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| 1. General information about Zinc |
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Zinc is an important trace mineral and is second only to iron in its concentration in the body. The human need for zinc is small, but its role in growth and well-being is enormous, starting even before birth. The entire body of a normal man weighing 70 kg may contain 1.4 to 2.3 g of zinc. Zinc is present in small amounts in all tissues. The bones, teeth and the pancreas contain slightly higher amounts of zinc than other tissues. Whole blood contains about 0.7mg/100ml , while blood serum or plasma contains 0.1 mg /100ml. zinc is a bluish- white, metallic element. It is present in the body mostly in combination with other constituents of the body. Nearly 99 percent of the total zinc in the body is stored in cells and the remainder in the plasma and extra cellular fluids.
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| 2. How much Zinc should we need daily? |
| Recommended Daily Allowance for zinc (RDA) : |
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| Infants: | 0-6 months | 2mg/day |
| | 7-12 months | 3mg/day |
| Children: | 1-3 years | 3mg/day |
| | 4-8 years | 5mg/day |
| | 9-13 years | 8mg/day |
| Adults: |
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| Men: | 14 and older | 11mg/day |
| Women: | 14 to 18 Years | 9mg/day |
| | 19 and older | 8mg/day |
| Pregnancy: |
| 12mg/day |
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| 3. Zinc roles in health : |
- For healthy skin and hair
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Zinc actively participates in skin regeneration and contributes to the treatment of skin inflammations and irritations, especially those common to teens as they undergo puberty. Zinc may accelerate the healing of chronic skin ulcers and wounds. Patients with these problems have a low content of zinc in the plasma for many weeks. Zinc seems to offer new promise of help for acne patients. Consumption of zinc can be making noticeable improvements. Also zinc has been found beneficial in the treatment of eczema. Many people with this skin problem have tried and benefited from Zinc supplements.
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| Role of zinc in wound healing is important in cases of burns or surgical incisions. |
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- Reproduction system health
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Zinc has a role in many aspects of reproduction system, such as male virility, successful pregnancy, and synthesis of sexual hormones. As a role in male virility zinc is necessary for the maturation of sperm and normal fetal development. Also Administration of zinc has been found to be helpful in cases of prostate enlargement, besides of other sexual benefits. Based upon scientific findings zinc has a role in preventing of infertility especially in men.
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| Zinc deficiency in men leads to: |
- reduction in the secretory function of the testicles
- erection dysfunction
- loss of libido
- Prostate hypertrophy
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Zinc is needed for the bodyۥs defensive (immune) system to properly work and it plays a vital role in guarding against disease and infection.Zinc as a immune-enhancing factor regulates T lymphocytes, CD4, natural- killer cells and interleukinII. In addition, zinc has been claimed to possess antiviral activity.
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- Control vitamin and hormone release
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Zinc controls the release of stored vitamin A from the liver and also it is needed to transport vitamin A to the retina. Within the endocrine system, zinc has been shown to regulate insulin activity and promote the conversion thyroid hormones thyronine to triodothyronine. Zinc is also necessary for the synthesis of insulin which is also known as the pancreas hormone, and for maintaining the acid-base balance and homeostasis in the organism.
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Zinc is necessary for the functioning of more than 300 different enzymes and plays a vital role in an enormous number of biological processes. Zinc is needed for break down of carbohydrates and is a cofactor for the antioxidant enzyme superoxide dismutase (SOD) and is in a number of enzymatic reactions involved in carbohydrate and protein metabolism.
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- Cell structure and signaling
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The structure and function of cell membranes are also affected by zinc loss. Loss of zinc from biological membranes increases their susceptibility to oxidative damage and impairs their function. Zinc also plays a role in cell signaling and has been found to influence hormone release and nerve impulse transmission.
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- Treatment of (childhood) malnutrition
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Recent clinical and experimental findings have reinforced the link among zinc deficiency, malnutrition and diarrheal disease. Because there is a strong association between protein and zinc content in virtually all types of foods, insufficient protein intake may often be the cause of zinc deficiency. In zinc deficiency, the organism is more susceptible to toxin-producing bacteria or enteroviral pathogens that producing diarrhea and diminishing absorption of nutrients, thus exacerbating an already compromised mineral status.
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- Prevention of peptic ulcers
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Stomach ulcer symptoms consist mainly of pain. Painful ulcer symptoms are reported to be burning or gnawing and may last between 30 minutes to 3 hours. Symptoms of ulcers are also interpreted as heartburn, indigestion or hunger. Stomach ulcer symptoms can be eliminated and healed with Zinc. Zinc supplement strengthens your stomach and eliminates stomach ulcer symptoms.
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- Taste and Smell perception
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| Zinc improves taste and smell sensation in the body and its role in this case is important because the loss of taste is the first sign of a zinc deficiency. |
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- Prevention of Wilson Disease
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Wilson disease is a genetic disorder that prevents the body from getting rid of extra copper. A small amount of copper obtained from food is needed to stay healthy, but too much copper is poisonous. In Wilson disease, copper builds up in the liver, brain, eyes, and other organs. Over time, high copper levels can cause life-threatening organ damage. Zinc makes a noticeable reduction in copper absorption in the body.
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- Prevention of common cold symptoms
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Zinc has an important role in reducing and prevention of common cold symptoms. Zinc reduces the duration and severity of symptoms. The beneficial clinical effects seen in the zinc consumption were due to the antioxidant and anti-inflammatory effects of zinc.
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- Contribution to body growth
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Zinc has a wide spectrum of biological activities and its deficiency has been related to various abnormalities of cell metabolism. Zinc is present in the cell nucleus, nucleolus and chromosomes, and zinc stabilizes the structure of DNA, RNA and ribosomes. In this way zinc involves in cell growth and division and growth of the body on the whole.
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| 4. Zinc Deficiency: |
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Zinc deficiency is:
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one of the numerous reasons for fatigue, tiredness, and loss of appetite;
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the basic reason for the loss of smell and taste sensations;
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also evidenced by the appearance of white spots on the nails;
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one of the possible reasons for hyper-activity in children;
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one of the probable reasons for infant retinal disorders
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Zinc deficiency in young boys leads to signs of infantilism, a badly developed prostate gland, and the underdevelopment of the testicles. In turn, this may lead to a number of hormonal disorders in young girls such as the dysfunction of the ovaries, delayed onset of the menstrual cycle and underdevelopment of the uterus.
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Zinc deficiency in the diet has been reported to be the cause of anemia, retardation in growth and delayed genital maturation. Other symptoms of zinc deficiency include:
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Frequent infections
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Hypogonadism in males
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Loss of hair
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Poor appetite
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Problems with the sense of taste and smell
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Trouble seeing in the dark
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Various skin lesions
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Wounds that take along time to heal
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Chronic and severe diarrheas
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Swelling of the corneas
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Behavioral disturbances
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It is notable that these symptoms depends on body condition and maybe seen in some cases.
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| 5. Food sources for Zinc : |
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High – protein foods contain high amounts of zinc. Dark meat has more zinc than the light meat. Other good sources of zinc are peanuts and legumens. Fruits and vegetable are not good sources, because zinc in plant- proteins is not as available for use by the body as the zinc from animal proteins. Therefore, low protein diets and vegetarian diets and vegetarian diets tend to be low in zinc.
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| 6. Who are in high need for Zinc supplements? |
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Remember that:
Zinc is needed for everyone in life because of enormous effects throughout body
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Infants and children
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Pregnant and lactating (breast- feeding) women
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Malnourished individuals
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Individuals with severe or persistent diarrhea
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Individuals with malabsorption syndromes including celiac disease and short bowel syndrome.
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Individuals with sickle cell anemia
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Older adults (65 years and older)
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Strict vegetarians
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| 7. Scientific researches about zinc: |
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1.Diarrhea (children)
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Multiple studies in developing countries found that zinc supplementation in malnourished children with acute diarrhea may reduce the severity and duration of diarrhea, especially in children with low zinc levels.
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2. Gastric ulcers
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The healing process of gastric ulcers may be enhanced through treatment with zinc, although further studies will be needed to determine to what extent zinc may be beneficial for patients with this condition. Most studies report no or few adverse effects associated with its use.
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3. Sickle cell anemia (management)
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There is strong scientific evidence to suggest that zinc may help manage or reduce symptoms of sickle cell anemia. Most of these studies reported increased height, weight, immune system function, and testosterone levels and decreased numbers of crises and sickled cells following zinc treatment.
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4. Acne vulgaris
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Based on high-quality studies, topical or oral use of zinc seems to be a safe and effective treatment for acne vulgaris; however, some studies report no or negative effects of zinc. Additionally, many studies used combination treatments. Several studies have identified a positive correlation between serum zinc levels and severity of acne, while others did not, and it remains to be determined to what degree internal zinc levels may correlate with the severity of acne.
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5. Attention deficit hyperactivity disorder (ADHD)
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Early studies have shown a correlation between low serum free fatty acids and zinc serum levels in children with attention deficit hyperactivity disorder. Additional studies found that zinc supplements reduced hyperactive, impulsive, and impaired socialization symptoms, but did not reduce attention deficiency symptoms. Zinc supplementation may be a more effective treatment for older children with higher body mass index (BMI) scores.
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6. Down's syndrome
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In several studies, zinc supplements seemed to counteract hypothyroidism and slightly reduce the number of infections in children with Down syndrome. However, zinc did not seem to improve depressed immune systems. Additional human research is needed before a firm conclusion can be made.
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7. Fungal infections (scalp)
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Evidence from human trials suggests that zinc pyrithione shampoo may be an effective treatment for tinea versicolor fungal infections of the scalp. No side effects were noted. Additional research is needed before a strong recommendation can be made.
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8. Herpes simplex virus
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Low-quality studies have been conducted to assess the effects of zinc (topical or taken by mouth) on herpes type I or II. Several of these studies used combination treatments or permitted the continued use of other medications, so the exact role of zinc in those studies is unclear. However, the positive results obtained in most trials suggest that zinc may represent a safe and effective alternative treatment for herpes type I and II and should encourage further research into the topic using well-designed studies.
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9. High cholesterol
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Zinc may improve blood cholesterol levels in hemodialysis patients. There is some evidence that zinc may improve cholesterol ratio of HDL "good cholesterol" versus LDL "bad cholesterol," which would be considered a positive effect. Well-designed clinical trials are needed before a strong recommendation can be made.
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10. Immune function
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Zinc appears to be an essential trace element for the immune system, but research on the effect of zinc supplementation on immune function is scant and mostly focuses on patients with specific diseases. Zinc gluconate appears to have beneficial effects on immune cells. There are relatively few studies that examine zinc levels and the effects of zinc supplementation on the health of the elderly population. Further research is needed before a recommendation can be made.
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11. Plaque/ gingivitis
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A few studies have reported significant reduction in plaque accumulation following treatment with zinc rinses and dentifrices. Preliminary research suggests that zinc citrate dentifrice may reduce the severity and occurrence of supragingival calculus formation. However, more well-designed studies are needed to confirm such benefits. More research might help to determine zinc's potential efficacy in other dental applications.
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12. Wilson's disease
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Wilson's disease is an inherited disorder of copper metabolism characterized by a failure of the liver to excrete copper, which leads to its accumulation in the liver, brain, cornea, and kidney, with resulting chronic degenerative changes. Early research suggests that zinc treatment may be effective in the management of Wilson's disease. Relatively few cases of adverse effects have been reported, including one case report presenting a fatality; however, it is unclear whether or not the death was caused by zinc. Several studies have been conducted by the same authors, resulting in possible bias. More well-designed trials are needed to confirm these early results.
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13. Alopecia (hair loss)
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A few studies that examined the efficacy of zinc in treating alopecia report conflicting results. Additional information is needed before a conclusion can be made.
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14. Anorexia nervosa
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Reports of zinc's effectiveness in treating symptoms of anorexia nervosa observed in young adults are based on small, low-quality studies, but all agree on the beneficial effects of zinc. Well-designed trials with a larger number of participants are needed to confirm these results.
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15. Bad breath
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Chewing gum containing zinc or rinsing out the mouth with a solution containing zinc seemed to reduce bad breath (halitosis) in early studies.
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16. Beta-thalassemia (hereditary disorder)
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One small study noted that children with beta-thalassemia who took oral zinc supplements for 1-7 years increased in height more than those who did not take zinc. More studies are needed to confirm these findings.
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17. Burns
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Study results of zinc sulfate supplements given to burn victims to increase healing rate yield mixed results. Further research is needed before a recommendation can be made.
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18. Chronic prostatitis (CP)
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Early studies suggest that zinc supplements taken with antibiotics may be more effective than antibiotics alone in reducing pain, urinary symptoms, quality of life, and maximum urethra closure pressure for patients with chronic prostatitis. Further research is needed to confirm these results.
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19. Cognitive deficits (children)
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Early studies indicate that daily supplementation with zinc may be of limited usefulness for improving cognition in lead-exposed schoolchildren. Further study may be warranted in this area.
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20. Common cold
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There are conflicting results regarding the effect of zinc formulations in treating duration and severity of common cold symptoms. Although zinc might be beneficial in the treatment of cold symptoms, more studies are needed to clarify which zinc formulations may be most effective, which rhinoviruses are affected by zinc, and if nasal sprays provide a useful alternative application route for zinc treatment. A recent study found no significant differences between zinc nasal spray and placebo.Negative results may be caused by using doses of zinc that are too low or they may be affected by the presence of compounds like citric or tartaric acid, which may reduce efficacy due to chelating of the zinc ion.
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21. Crohn's disease
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Early studies of zinc supplements in patients with Crohn's disease have found positive results. Well-designed clinical trials are needed to confirm these results.
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22. Dandruff
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Shampoo containing 1% of zinc pyrithione has been shown to reduce dandruff in some people.
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23. Diabetes (type 1 and type 2)
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Diabetic patients typically have significantly lower serum zinc levels compared with healthy controls. In early high-quality studies, zinc supplementation for type-2 diabetics may have beneficial effects in elevating serum zinc level and in improving glycemic control that is shown by decreasing HbA1c concentration. Further study is needed before a strong recommendation can be made.
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24. Diabetic neuropathy (nerve damage)
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Oral zinc supplementation may improve glycemic control and severity of peripheral neuropathy. Further research is needed before a recommendation can be made.
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25. Eczema
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There are conflicting data regarding the correlation of zinc serum levels and eczema. One study noted that zinc might have caused an increase in itching after several weeks of supplementation. Additional information is needed to help clarify these results.
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26. Exercise performance
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Zinc may improve exercise performance in athletes with low serum zinc or zinc deficiencies. Additional evidence is needed before a recommendation can be made.
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27. Gilbert's syndrome
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Gilbert's syndrome is a common, often inherited disorder that affects processing by the liver of the greenish-brown pigments in bile (called bilirubin). The resulting abnormal increase of bilirubin in the bloodstream can lead to yellowing of the skin (jaundice), but the liver itself remains normal. It is more common in men than women and is named after a French gastroenterologist. Zinc sulfate supplementation seemed to decrease serum unconjugated bilirubin levels in a small study. Well-designed clinical trials are needed to confirm these results.
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28. Growth (stunted infants)
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Evidence suggests that supplementation with zinc plus iron (but not with zinc alone) may improve linear growth (length) of stunted infants with low hemoglobin.
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29. Hepatitis C viral infection (chronic)
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Early studies have shown that zinc in combination with interferon or interferon and ribavirin for hepatitis C viral infection patients did not show significant benefits, except for lower incidence of gastrointestinal side effects in one study. Further study may be warranted in this area. Recent high-quality evidence suggests that supplementation with polaprezinc in patients undergoing treatment with pegylated interferon alpha-2b and ribavirin may decrease damage to the liver cells.
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30. HIV/AIDS
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Patients with HIV/AIDS, especially those with low zinc levels, may benefit from zinc supplementation. Some low-quality studies cite reduction in infections, enhanced weight gain, and immune system function, including increased CD4 and CD8 cells. However, other low quality studies conflict with these findings. Further research is needed before a conclusion can be drawn.
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31. Hypothyroidism
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Case report data suggest zinc supplementation may improve thyroid hormone levels (particularly T3) among women with hypothyroidism.
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32. Infertility
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Many studies report beneficial results of zinc supplements on infertility, as expressed in improved sperm quality and number, although this effect may depend on the cause of infertility. A minor increase in abnormal spermatozoa in subfertile males taking zinc was noted in one study. Additional information is needed before a firm conclusion can be drawn.
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33. Kidney function
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Early studies show potential improvement in uremic patients taking zinc supplements. Further research is needed to confirm these results. Zinc supplementation may be recommended only in the patients with proven zinc deficiency, but for all chronic renal failure patients it is questionable.
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34. Kwashiorkor (malnutrition from inadequate protein intake)
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Short-term zinc supplementation may increase weight gain and decrease infections, swelling, diarrhea, anorexia, and skin ulcers in children with extreme malnourishment.
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35. Leg ulcers
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There are conflicting findings regarding the potential benefit of zinc for healing leg ulcers. All studies, however, reported no or few adverse effects.
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36. Leprosy
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A few studies have examined the efficacy of zinc treatment in leprosy. Studies of zinc taken by mouth report positive results, while one study of topical zinc reports negative results. Further research is needed before a conclusion can be drawn.
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37. Liver cirrhosis
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People with alcoholic liver cirrhosis may be deficient in zinc. Preliminary studies suggest that zinc may benefit these patients. Further evidence is needed to confirm these findings.
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38. Lower respiratory infections in children
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Results from large clinical trials suggest that supplementation with zinc may reduce the incidence and severity of lower respiratory infections. Some studies suggest these effects to be only apparent in boys and not girls. A trend toward increased respiratory infections in children has been noted in one study. A recent study does not support the use of zinc supplementation in the management of acute lower respiratory infections requiring hospitalization in indigenous children living in remote areas. Due to conflicting results, further research is needed before a conclusion can be drawn. Future studies could examine whether these adult populations have a similar response.
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39. Macular degeneration
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Most studies examining the relationship between dietary zinc intake over many years and macular degeneration have not reported positive correlations. However, one large high-quality study, which examined the efficacy of zinc supplements in preventing loss of visual acuity, found that zinc supplements helped prevent the occurrence of age-related macular degeneration. Since study results are conflicting, additional well-designed clinical trials are needed before a recommendation can be made.
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40. Malaria
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Results are contradictory for the effect of zinc on malaria symptoms. Some high-quality studies suggest no effect of zinc supplementation on the severity of malaria. Other studies suggest that zinc supplementation may reduce the number of stays in hospital and death rate due to P . falciparum infection. Further well-designed trials are required to address these discrepancies.
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41. Menstrual cramps
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Case report data suggest a possible role for zinc supplementation in menstrual cramps. Additional study is needed to confirm these findings.
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42. Parasites
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In a few studies of varying quality, patients with cutaneous leishmaniasis were injected with zinc sulfate intralesionally. One study found zinc sulfate was better than meglumine antimoniate for the first four weeks, but no statistical differences were observed after six weeks. Zinc may decrease the severity of infection and re-infection of S . mansoni , but does not seem to prevent initial infection. More research should be done in this area to examine how zinc affects the S . mansoni life cycle and whether this data can be extrapolated to other species of Schistosoma . The effects of zinc on the rate of parasitic re-infestation have been examined in children. No significant effect of zinc treatment was found. Recent high-quality study data suggest that supplementation with zinc and vitamin A may favorably alter infection rate and duration among children. Due to conflicting results in this area, more research is needed before zinc can be recommended for the treatment of parasites.
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43. Pregnancy
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According to multiple reviews, there is no evidence to suggest that zinc supplementation offers benefits during pregnancy, although there is a possible reduction in labor complications and pre-term deliveries. However, results from individual studies suggest a possible benefit of zinc supplementation on blood pressure during pregnancy. Further research is needed before a conclusion can be drawn.
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