As humans age, physiological changes occur that can result in decreasing energy intakes. One of the direct problems associated with the reduced food volume is an associated decrease in the total quantities of essential nutrients ingested. In addition, deterioration in the digestive system can cause a reduction in the absorption of nutrients, compounding any nutrient deficiencies. Multiple nutrient deficiencies can then have an impact on various aspects of health leading to changes in biochemical markers and the acceleration of disease and degeneration. Short-term, decreases in plasma levels of water soluble vitamins can be problematic, but as aging continues, deficiencies of minerals and fat soluble vitamins can compound ill-health. In many cases deficiencies exist before old age arrives. Because old age is generally associated with decreases activity levels it is possible that some changes are as a result of a lack of exercise.
Researchers1 have investigated the effects of supplemental nutrients and exercise on the health of elderly frail subjects using a 17 week study in 145 free living men and women (mean age 78 years). Subjects were randomly assigned to receive nutrient supplemented foods, and prescribed exercise regimen, both exercise and supplemented foods or placed in a control group. Foods were fortified with 100% of the Dutch recommended daily amount (RDA) for vitamins D, vitamin E, thiamin, riboflavin, vitamin B6, folic acid, vitamin B12 and vitamin C as well as calcium (25% RDA), magnesium (25% RDA), zinc (50% RDA), iron (50% RDA) and iodine (100% RDA). The nutrients were fortified into various foods, and the control group and exercise only group received similar foods with no nutrient fortification. The exercise protocol included 45 minute sessions twice a week that focused on mobility and improving daily tasks, and included walking, stooping and chair stands.
Baseline measurements from subjects showed that vitamin deficiencies were common and that 93% of subjects had vitamin intakes below the Dutch RDA. In particular, deficiencies of vitamin D (79% of men and 93% of women), vitamin E (65% of men and 66% of women), vitamin A (44% of men and 32% of women) and riboflavin (26% of men and 16% of women) were common. After the 17 week study, deficiencies in vitamins were corrected in the two groups receiving the nutrient fortified foods with significant increases reported for 25-hydroxyvitamin D, vitamin B12, vitamin C and pyridoxal-5-phosphate. However, no significant improvements were seen in the exercise only and control groups suggesting that exercise did not cause any increase in the absorption of nutrients. The researchers did not measure the levels of minerals in subjects, but it is likely that if they did, similar nutrient deficiencies would be detected.
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