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  • 2010

Dieters may have an increased risk of vitamin and mineral deficiencies

Published on

06 August 2010

Popular weight loss diets may be accompanied by inadequate vitamin and mineral intake, suggests a new US study.

In the study, 291 overweight or obese women were randomly assigned to follow one of four weight-loss diets for one year (1). The participants were weighed and measured throughout the study, and their dietary intakes were assessed by asking them three times to recall what they had eaten over the previous 24 hours. The researchers found differences in what dieters ate not only with regard to macronutrients (carbohydrates, fat and protein) but also related to micronutrients (vitamins, minerals and trace elements), which left some women at risk of inadequate levels based on national recommendations. After two months, a significant proportion of the dieters showed intakes associated with risk of inadequacy for vitamin B1 (thiamine), vitamin B9 (folic acid), vitamin B12vitamin Cironmagnesium, and zincVitamin E posed the biggest problem across all groups: more than 65 percent of women were not getting enough.

The researchers concluded that the focus of the most popular diets typically rests on both the overall amount of food consumed and the relative quantities of proteins, fats and carbohydrates. Vitamins and minerals tend to be overlooked; as a result, deficiencies can arise that increase the risk of serious health problems. One potential way to fill in the holes of any diet is through vitamin and mineral supplements, the researchers added. However, they found that, of the four diets, only one made this recommendation.


  1. Gardner C. D. et al. Micronutrient quality of weight-loss diets that focus on macronutrients: results from the A TO Z study. American Journal of Clinical Nutrition. 2010; 92:304–12.

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