Dietary therapy as an initial step in the treatment of hyperlipidemia

Drug therapy with statins and other agents can result in dramatic lipidlowering effects. Despite the wealth of data supporting the beneficial effects of pharmacologic therapy on cardiovascular risk, patients often express a desire to accomplish similar goals with diet alone. And, except for patients with extreme cholesterol elevations, consensus panels all promote dietary therapy as an initial step in the treatment of hyperlipidemia. This review examines a variety of dietary strategies designed to lower lipid levels, including:

• The American Heart Association diet
• The Ornish diet
• The Mediterranean diet
• Exercise
• Phytosterols
• Fiber
• Soy products
• Fish oil. 

Though the declines in low-density lipoprotein cholesterol levels with these methods range from 0% to 37%, cardiovascular risk may be more significantly impacted than would be predicted from these changes alone. Significant benefits can be reaped from nonpharmacologic measures.

Coupling a low-fat diet with exercise produces better results than diet alone. It is known that exercise can raise the HDL level. Wood et al found that adding regular exercise (approximately 9 miles of walking or jogging per week) to a Step 1 low-fat diet in obese patients produced a 13% increase in HDL cholesterol levels, which offsets the small decline typically seen on a low-fat diet alone (17). This same group expanded these findings to a cohort of nonobese patients with high LDL and low HDL levels. At 1 year, those randomized to a Step 2 diet alone had a 7% to 11% decrease in LDL levels, which was statistically significant. Coupling diet with an exercise program of 10 miles of walking or jogging per week produced a more substantial 14% to 20% decrease in LDL cholesterol levels (18).

Weight loss, in and of itself, has salutary effects on lipid profile. These same investigators, in separate studies of obese patients, found that weight loss, achieved either through diet or exercise, resulted in equivalent increases in HDL cholesterol levels and reductions in triglyceride levels (19). It is especially important to identify and target a subset of patients who have the recently described “insulin resistance syndrome.” Typically these patients have central obesity or a relatively large abdomen, glucose intolerance, and hypertension. They have a characteristic lipid pattern with low HDL levels, high triglyceride levels, and smaller, dense LDL particles. In these patients weight loss alone can have a dramatically beneficial effect on lipid profiles (20).

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