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We compared the effects of a diet in which [nearly equal to]25% of the carbohydrate was replaced by high-amylose starch with those of a similar diet high in oat bran or low-amylose starch in 23 hypertriglyceridemic subjects who were overweight mostly because of abdominal adiposity. Each diet was consumed for 4 wk in random order and in a crossover fashion. Overall, the diets were high in carbohydrate (> 55% of energy) and low in fat (< 30% of energy); the amount of resistant starch in the foods containing high-amylose starch was 17 g in women and 25 g in men. The metabolic effects of specific starches on plasma lipids, fasting and postprandial glucose and insulin profiles, and bowel function were assessed at the end of each intervention. Plasma triacylglycerols (triglycerides) were significantly lower after the oat bran diet than after the other two diets (P < 0.02). No other effects on fasting plasma lipids, glucose, or insulin were noted. However, when the high-amylose starch comprised 33% of the carbohydrate content in a test meal, there was a significant but biologically small reduction in the overall postprandial plasma insulin concentration by 17% relative to the low-amylose diet (P < 0.01). Both the oat bran and the high-amylose diet resulted in an increased frequency of bowel actions and lower fecal pH (P < 0.02) relative to the low-amylose diet. However, unlike the oat bran diet, the high-amylose diet increased short-chain fatty acid concentrations in fecal water by 32% (P < 0.001).

Dietary cholesterol appears to be associated with long-term cardiovascular risk even after its potential for cholesterol elevation has been accounted for, but the mechanism is unknown. Our aim in this study was to determine the postprandial lipoprotein changes after a high-cholesterol load (equal to about three eggs) eaten with a low-fat meal by three phenotypic groups [normal, high low-density-lipoprotein (LDL)-cholesterol concentration, and high plasma triacylglycerol concentration] and compare them with the changes seen after a low-fat meal without cholesterol. Twenty-one normolipidemic and hyperlipidemic men and women were studied on two occasions after a single meal, one containing 19 g fat and 700 mg cholesterol, the other containing a similar amount of fat but no cholesterol. Their plasma interrnediate-density lipoproteins (IDLs), LDLs, and high-density lipoproteins (HDLs) were separated by isopycnic ultracentrifugation. The addition of 700 mg cholesterol to the meal increased the amount of cholesterol and triacylglycerol in the large triacylglycerol-rich lipoproteins ([S.sub.f] > 1000), particularly in the hypertriacylglycerolemic group (P = 0.02, fat meal compared with fat and cholesterol meal). In the hypertriacylglycerolemic group the normal fall in HDL cholesterol after a fat meal was reduced by 87% (P = 0.02, fat meal compared with fat and cholesterol meal). Both of these changes may be atherogenic. There was no increase in any candidate atherogenic particle (eg, small very-low-density lipoprotein, IDL, or LDL) with the acute dietary cholesterol load. Thus, dietary cholesterol does not acutely alter postprandial lipoproteins to produce a more atherogenic profile except possibly in hypertriacylglycerolemic subjects.

Intake of milk and butter has been clearly associated with higher coronary heart disease rates in different countries and this is likely to be mediated by the hypercholesterolemic effect of dairy fat. Fat-modified dairy products are an innovation involving a technology in which protected unsaturated lipids are fed to ruminants resulting in milk and tissue lipids with reduced saturated fatty acids. We examined the impact of these novel dairy fats on plasma lipids in a human dietary trial. Thirty-three men and women participated in an 8-wk randomized crossover trial comparing fat-modified with conventional dairy products. The trial consisted of a 2-wk low-fat baseline period followed by two 3-wk intervention phases. During the test periods, the fat-modified products resulted in a significant 0.28-mmol/L (4.3%) lowering of total cholesterol (P < 0.001). Most of this decrease was in LDL cholesterol, which decreased by 0.24 mmol/L (P < 0.001) whereas HDL cholesterol and triacylglycerols remained essentially unchanged. This alteration in the fatty acid profile of dairy products, if applied to populations typical of developed Western countries, represents a potential strategy to lower the risk of coronary heart disease without any appreciable change in customary eating patterns.

Sixteen normolipidemic male volunteers aged 41 [+ or -] 9 y ([x or -] [+ or -] SD) consumed a diet providing 36% of energy as fat (92 g fat/d) for 9 wk. A daily supplement of nuts (providing half of the total fat intake) was provided against a common background diet. In the first 3-wk period the background diet was supplemented with raw peanuts (50 g/d), coconut cubes (40 g/d), and a coconut confectionary bar (50 g/d), designed to provide 47 g fat with a ratio of polyunsaturated to monounsaturated to saturated fatty acids (P:M:S) to match the Australian diet (reference diet). During the following 3 wk the background diet was supplemented with monounsaturated fatty acid-rich raw almonds (84 g/d), equivalent to 46 g fat, and during the final 3-wk period the background diet was supplemented with polyunsaturated fatty acid-rich walnuts (68 g/d), equivalent to 46 g fat. Compared with the reference diet there were significant reductions in total and LDL cholesterol, 7% and 10%, and respectively, after supplementation with almonds, and 5% and 9%, respectively, after supplementation with walnuts.

Low-density-lipoprotein (LDL) oxidation was examined in 22 subjects (10 men, 12 women) after a daily dose of 18 mg [beta]-carotene, 900 mg vitamin C, and 200 mg [alpha]-tocopherol for 6 mo. Control subjects (12 men, 11 women) took no vitamin supplements. After 3-mo supplementation plasma concentrations of [beta]-carotene, [alpha]-tocopherol, and ascorbic acid increased fivefold (P < 0.001), 55% (P < 0.01), 27% (P < 0.05), respectively. There was no difference from baseline in rate of oxidation or total amount of conjugated diene produced between subjects taking or not taking vitamins. Malondialdehyde in LDL before and after oxidation was not different between the two groups. Lag time before the onset of oxidation was significantly lengthened after antioxidant supplementation (28% and 35% after 3 and 6 mo, respectively, P < 0.001). There was a significant independent correlation between percent change in lag time and percent change in plasma [alpha]-tocopherol (r = 0.47, P < 0.01).

Low-density lipoprotein (LDL) oxidation was measured in vitro to determine intraindividual variability and to relate oxidation to linoleic acid enrichment. Intraindividual variability was determined for eight subjects on 3 consecutive days after 14 d on a fixed diet. Coefficients of variation were 7.49 [+ or -] 1.50%, 6.58 [+ or -] 1.16%, and 4.58 [+ or -] 0.77% for oxidation rate, lag time, and diene concentration, respectively. In the second study 12 normolipidemic men consumed a daily diet supplement containing 35 g linoleate-rich oil in one period and 35 g oleate-rich oil in the other period (2 X 3 wk crossover). LDL oxidized faster after the linoleate diet than after the oleate diet (x [+ or -] SE: 16.42 [+ or -] 0.85 and 13.16 [+ or -] 0.68 nmol diene . mg LDL [protein.sup.1] . [min.sup.1], respectively, P < 0.02) and produced more conjugated diene (416 [+ or -] 12.60 and 379.29 [+ or -] 11.06 nmol/mg protein, respectively, P < 0.05) in proportion to the increase in LDL linoleate (r = 0.698, P < 0.001 and r = 0.618, P < 0.01 for rate and diene concentration, respectively). Lag time before onset of oxidation was not significantly altered by the linoleate-rich diet. Am J Clin Nutr 1993;57:391-8.

Many studies have documented the relationship between blood cholesterol levels and the risk of coronary heart disease. It is now evident that diet can influence blood cholesterol levels, and in this way may alter the risk of developing heart disease. Epidemiological studies have reported that the incidence of heart disease is lower in Japanese populations and Eskimos than in other populations. The Japanese and Eskimo diets contain larger amounts of fish than the typical Western diet. Several studies have shown that diets containing fish and fish oil can lower blood cholesterol levels. It has been suggested that eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), called n-3 fatty acids because of their chemical structure, are responsible for the cholesterol-lowering effect of fish. Previous studies have shown that n-3 fatty acids can reduce blood pressure, blood cholesterol and blood clot formation. To compare the effects of fish with the effects of fish oil on blood pressure, blood cholesterol and blood clot formation, 25 men with mildly elevated blood cholesterol levels were studied. Twelve of the men followed a five-week diet containing fish, 13 received fish oil (EPA and DHA), and six followed a similar diet with no fish or fish oil. The fish and fish oil lowered blood triglycerides by 20 percent and 28 percent, respectively, and very-low-density-lipoprotein (VLDL) was reduced by 42 percent and 52 percent, respectively. High-density-lipoprotein (HDL) cholesterol (thought to protect against heart disease) was increased by 10 percent and 9 percent by fish and fish oil, respectively. Total cholesterol, low-density-lipoprotein (LDL) cholesterol and blood pressure were no different for the fish and fish oil diets than for the diet containing no fish or fish oil. The fish diet decreased blood levels of factors associated with blood clot formation by 16 percent for fibrinogen and 11 percent for thromboxane. It is concluded that fish and fish oil produced similar effects on blood cholesterol, but that only the fish diet reduced blood factors associated with blood clot formation. (Consumer Summary produced by Reliance Medical Information, Inc.)

The relationship between high levels of cholesterol in the blood and an increased risk of coronary heart disease (CHD) has been well established. In recent years, research has focused on the influence of diet on fat and cholesterol levels in the blood. Previous studies have shown that dietary fiber, specifically water-soluble fibers such as pectin and gums, can lower blood cholesterol levels. However, insoluble dietary fibers, such as cellulose and lignin, do not lower blood cholesterol. Oat and barley grains are almost 50 percent soluble fiber. Barley contains beta-glucan, a soluble dietary fiber, while wheat is mostly made of insoluble cellulose fiber. To investigate further the effect of dietary fiber on blood cholesterol levels, 21 men (aged 30 to 59) with mildly elevated blood cholesterol levels (hypercholesteremia) followed a four-week diet that included either barley or wheat. For the second four weeks of the study the two diet groups were switched; those on the barley diet changed to the wheat diet and vice versa. On the barley diet, total cholesterol levels decreased by 6 percent on average, and low-density-lipoprotein (LDL) cholesterol decreased by 7 percent. The wheat diet did not lower blood cholesterol levels. Blood triglycerides and glucose were not altered by either diet. These findings indicate that barley can lower blood cholesterol levels in men with hypercholesteremia. (Consumer Summary produced by Reliance Medical Information, Inc.)

Previous studies have shown that dietary fiber decreases blood levels of lipids that may cause atherogenesis (the fatty degeneration or thickening of the walls of the arteries). Dietary fiber was also shown to decrease blood pressure and improve the metabolism of glucose. However, various types of fiber-containing bran, such as oat, wheat, and rice, have different effects on blood lipids, digestion, and bile. The effects of adding 11.8 grams (g) of dietary fiber per day to a low-fiber diet for four weeks were assessed in 24 men with hypercholesterolemia (high blood levels of cholesterol). The sources of dietary fiber were three cereal brans: oat, wheat, and rice, which were incorporated into bread and muffins. Oat bran decreased blood levels of total and low-density-lipoprotein (LDL) cholesterol, and increased the ratio of high-density-lipoprotein (HDL) cholesterol to total cholesterol. Rice bran increased the ratio of apolipoprotein A-I to B. There were no changes in blood pressure, blood levels of glucose, and insulin responses to the brans. These findings indicate that oat and rice bran have beneficial effects on blood lipids and may help to decrease the risk of developing cardiovascular disease. (Consumer Summary produced by Reliance Medical Information, Inc.)

Consumption of fish on a regular basis has been associated with reduced mortality from heart disease. This may be related to the presence in fish of two n-3 (omega-3) unsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Linoleic acid, an n-6 fatty acid which is derived from plants, may be the most effective of any known fatty acid in lowering plasma cholesterol, but its effect on blood pressure has been disputed. To evaluate the role of these fatty acids in cardiovascular disease prevention, the effects of linoleic acid, linolenic acid (an n-3 fatty acid found in plants), and fish oil containing EPA and DHA on blood lipids and blood pressure were studied. Thirty-three men who had normal blood pressure and mildly elevated blood cholesterol were included in this study. All subjects received a supplement of linoleic acid for three weeks, and then for six weeks, 11 subjects per group were given supplements of either fish oil, linoleic acid, or linolenic acid. Care was taken to match the proportions of saturated, monounsaturated, and total polyunsaturated fatty acids and cholesterol in the diets, which is not always done in this type of study. Compared with the effects of the baseline linoleic acid diet, only the fish oil-supplemented diet affected blood pressure or serum lipids. Systolic blood pressure dropped significantly, by 5.1 mm Hg, while plasma triglycerides and VLDL (very low-density lipoprotein) cholesterol decreased by 39 and 49 percent, respectively; also LDL (low-density lipoprotein) cholesterol rose significantly, by 9 percent. The changes in blood pressure, triglyceride, and VLDL levels were beneficial, while the increase in LDL was considered detrimental to cardiovascular health. According to the calculations, the benefit from the decline in blood pressure should outweigh the risk from the LDL increase. This study illustrates the complexity of cardiovascular disease risk factors; further research on the role of fatty acids in the disease process is needed. (Consumer Summary produced by Reliance Medical Information, Inc.)

The frequency of dyslipidaemia and treatment with lipid-lowering drugs in patients with type 2 diabetes in Australian primary care is studied. The total cholesterol level in 75% patients was found to be increased in spite of the widespread use of statins.