August 11/Stanford, Cal./Obesity, Fitness & Wellness Week -- A report, "Micronutrient Quality of Weight-loss Diets that Focus on Macronutrients: Results from the A to Z Study," is newly published data in The American Journal of Clinical Nutrition. "Information on the micronutrient quality of alternative weight-loss diets is limited, despite the significant public health relevance. Micronutrient intake was compared between overweight or obese women randomly assigned to four popular diets that varied primarily in macronutrient distribution," scientists in the U.S. report.
"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-day, unannounced 24-hour recalls at baseline and after eight weeks of instruction. Nutrient intakes were compared between groups at eight weeks and within groups for eight-week changes in risk of micronutrient inadequacy. At eight weeks, significant differences were observed between groups for all macronutrients and for many micronutrients (p <0.0001). Energy intake decreased from baseline in all four groups but was similar between groups. At eight weeks, 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. Weight-loss diets that focus on macronutrient composition should attend to the overall quality of the diet, including the adequacy of micronutrient intakes," wrote C.D. Gardner and colleagues, Stanford University, Research Center.
The researchers concluded, "Concerning calorie-restricted diets, there may be a micronutrient advantage to diets providing moderately low carbohydrate amounts and that contain nutrient-dense foods."
Gardner and colleagues published their study in The American Journal of Clinical Nutrition ("Micronutrient Quality of Weight-loss Diets that Focus on Macronutrients: Results from the A to Z Study," The American Journal of Clinical Nutrition, 2010;92(2):304-12).
For more information, contact C.D. Gardner, Stanford University Medical School, Stanford Prevention Research Center and Dept. of Medicine, Stanford, Cal.
From the August 30, 2010, Prepared Foods E-dition