Zinc Deficency Toxicity
Poor diet is only one risk factor of many that can contribute to zinc deficiency. Age, lifestyle, and overall health all enter into the equation, too. The following segments of the population are the most susceptible to deficiency.
• Infants and toddlers
• Elderly persons
• Severely malnourished persons
• Those with HIV
• Those with malabsorption disorders
• Pregnant and lactating women
• Vegetarians, especially vegans
• Female athletes
Any condition associated with overall poor nutrition in general will obviously have a significant impact on zinc intake, while those with absorption problems have a high risk for deficiency because of the poor utilization of the zinc they do consume. For example, strict vegetarians miss out on most of the more easily absorbed forms of zinc which are animal products. Instead, they are relying solely on plant sources of zinc whose high phytate content inhibits absorption, while another staple of their diet, fruit, contains very little zinc.
Pregnancy and lactation are associated with improved zinc absorption capability, but because the daily requirements also increase, women who are pregnant or nursing are still at risk of zinc deficiency. Zinc deficiency increases the likelihood of pregnancy-related complications and birth defects in the child.
Another at risk group that may seem a surprise is the very young. Babies and toddlers don’t need to consume anywhere near as much zinc as adults. But, particularly if they are finicky eaters, because of their preference for milk and foods like cereal over meat, they are at risk for zinc deficiency. Therefore, many cereals, breads, and other breakfast foods made from refined flour are now fortified with zinc. However, in certain Middle Eastern countries where unleavened breads remain a dietary staple, zinc deficiency continues to be a problem. Furthermore, while milk is a good source of zinc, the problem there is that milk also high in calcium, and high consumption of calcium inhibits zinc absorption.
Zinc deficiency can produce any or all of the following symptoms.
• Stunted growth in childhood
• Learning disabilities and attention deficit disorders in children
• Poor appetite
• Nausea and vomiting
• Reduced sense of smell and taste
• Altered food tastes
• Frequent colds and infections due to weakened immune system
• Skin and eye irritations and lesions
• Alopecia (hair loss)
• Delayed wound healing
• Delayed sexual maturity
• Hypogonadism and hypospermia
• Impotence and infertility
• Pregnancy complications
Even mild deficiency can slow down growth in children and impair immune system functioning. In more severe levels of deficiency, the impact is greater, and many of the other symptoms indicated above are apparent as well.
Zinc toxicity is uncommon from dietary sources alone but still possible. It is more likely from taking too high of a dose of zinc supplements. Symptoms of toxicity can include any or all of the following.
• Poor immune functioning
• Low HDL cholesterol
• Copper deficiency
• Stomach cramps
• Loss of appetite
• Metallic taste in the mouth
• Nausea and vomiting
• Central nervous system disturbances
Zinc toxicity sometimes occurs in dialysis patients due to contamination of the dialysis fluids from the adhesive plastic on the dialysis coils or galvanized pipes.