Iron and zinc status of women and men who followed cholesterol-lowering diets.

OBJECTIVE: To determine if men and women taught the National Cholesterol Education Program step 2 diet experienced diminished iron or zinc status after 2 years of consuming the diet. DESIGN: Subjects attended 8 weeks of diet classes and followup counseling. Four-day food records, zinc protoporphyrin/ heme (ZPP/H, a measure of iron stores), hematocrit, and plasma zinc values were collected at baseline, 1 year, and 2 years. SUBJECTS: Participants in a study of the efficacy of the step 2 diet (213 men and 151 women) who had low-density lipoprotein cholesterol levels above the 75th percentile, and who were not taking lipid-altering medication. STATISTICAL ANALYSES: Paired t tests to compare preintervention and postintervention test results. Two-sample t tests to compare gender, menopause status, and hormone-use groups. Analysis of variance was performed to compare plasma zinc levels among diet-adherence subgroups. Individual evaluation of outlying values and backward stepwise regression to determine the independent effects of variables were also completed. RESULTS: Mean dietary intake approached or exceeded step 2 guidelines. Density of iron intake increased. Density of zinc intake was unchanged, but mean intake was low. Mean ZPP/H and hematocrit did not change for premenopausal or postmenopausal women with or without supplemental hormones; men's values changed only slightly. Abnormal ZPP/H and hematocrit occurred sporadically. Mean plasma zinc levels did not differ from baseline for women, increased slightly for men, and did not differ by level of dietary adherence. No plasma zinc concentrations were below normal. APPLICATION: In this large-scale, 2-year prospective study of women and men, no adverse effects on intake or plasma indicators of iron and zinc were detected as a result of subjects being taught the NCEP step 2 diet.

Zinc intake and plasma zinc level are maintained in men consuming cholesterol-lowering diets.

OBJECTIVE: Reduced zinc intake has been reported when cholesterol-lowering diets are adopted. This study examined whether such diets compromise the zinc status of men with hypercholesterolemia. DESIGN: Zinc intake on baseline 4-day food records and baseline plasma zinc levels were compared with intake and levels 12 and 24 months after subjects adopted a low-fat, increased-fiber diet. Dietary fiber intake, supplement use, alcohol intake, and exercise were evaluated as possible confounding variables. SUBJECTS: Subjects were free-living men (n = 365) with baseline cholesterol level above the 75th percentile who were participants in a randomized trial comparing cholesterol-lowering diets with goals of 30%, 26%, 22%, and 18% of energy from fat and 300, 200, 100, and 100 mg cholesterol, respectively. STATISTICAL ANALYSES: Data were analyzed using two sample t tests, multiple linear regression, and analysis of variance. RESULTS: For all subjects combined, mean fat and cholesterol intakes approached or met the guidelines of the National Cholesterol Education Program step 2 diet, with approximately 30 g fiber per day. Density (mg/1,000 kcal) of zinc intake was unchanged from the baseline value. We found a slightly positive relationship between fiber and zinc intakes; no relationship between fiber intake and plasma zinc level; no effect of supplement use (category included all types of supplements), alcohol use, or level of exercise on plasma zinc levels; and no difference by dietary assignment in zinc intake or plasma zinc levels. APPLICATION: Zinc status does not appear to be at risk in adult men who adopt cholesterol-lowering diets. These results may not be generalized to higher-risk population groups or situations in which dietary counseling is less comprehensive.

Changes in vitamin and mineral intakes and serum concentrations among free-living men on cholesterol-lowering diets: the Dietary Alternatives Study.

Nutritional adequacy of diets with 18-30% of calories from fat was investigated in men with elevated serum cholesterol (n = 396) at the end of diet classes and 1 and 2 y later. On 4-d food records, intakes of vitamin A, beta-carotene, folate, vitamin C, magnesium, vitamin B-6, iron, thiamin, and riboflavin increased from baseline whereas niacin, selenium, vitamin E, and zinc decreased. Median zinc intake, 80% of the recommended dietary allowance (RDA) at baseline, decreased to approximately 75% of the RDA, most markedly when intakes of meat, fish, and poultry were limited to 85 g/d. Nutrient densities generally increased. Of the serum nutrients measured, median beta-carotene and vitamin C increased, whereas vitamin B-6, iron, and zinc were unchanged. Below-normal values were fewer for vitamin C and magnesium. Diets similar to the National Cholesterol Education Program Step-Two Diet [less than 7% saturated fatty acids, less than 200 mg cholesterol/d] appeared to provide increased levels of most micronutrients both short and long term to men receiving comprehensive dietary counseling.