Objectives: To determine the efficacy of the American Heart Association Step-One Diet for lowering blood lipid levels and to assess its nutritional adequacy in younger (< 50 years old) and older (> or = 50 years old) subgroups.
Study design: A prospective cohort study; 383 subjects were instructed in the American Heart Association Step-One Diet. Adherence to the diet was assessed at 6 weeks. Eighty-seven subjects continued the diet for an additional 12 weeks.
Setting: General community participants: volunteers from community cholesterol screening programs and chart reviews at family practice clinics.
Study participants: Men and women, aged 20 to 70 years, with baseline low-density lipoprotein cholesterol levels between the 50th and 95th percentile, and excluded if receiving any medications that affect blood lipid levels or if there was a history of diabetes, gout, peptic ulcer, or liver disease.
Intervention: Instruction by a registered dietitian and adherence to the American Heart Association Step-One Diet for 6 (n = 383) and 18 weeks (n = 87). This diet involves an intake of total fat not to exceed 30% of calories, saturated fatty acids not to exceed 10% of calories, and dietary cholesterol limited to 300 mg/d.
Results: Subjects aged 50 to 70 years averaged a reduction in total cholesterol level and low-density lipoprotein cholesterol level of 4% after 6 weeks. At the end of 18 weeks, mean total cholesterol and low-density lipoprotein cholesterol levels in subjects younger than 50 years exceeded their baseline levels, and in those older than 50 years returned to baseline lipid levels. Inadequate intake of several micronutrients were reported, notably, zinc, calcium, and vitamins A, D, and E.
Conclusions: When recommending the American Heart Association Step-One Diet to persons with hyperlipidemia, baseline dietary behavior should be assessed to determine whether that diet offers therapeutic advantage over the persons's self-selected diet. Follow-up should include monitoring of lipid response and nutritional adequacy. Special emphasis should be placed on selection of foods with appropriate micronutrient content.