Study finds that dieting individuals might need to watch their vitamin and mineral intakes


A study recently published in the American Journal of Clinical Nutrition (1) has found that weight loss diets that focus on the amount of food consumed and the proportions of proteins, fats and carbohydrates (the so called macronutrients) might be lacking in essential minerals and vitamins

The study researchers wanted to look at the intakes of vitamins and minerals (the micronutrients) of 4 popular diets being undertaken by overweight or obese women.  They note in their study that information on the micronutrient quality of weight loss diets is very limited and this is worrying considering the importance of vitamins and minerals for health.  Dietary data was collected from women following the Atkins diet, the Zone diet, LEARN (Lifestyle, Exercise, Attitudes, Relationships, Nutrition), and the Ornish diet.  There were about 70 women following each diet plan for 8 weeks.  After 8 weeks there were significant differences observed between groups for all macronutrients and for many micronutrients.  Energy (calorie) intakes decreased from baseline in all 4 groups but was similar between groups.  After 8 weeks a significant proportion of individuals in all groups shifted to micronutrient intakes associated with risk of inadequacy:

*In the Atkins group for thiamine, folic acid, vitamin C, iron, and magnesium

*In the LEARN group for vitamin E, thiamine, and magnesium

*In the Ornish group for vitamins E and B-12 and zinc

*In the Zone group for vitamins A, E, K, and C

The authors conclude that “Weight-loss diets that focus on macronutrient composition should attend to the overall quality of the diet, including the adequacy of micronutrient intakes”.

The results of the study indicate a need for dieters to really attend to the quality of their food intakes and not just the quantity in order to get enough vitamins and minerals daily.  Eating enough vegetables, fruits, beans/pulses, wholegrains, unprocessed meats/fish, nuts and seeds is a good way to ensure adequate intakes of vitamins and minerals.  These kinds of foods are nutrient dense.  Vitamins and minerals are essential for the efficient functioning of the body.  Only one of the diets, the Atkins diet, recommended that participants take a vitamin and mineral supplement, though only 3 women in the study followed the advice.  Supplements should never be considered as an alternative to a healthy diet, however if you are following a diet at the moment and are not regularly consuming vegetables, fruits and the other foods listed above you might want to check with your doctor about the suitability of a daily multi-vitamin and mineral supplement to provide any shortfalls.

(1)Christopher D Gardner CD et al.  2010.  Micronutrient quality of weight-loss diets that focus on macronutrients: results from the A TO Z study. Am J Clin Nutr.  E-Pub (June 23, 2010). doi:10.3945/ajcn.2010.29468


Written by Ani Kowal