Impact of micronutrient deficiencies on obesity Olga P García, Kurt Z Long, and Jorge L Rosado Micronutrient deficiencies have been found in obese individuals across age groups worldwide. While the effects of micronutrient deficiencies on human functions have been studied widely in different populations, there is limited information on how these micronutrient deficiencies affect obese populations. An examination of the available literature suggests associations exist between micronutrient deficiencies and obesity in different populations. These associations and possible mechanisms of the deficiencies' metabolic effects, such as their influence on leptin and insulin metabolism, are discussed here. Further studies are needed to clarify the roles of the different micronutrient deficiencies with respect to obesity and its comorbid conditions. © 2009 International Life Sciences Institute INTRODUCTION Obesity has become one of the primary health concerns in many regions of the world due to its increasing con- tribution to overall disease burden. Its rising impact is especially apparent in developing countries, where approximately 115 million people have developed obesity-associated diseases over the past decade. 1 Heart disease, a consequence of hyperlipidemia, is a significant cause of death worldwide, followed by diabetes and cancer. Diabetes has also become one of the main causes of mortality in a number of developing countries and, as such, represents a high economic burden for the public health sector in these countries. Obesity studies have generally focused on examining the associations between obesity and risk factors for its associated chronic diseases. As a result, it is well estab- lished that excess body fat in the form of central adiposity is associated with insulin resistance and an increase in the concentration of circulating lipids, both of which are important risk factors for type 2 diabetes and hyperlipi- demia. Little is known, however, about what risk factors may be contributing to the increasing rates of obesity in many parts of the world. Recent research suggests that deficient levels of some micronutrients may be associated with increased fat deposition in the body. It is now rec- ognized that overweight and obese individuals have lower blood concentrations of vitamins and minerals compared to non-overweight and non-obese individuals. 2–4 It is not clear, however, whether this association represents a causal relationship and, if so, the direction of causality. Micronutrient deficiencies continue to be a public health problem in a number of regions of the world, not only in impoverished communities but also in popula- tions in developed countries. It is interesting to note that some studies have suggested the rates of obesity are increasing more rapidly in some regions of the world where micronutrient deficiencies are more prevalent. 5,6 This pattern could suggest that the micronutrient defi- ciencies of individuals in these communities may be con- tributing to the increase in obesity rates. Insight regarding the direction of causality may be gained by examining the physiological mechanisms that may underlie these associations. For example, concentra- tions of different antioxidants, vitamins, and minerals have been found to be correlated with serum leptin con- centrations. 7 Leptin maintains the constancy of adipose tissue mass through the regulation of food intake and energy expenditure; it also regulates components of the inflammatory response that are risk factors for obesity. Affiliations: OP García is with the School of Natural Sciences, Universidad Autónoma de Querétaro, Juriquilla, Mexico. KZ Long is with the School of Population Health, University of Queensland, Herston, Australia. JL Rosado is with the School of Natural Sciences, Universidad Autónoma de Querétaro, Querétaro and CINDETEC, Mexico. Correspondence: OP García, School of Natural Sciences, Universidad Autónoma de Querétaro, Av. de la Ciencias S/N, Juriquilla, QRO, Mexico 76230. E-mail: opgarciao@yahoo.com.mx. Key words: micronutrient deficiencies, obesity, minerals, vitamins Lead Article doi:10.1111/j.1753-4887.2009.00228.x Nutrition Reviews® Vol. 67(10):559–572 559