The prostate gland in men contains the highest amount of zinc of any soft tissue. Adequate zinc levels support prostate health and the body's normal production of testosterone. The skin has the third highest amount of zinc of the various organs in the body. A zinc deficiency can depress your body's immune response, which reduces the ability to eliminate pathogens, mount a response against threats, and produce antibodies. A study of immune function in the elderly found that even a marginal zinc deficiency in this population adversely impacts immune function and that zinc supplementation promotes a healthy immune response.
When it comes to taking supplemental zinc, there are several things to consider. The primary objective is to absorb the greatest amount of zinc from the fewest number of capsules and without side effects. So, how is this best accomplished? The form of the mineral — including the compound it is bound to — matters. One factor that is always an issue when supplementing minerals is that, by their very nature, they are not particularly well absorbed by the human body.
This obstacle to absorption can be partially overcome by optimizing the form the mineral comes in. This is simple chemistry — certain forms of minerals are better absorbed than others.
Thorne offers two forms of well-absorbed zinc — zinc picolinate and zinc bisglycinate — in many of their product formulas, as well as standalone products. For that reason, many doctors recommend that you take 2 mg of copper along with a zinc supplement.
Some studies suggest that taking oral zinc supplements may help improve acne. However, most studies used a high dose of zinc that could have toxic effects, and not all studies found any benefit.
There is some evidence that a topical form of zinc, used along with the topical antibiotic erythromycin, might be helpful.
Doctors often recommend zinc to slow the progress of AMD, an eye disease that occurs when the part of the retina that is responsible for central vision starts to deteriorate. A major clinical trial, the Age Related Eye Disease Study AREDS1 , found that people who had macular degeneration could slow down the damage by taking zinc 80 mg , vitamin C mg , vitamin E mg , beta-carotene 15 mg , and copper 2 mg.
If you have macular degeneration, ask your doctor whether these vitamins and minerals might help you. This is a very large amount of zinc and should only be used under a doctor's supervision. Many people believe that taking zinc lozenges or using zinc nasal spray when they first show signs of a cold can reduce the duration and severity of symptoms.
Not all studies agree, but most suggest that zinc acetate or gluconate lozenges may help you get over a cold faster. In one study, people who had early symptoms of a cold took either a lozenge with Those who took the zinc saw symptoms, such as coughing, runny nose, and sore throat, disappear faster than those who took placebo.
Zinc nasal sprays are controversial. Some studies have found zinc nasal sprays may help reduce cold symptoms, but other studies have found no effect. In addition, zinc nasal sprays may cause some people to lose their sense of smell. To be safe, talk to your doctor before using a zinc nasal spray. There is some evidence that zinc supplements not lozenges may help lower the risk of getting a cold in the first place. In one study, elderly people in a nursing home who had normal levels of zinc had a lower risk of pneumonia, fewer new antibiotic prescriptions and fewer days of antibiotic use.
More and better studies are needed that examine which kinds of zinc may be effective and against which kinds of cold viruses. People who have sickle cell disease are often deficient in zinc. Studies suggest that taking zinc supplements may help reduce symptoms of the disease. Children who took zinc showed improvements in height and weight, and had fewer sickle-cell crises.
Some studies suggest that zinc may help speed the healing of stomach ulcers. The studies used a form of zinc not available in the U. For children who have low levels of zinc, some evidence suggests that taking zinc may cause a slight improvement in symptoms, reducing hyperactivity, impulsivity, and impaired socialization in children. However, there was no change in attention deficit symptoms. Zinc may be most helpful to children with a high body mass index, low levels of free fatty acids in their blood, and low levels of zinc.
Cold sores are caused by the herpes simplex virus. In one study, people with cold sores used either a zinc oxide cream or placebo every 2 hours until their cold sores got better. Those who used the zinc cream had fewer symptoms and got better faster. In people with AIDS, low levels of zinc may be a result of poor absorption, medications, and loss of this important nutrient through vomiting or diarrhea.
Low levels of zinc can make the body more susceptible to infection, called an opportunistic infection. Some studies show that HIV positive people who take zinc have fewer infections, gain more weight, and have a better immune system response. But not all studies agree, and one even suggests that taking zinc may be associated with higher death rates. Preliminary evidence suggests that zinc may help treat Wilson's disease, a condition which causes copper to build up in the body.
Because zinc reduces how much copper the body absorbs, it may help reduce levels of copper in people with Wilson's disease. Other conditions may increase the need for zinc or affect how your body absorbs or uses this mineral.
Zinc from animal foods like red meat, fish, and poultry is more readily absorbed by the body than zinc from plant foods. Zinc is best absorbed when taken with a meal that contains protein.
The best sources of zinc are oysters richest source , red meats, poultry, cheese ricotta, Swiss, gouda , shrimp, crab, and other shellfish. Other good, though less easily absorbed, sources of zinc include legumes especially lima beans, black-eyed peas, pinto beans, soybeans, peanuts , whole grains, miso, tofu, brewer's yeast, cooked greens, mushrooms, green beans, tahini, and pumpkin, and sunflower seeds.
Zinc is available in several forms. Zinc sulfate is the least expensive form, but it is the least easily absorbed and may cause stomach upset. More easily absorbed forms of zinc are zinc picolinate, zinc citrate, zinc acetate, zinc glycerate, and zinc monomethionine.
If zinc sulfate causes stomach irritation, you can try another form, such as zinc citrate. The amount of elemental zinc is listed on the product label usually 30 - 50 mg. To determine the amount to take in supplement form, remember that you get about 10 - 15 mg from food.
Zinc lozenges, used for treating colds, are available in most drug stores. You should take zinc with water or juice. If zinc causes stomach upset, it can be taken with meals. Don't take zinc at the same time as iron or calcium supplements. A strong relationship exists between zinc and copper. Too much of one can cause a deficiency in the other. If you take zinc, including zinc in a multivitamin, you should also take copper.
You should not take high doses of zinc for more than a few days unless your doctor tells you to. Talk to your doctor before taking more than 40 mg of zinc per day and take breaks from zinc supplementation. During those breaks, get zinc from a well-balanced diet. Because of the potential for side effects and interactions with medications, you should take dietary supplements only under the supervision of a knowledgeable health care provider.
Research has shown that less than 40 mg a day is a safe amount to take over time, but researchers are not sure what happens if more is taken over a long period. Additional concerns have been raised about combining multivitamins and additional zinc supplements and an increased risk of dying from prostate cancer. Speak with physician. Taking mg of zinc daily, or taking supplemental zinc for 10 years or longer, has been linked with a doubling of the risk developing prostate cancer in men.
All statistical analyses were performed with the per-protocol individuals. Results are presented as medians IQRs. In 1 of the participants, a slightly elevated CRP concentration 3.
Anthropometry and PZn and CRP concentrations of male and female study participants before administration of the first test supplement 1. Median IQR zinc absorption in percentage from zinc citrate, zinc gluconate, and zinc oxide were The absorption of zinc citrate did not differ from that of zinc gluconate. Fractional absorption of zinc from zinc citrate, zinc gluconate, and zinc oxide supplements, including and excluding outlier participants of zinc oxide 1. The box plots show the median and 25th and 75th percentiles.
The open square and open circle are values below the limit of detection of 1. Two 1 male, 1 female of the 15 participants who had completed the study per protocol did not absorb zinc from zinc oxide. The measured zinc FA was below the limit of detection of the method, which was 1. Although there is no reason for excluding these 2 participants because they were apparently healthy on the day of administration of the zinc oxide supplement and up to 4 d later when the urine sample was collected, these are outliers, and statistical analysis was also performed without these 2 participants.
Additionally, because the enrichment in 70 Zn i. The principal finding of this study is that zinc absorption from zinc citrate is relatively high and is equivalent to that from zinc gluconate. Additionally, our results indicate that zinc oxide, the cheapest and most insoluble zinc supplementation compound, is significantly less well absorbed than citrate or gluconate, although admittedly only when the 3 outliers are included in the statistical analysis.
However, we could find no sound reason to exclude them. They all appeared healthy, and their absorption from zinc gluconate and zinc citrate was comparable with that of other study participants. Two previous studies also reported lower zinc absorption from zinc oxide supplements than from zinc acetate or sulfate supplements.
Henderson et al. Similarly, PZn concentration in pregnant women after 4 wk of consumption of a supplement containing zinc sulfate was higher than when consuming a supplement of zinc oxide 8. Our results indicate that zinc citrate could be a useful compound for zinc supplementation.
At the present time, WHO recommends the use of the water-soluble compounds zinc sulfate, zinc acetate, or zinc gluconate in the form of syrups or dispersible tablets in the management of diarrhea 6. We used stable isotopes to quantify zinc absorption with the DITR technique, which was developed by Friel et al.
It is recommended as the method of choice for determination of fractional zinc absorption 12 , 13 , 15 , The technique applied to a spot urine specimen is easy to implement and not sensitive to participant compliance. The DITR technique has been more frequently used to estimate absorption of zinc sulfate and oxide from zinc-fortified foods than from zinc supplements.
Supplemental Table 1 summarizes the results of absorption studies with different zinc compounds added to foods and measured using the DITR technique. There are no human absorption data to compare absorption of zinc citrate or zinc gluconate with zinc sulfate or zinc acetate, the other zinc supplements recommended by the WHO for diarrhea treatment 6. The WHO recommendations are based on randomized placebo-controlled trials investigating the effect of zinc supplementation on diarrhea treatment All the trials used zinc sulfate, zinc acetate, or zinc gluconate and reported similar efficacy.
Zinc citrate supplements would also be expected to improve diarrheal treatment, but additional studies are needed to confirm this. A surprising finding from the present study is that 3 participants of the 15 absorbed little or no zinc from zinc oxide, suggesting that there is a portion of the population that is not able to dissolve zinc oxide in the gastric juice, probably because of a high intragastric pH making it poorly absorbable.
Because the low absorption was measured in 3 individuals who absorbed zinc gluconate and zinc citrate normally and because all were apparently healthy at the time of supplement consumption, it is unlikely that this was a coincidence. Additional repeated measurements of their urine samples excluded an analytical error. Several studies have suggested that Helicobacter pylori -associated hypochlorhydria will decrease gastric acid and decrease iron absorption 25 ; however, results in relation to iron are contradictory 26 , and the prevalence of H.
Additionally, Serfaty-Lacrosniere et al. Additional investigations in relation to the influence of gastric pH on zinc absorption from zinc oxide supplements are recommended. In conclusion, our results indicate that zinc is as well absorbed from zinc citrate as from zinc gluconate and that zinc citrate should be as effective as zinc gluconate in the prevention of zinc deficiency and presumably also in the treatment of diarrhea. Its higher zinc content, good sensory properties, and lower price make it an attractive alternative to gluconate and other water-soluble zinc compounds.
Zinc oxide appears to be less well absorbed than other zinc compounds when given without food and may be minimally absorbed by some individuals. We thank A. Krzystek for technical assistance and the Clinical Trials Center team N.
Spitaleri, and R. Grossmann for their assistance in performing the study. All authors read and approved the final manuscript. National Center for Biotechnology Information , U. J Nutr. Published online Nov Hurrell 4. Richard F. Author information Article notes Copyright and License information Disclaimer.
Tay, C. Zeder, M. Hurrell, no conflicts of interest. E-mail: mg. This article has been cited by other articles in PMC. Abstract The water-soluble zinc salts gluconate, sulfate, and acetate are commonly used as supplements in tablet or syrup form to prevent zinc deficiency and to treat diarrhea in children in combination with oral rehydration. Materials and Methods Participants. Test compounds and stable isotope labels. Study design.
0コメント