Micronutrient quality of weight-loss diets that focus on macronutrients: results from the A TO Z study.

Am J Clin Nutr. 2010 Aug;92(2):304-12. Epub 2010 Jun 23.

Micronutrient quality of weight-loss diets that focus on macronutrients: results from the A TO Z study.
Gardner CD, Kim S, Bersamin A, Dopler-Nelson M, Otten J, Oelrich B, Cherin R.

Stanford Prevention Research Center and Department of Medicine, Stanford University Medical School, Stanford, CA, USA. cgardner@stanford.edu

Abstract
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.

PMID: 20573800 [PubMed - indexed for MEDLINE]PMCID: PMC2904033 [Available on 2011/8/1]

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