How common is zinc deficiency?
Was I deficient?
I believe I did have a mild zinc deficiency (and later confirmed the deficiency with a Spectra Cell test) as a side effect of transitioning to a more plant based diet. It should be noted that while vegetarian and vegan diets are typically lower in zinc, it is possible to maintain healthy zinc levels on plant forward diets with proper planning.
In the western world, acute severe zinc deficiency is rare, but as with magnesium deficiency, it’s a real issue that can go unnoticed. However, in the developing world, where zinc deficiency is far more common, it can cause stunted growth, severe immune system dysfunction and even early death. 1
It has been estimated that zinc deficiency impacts as many as 2 billion people in third world countries. 2
Why would you have a zinc deficiency?”
First, mild zinc deficiency like we see in the West, is largely sub-clinical, meaning it’s very difficult to identify.
Phytic acid rich foods can block zinc absorption
Finding the right dose of zinc
According to the National Institute of Health, the upper limit for dosing zinc is 40 mg a day. This seems like a very high dose to me if the plan is to take zinc long term.
When I believed I was suffering from mild deficiency, I felt my zinc levels rapidly stabilize with just a few days of 50 mg dosing, and I did take it a bit too far, so much so that I developed some side effects like an upset stomach and dizziness.
You do not want to overdo it with zinc. Taking too much zinc will eventually draw down your copper and magnesium levels, both of which can cause health issues. 5 I now find that about 15mg of zinc 3-4 days per week is ideal for me.
With those personal factors out of the way, what do studies have to say about zinc supplements?
Are there proven benefits?
Benefits of zinc supplements
Zinc boosts the immune system
The research is clear that zinc supplements can have a positive impact on the immune system through a number of different mechanisms.
Zinc increases testosterone
There is evidence that supplementing with zinc can help the body make more testosterone.8
Histamine intolerance and allergy
I’ve blogged a good bit about histamine intolerance. Histamine is released from immune cells when the body perceives a threat, both real (a virus), or imagined (pollen). When you add the histamine in food and genetic predispositions to the equation, some people begin to develop symptoms.
Zinc has been shown to inhibit the release of histamine from mast cells, which is a blessing for anyone who is trying to bring their histamine levels under control. 9
Note: if you’re looking at zinc because of an issue with histamine, remember copper. Zinc draws down on copper levels and copper is a co-factor for diamine oxidase production, the enzyme that clears extracellular histamine. For more, check out our AOC1 gene page.
Zinc and infectious disease
There are multiple studies, in both the elderly and in younger populations, which found zinc plays an important role in combating infectious disease.
Double blind, placebo controlled studies (the gold standard of studies) found zinc supplementation reduced the severity and incidence of diarrhea in infants and young kids in India. 10
This study found that zinc supplementation saved the lives of children in developing countries with lower respiratory tract infections. 11
Supplementing with zinc has also been shown to decrease the number of infections in the elderly. 12
As we mentioned in a men’s health post Gene Food did on chronic prostatitis, adequate levels of zinc in the prostate are associated with increased ability to ward off trichomonas vaginalis, a parasite that can infect the prostate gland. This makes sense because zinc levels are 10 times higher in the prostate than in other soft tissue. 13
This meta-analysis found significant reduction in the duration of cold symptoms when patients were administered doses of zinc > 75mg.
Zinc acts as an antioxidant and decreases oxidative stress
This small (10 subjects), but double blind, placebo controlled study found supplementing with zinc decreased oxidative stress markers in patients who took 45 mg of zinc (again, a large dose in my view).
Put simply, our mitochondria use oxygen as part of the process of generating ATP, which is the energy currency of the body. This is a good thing. But as with any process of burning fuel, there are waste products associated with oxygen metabolism. One of these is called superoxide, which is a harmful free radical that can damage our cells if left unchecked.
In order to neutralize superoxide, our bodies generate a native, or “endogenous,” antioxidant called superoxide dismutase, or SOD. SOD converts the harmful free radical superoxide into the much less harmful hydrogen peroxide, which our bodies further break down from there. But when we lack SOD, and people born with certain variants in this gene are thought to have lower SOD2 levels, our bodies aren’t as good at mopping up free radicals.
Still with me?
Good, because SOD is made up of both copper and zinc.
Zinc, along with copper, is one of two metal co-enzymes required by SOD3 to function 7. There is no evidence demonstrating a beneficial effect on SOD3 activity following zinc supplementation. However, zinc has been shown to demonstrate an antioxidant capacity through unknown means 9, therefore supplementation may benefit those carrying the risk ‘G’ allele of C691G.
I think the bottom line here is that, whether you supplement, or eat foods rich in zinc, zinc is a mineral that should be on your radar. It has proven health benefits. However, at large doses over long periods of time many people will experience side effects.