Nutritional adequacy of diets reported at baseline and during trial years 1–6 by the special intervention and usual care groups in the Multiple Risk Factor Intervention Trial

Abstract

This chapter addresses whether a fat-modified diet as implemented by special intervention participants in the Multiple Risk Factor Intervention Trial affected intake of vitamins and minerals, and whether nutritional adequacy was altered by this dietary intervention. Despite likely underreporting of intake, for men in the special intervention group, most mean intakes of 15 micronutrients estimated from 24-h recalls were above established recommended dietary allowances. A few means were slightly below; lowest was zinc at 77% (from 98% at baseline) followed by calcium at 79% (from 102% at baseline). Calculated as nutrient densities (per 1000 kcal), nutrients that were below indexes of nutritional quality (the corresponding standard based on nutrient density) during follow-up, although not reduced below baseline by this measure, were vitamin D, calcium, iron (marginally), and zinc. Analyses by food groups indicated that intake of these nutrients might have been improved by greater replacement of high- and medium-fat dairy products with low-fat dairy products (for vitamin D and calcium) and of high-fat meats with low-fat meats, fish, or poultry (for iron and zinc), or (because iron was adequate) by increasing consumption of vegetables and whole-grain products. The safety of the eating pattern was further confirmed by more favorable micronutrient profiles in men who adhered best to the intervention program, as measured by degree of serum cholesterol reduction and weight loss.