Zinc: A Trace Element Essential in Vitamin A Metabolism

Smith, James C.; McDaniel, E. G.; Fan, Fan; Halsted, James A.

doi:10.1126/science.181.4103.954

Cited by 200 publications

(48 citation statements)

References 7 publications

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“…Pre-albumin levels increase rapidly with a zinc supplementation of 10 ± 15 days in zinc-de®cient subjects (Bates & McClain, 1981). This effect is probably mediated through the effect of zinc on protein synthesis, most noticeable in the effect of zinc de®ciency on the synthesis of retinol binding protein (Smith et al, 1973). Zinc was found to be necessary for normal mobilisation of vitamin A from the liver and for maintaining normal serum levels.…”

Section: Introductionmentioning

confidence: 90%

Treatment for iron deficiency anaemia with a combined supplementation of iron, vitamin A and zinc in women of Dinajpur, Bangladesh

et al. 1999

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Objective: The study was set up to determine to what extent the addition of a supplement of vitamin A alone or in combination with zinc would improve standard iron treatment and correction of iron de®ciency anaemia. Design: 216 non-pregnant anaemic women of 15 ± 45 years of age with haemoglobin levels 100 gal were randomly assigned to three treatment groups. One group (A) received iron alone, a second group (B) received iron and vitamin A, and a third group (C) received iron, vitamin A and zinc. Every woman was given one iron capsule per day for 60 days as FeSO 4 containing 60 mg of elemental iron. In addition, groups B and C received 200 000 IU of vitamin A, given as a supervised dose, on the ®rst day of the treatment after collection of the blood sample. Group C received one zinc tablet per day for 60 days as zinc gluconate containing 15 mg of elemental zinc. Setting: The north-western part of Bangladesh in the urban slums of Dinajpur district between February and August 1995. Subjects: To select women with a haemoglobin level of 100 gal, all the women of four randomly selected municipal slums of the district in the targeted age group (328) were invited to take part in the study. Blood samples were analysed for haemoglobin, serum iron, total iron binding capacity (TIBC), ferritin, retinol and zinc. Results: Out of the 328 women screened, 254 (77.5%) had a haemoglobin level 100 gal and 322 (98%) 120 gal. The three treatment schedules signi®cantly increased haemoglobin levels and improved iron parameters, except for serum iron in the group who received iron alone. The group who received iron, vitamin A and zinc responded best with an increase in haemoglobin of 17.9 gal as compared to the group receiving iron alone (13.4 gal). Iron and vitamin A treatment gave an intermediate response of 15.9 gal. However, these differences are only statistically signi®cant only for the group who received iron, vitamin A and zinc and only for the increase in haemoglobin, P 0.03. Conclusion:The results are suggestive that the addition of vitamin A and zinc to the treatment for anaemia can increase haemoglobin levels more than with iron alone. Sponsorship: The present study was ®nanced by grant FWO 1.5.092.96 and Nutrition Tiers Monde.

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Section: Introductionmentioning

confidence: 90%

Treatment for iron deficiency anaemia with a combined supplementation of iron, vitamin A and zinc in women of Dinajpur, Bangladesh

et al. 1999

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“…We found a moderate positive correlation between plasma vitamin A and serum zinc or red blood cell zinc and between erythrocyte folate and red blood cell zinc, suggesting the possible role of zinc in the metabolism of these vitamins. In fact, zinc is necessary for normal mobilisation of vitamin A from the liver and therefore to maintain the normal concentration of vitamin A in the plasma (Smith et al, 1973). Marginal or low zinc status has been shown to decrease absorption of food folate because the brushborder membrane folate conjugase, responsible for cleaving folate prior to absorption, is zinc dependent (Milne et al, 1984).…”

Section: Discussionmentioning

confidence: 99%

“…Several factors can contribute to vitamin status in the elderly. For example, it is known that zinc deficiency may be associated with altered vitamin metabolism (Smith et al, 1973;Milne et al, 1984;Hong et al, 2000;Dijkhuizen et al, 2004). However, studies of the effects of zinc on vitamin status in the elderly are lacking.…”

Section: Introductionmentioning

confidence: 99%

Estimation of intake and status of vitamin A, vitamin E and folate in older European adults: the ZENITH

et al. 2005

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Objective: To report selected dietary intake and vitamin status at baseline of volunteers participating in the ZENITH study and the correlation of vitamin status with zinc. Design: A multicentre prospective intervention study employing a randomised double-blind design. Setting: Clermont-Ferrand, Theix (France), Coleraine (Northern Ireland), Grenoble (France), Rome (Italy). Participants: In total, 387 healthy middle-aged (55-70 y) and older (70-87 y) men and women participated in the study. Methods: Dietary intake was assessed by means of a validated 4-d recall record. Fasting blood samples were simultaneously analysed for retinol and a-tocopherol by the HLPC method. Erythrocyte folates were measured by a competitive immunoassay with direct chemiluminescence detection on an automatised immunoanalyser. Results: In all centres, men had a significantly (Po0.0001) higher mean nutrient intake than women. Comparison between age-groups showed that older individuals had significantly lower intakes of macro-and selected micronutrients than middleaged subjects (Po0.0001). A high fat intake (from 36 to 40% of total energy) was observed in all examined groups. In relation to biochemical measures of vitamin status, all parameters were above their respective cut-off values for normality and, thus, none of the subjects had biochemical evidence of deficiency of these selected vitamins. A moderate correlation was found with plasma vitamin A and serum zinc (r ¼ 0.12, Po0.05) or red blood cell zinc (r ¼ 0.12, Po0.01) and with erythrocyte folates and red blood cell zinc (r ¼ 0.11, Po0.05). Conclusions: There were only moderate differences in the nutrient intake of the ZENITH study volunteers among the four European centres. Their biochemical status for retinol, a-tocopherol and folate appeared adequate.

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“…Apart from the possible direct involvement of zinc in the accumulated genetic events, Zn may also be indirectly involved in epithelial carcinogenesis through its regulation of Vitamin A metabolism. (Smith et al, 1973) Vitamin A is a retinoid which binds to nuclear retinoid receptors, the activation of which results in changes that include controlling cell differentiation. Retinoids, including vitamin A have anti-cancer properties which may reflect their ability to induce differentiation (Brietman et al, 1980;Bollag and Holdener, 1992).…”

Section: Discussionmentioning

confidence: 99%

High cadmium / zinc ratio in cigarette smokers: potential implications as a biomarker of risk of prostate cancer.

Anetor

Ajose²,

Anetor³

et al. 2010

Nig. J. Phys Sci

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SummaryTobacco smoke may be one of the most common sources of cadmium (Cd) in the general population, particularly in the rising population of smokers in developing countries. Although a relationship between both cigarette smoking and environmental Cd contamination with prostate cancer exist, the mechanisms are unclear. Most prospective cohort studies found a positive association between current smoking and a fatal cancer of the prostate. We investigated the interaction between zinc and cadmium and the potential risk of prostate cancer in smokers. Serum cadmium level was significantly (P<0.001) higher in smokers compared with non-smokers, the level in smokers was three-fold that in non-smokers. In contrast zinc was significantly (P<0.001) reduced in smokers compared with non-smokers. Unlike Zn, Cu was significantly (P<0.05) higher in smokers than in nonsmokers. Iron (Fe) though higher in smokers was not significantly different. Zinc: cadmium ratio was very significantly (P<0.001) reduced, implying high cadmium: zinc ratio. This ratio was 4.5-fold the level in nonsmokers. Total protein, albumin and total globulin levels were all significantly (P<0.001) reduced in smokers compared with non-smokers respectively. Potassium (K + ) was significantly (P<0.05) higher in smokers than in non-smokers. Magnesium (Mg) was significantly (p<0.01) reduced in smokers compared to non-smokers. Altered Zn status culminating in high Cd:Zn ratio appears the central factor in smokers; leading to oxidative stress, DNA damage, mutation, impaired DNA repair, P 53 expression, angiogenic effect of Cu and impaired vitamin A metabolism. These converge in the risk of the carcinogenic process, suggesting high Cd: Zn ratio as the critical determinant of the risk of prostate cancer in smokers and possibly a biomarker of susceptibility to this environmental disease.

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Zinc: A Trace Element Essential in Vitamin A Metabolism

Cited by 200 publications

References 7 publications

Treatment for iron deficiency anaemia with a combined supplementation of iron, vitamin A and zinc in women of Dinajpur, Bangladesh

Treatment for iron deficiency anaemia with a combined supplementation of iron, vitamin A and zinc in women of Dinajpur, Bangladesh

Estimation of intake and status of vitamin A, vitamin E and folate in older European adults: the ZENITH

High cadmium / zinc ratio in cigarette smokers: potential implications as a biomarker of risk of prostate cancer.

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