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The consequences of zinc deficiency, including stunted growth, skin rash, impaired cognitive development, and malignant transformations. The document also discusses the role of zinc in cell survival, immune system function, and cognitive development, as well as research findings on zinc supplementation and its effects on cognitive function and cancer risk.
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Zn
Zn
Zn and Cognitive Development
Zn is involved in all phases of mental development and function
Testament to this is seen in brain disorders and cognitive development arrest in malnourished individuals. These individuals regardless of age seem to gain back their mental acuteness when given supplements of Zn.
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James G. Penland
Zn supplementation of young children was assessed in Chinese children (aged 6-9 years) treated daily with 20 mg Zn alone (Zn), Zn plus micronutrients (Zn+M) or micronutrients alone (M) in a double-blind manner for 10 wks. In 740 urban children, compared to treatment with M, treatment with Zn+M or Zn was associated with improved attention (continuous vigilance task), reasoning (oddity task) and psychomotor function (tapping and tracking tasks). In 540 rural children, compared to either M or Zn alone, treatment with Zn+M resulted in greater improvement in perception (object search), reasoning (oddity task) and manual dexterity (finger tapping). Compared to M alone, Zn alone resulted in greater improvement in memory for both objects and complex shapes.
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Effects of Zn supplementation on cognitive function in healthy middle- aged and older adults: the ZENITH study Maylor, EA, Simpson, EEA, Secker, DL, Meunier, N, Andriollo-Sanchez, M, Polito, A, Stewart-Knox, B, McConville, C, O'Connor, JM, Coudray, C British Journal of Nutrition, 96, (4), 2006, 752-
A randomized double-blind placebo-controlled design was employed to investigate the effects of Zn supplementation on cognitive function in 387 healthy adults aged 55-87 years. Several measures of visual memory, working memory, attention and reaction time were obtained at baseline and after 3 and 6 months of 0 (placebo), 15 or 30 mg Zn/d. Younger adults (<70 years) performed significantly better on all tests than older adults (>70 years), and performance improved with practice on some measures. For 2 out of 8 dependent variables, there were beneficial effects (at 3 months only) of both 15 and 30 mg/d on one measure of spatial working memory and a detrimental effect of 15 mg/d on one measure of attention.
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Inadequate dietary Zn can also lead to lymphopenia (reduced number of lymphocytes in the blood) which is a consequence of impaired lymphopoiesis (white blood cell synthesis) related to an increase in apoptosis (cell death) among precursor T and B-cells. This may reflect chronic production of glucocorticoids induced during Zn deficiency.
Nanomoles of free Zn can induce apoptosis in a variety of cells. Release of Zn within cells may cause neurological damage and other situations where cells are under stress.
Pamala J. Fraker Professor Michigan State University
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Zn and Malignant Transformation
Combining human and animal studies with cell culture studies has established a link between Zn deficiency and cancer.
Compared with healthy people, Zn status is compromised in cancer patients. As yet it is not known if compromised Zn status is before or after the fact.
According to one theory, oxidative DNA damage and chromosome breaks that have been reported in animals fed a low Zn diet lead to an increased susceptibility to tumor development when exposed subsequently to carcinogens.
Zn supplementation beyond a dose of 40 mg/day or for long duration at lower levels may induce cancer
Zn
The immune system is adversely affected by even moderate degrees of Zn deficiency. Severe Zn deficiency depresses immune function. Zn is required for the development and activation of T-lymphocytes, a kind of white blood cell that helps fight infection. When Zn supplements are given to individuals with low Zn levels, the numbers of T-cell lymphocytes circulating in the blood increase and the ability of lymphocytes to fight infection improves. Studies show that poor, malnourished children in India, Africa, South America, and Southeast Asia experience shorter courses of infectious diarrhea after taking Zn supplements (29). Amounts of Zn provided in these studies ranged from 4 mg a day up to 40 mg per day and were provided in a variety of forms (Zn acetate, Zn gluconate, or Zn sulfate) (29). Zn supplements are often given to help heal skin ulcers or bed sores (30), but they do not increase rates of wound healing when Zn levels are normal.
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Stinky zinc problem
Is your cologne too strong? If so you may have a zinc deficiency. University of Tennessee research discovered that nearly 80% of a group of women and men who unknowingly sprayed on too much cologne or per- fume had low blood levels of zinc. But, after six months of being fed a 50 mg daily dose of zinc gluconate, their sense of smell returned, and most cut back on their scent. About 20% to 25% of smell and taste problems are zinc-related says Thomas Namey, M.D., the researcher in the study.
