Zinc is an essential mineral found in some foods such as beans, legumes, nuts, whole grains, fortified cereals, dairy products, meat, and seafood such as crab and lobster. It is also available as a dietary supplement. Supplements contain several forms of zinc, including zinc gluconate, zinc sulfate, zinc orotate and zinc acetate. Zinc support normal growth and development as well as playing a role in immune function. Zinc affects protein synthesis and is required for proper function of red and white blood cells. It is highly concentrated in our bones, the pancreas, kidneys, liver, and retina. The data below will discuss evidence based applications of zinc for the common cold, zinc deficiency avoidance, incidence of infections with zinc nutritional status, zinc as it relates to immunity, zinc in pregnancy, and the best form of zinc supplements. It is our view that zinc should be consumed whenever possible in the form of zinc containing foods, but it is difficult to obtain the necessary amounts of the mineral supported in randomized controlled trials. Many of these trials show evidence of benefit for various health conditions at doses above the maximum recommended intakes.
Different zinc preparations:
There are many forms of the essential mineral zinc including zinc orotate, zinc picolinate, zinc gluconate, zinc acetate, zinc oxide, zinc sulfate, and chelated zinc. Many of these trials show evidence of benefit for various health conditions at doses above the maximum recommended intakes. The research data based on the most positive randomized controlled trials support zinc gluconate and zinc acetate as having the greatest amount of supportive evidence for making an impact in various health conditions. The elemental zinc was believed to be bound tighter in zinc orotate and zinc citrate forms possibly reducing effectiveness of zinc treatments in some trials. (2,3) According to other sources, the best form of zinc is zinc orotate because it is the most readily absorbed by the body due to neutral charge, but the use of this form of zinc is more anecdotal and does not have evidence supported by randomized controlled trials. (1)
Zinc and the common cold:
Zinc and a review of randomized controlled trials: A systematic review and meta-analysis by Science M et al looked at 17 randomized controlled trials, involving 2,121 participants suggested that oral zinc supplementation may shorten the duration of cold symptoms. The team observed that zinc shortened the duration of cold symptoms by an average of 1.65 days in a total of 934 adults in 8 different studies, but no significant effect was seen among children. In addition, the researchers reported more common instances of side effects– most notably bad taste and nausea, in the zinc group (as compared to placebo group). The majority of trials reviewed in this study used zinc gluconate, zinc acetate, and zinc sulfate. The researchers observed that a reduction in the duration of cold symptoms was greater with high doses (≥75 mg versus <75 mg) of ionic zinc. In addition, the researchers reported more common instances of side effects– most notably bad taste and nausea, in the zinc group (as compared to placebo group). (2)
Zinc is an essential micronutrient for human health:
Zinc is vital for many biological functions including healthy immune response. A review of 13 trials looking at the link between zinc and treatment of the common cold in adults suggests zinc may be mildly effective for management of colds. The review did not find any trials which evaluated zinc in cold prevention. Compared to placebo, nasal sprays, were found to reduce the duration and severity of a cold in 4 trials and 2 trials, respectively. Lozenges, small medicated tablets intended to be dissolved slowly in the mouth (like a cough drop), containing at least 13mg of zinc are recommended every 2 hours during a cold episode but individuals may experience bitter taste, nausea, and impaired smell and taste while taking zinc. Zinc use should be stopped after 6-8 weeks or the individual may become copper deficient. In 5 trials lozenges were found to reduce cold symptom duration and severity. Lozenges containing 13-24 mg of zinc taken every 2 hours were associated with a reduced cold duration of 1.3-6.9 days. Severity also improved. Results were difficult to decipher in the studies due to dosing and formulation questions. (3)
Zinc requirement:
Zinc requirement for non-vegetarians and vegetarians: A study by Hunt JR found that Vegetarians may require 50% more zinc than non-vegetarians based on phytate-zinc molar ratios >15. Phytate is a non-digestible salt responsible for the storage of phosphorus. Phytate in plant tissues reduces the bioavailability of zinc and iron in humans. Therefore, the higher the amount of phytate consumed, the higher the ratio of phytate will be to zinc and iron resulting in less absorption. Compared to non-vegetarian diets, lacto-ovo-vegetarian diets (which includes consumption of eggs and dairy products, but not meat) were associated with a reduced zinc absorption of about 35%. Meat was replaced by legumes, whole grains, seeds, and nuts, resulting in phytate-zinc molar ratios of 14 and 5 for the lacto-ovo-vegetarian and non-vegetarian diets, respectively. After 4 weeks, women on the vegetarian diet absorbed less zinc (2.4 mg Zn/d) than their non-vegetarian counterparts 3.7 mg Zn/d (26% vs 33%). After about 8 weeks, this difference was associated with a 5% reduction in zinc in the blood. The information in this study supports that vegetarians would benefit from zinc supplementation. (4)
Institute of Medicine zinc intake recommendations:
According to the Food and Nutrition Board Institute of Medicine, zinc intake by vegetarians was suggested by this source to be consumed in 2-fold greater amounts than those eating a non-vegetarian diet to meet requirements. Vegetarians of the corresponding age groups below are encourage to obtain twice the amounts recommended. This source recommends the following daily zinc requirement for each of the mentioned age groups (5):
- 6 months, 2 mg
- 7-12 month olds, 3 mg
- children 1-3 years old, 3 mg
- 4-8 year olds, 5 mg
- 9-13 year olds, 8 mg
- all males over 14 years old, 11 mg
- females 9-13 years old, 8 mg
- females age 14-18, 9 mg
- females over age 18, 8 mg
- all pregnant women under 18 years old, 12 mg
- all pregnant women age 19-50, 11 mg
- lactating females under age 18, 13mg
- lactating females over age 18, 12 mg
Daily allowance of zinc:
Daily allowance of zinc may be found at the following link for all ages (5) : http://iom.edu/~/media/Files/Activity%20Files/Nutrition/DRIs/DRI_Elements.pdf
Zinc and infection in the elderly:
Seniors and zinc benefits: Prasad AS et al found that healthy seniors who supplement with zinc experience a reduced rate of infections and oxidative stress. In the current randomized, double-blind, placebo-controlled trial, researchers determined whether zinc would have an effect on the incidence of total infections in 50 subjects aged 55 to 87 years. They also investigated if zinc would have an effect on oxidative stress markers, and on the generation of tumor necrosis factor, a group of white blood cells known as cytokines responsible for inflammation that are linked to everything from psoriasis to heart failure. Researchers gave the zinc-supplemented group 45 mg zinc gluconate orally on a daily basis for 12 months. Researchers documented the incidence of infections during the supplementation period as well as the generation of inflammatory cytokines, T helper 1 and T helper 2 cytokines, and oxidative stress markers. The plasma concentrations of zinc were measured at baseline and after supplementation. Compared with a group of younger adults, at baseline, the older subjects had significantly lower plasma zinc, higher generation of inflammatory cytokines and interleukin 10, and higher plasma oxidative stress markers and endothelial cell adhesion molecules. Endothelial cells are the cells lining the arteries and the increase in adhesion molecules signifies that increased build up and inflammation was occurring in the arteries of the subjects. In subjects supplemented with zinc, the incidence of infections declined. In addition, the generation of tumor necrosis factor and plasma oxidative stress markers were significantly lower in zinc-supplemented subjects compared to the placebo group. (6)
Elderly, rates of infection, and zinc:
An observational study by Meydani SM et al, researchers looked at the link between zinc, which is important for immune function, and pneumonia among the elderly. Researchers analyzed blood samples from a previous study that investigated the role of Vitamin E in preventing respiratory infections in nursing home residents. All of the participants received daily supplements containing 50 percent of the recommended dietary allowance of several vitamins and minerals, including zinc, for one year. Participants with baseline (n = 578) or final (n = 420) zinc concentrations were categorized as having low (<70 microg/dL) or normal (>or=70 microg/dL) zinc concentrations. The results indicate that the participants whose zinc concentrations remained low throughout that 12-month period had more difficulty battling pneumonia. Maintaining normal zinc concentration in the blood throughout the 12-month study period benefited the participants even if they did develop pneumonia. Those with normal zinc concentration had lower rates of pneumonia, fewer (by almost 50%) antibiotic prescriptions, a shorter duration of pneumonia, and fewer days of antibiotic use (3.9 d compared with 2.6 d) (P
Zinc and mortality risk in the elderly:
Age-related macular degeneration (AMD) is an aging change in the back of the eye that may lead to loss of the central vision. The study reports the beneficial effect of antioxidants (vitamin C, 500 mg; vitamin E, 400 IU; beta carotene, 15 mg; and zinc, 80 mg as zinc oxide with 2 mg of cupric oxide) on the risk of AMD progression among Age-Related Eye Disease Study (AREDS) participants. Investigators also examined the relationship between AMD, cataracts and mortality. During a median follow-up of 6.5 years, 11% or 534 participants had died. This marked an increased mortality risk among participants with advanced AMD. However, participants randomly assigned to receive 80 mg zinc with 2 mg cupric oxide, whether alone or combined with antioxidants, had lower mortality than those not taking the mineral. They report a 27% lower relative risk of mortality for zinc alone, and a 12% lower relative risk for those who took zinc combined with beta-carotene, vitamin C and vitamin E. The beneficial effect of zinc on mortality was associated with less death from respiratory causes. (8). This study supports the findings of Meydani SM et al mentioned above.
Zinc during pregnancy:
Hovdenak performed a review of zinc in pregnancy who found that it may be beneficial to pregnant women with zinc deficiency due to risk of reduced fetal growth seen in zinc deficient pregnant animals. There was also lower birth weight, and lower head circumference seen in zinc deficient pregnant women. Diets high in phosphorus, excessive iron supplements, and gastrointestinal diseases may reduce absorption of zinc. There is a lack of evidence seen in the literature for zinc supplements during pregnancy unless deficiency exists. (9)
Zinc and Alzheimer’s disease:
Over a placebo, zinc given to zinc deficient elderly patients age 70 and older at a dose of 150 mg oral daily (unknown zinc formula) for 6 months resulted in protection from cognitive decline after assessed by three different scoring methods including the Alzheimer’s Disease Assessment Scale, cognitive subsection (ADAS-Cog), Clinical Dementia Rating Scale Sum of Boxes (CDR-SOB), and the mini–mental state examination (MMSE) scores. The results were statistically significant for the ADAS-Cog and CDR-SOB scores, but not for the MMSE scores. Zinc levels in the Alzheimer’s patients were found to be about 8% lower than age-matched controls and about 24% lower than young adults on average. Copper is believed by the authors of the study to oxidize molecules which become toxic to neurons. The protection in cognitive decline by the zinc supplement was believed to be either restoration of neuronal zinc levels or reduction in serum copper levels by the zinc supplement or both. (12)
Zinc and sickle cell anemia patients:
Tapazoglou et al studied the relationship between zinc and natural killer activity in adults with sickle cell disease and 2 volunteers without the disease that were zinc deficient due to diet. Zinc deficiency is associated with lower immune response. Natural killer cells are critical to the immune system by providing rapid immune response to virally infected cells. Researchers found a significantly lower level of natural killer activity in patients with sickle cell and zinc deficiency (5.1 lytic units per 10(6) cells) than in controls (11.7 lytic units per 10(6) cells). However, when the two volunteers’ zinc intake was increase, natural killer activity also increased. Therefore, authors conclude there is a linear relationship between zinc and natural killer cell activity. (10)
Common Highest Zinc Containing Foods:
| Mollusks, oyster, eastern, cooked, breaded and fried, 3 oz | 74.06 mg |
| Mollusks, oyster, eastern, wild, raw, 6 medium | 33.01 mg |
| GENERAL MILLS, TOTAL Raisin Bran, 1 cup | 15.57 mg |
| KELLOGG, KELLOGG’S PRODUCT 19, 1 cup | 15.30 mg |
| KELLOGG, KELLOGG’S ALL-BRAN COMPLETE Wheat Flakes, 3/4 cup | 15.08 mg |
| Cereals ready-to-eat, GENERAL MILLS, Whole Grain TOTAL, 3/4 cup | 15.00 mg |
| Beans, baked, canned, with pork and tomato sauce, 1 cup | 13.86 mg |
| Beef, chuck, blade roast, trimmed to 0″ fat, braised, 3 oz | 8.73 mg |
| Cereals ready-to-eat, GENERAL MILLS, WHEATIES, 1 cup | 8.34 mg |
| Beef, chuck, blade roast, trimmed to 1/8″ fat, braised, 3 oz | 7.00 mg |
| Crustaceans, crab, alaska king, cooked, moist heat, 3 oz | 6.48 mg |
| Turkey, whole, giblets, cooked, simmered, 1 cup | 6.22 mg |
| Chicken, broilers or fryers, giblets, cooked, simmered, 1 cup | 6.13 mg |
| Turkey from whole, neck, meat only, cooked, simmered, 1 neck | 6.13 mg |
| Fast foods, hamburger; double, regular patty; condiments, 1 sandwich | 5.81 mg |
| Beans, baked, canned, plain or vegetarian, 1 cup | 5.79 mg |
| Fast foods, hamburger; double, large patty; condime, vegetables | 5.67 mg |
| Cereals ready-to-eat, GENERAL MILLS, LUCKY CHARMS, 1 cup | 5.59 mg |
| Cereals ready-to-eat, GENERAL MILLS, KIX, 1-1/3 cup | 5.23 mg |
| Fast foods, cheeseburger; large patty; condiments, bacon, 85 3 oz | 5.17 mg |
| Crustaceans, crab, blue, canned 135 1 cup | 5.14 mg |
| GENERAL MILLS, CINNAMON TOAST CRUNCH, 3/4 cup | 5.11 mg |
| GENERAL MILLS, CHEERIOS, 1 cup | 5.02 mg |
| Fast foods, chimichanga, with beef , 1 chimichanga | 4.96 mg |
| Fast foods, hamburger; single, large patty; condiments and vegetables | 4.88 mg |
| Beans, baked, canned, with franks, 1 cup | 4.84 mg |
| Fast foods, cheeseburger; large patty; with condiments and vegetables | 4.75 mg |
| Fast foods, taco with beef, cheese and lettuce, hard shell, 1 large | 4.60 mg |
| Snacks, trail mix, regular, chocolate chips, salted nuts,seeds, 1 cup | 4.58 mg |
| Cereals ready-to-eat, QUAKER, QUAKER OAT CINNAMON LIFE, 3/4 cup | 4.41 mg |
| Fast foods, submarine sandwich, with roast beef, 1 sandwich, 6″ roll | 4.38 mg |
| Cereals ready-to-eat, QUAKER, CAP’N CRUNCH, 3/4 cup | 4.36 mg |
| Cereals ready-to-eat, GENERAL MILLS, Rice CHEX, 1-1/4 cup | 4.31 mg |
| Beef, round, eye of round, roast, trimmed to 1/8″ fat roasted, 3 oz | 4.30 mg |
| QUAKER, CAP’N CRUNCH with CRUNCHBERRIES, 3/4 cup | 4.30 mg |
| Fast foods, cheeseburger; double, regular patty; plain, 1 sandwich | 4.26 mg |
| Barley, pearled, raw, 1 cup | 4.26 mg |
| GENERAL MILLS, RAISIN NUT BRAN, 1 cup | 4.24 mg |
| GENERAL MILLS, COCOA PUFFS, 1 cup | 4.17 mg |
| QUAKER, CAP’N CRUNCH’S PEANUT BUTTER CRUNCH, 3/4 cup | 4.13 mg |
| Cereals ready-to-eat, GENERAL MILLS, HONEY NUT CHEERIOS, 1 cup | 4.02 mg |
| Pork, fresh, spareribs, separable lean and fat, cooked, braised, 3 oz | 3.91 mg |
| GENERAL MILLS, REESE’S PUFFS, 3/4 cup | 3.87 mg |
| GENERAL MILLS, APPLE CINNAMON CHEERIOS, 3/4 cup | 3.75 mg |
| Buckwheat flour, whole-groat, 1 cup | 3.74 mg |
| Cereals ready-to-eat, GENERAL MILLS, BASIC 4, 1 cup | 3.74 mg |
| Cereals ready-to-eat, KELLOGG, KELLOGG’S ALL-BRAN, 1/2 cup | 3.72 mg |
| Cereals ready-to-eat, QUAKER, QUAKER OAT LIFE, plain, 3/4 cup | 3.66 mg |
| Cereals ready-to-eat, GENERAL MILLS, HONEY NUT CLUSTERS, cup | 3.63 mg |
| Cereals ready-to-eat, GENERAL MILLS, GOLDEN GRAHAMS, 3/4 cup | 3.63 mg |
| Cereals ready-to-eat, GENERAL MILLS Corn CHEX, 1 cup | 3.63 mg |
| Pork, fresh, loin, country-style ribs, cooked, braised, 3 oz | 3.60 mg |
| Cereals ready-to-eat, GENERAL MILLS, Honey Nut CHEX, 3/4 cup | 3.52 mg |
| Cereals ready-to-eat, GENERAL MILLS, TRIX, 1 cup | 3.51 mg |
| Fast foods, cheeseburger; double, regular patty, condiments, vegetables | 3.49 mg |
| Veal, rib, separable lean and fat, cooked, roasted, 3 oz | 3.48 mg |
| Crustaceans, lobster, northern, cooked, moist heat, 3 oz | 3.44 mg |
| Cereals ready-to-eat, GENERAL MILLS, BERRY BERRY KIX, 3/4 cup | 3.42 mg |
| Fast foods, roast beef sandwich, plain, 1 sandwich | 3.39 mg |
| Veal, leg (top round), separable lean and fat, cooked, braised, 3 oz | 3.37 mg |
| Cereals ready-to-eat, GENERAL MILLS, Wheat CHEX, 1 cup | 3.36 mg |
| Cheese, ricotta, part skim milk, 1 cup | 3.30 mg |
| Crustaceans, crab, blue, cooked, moist heat, 3 oz | 3.24 mg |
| Fast foods, tostada, with beans, beef, and cheese, 1 tostada | 3.17 mg |
| Wheat flour, whole-grain, 1 cup | 3.12 mg |
| Soup, chunky vegetable, canned, ready-to-serve, 1 cup | 3.12 mg |
| Cheese sauce, prepared from recipe, 1 cup | 3.06 mg |
| Fast foods, taco with beef, cheese and lettuce, hard shell, 1 small | 2.99 mg |
| Beans, white, mature seeds, canned, 1 cup | 2.93 mg |
| Oat bran, raw, 1 cup | 2.92 mg |
| Pork, fresh, loin, center loin (chops), bone-in, cooked, pan-fried, 3 oz | 2.91 mg |
| Turkey, enhanced, dark meat, meat only, roasted, 1 serving (3 oz) | 2.89 mg |
| Chicken, stewing, meat only, cooked, stewed, 1 cup | 2.88 mg |
| Milk, canned, condensed, sweetened, 1 cup | 2.88 mg |
| Cheese, ricotta, whole milk, 1 cup | 2.85 mg |
| Baking chocolate, unsweetened, squares, 1 square | 2.73 mg |
| Lentils, mature seeds, cooked, boiled, without salt, 1 cup | 2.51 mg |
| Chickpeas (garbanzo beans, bengal gram), mature seeds, boiled, 1 cup | 2.51 mg |
| Cowpeas (blackeyes), immature seeds, frozen, boiled, drained, 1 cup | 2.41 mg |
| Macaroni and cheese, frozen entrée, 1 package | 2.26 mg |
| Fast foods, cheeseburger; single, regular patty; plain, 1 sandwich | 2.24 mg |
| Cornmeal, whole-grain, yellow,1 cup | 2.22 mg |
| Cowpeas (blackeyes, crowder, southern), boiled, no salt, 1 cup | 2.22 mg |
| Yogurt, plain, skim milk, 13 grams protein per 8 ounce, 8-oz container | 2.20 mg |
| Wild rice, cooked, 1 cup | 2.20 mg |
| Seeds, pumpkin and squash seeds, roasted, salt added, 1 oz (142 seeds) | 2.17 mg |
| Soup, chicken vegetable, chunky, canned, ready-to-serve, 1 cup | 2.16 mg |
| Cereals ready-to-eat, KELLOGG, KELLOGG’S RAISIN BRAN, 1 cup | 2.07 mg |
| Beans, baked, canned, with pork and sweet sauce, 1 cup | 2.05 mg |
| Tostada with guacamole, 1 tostada | 2.04 mg |
| Yogurt, plain, low fat, 12 grams protein per 8 ounce, 8-oz container | 2.02 mg |
| Rice, white, long-grain, regular, raw, enriched, 1 cup | 2.02 mg |
| Soybeans, mature cooked, boiled, without salt, 1 cup | 1.98 mg |
| Chili con carne with beans, canned entrée, 1 cup | 1.98 mg |
| Peas, split, mature seeds, cooked, boiled, without salt, 1 cup | 1.96 mg |
| Milk, canned, evaporated, with added vitamin D, no vitamin A, 1 cup | 1.94 mg |
| Turkey, whole, enhanced, meat only, roasted, 1 serving (3 oz) | 1.94 mg |
| Mushrooms, shiitake, cooked, without salt, 1 cup | 1.93 mg |
| Beans, black, mature seeds, cooked, boiled, without salt, 1 cup | 1.93 mg |
| Shake, fast food, vanilla, 16 fl oz | 1.90 mg |
| Fast foods, croissant, with egg, cheese, and bacon, 1 croissant | 1.90 mg |
| Beans, kidney, red, mature seeds, cooked, boiled, without salt, 1 cup | 1.89 mg |
| Rice, white, long-grain, parboiled, enriched, dry,1 cup | 1.89 mg |
| Fast foods, chicken fillet sandwich, plain, 1 sandwich | 1.87 mg |
| Beans, navy, mature seeds, cooked, boiled, without salt, 1 cup | 1.87 mg |
| Fast foods, submarine sandwich, with tuna salad, 1 sandwich, 6″ roll | 1.87 mg |
| Nuts, pine nuts, dried, 1 oz | 1.83 mg |
| Lima beans, large, mature seeds, cooked, boiled, without salt, 1 cup | 1.79 mg |
| Fast foods, nachos, with cheese, 6-8 nachos | 1.79 mg |
| Fast foods, english muffin, with egg, cheese, Canadian bacon, 1 muffin | 1.77 mg |
| Miso, 1 cup | 1.76 mg |
| Seeds, sunflower seed kernels, dry roasted, with salt added, 1/4 cup | 1.69 mg |
| Nuts, coconut meat, dried (desiccated), sweetened, shredded, 1 cup | 1.69 mg |
| Bagels, plain, w/ calcium propionate (onion, poppy, sesame), 4″ bagel | 1.69 mg |
| Potatoes, au gratin, home-prepared from recipe using butter, 1 cup | 1.69 mg |
| Cowpeas (blackeyes, crowder, southern), mature seeds, canned, 1 cup | 1.68 mg |
| Yogurt, fruit, low fat, 10 grams protein per 8 ounce, 8-oz container | 1.68 mg |
| Beans, pinto, mature seeds, cooked, boiled, without salt, 1 cup | 1.68 mg |
| Tomato products, canned, paste, without salt added, 1 cup | 1.65 mg |
| Soybeans, green, cooked, boiled, drained, without salt, 1 cup | 1.64 mg |
| Refried beans, canned, traditional style (includes USDA commodity), 1 cup | 1.64 mg |
| Nuts, cashew nuts, dry roasted, with salt added, 1 oz | 1.59 mg |
Adapted from: Nutritive Value of Foods, United States Department of Agriculture, Agricultural Research Service, Home and Garden Bulletin Number 72. May be accessed at:https://www.ars.usda.gov/SP2UserFiles/Place/12354500/Data/SR25/nutrlist/sr25w309.pdf and http://www.nal.usda.gov/fnic/foodcomp/Data/HG72/hg72_2002.pdf
Assessment and Plan: Zinc
- Zinc should be consumed in the form of zinc containing foods, but the amount supported by research in randomized controlled trials is difficult to obtain from foods alone. Many of these trials show evidence of benefit for various health conditions at doses above the maximum recommended intakes. The most positive randomized controlled trials have supportive evidence for zinc gluconate and zinc acetate forms of the mineral to have the best potential for benefit in various health conditions. (2,3) Zinc orotate does not have enough research backed by randomized controlled trials to support its use. (1)
- Zinc shortened the duration of cold symptoms by an average of 1.65 days in a total of 934 adults in 8 different studies, but no significant effect was seen among children. A reduction in the duration of cold symptoms was greater with high doses (≥75 mg versus <75 mg) of ionic zinc. In addition, the researchers reported more common instances of side effects– most notably bad taste and nausea, in the zinc group compared to placebo group. (2)
- In 5 trials lozenges were found to reduce cold symptom duration and severity. Lozenges containing 13-24 mg of zinc taken every 2 hours were associated with a reduced cold duration of 1.3-6.9 days. Severity also improved. (3)
- According to the Food and Nutrition Board Institute of Medicine, zinc intake was suggested by this source to be consumed in 2-fold greater amounts than those eating a non-vegetarian diet to meet requirements. Daily allowance of zinc may be found at the following link for all ages: (5) http://iom.edu/~/media/Files/Activity%20Files/Nutrition/DRIs/DRI_Elements.pdf
- In 50 subjects aged 55 to 87 years, 45 mg zinc gluconate orally on a daily basis for 12 months reduced the incidence of infections. (6)
- Patients with normal zinc concentration had lower rates of pneumonia, almost 50% fewer antibiotic prescriptions, a shorter duration of pneumonia, and fewer days of antibiotic use (3.9 d compared with 2.6 d) (7)
- The Age-Related Eye Disease Study (AREDS) found an increased mortality risk among participants with advanced age-related macular degeneration. Those subjects assigned to receive 80 mg zinc with 2 mg cupric oxide were note to have a 27% lower relative risk of mortality for zinc alone, and a 12% lower relative risk for those who took zinc combined with beta-carotene, vitamin C and vitamin E. The beneficial effect of zinc on mortality was associated with less death from respiratory causes. (8)
- Pregnant women with zinc deficiency may pose a risk of reduced fetal growth, lower birth weight, and lower head circumference. (9)
- Zinc deficiency is associated with lower degree of immune response. (10)
- Zinc and Alzheimer’s disease: Over a placebo, zinc given to zinc deficient elderly patients age 70 and older at a dose of 150 mg oral daily (unknown zinc formula) for 6 months resulted in protection from cognitive decline believed due to either restoration of neuronal zinc levels or reduction in serum copper levels by the zinc supplement or both (12).
References:
1.Group E, MD, The Global Healing Center. 7 Common Type of Zinc Explained. Dec11, 2009. http://www.globalhealingcenter.com/natural-health/types-of-zinc/
2.Science M, Johnstone J, Roth DE, Guyatt G, Loeb M. Zinc for the treatment of the common cold: a systematic review and meta-analysis of randomized controlled trials. CMAJ. 2012 Jul 10;184(10):E551-61. http://www.ncbi.nlm.nih.gov/pubmed/22566526
3.Nahas, Richard. Complementary and alternative medicine for prevention and treatment of the common cold. Can Fam Physician. 2011 January; 57(1): 31–36. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3024156/
4.Hunt JR. Bioavailability of iron, zinc, and other trace minerals from vegetarian diets. Am J Clin Nutr. 2003;78(3 Suppl):633S-639S. http://ajcn.nutrition.org/content/78/3/633S.full
5.Food and Nutrition Board, Institute of Medicine. Dietary reference intakes for vitamin A, vitamin K, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc. Washington, DC: National Academy Press, 2001. http://iom.edu/~/media/Files/Activity%20Files/Nutrition/DRIs/DRI_Elements.pdf
6.Prasad AS, Beck FWJ, Bao B, Fitzgerald JT, Snell DC, Steinberg JD, Cardozo LJ. Zinc supplementation decreases incidence of infections in the elderly: effect of zinc on generation of cytokines and oxidative stress. American Journal of Clinical Nutrition. March 2007;85(3):837-844. http://ajcn.nutrition.org/content/85/3/837.abstract?ijkey=a1548bc72a0a7475c413c366cc330660f56f25a7&keytype2=tf_ipsecsha
7.Meydani SM, , Barnett JB, Dallal ,GE, Fine BC, Jacques PF, Leka LD, and Hamer, DH. Serum zinc and pneumonia in nursing home elderly. American Journal of Clinical Nutrition. 2007: 86: 1167-1173. http://www.sciencedaily.com/releases/2007/10/071022120214.htm
8.AREDS Research Group. Associations of mortality with ocular disorders and an intervention of high-dose antioxidants and zinc in the Age-Related Eye Disease Study. AREDS Report No. 13. Arch Ophthalmol. 122:716-726, 2004. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1473208/?report=abstract
9.Hovdenak N, Haram K. Influence of mineral and vitamin supplements on pregnancy outcome. Eur J Obstet Gynecol Reprod Biol. 2012 Oct;164(2):127-32. http://www.ncbi.nlm.nih.gov/pubmed/22771225
10.Tapazoglou E, Prasad AS, Hill G, Brewer GJ, Kaplan J. Decreased natural killer cell activity in patients with zinc deficiency with sickle cell disease. J Lab Clin Med. 1985 Jan;105(1):19-22. http://www.ncbi.nlm.nih.gov/pubmed/3968462?dopt=Abstract
11.Nutritive Value of Foods, United States Department of Agriculture, Agricultural Research Service, Home and Garden Bulletin Number 72. May be accessed at: https://www.ars.usda.gov/SP2UserFiles/Place/12354500/Data/SR25/nutrlist/sr25w309.pdf and http://www.nal.usda.gov/fnic/foodcomp/Data/HG72/hg72_2002.pdf
12.Brewer GJ, Kaur S. Zinc Deficiency and Zinc Therapy Efficacy with Reduction of Serum Free Copper in Alzheimer’s Disease. Int J Alzheimers Dis. 2013;2013:586365. Epub 2013 Oct 10. http://www.ncbi.nlm.nih.gov/pubmed/24224111