Zinc
Zinc is an essential mineral involved in hundreds of enzymes. It plays many roles, including in antioxidant enzymes, brain function, and the immune system. Zinc is most commonly taken to reduce the duration of the common cold and support optimal testosterone levels.
Zinc is most often used for
Last Updated: September 28 2022
Zinc is an essential mineral and has a multitude of biological roles due to being a functional component of over 300 hundred enzymes. Many enzymes rely on zinc to be able to catalyze chemical reactions. Zinc also participates in the structure of important proteins and is involved in the regulation of gene expression.[1]
Oysters contain substantially more zinc than any other food, although red meat (e.g., beef, pork) and poultry provide the majority of zinc in the American diet. Other good sources of zinc are legumes, nuts, and dairy products.
The potential benefits of supplementation with zinc are largely dependent on the individual’s zinc status. That is, supplementation with zinc is unlikely to provide a benefit if zinc levels are already adequate. One exception to this rule may be in the case of respiratory tract infections, in which supplementation with zinc (in the form of lozenges) has been shown to reduce the duration of illness.[2][3]
Supplementation with zinc has been shown to improve severe acne,[4] depressive symptoms,[5] testosterone levels and sperm quality,[6] and markers of glycemic control and blood lipids, particularly in people with chronic disease.[7]
In the short term, consuming zinc in excess of the recommended upper limit (40 mg/day) can result in gastrointestinal symptoms (e.g., abominable pain, nausea, vomiting, diarrhea).[1] In the long term, excessive zinc intake can cause copper deficiency and associated anemia, as well as suppression of the immune system.[8] Also, the application of intranasal zinc has been reported to cause a loss of smell in some people.[9]
The potential benefits derived from supplementation with zinc seem to be at least partly attributable to zinc’s anti-inflammatory and antioxidant properties.
Additionally, zinc is required for normal development, activity, and function of both innate and adaptive immune cells;[8][10] the proper function of pancreatic beta-cells and glucose uptake;[11] and spermatogenesis and normal sperm physiology (e.g., sperm motility).[12]
In the brain, zinc ions inhibit N-methyl-D-aspartate (NMDA) receptors,[13] which is relevant to depression because the condition is characterized by elevated glutamatergic neurotransmission (which NMDA receptors contribute to).[14] Zinc may also benefit depression by increasing brain-derived neurotrophic factor levels.[15][16]
Zinc has two standard dosages. The low dosage is 5–10 mg, while the high dosage is 25–45 mg. The low dose works well as a daily preventative, while the high dosage should be taken by anyone at risk for a zinc deficiency.
Different forms of zinc contain different amounts of elemental zinc, which refers to the weight of the zinc molecule by itself (Note: Product labels tend to mark the elemental weight)
- Zinc citrate is approximately 34% zinc by weight. For a dose of 50 mg elemental zinc, take 146 mg of zinc citrate.
- Zinc sulfate depends on which form of salt is used. Most zinc sulphate used is presumably the heptahydrate form, which is 22% zinc by weight. For a dose of 50 mg elemental zinc, this is 220 mg of zinc sulfate. However, the anhydrous form is 40% and monohydrate is 36%, which would require roughly 125 and 139 mg, respectively.
- Zinc gluconate is approximately 13% zinc by weight. For a dose of 50 mg elemental zinc, take 385 mg of zinc gluconate.
- Zinc monomethionine is approximately 21% zinc by weight. For a dose of 50 mg elemental zinc, take 238 mg of zinc monomethionine.
Zinc should be supplemented daily.
Superloading zinc by taking up to 100 mg zinc a day is confirmed to be safe in the short term (2-4 months), but because this dose is higher than the 40 mg Tolerable Upper Limit (TUL) of zinc, prolonged superloading is not advised. Zinc’s intestinal uptake is hindered by other minerals, including calcium, magnesium, and iron, since they all use the same transporter. If the transporter’s uptake limit (800 mg) is exceeding between these four minerals, absorption rates will fall. Taking less than 800 mg of these four minerals at the same time is fine.
Zinc lozenges, for the purpose of reducing the common cold, seem to be most effective when the total daily dose is over 75 mg and is divided into 6-8 doses, each separated by 2-3 hours when awake. It is likely dangerous to take zinc lozenges for extended periods of time.