Effect of zinc supplementation on vitamin status of middle-aged and older European adults: the ZENITH study

Abstract

Objective: To assess the effects of zinc supplementation on vitamin status in middle-aged and older volunteers. Subjects/Methods: Three hundred and eighty-seven healthy middle-aged (55-70 years) and older (70-85 years) men and women, randomly allocated to three groups to receive 15 or 30 mg Zn/day or placebo for 6 months. Dietary intake was assessed by means of a validated 4-day recall record. Fasting blood samples were simultaneously analysed for levels of plasma retinol and a-tocopherol by high-performance liquid chromatography. Erythrocyte folates were measured by a competitive immunoassay with direct chemiluminescence detection on an automatized immunoanalyser. Biochemical measurements were performed at baseline and after 3 and 6 months of zinc supplementation. Results: Plasma vitamin A levels were significantly increased proportionally with zinc dose and period of treatment, particularly at 6 months (for 15 mg Zn/day, Po0.05; for 30 mg Zn/day, Po0.0001); no significant changes were observed in the placebo group. There was no effect of zinc supplementation on vitamin E/cholesterol ratio and erythrocyte folates. Conclusions: Our results show that a long-term zinc supplementation increases plasma vitamin A levels in middle-aged and older people of similar characteristics to those involved in this study. Moreover, supplementation influences serum zinc levels but does not affect erythrocyte zinc concentration and both plasma vitamin E and erythrocyte folate status.

Role of fatty acids and micronutrients in healthy ageing: a systematic review of randomised controlled trials set in the context of European dietary surveys of older adults

“…Finally, a trial of middle and older‐aged men found that long‐term zinc supplementation (i.e. for 6‐months) was associated with increased plasma vitamin A levels (for 30 mg of zinc daily; P < 0.0001) .…”

Both human immunodeficiency virus–infected and human immunodeficiency virus–exposed, uninfected children living in Brazil, Argentina, and Mexico have similar rates of low concentrations of retinol, β-carotene, and vitamin E

“…The explanation for this relative preservation of β-carotene in the face of retinol deficiency is not known. Possible explanations, none of which we were able to assess in this study, include a plant-based diet, which has been shown to have a significant impact on β-carotene serum levels but no significant effect on retinol levels (40, 41), the presence of another deficiency, such as zinc, that negatively affects retinol mobilization from the liver (42) or the negative impact of the acute phase response on retinol levels as has been shown in children with malaria (43), and in HIV-1 seropositive subjects (44). …”

Nutritional Interventions for Elderly and Considerations for the Development of Geriatric Foods

“…Low zinc status increases vitamin E requirement due to decreased intestinal absorption. Whereas this low or marginal zinc status also decreases folate absorption from food [44]. The decreased gustatory sense which strongly affects the food intake among the elderly is also due to zinc deficiencies [16].…”