Research suggests that large numbers of individuals in Western nations have marginal vitamin and mineral status. This results from a combination of poor quality diet, along with food manufacturing, processing and growing techniques that are detrimental to the micronutrient content of the food. Marginal vitamin and mineral status can over time, produce sub-clinical illness that manifests as chronic conditions often classified as lifestyle diseases. Commonly, trace minerals such as chromium and selenium are deficient in Western populations and a sub-clinical deficiencies of these minerals is associated with diabetes and cancer, respectively. However, the vitamin status of some individuals is also found to be marginal in studies suggesting that fortification or supplementation is required in order to provide individuals with recommended intakes. For example, vitamin A and vitamin E have both been found to be marginal in some individuals suggesting poor quality diets are being consumed.
For example, researchers1 have assessed plasma concentrations of retinol, β-carotene and α-tocopherol, while assessing dietary intakes of vitamin A and vitamin E from 7 day diet records collected from 200 women and 231 men aged between 20 and 95 years. The results showed that generally vitamin A intakes were above the recommended intake of 0.70µmol/L However, 20% of subjects had intakes of vitamin A below this level, although only 2 subject had marginal retinol plasma levels of less than 0.35µmol/L. For vitamin E, 42 men and 35 women had plasma α-tocopherol concentrations that were considered marginal (<16.25 µmol/L). Plasma β-carotene was higher in women than men but 9 women (3%) and 20 men (5%) had levels that were below the lower limit of detection, suggesting very low dietary intakes. These results are consistent with other studies that show marginal vitamin intakes in Western populations.
Interestingly, supplementation increased with age in this study, which may suggest that the cost of supplementation is prohibitive to younger individuals or that concern over health increases with age. The authors noted that individuals were supplementing with vitamin A doses between 5000 to 25000IU, which is 1 to 5 times the recommended level. For vitamin E, one fourth of subjects were taking supplements over 20 times the recommended level. However, no hypervitmainosis was reported by the study authors. Talking vitamin A supplements is associated with increased β-carotene plasma levels, because when retinol status improves, there is less need to convert β-carotene to retinol. Data from this study supports this hypothesis, with vitamin A and retinyl intakes increasing β-carotene levels but not plasma retinol levels. Intake of β-carotene were positively associated with age and the higher intakes in older individuals may reflect changing dietary practices.
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