Zinc is one of the 24 micronutrients needed for survival. It is found in meat, egg, and legume products. Oysters are particularly good sources of zinc.
Zinc is an aphrodisiac and Testosterone Booster, but it will only raise testosterone levels if the user is deficient in zinc. Zinc is also very important for the functioning of the enzyme, hormone, and immune systems.
In very high doses, zinc can act as an aromatase inhibitor and reduce estrogen levels. It is also a potent antioxidant and can provide benefits for prostate issues. Zinc also plays a role in the repair of intestinal mucosa, when supplemented in high doses.
Zinc is lost through sweat, making supplementation very important for athletes that don’t get a lot of zinc through food.
A cross-sectional study of data gathered from 14,834 Americans (7,435 women and 7,399 men) between 2009 and 2014 found an association between depression and zinc deficiency. Likewise, a cross-sectional study of data gathered from 2,019 pregnant Canadian women between 2002 and 2005 reported that being in the highest quintile for zinc intake appeared to buffer the impact of stress and thus the development of depressive symptoms.
Cross-sectional studies are snapshots in time, though: they might show correlation, but they cannot establish causation. Zinc deficiency was associated with depression, but did it cause the depression? Or did depression cause the zinc deficiency? Or could it be that depression and zinc deficiency were both caused by some other, undetermined factor?
Those are questions cross-sectional studies cannot answer. Fortunately, some randomized trials, which follow people over time, suggest that supplemental zinc makes antidepressant therapies more effective.
Here again, we don’t yet know all the mechanisms at play. We know that zinc influences the immune system and brain homeostasis, and like magnesium it may act on your brain’s NMDA receptors. Also, as with magnesium and Vit D, low zinc levels may impair testosterone production, and as we saw, low testosterone is associated with low mood in both men and women.
If you are not deficient, though, just taking more zinc isn’t likely to help, which might be why, in a recent triple-blind RCT, supplemental zinc failed to alleviate postpartum anxiety and depression. (The factors leading to postpartum anxiety and depression, it should be noted, may differ substantially from the factors that lead to clinical anxiety and depression in the general population.)
In any case, getting too much zinc is not a good idea. In fact, far overshooting your Recommended Daily Intake (RDA) can be harmful: in the short term, it can cause nausea and vomiting; in the long term, it can lead to a copper deficiency, which may be inversely associated with depression.
Still, while overt zinc deficiency is uncommon, it isn’t entirely unknown. It has notably been documented in people suffering from malabsorption syndromes — including Crohn’s disease, celiac disease, and short-bowel syndrome. Furthermore, even healthy people can have suboptimal levels — especially the elderly. Finally, since zinc is lost through sweat, like magnesium, athletes should take special care of their zinc intake.
Fortunately, zinc rich foods are not rare. Zinc is mostly found in animal-based foods, but with some planning, vegans can reach their RDAs without resorting to supplementation.
Zinc Rich Foods
* DV = Daily Value. The U.S. Food and Drug Administration (FDA) developed DVs to help consumers compare the nutrient contents of products within the context of a total diet. The DV for zinc used for the values in Table 2 is 15 mg for adults and children age 4 years and older. This DV, however, is changing to 11 mg as the updated Nutrition and Supplement Facts labels are implemented . The updated labels must appear on food products and dietary supplements beginning in January 2020, but they can be used now. FDA does not require food labels to list zinc content unless a food has been fortified with this nutrient. Foods providing 20% or more of the DV are considered to be high sources of a nutrient, but foods providing lower percentages of the DV also contribute to a healthful diet.
Supplements contain several forms of zinc, including zinc gluconate, zinc sulfate, and zinc acetate. The percentage of elemental zinc varies by form. For example, approximately 23% of zinc sulfate consists of elemental zinc; thus, 220 mg of zinc sulfate contains 50 mg of elemental zinc. The elemental zinc content appears in the Supplement Facts panel on the supplement container. Research has not determined whether differences exist among forms of zinc in absorption, bioavailability, or tolerability.
In addition to standard tablets and capsules, some zinc-containing cold lozenges are labeled as dietary supplements.
The above information is taken from the folks at examine.com and US National Institutes Of Health