsaturated fatty acids during infancy has been related to neonatal growth and development. Fatty acid concentration at birth is an important predictor of postnatal level. The primary aim of this study was to provide a description of the distribution of n-3 and n-6 polyunsaturated fatty acids in the plasma phospholipid fraction of pregnant women remaining on a Western-style diet and their neonates. The plasma phospholipid polyunsaturated fatty acid composition was determined by gas-liquid chromatography in 889 mother-infant pairs. Blood samples were taken during the first, second and third trimester of pregnancy, at delivery, and from the umbilical vein at birth. Mean (+/- SD) fatty acid concentrations are reported in mg/l and as percentage of total fatty acids (% wt/wt). In addition, the 10th, 25th, 50th, 75th and 90th percentiles are given. The distribution of docosahexaenoic acid (22:6n-3) and arachidonic acid (20:4n-6) concentrations in umbilical plasma phospholipids is also reported as a function of gestational age and maternal linoleic acid intake during pregnancy. This data can be be used as a reference for future studies and may aid in identifying term infants with a relatively low long-chain polyene status at birth.