(06-08-10) Micronutrient quality of weight-loss diets that focus on macronutrients: results from the A TO Z study1,2,3

Christopher D Gardner, Soowon Kim, Andrea Bersamin, Mindy Dopler-Nelson, Jennifer Otten, Beibei Oelrich and Rise Cherin
1 From the Stanford Prevention Research Center and the Department of Medicine, Stanford University Medical School, Stanford, CA.
2 Supported by NIH grant R21AT1098, a grant from the Community Foundation of Southeastern Michigan, and Human Health Service grant M01-RR00070, General Clinical Research Centers, National Center for Research Resources, National Institutes of Health.
3 Address reprint requests and correspondence to CD Gardner, 251 Campus Drive, SPRC X310, Stanford, CA 94305-5411. E-mail: [email protected] .
Background: Information on the micronutrient quality of alternative weight-loss diets is limited, despite the significant public health relevance.
Objective: Micronutrient intake was compared between overweight or obese women randomly assigned to 4 popular diets that varied primarily in macronutrient distribution.
Design: Dietary data were collected from women in the Atkins (n = 73), Zone (n = 73), LEARN (Lifestyle, Exercise, Attitudes, Relationships, Nutrition) (n = 73), and Ornish (n = 72) diet groups by using 3-d, unannounced 24-h recalls at baseline and after 8 wk of instruction. Nutrient intakes were compared between groups at 8 wk and within groups for 8-wk changes in risk of micronutrient inadequacy.
Results: At 8 wk, significant differences were observed between groups for all macronutrients and for many micronutrients (P < 0.0001). Energy intake decreased from baseline in all 4 groups but was similar between groups. At 8 wk, a significant proportion of individuals shifted to intakes associated with risk of inadequacy (P < 0.05) in the Atkins group for thiamine, folic acid, vitamin C, iron, and magnesium; in the LEARN group for vitamin E, thiamine, and magnesium; and in the Ornish group for vitamins E and B-12 and zinc. In contrast, for the Zone group, the risk of inadequacy significantly decreased for vitamins A, E, K, and C (P < 0.05), and no significant increases in risk of inadequacy were observed for other micronutrients.
Conclusions: Weight-loss diets that focus on macronutrient composition should attend to the overall quality of the diet, including the adequacy of micronutrient intakes. Concerning calorie-restricted diets, there may be a micronutrient advantage to diets providing moderately low carbohydrate amounts and that contain nutrient-dense foods.

Am J Clin Nutr 92: 304-312, 2010.

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