Zinc
Zinc is a trace mineral that the body needs but can’t make on its own, so it has to come from food or supplements. It helps the immune system fight off germs, supports metabolism by helping the body turn food into energy, and plays a role in wound healing and the senses of taste and smell. Zinc also helps cells grow and repair properly. Most people get enough zinc from a varied diet that includes foods like beef, chicken, fish, shellfish, dairy products, beans, nuts, and fortified cereals.
Is this used to correct a deficiency or achieve supramaximal levels?
Deficiency
Is it taken for life span or health span?
Healthspan
Is it targeting a specific disease? Or general health?
General and cold, diarrhoea
Any genetic involvement?
AE gene, increased susceptibility to infection which can be corrected with zinc supplementation
Is there a biomarker to track its effects?
Plasma, urinary and hair zinc biomarkers
MOA of supplement
Zinc plays a role in various physiological processes, acting as a co-factor for over 300 enzymes and more than 2000 transcription factors. It supports immune function by acting as a second messenger for immune cells, assisting in both innate and adaptive immunity. Zinc is also vital for wound healing, it is involved in collagen synthesis and the activity of enzymes that promote tissue repair. Additionally, zinc protects against oxidative stress and bacterial toxins by enhancing antioxidant activity. It also helps regulate copper levels in the body by inducing the synthesis of copper-binding proteins that reduces copper availability for absorption in the GI tract.
Risk vs reward
+ May reduce severity and duration of a cold
+ Shorten diarrhoea by maintaining GI mucosal integrity
+ Zinc is important in maintaining skin health. It can reduce symptoms and improve outcomes in various skin disease inc acne vulgaris
- High zinc intake can cause GI disturbance, headache reduce immune function and lower HDL levels. Very high doses (142mg/day) can disrupt magnesium balance
- Drug interactions include some antibiotics, penicillamine and thiazide diuretics
Evidence for it?
Systematic review of 28 RTC. Zinc, when compared to a placebo, can help prevent respiratory tract infections (RTIs) and shorten the duration of symptoms by about 2 days. It also made symptoms less severe. However, it can cause some mild side effects like nausea or irritation. The exact best form or dose of zinc isn't clear yet, and it wasn't more effective than other treatments for RTIs in some cases.
2016 Cochrane Review included 33 trials found that in children with acute diarrhoea, Zinc supplementation may shorten the duration of the illness by about half a day, especially in children over six months old and those with malnutrition. However, in children under six months, zinc may not have much impact on the duration or persistence of diarrhoea. Zinc also reduces the likelihood of diarrhoea lasting more than seven days in older children. While no serious adverse events were reported, zinc supplementation increased the risk of vomiting.
Meta analysis of 25 articles found low serum zinc levels in patients with acne. It helps control acne inflammation, accelerates wound healing by supporting collagen formation, and enhances tissue repair, particularly in zinc-deficient individuals.
Evidence against it?
Zinc toxicity High zinc intake can cause gastrointestinal symptoms such as nausea, stomach pain, and diarrhea, particularly in women. It may also disrupt gut microbiota, increase gut permeability, and lead to mild inflammation. Animal studies show changes in the colon and pancreas, though without clear functional harm.
Best bioavailable form?
Capsule or tablet
Advice on taking it?
Increased dietary protein leads to increased zinc intake and higher bioavailability. Zinc diglycinate has highest bioaccessibility, zinc sulphate has the lowest