The decline in physical function that occurs with aging often represents the early stage of a continuum leading to disability and other important adverse outcomes such as institutionalization, the authors write. Understanding the mechanisms associated with this process has been identified as a priority. The potential harmful effect of poor nutrition on physical function in older persons is not well understood.

Benedetta Bartali, R.D., Ph.D., of Yale University School of Medicine, New Haven, Conn., and colleagues conducted a study to determine whether a low concentration of specific micronutrients is associated with subsequent decline in physical function. The study included 698 community-living persons 65 years or older who were randomly selected from a population registry in Tuscany, Italy. To measure nutritional status and physical function, participants completed a baseline examination, conducted from November 1998 through May 2000, and 3-year follow-up assessments from November 2001 through March 2003. Measurements were obtained for several micronutrients, including serum folate and vitamins B6, B12, D and E. Decline in physical function was defined as a loss of at least 1 point in the Short Physical Performance Battery during the follow-up, which included three objective tests of physical function.

The average decline in physical function score was 1.1 point. In analyses adjusted for other factors, only a low concentration of vitamin E was significantly associated with subsequent decline in physical function. Additional analyses indicated that age older than 81 years and vitamin E (in participants 70-80 years) were the strongest determinants of decline in physical function.

The hypothesis that antioxidants [such as vitamin E] play a role in the etiology of decline in physical function and disability is supported by our previous findings and other studies suggesting that oxidative stress is involved in muscle fatigue and that antioxidants play a preventive role in muscle damage by reducing oxidative injury, the authors write.

Thus, at least 3 different mechanisms may explain the effect of low concentration of vitamin E on subsequent decline in physical function: (1) increased oxidative stress leading to muscle or DNA damage, (2) exacerbation of atherosclerosis or other pathologic conditions, and (3) development of neurodegenerative disorders.

Participants in the study did not take vitamin supplements and the authors do not recommend vitamin E supplements to increase levels. They state, Approximately 15 to 30 mg/d of dietary alpha-tocopherol [a component of vitamin E] is needed this amount can be easily reached through diet, from sources such as almonds, tomato sauce, and sunflower seeds among others.

In conclusion, the current study provides empirical evidence that a low concentration of vitamin E is associated with subsequent decline in physical function in a population-based sample of older persons living in the community. Although the findings from this epidemiological study cannot establish causality, they provide a solid base that low concentration of vitamin E contributes to decline in physical function. Clinical trials may be warranted to determine whether optimal concentration of vitamin E reduces functional decline and the onset of disability in older persons with a low concentration of vitamin E, the researchers write.

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