Reduction of risk factors for atherosclerosis in diabetic patients treated with a high-fiber diet

Abstract

A protective effect of dietary fiber against atherosclerosis could be mediated through the influence of fiber on risk factors such as hyperlipidemia and hyperglycemia. To clarify this matter 14 diabetic patients (6 insulin-dependent and 8 noninsulin-dependent) were submitted, in metabolic ward conditions, to three weight maintaining diets for 10 days each: Diet A (carbohydrates 53%, lipids 30%, proteins 17%, fiber 20 g); Diet B, identical to diet A except for its fiber content (54 g); Diet C, lower in fiber and carbohydrates (carbohydrates 42%, lipids 37%, proteins 21%, fiber 20 g). The three diets were similar in their $\text{P}\text{S}$ ratio and were composed only of natural foodstuffs. The 2-hr postprandial blood glucose concentration and the daily blood glucose were significantly lower during the high-fiber diet than during either diet A or C as were total and low-density lipoprotein (LDL) cholesterol. Very low-density lipoprotein triglyceride (VLDL-TG) was significantly lower during the high-fiber diet in comparison with diet A, but then did not change during diet C. The hypolipidemic effect of a fiber-rich diet was then evaluated in hyperlipidemic patients (type II) with diabetes (n = 5) and without diabetes (n = 6). LDL cholesterol was significantly reduced by the high-fiber diet in both groups. However, in diabetic patients LDL reduction was significantly higher than in nondiabetic patients (P < 0.01). In conclusion, a high-fiber diet with lipid composition similar to southern Italian diets, composed only of natural foodstuffs, is able to reduce blood glucose and blood lipids in diabetic patients, over and above the effects of low saturated fat and low cholesterol intake. Moreover, it significantly reduces LDL-cholesterol in patients with type II hyperlipidemia and therefore can be utilized for prevention of atherosclerosis in the general population.