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Zinc has many health benefits, but don’t overdo it

Zinc Supplements Benefits Side Efffects

We’ve all been there. I first discovered the health benefits of zinc supplements two years during the holidays.

A few weeks into the craziness of Christmas parties and year end dinners with friends, our body is telling us stop, but the calendar is saying Go!

Partying and poor food choices had me feeling like I was coming down with something, so I reached for the zinc.

I took a product that contains 4 mg of zinc (2 mg if you take one pill), which as we will see in a moment, is actually a perfect dose for most people, but I felt like I needed more, so I “mega-dosed” with a couple 50 mg days. I never did end up getting sick. In fact, I rebounded and ended up feeling great.

50 mg of zinc is a large dose.

Zinc deficiency

Was I deficient?

I believe I did have a mild zinc deficiency (and later confirmed the deficiency with Spectra Cell labs) as a side effect of transitioning to a more plant based diet.

In the western world, acute severe zinc deficiency is rare, but as with magnesium, 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

Ok, but I can hear you saying: “John, you lived in Austin, Texas, not the developing world. Why would you have a zinc deficiency?”

I had been eating a lot of food, like oatmeal, that was high in phytic acid, which can block mineral absorption.3 I also regularly supplement with magnesium, and as with many mineral combinations, one can affect the other. Magnesium competes with zinc for absorption, although most of the literature I have seen seems to indicate that taking zinc in excess draws down magnesium, not the other way around.4

On the flip side, I will say that 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. 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 just a few milligrams 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. The two primary drivers appear to be IL-2 activation and the corresponding increase in T cells.67 T cells “hunt down” and kill bad cells, like germs/infections and cancer cells.

Zinc increases testosterone

There is evidence that supplementing with zinc can help the body make more testosterone.8

For more tips for optimizing testosterone levels, take a look at the recent interview I did with Dr. Amy Killen, an anti-aging doctor in Utah specializing in sexual optimization.

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. I am now repeating myself, but 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 I mentioned in a men’s health post I 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

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).

We’ve touched on oxidative stress in a number of posts, with perhaps the best explanation in our SOD2 A16V post. 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.

In our Guide to Nutrigenomics, Aaron also lists zinc as a nutrient that directly enhances expression of the SOD3 gene, as well as for ADA. To quote Aaron:

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.

Closing thoughts

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.

John O'Connor

John O'Connor is the founder of Gene Food, host of the Gene Food Podcast and a health coach trained at Duke's Integrative Medicine Program. Read his full bio here.

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