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

Article at a Glance
  • Zinc deficiency is a major problem in the developing world, affecting an estimated 2 billion people worldwide.
  • A diet high in phytic acid can block mineral absorption and contribute to zinc deficiency.
  • Zinc’s many health benefits include boosting immune function and reducing oxidative stress.
  • Zinc supplements are best used in conservative dosages of between 2 – 8 mg. Although many zinc supplements contain doses of 50 mg or higher, many people will begin to experience side effects with long term use at that dosage, often due to copper and magnesium deficiency.
  • Pumpkin seeds and oysters are excellent natural sources of zinc.
Genes Mentioned
Zinc Supplements Benefits Side Efffects

We’ve all been there. A few weeks in to the craziness of Christmas parties and year end dinners with friends, our body is telling us stop, but the calendar is saying Go!

This year, 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 spectacularly and ended up feeling amazing.

50 mg of zinc is a large dose.

Was I deficient?

I believe I did have a mild zinc deficiency as a side effect of transitioning to a more plant based diet over the last 6 months or so. In the western world, acute severe zinc deficiency is rare, but as with magnesium, it’s a real issue that goes 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. (R) It has been estimated that zinc deficiency impacts as many as 2 billion people in third world countries. (R)

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

Good question, and to be fair, I don’t think it was severe, and I did not have labs done as I normally would, however, I did notice such a “pop” from taking zinc that my hunch is my body needed more of this mineral. I also had been eating a lot of food, like oatmeal, that was high in phytic acid, which can block mineral absorption. 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. (R) If you have a good study, please add to the comments.

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. (R) I find that just a few milligrams of zinc 3-4 days per week is ideal for me. I am now in that 2 – 4 mg range that we identified as ideal for Immune Engine.

With those personal factors out of the way, what do studies have to say about zinc supplements? Can they be helpful?

Yes, Zinc does boost 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. (R) T cells “hunt down” and kill bad cells, like germs/infections and cancer cells. (R)

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 to the equation as well as genetic variants in genes like AOC1, man 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. (R)

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.

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. (R)

This study found that zinc supplementation saved the lives of children in developing countries with lower respiratory tract infections. (R)

Supplementing with zinc has also been shown to decrease the number of infections in the elderly. (R)

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. (R)

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.

Zinc supplement comparison

Country Life Zinc50 mg tablets100 tablets
TheraZinc Spray7.4 mg per 8 sprays4 fl oz
Gene Food Immune Engine4 mg capsules, with vitamin A, C, L-lysine, pantothenic acid, B1260 capsules
Ionic Zinc50 mg drops, with 2 mg copper sulfate and magnesium2 fl oz

Choosing a zinc supplement

I am knowledgable about four good ones, although again, I would caution not to overdo it. Zinc is a supplement best taken in small doses. In fact, some may want to avoid supplementing altogether and instead opting for foods, like pumpkin seeds and oysters, that are highest in zinc.

With that said, these are the supplements on my radar.

Country Life Zinc – 50 mg tablets


I have literally had a bottle of this stuff rattling around in my suitcase and medicine cabinet for years and never used it until the experiment I discuss here. Cheap and effective, not much else to say about Country Life Zinc other than the 50 mg dose will be a very large one for most people, and especially over an extended period of time. The tablets themselves are hard coated and difficult to break into smaller doses.

TheraZinc Spray


Fellow Ausinite Tim Ferriss turned me on to this product. He claims to have found value in TheraZinc Spray as a travel supplement. I have used it for the same purpose and can recommend it, but you’re not getting just zinc. This is a liquid spray that comes in a formula with vegetable glycerin, castor oil, menthol, lecithin, echinacea, and a few other herbals. Not a big deal, but not every ingredient on that list is necessarily something I want to be supplementing with every day. However, because it is a spray, one of the primary benefits is the ability to micro-dose. 8 sprays equals 7.4 mg of zinc, so one or two small sprays is an excellent way to achieve a maintenance dose.

Zinc and Copper supplement


As I mention above, taking zinc impacts magnesium levels, which is another reason you don’t want to overdo it. However, supplementing with zinc can also draw down copper levels, which is why some manufacturers add copper to their formulas. Ionic Zinc by Trace Minerals is one of these brands, offering a formula that comes in a dropper, with a mineral blend of primarily zinc but also copper and magnesium. This product was the one that gave me the worst side effects, but that could be due to the fact that I’d been taking relatively high doses of zinc for a few days prior. For regular dosing, I will go with the 2 – 4mg in Immune Engine, or TheraZinc.

Closing thoughts

I think the bottom line here is that, whether you supplement, or eat foods that contain 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 most people will experience side effects.

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  1. Gianluca says:

    Very interesting article!

    I am actually takin some zinc supplement now (22mg picolinate) and i think it is maybe too much.. i feel like it is protecting me from stress bit at the same time creating some brainpeople confusion.. i am a bit concerned of depleting too much copper.. i m tjinking to cut it down to lower doses (1/4 of a pill o, around 5mg).. how many days did you supplément at high dosages before slowing down?

    • Hey Gianluca, I can’t say, you’d have to ask your doctor that. Having said that, if you’re having doubts best to stop altogether or go down to one small dose every 5 days or so. 22 mg a day is a pretty hefty daily dose of zinc over time.

  2. Maria says:

    Have you ever heard of a small dose of zinc helping someone within five minutes? Every once in awhile my glands under my neck feels sore and I feel hot and generally unwell. Almost as if I am on the verge of getting a cold. I noticed that if I take a zinc lozenge of 5 mg, which I know is a small one, all of my symptoms disappear. I felt sick like this last night and I took a zinc lozenge and I felt 100% better. Not only did I feel better, but I also fell asleep extremely quickly. I usually can’t fall asleep until 3 in the morning, but I was out like a light at 12 a.m.. I usually don’t remember my dreams at night, but last night I had a lot of them, which I like. Over the years I always thought that I had a zinc deficiency, as taking zinc makes whatever this is go away. But what’s weird is that my zinc levels have always come back normal. It is one of the few minerals that is in its proper place. I had various forms of testing, one of which was hair analysis. From everything I’ve read on the internet, it doesn’t seem like zinc should have this quick of a positive effect on people.

    Thanks for this article. It was extremely helpful. I loved learning how it helps boost the immune system.

  3. Rene G Volpi says:

    I find it very peculiar that the supplement manufacturers almost consistently make the 50 mg the regular dosage amount in the bottles. Don’t they know such high amounts could cause issues? Just wondering.

  4. Joe says:

    John, larger dosages of zinc really seemed to improve symptoms of an autoimmune issue I was dealing with but with some negative side effects. Can you go into more details on what side effects you experienced with the larger doses?

    • Hey Joe, it’s been awhile since I experimented with high doses of zinc, but dizziness was definitely one of the side effects for me. I now stay around the 7-8mg per dose “sweet spot.”

  5. Shawn says:

    With the 5mg zinc dose, would you still need cooper to balance it out or that dose is too small to cause any problems long term?

  6. Diana Nieto says:

    2 weeks ago i started supplementing with copper ask me why ? I been suffering from lower back pain , seen drs but they all said it was sciatica . so at first taking copper pain went away at the same time i deleted alot of high histamine foods that were causing me issues ,but then i started to feel bad and i also got a yeast infaction brainfog confusion . so i stopped and started taking zinc 50-100mg at day and avoiding rich copper foods . but now i feel worst and im getting skin rashes . what should i do ? I just had a baby and i feel guilty because im never happy my poor memory is causing problems 🙁 please help

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