STANFORD, Calif.—Dieters may choose a popular weight-loss plan to reduce pounds, but a new study suggests some common diets also cut essential nutrients. The study found the Atkins, Zone, LEARN (Lifestyle, Exercise, Attitudes, Relationships, Nutrition) and Ornish diets are all deficient in vitamins and minerals, which could lead to health risks and diseases (Am J Clin Nutr. 2010 Jun 23. doi:10.3945/ajcn.2010.29468).
This research echoes a study publish a month ago in Journal of the International Society of Sports Nutrition that found individuals following the Atkins for Life diet, The South Beach Diet, the DASH diet and The Best Life Diet, without adding supplements, also have a high likelihood of becoming micronutrient deficient.
In this current study, researchers from the Stanford Prevention Research Center and the Department of Medicine, Stanford University Medical School compared micronutrient intake between overweight or obese women randomly assigned to the four popular diets that varied primarily in nutrient distribution. The collected dietary data 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 unannounced phone calls at the beginning of the study and after eight weeks following the diet. The women were asked to recall what they ate during the previous 24-hour period. Nutrient intakes were compared between groups at eight weeks and within groups for eight-week changes in risk of micronutrient inadequacy.
At eight weeks, the researchers found significant differences were observed between groups for all macronutrients and for many micronutrients (P<0.0001). Caloric 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 B12 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.
The researchers recommended, “Weight-loss diets that focus on macronutrient composition should attend to the overall quality of the diet, including the adequacy of micronutrient intakes,” adding diets that provide moderately low carbohydrate amounts and contain nutrient-dense foods may offer a micronutrient advantage.
The study was supported by a National Institutes of (NIH) Health grant.