Effect of a diet enriched with monounsaturated or polyunsaturated fatty acids on levels of low-density and high-density lipoprotein cholesterol in healthy women and men

Polyunsaturated fatty acids are thought to lower the serum cholesterol level more effectively than monounsaturated fatty acids. It is unclear whether the difference--if any--is due to a lowering of the level of high-density lipoprotein (HDL) or low-density lipoprotein (LDL) cholesterol. We therefore placed 31 women and 27 men on a mixed natural diet rich in saturated fat (19.3 percent of their daily energy intake from saturated fat, 11.5 percent from monounsaturated fat, and 4.6 percent from polyunsaturated fat) for 17 days. For the next 36 days, they received a mixed diet with the same total fat content, but enriched with olive oil and sunflower oil ("monounsaturated-fat diet": 12.9 percent saturated fat, 15.1 percent monounsaturated fat, and 7.9 percent polyunsaturated fat) or with sunflower oil alone ("polyunsaturated-fat diet": 12.6 percent saturated fat, 10.8 percent monounsaturated fat, and 12.7 percent polyunsaturated fat). The serum LDL cholesterol level decreased by 17.9 percent in those on the monounsaturated-fat diet and by 12.9 percent in those on the polyunsaturated-fat diet (95 percent confidence interval for the difference between the effects of the two unsaturated-fat diets, -9.9 percent to 0.0 percent). In men, the HDL cholesterol level fell slightly but not significantly with both diets. In women, the HDL cholesterol level did not change with either. We conclude that a mixed diet rich in monounsaturated fat was as effective as a diet rich in (n-6)polyunsaturated fat in lowering LDL cholesterol. Both diets lowered the level of HDL cholesterol slightly in men but not in women.     

Comparison of a high-carbohydrate diet with a high-monounsaturated-fat diet in patients with non-insulin-dependent diabetes mellitus

We compared a high-carbohydrate diet with a high-fat diet (specifically, a diet high in monounsaturated fatty acids) for effects on glycemic control and plasma lipoproteins in 10 patients with non-insulin-dependent diabetes mellitus (NIDDM) receiving insulin therapy. The patients were randomly assigned to receive first one diet and then the other, each for 28 days, in a metabolic ward. In the high-carbohydrate diet, 25 percent of the energy was in the form of fat and 60 percent in the form of carbohydrates (47 percent of the total energy was in the form of complex carbohydrates); the high-monounsaturated-fat diet was 50 percent fat (33 percent of the total energy in the form of monounsaturated fatty acids) and 35 percent carbohydrates. The two diets had the same amounts of simple carbohydrates and fiber. As compared with the high-carbohydrate diet, the high-monounsaturated-fat diet resulted in lower mean plasma glucose levels and reduced insulin requirements, lower levels of plasma triglycerides and very-low-density lipoprotein cholesterol (lower by 25 and 35 percent, respectively; P less than 0.01), and higher levels of high-density lipoprotein (HDL) cholesterol (higher by 13 percent; P less than 0.005). Levels of total cholesterol and low-density lipoprotein (LDL) cholesterol did not differ significantly in patients on the two diets. These preliminary results suggest that partial replacement of complex carbohydrates with monounsaturated fatty acids in the diets of patients with NIDDM does not increase the level of LDL cholesterol and may improve glycemic control and the levels of plasma triglycerides and HDL cholesterol.     

Reduction of plasma cholesterol levels in normal men on an American Heart Association Step 1 diet or a Step 1 diet with added monounsaturated fat

The design of diets to achieve optimal changes in plasma lipid levels is controversial. In a randomized, double-blind trial involving 36 healthy young men, we evaluated the effects on plasma lipid levels of both an American Heart Association Step 1 diet (in which 30 percent of the total calories were consumed as fat: 10 percent saturated, 10 percent monounsaturated, and 10 percent polyunsaturated fats, with 250 mg of cholesterol per day) and a monounsaturated fat-enriched Step 1 diet (with 38 percent of the calories consumed as fat: 10 percent saturated, 18 percent monounsaturated, and 10 percent polyunsaturated fats, with 250 mg of cholesterol per day). The effects of these diets were then compared with those of an average American diet, in which 38 percent of the total calories were consumed as fat: 18 percent saturated, 10 percent monounsaturated, and 10 percent polyunsaturated fats, with 500 mg of cholesterol per day. The men consumed the average American diet for 10 weeks before random assignment to one of the two Step 1 diets or to continuation of the average diet for an additional 10 weeks. Caloric intake was adjusted to maintain a constant body weight. As compared with the mean (+/- SD) change in the plasma total cholesterol level in the group that followed the average American diet throughout the study (-0.05 +/- 0.36 mmol per liter), there were statistically significant reductions (P less than 0.025) in the plasma total cholesterol level in the group on the Step 1 diet (-0.37 +/- 0.27 mmol per liter) and in the group on the monounsaturated fat-enriched Step 1 diet (-0.46 +/- 0.36 mmol per liter). There were parallel reductions in the plasma low-density lipoprotein cholesterol levels in these two groups. Neither the plasma triglyceride levels nor the high-density lipoprotein cholesterol concentrations changed significantly with any diet. We conclude that enrichment of the Step 1 diet with monounsaturated fat does not alter the beneficial effects of the Step 1 diet on plasma lipid concentrations.     

Effects of different forms of dietary hydrogenated fats on serum lipoprotein cholesterol levels.

BACKGROUND: Metabolic studies suggest that fatty acids containing at least one double bond in the trans configuration, which are found in hydrogenated fat, have a detrimental effect on serum lipoprotein cholesterol levels as compared with unsaturated fatty acids containing double bonds only in the cis configuration. We compared the effects of diets with a broad range of trans fatty acids on serum lipoprotein cholesterol levels. METHODS: Eighteen women and 18 men consumed each of six diets in random order for 35-day periods. The foods were identical in each diet, and each diet provided 30 percent of calories as fat, with two thirds of the fat contributed as soybean oil (<0.5 g of trans fatty acid per 100 g of fat), semiliquid margarine (<0.5 g per 100 g), soft margarine (7.4 g per 100 g), shortening (9.9 g per 100 g), or stick margarine (20.1 g per 100 g). The effects of those diets on serum lipoprotein cholesterol, triglyceride, and apolipoprotein levels were compared with those of a diet enriched with butter, which has a high content of saturated fat. RESULTS: The mean (+/-SD) serum low-density lipoprotein (LDL) cholesterol level was 177+/-32 mg per deciliter (4.58+/-0.85 mmol per liter) and the mean high-density lipoprotein (HDL) cholesterol level was 45+/-10 mg per deciliter (1.2+/-0.26 mmol per liter) after subjects consumed the butter-enriched diet. The LDL cholesterol level was reduced on average by 12 percent, 11 percent, 9 percent, 7 percent, and 5 percent, respectively, after subjects consumed the diets enriched with soybean oil, semiliquid margarine, soft margarine, shortening, and stick margarine; the HDL cholesterol level was reduced by 3 percent, 4 percent, 4 percent, 4 percent, and 6 percent, respectively. Ratios of total cholesterol to HDL cholesterol were lowest after the consumption of the soybean-oil diet and semiliquid-margarine diet and highest after the stick-margarine diet. CONCLUSIONS: Our findings indicate that the consumption of products that are low in trans fatty acids and saturated fat has beneficial effects on serum lipoprotein cholesterol levels.     

Effect of dietary stearic acid on plasma cholesterol and lipoprotein levels

We studied the metabolic effects of stearic acid (18:0) on plasma lipoprotein levels in 11 subjects during three dietary periods of three weeks each. The three liquid-formula diets, which were used in random order, were high in palmitic acid (16:0), stearic acid, and oleic acid (18:1), respectively. Caloric intakes were the same during the three periods. As compared with the values observed when the subjects were on the high-palmitic-acid diet, plasma total cholesterol decreased by an average of 14 percent during consumption of the high-stearic-acid diet (P less than 0.005) and by 10 percent during consumption of the high-oleic-acid diet (P less than 0.02). Low-density lipoprotein cholesterol levels fell by 21 percent in subjects on the high-stearic-acid diet (P less than 0.005) and by 15 percent in subjects on the high-oleic-acid diet (P less than 0.005). No significant differences were observed in the plasma levels of triglycerides or high-density lipoprotein cholesterol among the three diets. Measurements of the intestinal absorption of palmitic, stearic, and oleic acids revealed essentially complete absorption of each during the three dietary periods. The oleic acid content of plasma triglycerides and cholesteryl esters increased significantly during the high-stearic-acid period, suggesting that stearic acid is rapidly converted to oleic acid. We conclude that stearic acid appears to be as effective as oleic acid in lowering plasma cholesterol levels when either replaces palmitic acid in the diet.     

Effect of dietary trans fatty acids on high-density and low-density lipoprotein cholesterol levels in healthy subjects

BACKGROUND. Fatty acids that contain a trans double bond are consumed in large amounts as hydrogenated oils, but their effects on serum lipoprotein levels are unknown. METHODS. We placed 34 women (mean age, 26 years) and 25 men (mean age, 25 years) on three mixed natural diets of identical nutrient composition, except that 10 percent of the daily energy intake was provided as oleic acid (which contains one cis double bond), trans isomers of oleic acid, or saturated fatty acids. The three diets were consumed for three weeks each, in random order. RESULTS. On the oleic acid diet, the mean (+/- SD) serum values for the entire group for total, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol were 4.46 +/- 0.66. 2.67 +/- 0.54, and 1.42 +/- 0.32 mmol per liter (172 +/- 26, 103 +/- 21, and 55 +/- 12 mg per deciliter), respectively. On the trans-fatty-acid diet, the subjects' mean HDL cholesterol level was 0.17 mmol per liter (7 mg per deciliter) lower than the mean value on the diet high in oleic acid (P less than 0.0001; 95 percent confidence interval, 0.13 to 0.20 mmol per liter). The HDL cholesterol level on the saturated-fat diet was the same as on the oleic acid diet. The LDL cholesterol level was 0.37 mmol per liter (14 mg per deciliter) higher on the trans-fatty-acid diet than on the oleic acid diet (P less than 0.0001; 95 percent confidence interval, 0.28 to 0.45 mmol per liter) and 0.47 mmol per liter (18 mg per deciliter) higher on the saturated-fat diet (P less than 0.001; 95 percent confidence interval, 0.39 to 0.55 mmol per liter) than on the oleic acid diet. The effects on lipoprotein levels did not differ between women and men. CONCLUSIONS. The effect of trans fatty acids on the serum lipoprotein profile is at least as unfavorable as that of the cholesterol-raising saturated fatty acids, because they not only raise LDL cholesterol levels but also lower HDL cholesterol levels.     

Fatty acids in cardiovascular health and disease: a comprehensive update

Research dating back to the 1950s reported an association between the consumption of saturated fatty acids (SFAs) and risk of coronary heart disease. Recent epidemiological evidence, however, challenges these findings. It is well accepted that the consumption of SFAs increases low-density lipoprotein cholesterol (LDL-C), whereas carbohydrates, monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs) do not. High-density lipoprotein (HDL)-C increases with SFA intake. Among individuals who are insulin resistant, a low-fat, high-carbohydrate diet typically has an adverse effect on lipid profiles (in addition to decreasing HDL-C, it also increases triglyceride and LDL particle concentrations). Consequently, a moderate fat diet in which unsaturated fatty acids replace SFAs and carbohydrates are not augmented is advised to lower LDL-C; compared with a low-fat diet, a moderate-fat diet will lower triglycerides and increase HDL-C. Now, there is some new evidence that is questioning the health benefits of even MUFAs and PUFAs. In addition, in a few recent studies investigators have also failed to demonstrate expected cardiovascular benefits of marine-derived omega-3 fatty acids. To clarify the clinical pros and cons of dietary fats, the National Lipid Association held a fatty acid symposium at the 2011 National Lipid Association Scientific Sessions. During these sessions, the science regarding the effects of different fatty acid classes on coronary heart disease risk was reviewed.     

Use of complementary/alternative therapies by women with advanced-stage breast cancer

Background

Fermented milk products have been shown to affect serum cholesterol concentrations in humans. Kefir, a fermented milk product, has been traditionally consumed for its potential health benefits but has to date not been studied for its hypocholesterolemic properties.

Methods

Thirteen healthy mildly hypercholesterolemic male subjects consumed a dairy supplement in randomized crossover trial for 2 periods of 4 wk each. Subjects were blinded to the dairy supplement consumed. Blood samples were collected at baseline and after 4 wk of supplementation for measurement of plasma total, low-density lipoprotein, and high-density lipoprotein cholesterol and triglyceride concentrations, as well as fatty acid profile and cholesterol synthesis rate. Fecal samples were collected at baseline and after 2 and 4 wk of supplementation for determination of fecal short chain fatty acid level and bacterial content.

Results

Kefir had no effect on total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol or triglyceride concentrations nor on cholesterol fractional synthesis rates after 4 wk of supplementation. No significant change on plasma fatty acid levels was observed with diet. However, both kefir and milk increased (p < 0.05) fecal isobutyric, isovaleric and propionic acids as well as the total amount of fecal short chain fatty acids. Kefir supplementation resulted in increased fecal bacterial content in the majority of the subjects.

Conclusions

Since kefir consumption did not result in lowered plasma lipid concentrations, the results of this study do not support consumption of kefir as a cholesterol-lowering agent.     

Nibbling versus gorging: metabolic advantages of increased meal frequency

We studied the effect of increasing the frequency of meals on serum lipid concentrations and carbohydrate tolerance in normal subjects. Seven men were assigned in random order to two metabolically identical diets. One diet consisted of 17 snacks per day (the nibbling diet), and the other of three meals per day (the three-meal diet); each diet was followed for two weeks. As compared with the three-meal diet, the nibbling diet reduced fasting serum concentrations of total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein B by a mean (+/- SE) of 8.5 +/- 2.5 percent (P less than 0.02), 13.5 +/- 3.4 percent (P less than 0.01), and 15.1 +/- 5.7 percent (P less than 0.05), respectively. Although the mean blood glucose level and serum concentrations of free fatty acids, 3-hydroxybutyrate, and triglyceride were similar during both diets, during the nibbling diet the mean serum insulin level decreased by 27.9 +/- 6.3 percent (P less than 0.01) and the mean 24-hour urinary C-peptide output decreased by 20.2 +/- 5.6 percent (P less than 0.02). In addition, the mean 24-hour urinary cortisol excretion was lower by 17.3 +/- 5.9 percent (P less than 0.05) at the end of the nibbling diet than at the end of the three-meal diet. The blood glucose, serum insulin, and C-peptide responses to a standardized breakfast and the results of an intravenous glucose-tolerance test conducted at the end of each diet were similar. We conclude that in addition to the amount and type of food eaten, the frequency of meals may be an important determinant of fasting serum lipid levels, possibly in relation to changes in insulin secretion.     

Lower high-density lipoprotein cholesterol and increased omega-6 polyunsaturated fatty acids in first-degree relatives of bipolar patients

BACKGROUND: Lower serum high-density lipoprotein cholesterol and increased ratio of omega-6/omega-3 fatty acids have been reported in unipolar and bipolar depressed patients. Changes in cholesterol and fatty acids have been suggested to affect membrane viscosity and consequently serotonergic neurotransmitter expression. The goal of this study was to investigate whether lower baseline cholesterol and increased omega-6 and lower omega-3 fatty acids are present in healthy first-degree relatives of bipolar patients compared with controls and whether these changes were associated with neuroendocrine responses to an i.v. tryptophan challenge or mood. METHOD: Baseline cholesterol, fatty acids and mood were determined in healthy first-degree relatives of patients with bipolar disorders (N = 30) and healthy matched controls (N = 15) (parallel-group design). Prolactin and cortisol were measured following tryptophan infusion. RESULTS: First-degree relatives showed significantly lower plasma high-density lipoprotein cholesterol and increased total omega-6 fatty acids in phospholipids. Lower total omega-3 and higher total omega-6 fatty acids in phospholipids were positively correlated with peak prolactin response to tryptophan. Lower total omega-3 fatty acids in phospholipids and cholesteryl esters were associated with lower mood. CONCLUSIONS: Abnormalities of lower plasma high-density lipoprotein cholesterol and increased total omega-6 fatty acids in phospholipids in these subjects are in agreement with findings in bipolar and major depressed patients. Changes in fatty acids show an association with central serotonergic parameters. It is suggested that these abnormalities in cholesterol and fatty acids may constitute a trait marker for bipolar disorders.     

Fat intake in patients newly diagnosed with type 2 diabetes: a 4-year follow-up study in general practice.

BACKGROUND: Although treatment targets for the consumption of dietary fat in patients with type 2 diabetes mellitus are well accepted, little is known about the actual fat consumption by newly diagnosed patients or the dietary adjustments that they make in the following years. AIMS: To measure fat intake in patients with type 2 diabetes in general practice at diagnosis, shortly after dietary consultation, and after 4 years. DESIGN OF STUDY: A prospective cohort study. SETTING: Thirty-three general practices in The Netherlands. METHOD: One hundred and forty-four patients with newly diagnosed type 2 diabetes were referred to a dietician, and fat consumption (the main outcome measure) was assessed with a 104-item food frequency questionnaire at diagnosis, 8 weeks following diagnosis, and after 4 years. Reference values for fat consumption were obtained from an age-matched sample of a population-based survey. RESULTS: At diagnosis, total energy intake was 10.6 MJ/day and cholesterol intake was 300 mg/day. Total fat consumption was 40.9% of energy intake, with saturated fatty acids 15.0%, monounsaturated fatty acids 14.3%, and polyunsaturated fatty acids 9.2% of energy intake. All levels, except for polyunsaturated fatty acids, were significantly unfavourable compared with those for the general population. After 8 weeks, consumption of saturated fatty acids had decreased to a lower level than in the general population and all other levels measured were similar to those for the general population. After 4 years there was a slight increase in the consumption of total fat and monounsaturated fatty acids, but cholesterol and saturated fatty acid consumption had decreased further. CONCLUSIONS: Patients with newly diagnosed type 2 diabetes have an unfavourable fat consumption at diagnosis. They adapt to a more desirable consumption shortly after diagnosis, and this improved dietary behaviour is sustained for 4 years. Recommendations regarding consumption of total and saturated fat are, in contrast to those for cholesterol, not met by patients in general practice.     

Dietary herring improves plasma lipid profiles and reduces atherosclerosis in obese low-density lipoprotein receptor-deficient mice

Diet is a significant modifiable risk factor for cardiovascular disease and high fish intake has been associated with vascular health in population studies. However, intervention studies have been inconclusive. In this study, male low-density lipoprotein receptor-deficient mice were given 16-week high fat/high sucrose diets, supplemented with either minced herring fillets or minced beef. The diets were matched in total fat and cholesterol content; taurine content and fatty acid composition was analysed. Body weights were recorded throughout the study; plasma lipids were analysed at week 8 and 16. Body composition and adipocyte size were evaluated at study end. Atherosclerosis was evaluated at week 12 (ultrasound) and at termination (en?face histology). Herring-fed mice had a higher proportion of long-chain n-3 polyunsaturated fatty acids in the hepatic triacylglycerides (TAG) and phospholipid fractions. The herring-fed mice had increased body weight (P=0.007), and reduced epididymal adipocyte size (P=0.009), despite similar food intake and body composition as the beef-fed mice. The herring-fed mice had lower plasma TAG and very-low-density lipoprotein (VLDL)-cholesterol concentrations throughout the study (TAG; P=0.0012 and 0.004, VLDL-cholesterol; P=0.006 and 0.041, week 8 and 16, respectively). At week 16, the herring-fed had higher plasma concentrations of HDL-cholesterol (P=0.004) and less atherosclerotic lesions in the aortic arch (P=0.007) compared with the beef-fed mice. In conclusion, dietary herring in comparison to beef markedly improved vascular health in this mouse model, suggesting that herring provides an added value beyond its content of macronutrients.     

Moringa oleifera-based diet protects against nickel-induced hepatotoxicity in rats

Multiple health-promoting effects have been attributed to the consumption of Moringa oleifera leaves, as part of diet without adequate scientific credence. This study evaluated the effect of M. oleifera-based diets on nickel (Ni) - induced hepatotoxicity in rats. Male rats assigned into six groups were given oral administration of 20 mg/kg body weight nickel sulfate in normal saline and either fed normal diet or M. oleifera-based diets for 21 days. All animals were sacrificed under anesthesia 24 hours after the last treatment. Ni exposure elevated the rat plasma activities of alanine transaminase, aspartate transaminase and alkaline phosphatase significantly. Ni exposure also raised the levels of triglyceride, total cholesterol and low-density lipoprotein cholesterol while depleting the high-density lipoprotein cholesterol concentration. Further, Ni exposure raised rat plasma malondialdehyde but depleted reduced glutathione concentrations. The histopathological presentations revealed inflammation and cellular degeneration caused by Ni exposure. We show evidence that M. oleifera-based diets protected against Ni-induced hepatotoxicity by improving the rat liver function indices, lipid profile as well as restoring cellular architecture and integrity. Study lends credence to the health-promoting value of M. oleifera as well as underscores its potential to attenuate hepatic injury.     

Reduction of plasma lipids, lipoproteins, and apoproteins by dietary fish oils in patients with hypertriglyceridemia

Dietary fish oils, which are rich in omega-3 fatty acids, have been reported to reduce plasma lipid levels in normolipidemic subjects. We examined the effects of fish oil in 20 hypertriglyceridemic patients: 10 with Type IIb hyperlipidemia and 10 with Type V. These patients were put on three diets differing primarily in fatty acid composition and fat content. The control diet contained a fatty acid mixture typical of a low-fat therapeutic diet (ratio of polyunsaturated to saturated fat, 1.4), the fish-oil diet contained omega-3 fatty acids, and the vegetable-oil diet was rich in the omega-6 fatty acid, linoleic acid. Each diet was followed for four weeks. In the Type IIb group, the fish-oil diet led to decreases in both plasma cholesterol (-27 per cent) and triglyceride (-64 per cent), as compared with the control diet. Very-low-density lipoproteins (VLDLs) were also reduced markedly. The vegetable-oil diet had much less effect. With fish oil, the Type V group had marked decreases in total cholesterol and triglyceride levels (-45 and -79 per cent, respectively). VLDL levels were dramatically lowered, as were apoprotein E levels. The vegetable-oil diet (unlike the fish-oil diet) produced a rapid and significant rise in plasma triglyceride levels. We conclude that fish oils and fish may be useful components of diets for the treatment of hypertriglyceridemia.     

Diet induced changes in sympatho-adrenal activity during submaximal exercise in relation to substrate utilization in man

In order to study how the diet may influence sympatho-adrenal activity during exercise, 7 subjects were examined at rest and during submaximal exercise (25 min at 65% of VO2 max) on two occasions. The first occasion was preceded by 5 days on a carbohydrate poor diet (5% carbohydrate, 72% fat and 23% protein) and the second one by 5 days on a carbohydrate rich diet (78% carbohydrate, 8% fat and 14% protein) with the same energy content. Oxygen uptake, respiratory exchange ratio (R), heart rate and arterial plasma concentrations of adrenaline, noradrenaline, dopamine, insulin, glucose, lactate, free fatty acids (FFA), glycerol and beta-hydroxybutyrate were measured at rest and during exercise. Oxygen uptake and heart rate during exercise were higher and R was lower after the carbohydrate poor than after the carbohydrate rich diet. During exercise the arterial plasma concentrations of FFA, glycerol and beta-hydroxybutyrate were higher after the carbohydrate poor than after the carbohydrate rich diet whereas concentrations of insulin and lactate were lower. At rest arterial plasma noradrenaline and adrenaline levels were similar on the two diets (0.70 +/- 0.31 nM noradrenaline and 0.35 +/- 0.32 nM adrenaline one the carbohydrate rich diet, mean values +/- SD). Exercise induced increases in noradrenaline were more pronounced after the carbohydrate poor than after the carbohydrate rich diet (12.42 +/- 3.41 vs. 7.45 +/- 2.68 at 25 min of exercise, p less than 0.001). A similar, although more variable accentuation of exercise induced increases in adrenaline was found. It is concluded that, when compared to a carbohydrate rich diet, a carbohydrate poor diet increases the relative contribution of fat to oxidative metabolism and increases the sympatho-adrenal response to exercise. Stimulation of lipolysis by sympatho-adrenal mechanisms might be of importance for the substrate availability when carbohydrate intake in low.     

Ability of omega-3 fatty acids to restore the impaired glucose tolerance in a mouse model for type-2 diabetes. Different effects in male and female mice

Mice of both sexes were fed diets with 80 per cent animal or vegetable fat for 3 months. Half of the animals also received SuperEPA, which contains 61% omega-3 fatty acids. At the end of the feeding period the mice receiving animal fat had gained more weight than the controls and the mice receiving vegetable fat, and all fat diet groups, irrespective of sex or kind of diet, had become hyperglycaemic and had impaired intravenous glucose tolerance. The decay in plasma glucose during the tolerance tests was, however, significantly slower in the groups getting animal fat than in the groups getting vegetable fat. Supplementation with omega-3 fatty acids only affected the male mice receiving the animal fat diet. Thus, these mice gained less weight, and both the hyperglycaemia and the impairment of the glucose tolerance were significantly less pronounced in this group than in the male mice fed animal fat without SuperEPA. In the groups eating fat diets, the plasma total cholesterol levels increased 50-100 per cent during the first 2 weeks of the experiment and then plateaued. In both sexes HDL-cholesterol averaged approx. sixty-five per cent of the total cholesterol content at the start of the experiment and was not changed significantly during the feeding period. It is concluded, that omega-3 fatty acids do not seem to be suitable as a general means of ameliorating impaired glucose tolerance. It is further suggested that the fat-fed mouse may be a useful animal model for further studies of the regulation of metabolism in type-2 diabetes.     

Saturated fats and cardiovascular health: Current evidence and controversies

A diet high in saturated fatty acids (SFA) is a suspected contributor to atherosclerotic cardiovascular disease (ASCVD) risk, in large part because of an effect to raise the low-density lipoprotein cholesterol (LDL-C) concentration. Most dietary guidance from health authorities advocates limiting intake of SFA, particularly for people with clinical ASCVD, dyslipidemia, or diabetes mellitus. However, recent reviews have highlighted controversies regarding SFA intake and cardiovascular health. This brief editorial commentary includes a discussion of the evidence regarding SFA intake and cardiovascular health, outlines gaps in the available evidence, and proposes tentative conclusions based on what is known today about SFA consumption and ASCVD risk. Results from observational studies demonstrate that dietary patterns with lower average intakes of SFA are associated with favorable cardiovascular outcomes. Additionally, although the number of randomized controlled trials testing the effects of reducing SFA intake on ASCVD outcomes is limited, the available evidence supports the view that replacing SFA with unsaturated fatty acids, particularly polyunsaturated fatty acids, may reduce ASCVD risk. Beyond raising LDL-C and atherogenic lipoprotein particle concentrations, higher intakes of SFA may influence pathways affecting inflammation, cardiac rhythm, hemostasis, apolipoprotein CIII production, and high-density lipoprotein function. However, the impacts of these effects on ASCVD risk remain uncertain. In the authors’ view, the totality of the evidence supports the current recommendation to limit SFA intake to <10% of total daily energy for the general healthy population and further (e.g., to 5-6% of total daily energy) for patients with hypercholesterolemia.     

Changes in lipid and lipoprotein levels and body weight in Tarahumara Indians after consumption of an affluent diet

BACKGROUND. Major new public health problems occur in developing countries as they become more affluent and change their traditional dietary patterns. To study this phenomenon in microcosm, we substituted an "affluent" diet for the traditional diet of a group of Tarahumara Indians, a Mexican people known to consume a low-fat, high-fiber diet and to have a very low incidence of risk factors for coronary heart disease. METHODS. Thirteen Tarahumara Indians (five women and eight men [including one adolescent]) consumed their traditional diet (2700 kcal per day) for one week, and were then fed a diet typical of affluent societies, which contained excessive calories (4100 kcal per day), total fat, saturated fat, and cholesterol, for five weeks. RESULTS. After five weeks of consuming the affluent diet, the subjects' mean (+/- SE) plasma cholesterol level increased by 31 percent, from 121 +/- 5 to 159 +/- 6 mg per deciliter (3.13 +/- 0.13 to 4.11 +/- 0.16 mmol per liter, P less than 0.001). The increase in the plasma cholesterol level was primarily in the low-density lipoprotein (LDL) fraction, which rose 39 percent, from 72 +/- 3 to 100 +/- 4 mg per deciliter (1.86 +/- 0.08 to 2.59 +/- 0.10 mmol per liter, P less than 0.001). High-density lipoprotein (HDL) cholesterol, usually low in this population, increased by 31 percent, from 32 +/- 2 to 42 +/- 3 mg per deciliter (0.83 +/- 0.05 to 1.09 +/- 0.08 mmol per liter). Consequently, the ratio of LDL to HDL levels changed little (2.25 with the base-line diet and 2.38 with the affluent diet). Plasma triglyceride levels increased by 18 percent, from 91 +/- 8 to 108 +/- 11 mg per deciliter (1.03 +/- 0.09 to 1.22 +/- 0.12 mmol per liter, P less than 0.05), with a significant increase in the very-low-density lipoprotein triglyceride fraction. All the subjects gained weight, with a mean increase of 3.8 kg (7 percent). CONCLUSIONS. When Tarahumara Indians from a population with virtually no coronary risk factors consumed for a short time a hypercaloric diet typical of a more affluent society, they had dramatic increases in plasma lipid and lipoprotein levels and body weight. If sustained, such changes might increase their risk of coronary heart disease.     

Circulating immune cell activation and diet: A review on human trials

Protein energy malnutrition is the main cause of immunodeficiency and, secondarily, of several infections. However, immune cell activation is involved in several pathophysiological processes that play a crucial role in the appearance of cardiovascular disease(CVD) or cancer. The aim of this review is to update the knowledge of the modulation of immune cell activation by different dietary patterns and its components focusing on CVD or cancer. While a westernized high-saturated fat highcarbohydrate diet is positively associated with lowgrade inflammation, vegetable- and fruit-based diets rich in monounsaturated fatty acids, polyunsaturated fatty acids and polyphenols, key nutrients of Mediterranean diet, decrease the levels of cellular and circulating inflammatory biomarkers thereby reducing the risk of related chronic diseases.     

Beneficial effects of high dietary fiber intake in patients with type 2 diabetes mellitus

BACKGROUND: The effect of increasing the intake of dietary fiber on glycemic control in patients with type 2 diabetes mellitus is controversial. METHODS: In a randomized, crossover study, we assigned 13 patients with type 2 diabetes mellitus to follow two diets, each for six weeks: a diet containing moderate amounts of fiber (total, 24 g; 8 g of soluble fiber and 16 g of insoluble fiber), as recommended by the American Diabetes Association (ADA), and a high-fiber diet (total, 50 g; 25 g of soluble fiber and 25 g of insoluble fiber), containing foods not fortified with fiber (unfortified foods). Both diets, prepared in a research kitchen, had the same macronutrient and energy content. We compared the effects of the two diets on glycemic control and plasma lipid concentrations. RESULTS: Compliance with the diets was excellent. During the sixth week, the high-fiber diet, as compared with the the sixth week of the ADA diet, mean daily preprandial plasma glucose concentrations were 13 mg per deciliter [0.7 mmol per liter] lower (95 percent confidence interval, 1 to 24 mg per deciliter [0.1 to 1.3 mmol per liter]; P=0.04) and mean median difference, daily urinary glucose excretion 1.3 g (0.23; 95 percent confidence interval, 0.03 to 1.83 g; P= 0.008). The high-fiber diet also lowered the area under the curve for 24-hour plasma glucose and insulin concentrations, which were measured every two hours, by 10 percent (P=0.02) and 12 percent (P=0.05), respectively. The high-fiber diet reduced plasma total cholesterol concentrations by 6.7 percent (P=0.02), triglyceride concentrations by 10.2 percent (P=0.02), and very-low-density lipoprotein cholesterol concentrations by 12.5 percent (P=0.01). CONCLUSIONS: A high intake of dietary fiber, particularly of the soluble type, above the level recommended by the ADA, improves glycemic control, decreases hyperinsulinemia, and lowers plasma lipid concentrations in patients with type 2 diabetes.