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Aims/hypothesis: We examined the acute postprandial effects of meals containing unsaturated fatty acids on flow-mediated dilation (FMD) of the brachial artery and triacylglycerols in individuals with type 2 diabetes. We hypothesised that consumption of omega-3 fatty acids would enhance vascular function. Saturated fat reduces FMD for several hours, but there is inconsistent evidence about whether foods containing unsaturated fats impair FMD acutely. Little is known about the acute effects of omega-3 fatty acids on vascular reactivity. Methods: We measured FMD before and 4 h after 3 test meals (50 g fat, 2,615 kJ) in 18 healthy adults with type 2 diabetes. The monounsaturated fatty acids (MUFA) meal contained 50 g fat from high oleic safflower and canola oils. Two additional meals were prepared by replacing 7% to 8% of MUFA with docosahexaenoic acid and eicosapentaenoic acid from sardine oil or α-linolenic acid from canola oil. Results: In the sample as a whole, FMD was increased 17% at 4 h vs. the fasting baseline. After the MUFA meal, subjects with the largest increases in triacylglycerols had the largest FMD decreases. The opposite pattern was observed after meals containing docosahexaenoic acid and eicosapentaenoic acid or α-linolenic acid. In subjects with high fasting triacylglycerols, meals containing 3 to 5 g of omega-3 fatty acids increased FMD by 50% to 80% and MUFA alone had no significant effects on FMD. Conclusions/ interpretation: Endothelium-dependent vasodilation was not impaired 4 h after meals containing predominantly unsaturated fatty acids. The fatty acid composition of the meal and the metabolic status of the individual determine the vascular effects of a high-fat meal.

Epidemiologic studies have shown a beneficial association between polyunsaturated fatty acid (PUFA), specifically linoleic acid (C18:2, n-6), intake and cardiovascular disease morbidity and mortality. Clinical studies have shown that n-6 PUFAs have the most potent cholesterol-lowering effects of the individual fatty acid classes, and emerging evidence suggests that PUFAs have favorable effects on postprandial lipemia. However, some studies suggest that high intakes of linoleic acid may have adverse effects on proinflammatory cytokines and adhesion molecules. Research is needed to establish the optimal level of dietary PUFAs that maximally affects the greatest number of health risk factors.

Aims/hypothesis. Dysfunction of the vascular endothelium is commonly observed in Type 2 diabetes, and endothelial function may be an important outcome for clinical trials in diabetic samples. However, the most commonly used non-invasive test of endothelial function (flow-mediated dilation [FMD]) is technically challenging to perform, and no previous studies have carefully examined the reproducibility of FMD measurements in individuals with Type 2 diabetes. In this study, we tested the hypothesis that larger day-to-day changes in insulin and glucose are associated with larger fluctuations in FMD. Methods. Ultrasound was used to measure the FMD (% change from baseline diameter) of the brachial artery in 18 healthy adults with Type 2 diabetes on three separate occasions, in the absence of changes to diet, activity level or medications. The CV and mean deviations between pairs of FMD scores in the same individual were used as the primary outcome variables.Results. The CV for FMD (29.7%) was higher than the level traditionally accepted for biochemical assays. However, this CV estimate is within the low range of published values for FMD in healthy individuals. FMD scores were not significantly correlated with glucose or insulin levels. However, subjects with the largest variability in FMD also showed the largest fluctuations in glucose (r=0.52), insulin (r=0.47) and heart rate (r=0.48) (p≤0.05). Conclusions/interpretation. FMD can be reliably measured in individuals with Type 2 diabetes, and population-specific data on reliability is critical for the design of adequately powered studies of endothelial function.Keywords Coefficient of variation · Endothelium-dependent vasodilation · Flow-mediated dilation · Glucose · Heart rate · Insulin resistance · Test-retest reliability · Type 2 diabetes mellitus

Barley contains high levels of soluble dietary fibre, including mixed linked 1→3, 1→4β‐D‐glucans (β‐glucan). An extract of β‐glucan from waxy, hulless barley containing 56% total dietary fibre (TDF) was incorporated into flour tortillas, cornstarch pudding and apple granola bars to provide 2 g soluble fibre as β‐glucan per serving. The foods were tested for objective functional properties. Flour tortillas with β‐glucan were incorporated into rat diets and compared to diets containing an equivalent amount of cellulose, to test the fibre effect on growth and lipid metabolism parameters. Rats fed β‐glucan tortillas had lower feed consumption and body weight (P<0·05) compared to those fed the cellulose tortillas, although feed/gain ratios were not different (P>0·05). Plasma LDL‐cholesterol of rats fed β‐glucan was lower (P<0·05) than cellulose‐fed controls, although total cholesterol and triglycerides did not differ (P>0·05). Rats fed β‐glucan tortillas had higher (P<0·05) faecal fat excretion, suggesting impairment of intestinal fat absorption. Liver composition data showed lower (P<0·05) levels of total lipid and cholesterol in β‐glucan‐fed rats. The results suggest that the barley β‐glucan concentrate has potential as a food ingredient to provide supplemental soluble fibre which may be beneficial in reducing plasma LDL‐cholesterol in humans. © 1998 SCI.

The results suggest that unsaturated fatty acids differentially affect concentrations of apo B-containing lipoprotein subclasses. A rise in LpB:C adversely affects endothelial function. Meals containing MUFA + EPA/DHA attenuated the postprandial rise in LpB:C and the impairment of endothelial function.

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There is a growing database that has evaluated the effects of varying amounts of total fat on risk factors for cardiovascular disease, diabetes and overweight and obesity. The evidence clearly suggests that extremes in dietary fat should be avoided, and instead a diet moderate in total fat (25-35 % energy) is preferable for the majority of individuals. Moreover, we now appreciate the importance of individualizing dietary fat recommendations within this range of total fat. With respect to cardiovascular disease, a diet higher in total fat (30-35 % energy) affects the lipid and lipoprotein risk profile more favourably than a lower-fat diet; this is also the case for individuals with diabetes, with the added benefit of better glycaemic control. Dietary fibre (>25g/d) attenuates and even prevents the potentially adverse lipid and lipoprotein effects of a lower-fat diet. With respect to weight control, a moderate-fat diet can be as, or even more, effective than a lower-fat diet, because of advantages with long-term adherence and potentially favourable effects on lipids and lipoproteins. Thus, there is now a convincing scientific basis to advocate a diet moderate in total fat for the majority of individuals. Implicit to this position is that unsaturated fat has numerous beneficial health effects. However, because fat is energy dense, moderation in fat intake is essential for weight control. Consequently, a simple message to convey is to avoid diets that are very low and very high in fat. Moreover, within the range of a moderate-fat diet it is still important to individualize the total fat prescription. Nonetheless, the guiding principle is that moderation in total fat is the defining benchmark for a contemporary diet that reduces risk of chronic disease. Moderate-fat diet: Lipoprotein metabolism: Health benefits: Cardiovascular disease:Type 2 diabetes: Weight control