Dietary and pharmacologic regimens to reduce lipid peroxidation in non-insulin-dependent diabetes mellitus

Persons with diabetes are at increased risk for developing coronary heart disease (CHD): although the standard risk factors are also applicable, there are other major nontraditional risk factors for these persons. For example, oxidation of lipoproteins may play an important role in the development of atherosclerosis. Another risk factor is the presence of small, dense low-density lipoprotein (LDL), which may have enhanced atherogenicity because it enters the arterial wall more readily and is more easily oxidized. Both of these factors may be particularly important in persons with non-insulin-dependent diabetes mellitus (NIDDM), because these persons may have greater rates of lipid oxidation in vivo than do nondiabetic persons and also have an increased prevalence of small, dense LDL. I describe potential dietary and pharmacologic regimens in patients with NIDDM to decrease in vivo lipid peroxidation, and the susceptibility of LDL and dense LDL subfractions to oxidative modification. In nearly all NIDDM patients, reducing dietary saturated fat helps lower plasma cholesterol and reduces the risk for CHD. There is, however, some controversy as to whether dietary saturated fat should be replaced by carbohydrates or by monounsaturated fatty acids (MUFAs) in NIDDM. Recent studies showed reduced susceptibility to oxidation of LDL in subjects consuming MUFA-enriched diets, thus adding another dimension to the ongoing debate over the most appropriate diet for NIDDM patients. Additionally, supplemental antioxidants such as probucol and vitamin E alone or in combination with MUFA-enriched diets have shown promise in protecting LDL from oxidation when given to nondiabetic populations. I also present recent results from an antioxidant trial in NIDDM subjects.