Excess Zinc Side Effects and Excessive Zinc Supplementation

  • By Gary Binkow
  • May 30
Excess Zinc Side Effects and Excessive Zinc Supplementation

You may be familiar with the micronutrient zinc because you rely on zinc lozenges to give your immune system a boost when you have a cold. Zinc is a metal that is a part of a group of micronutrients that includes iron, manganese, copper, iodine, and selenium. The reason this class of nutrients is called micronutrients is because they are required in doses 20x-100x lower that other nutrients. Zinc is the second most abundant trace mineral in the human body with iron being the first.

Why is this biometal so important to proper health? This metal is needed for the proper functioning of over 300 different enzymes, which are activated proteins that are responsible for making our millions of cellular biochemical pathways function. Zinc helps boost the immune system, supports the making of DNA, helps with wound healing, and is involved with slowing the aging process by fighting free-radical damage. Zinc is very important for the proper functioning of the brain and, in particular, keeping the blood-brain barrier intact.

It would seem with all these great benefits from zinc, you would want to always include it as part of your daily supplement regimen. Zinc is one of those nutrients where “more is better” does not apply and caution needs to be taken before taking zinc as a supplement.

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Excessive Zinc Intact and Toxicity

A few weeks ago when I was in my local grocery store, I overhead the store specialist in the supplement section tell an inquiring shopper that they were currently out of zinc supplements. I inquired as to whether that was a backorder issue or increased demand from consumers. Due to so many people becoming educated on how to protect themselves from coronavirus infection, supplements such as zinc, aged garlic, colloidal silver, and curcumin can be in shorter supply.

Zinc and all biometals are toxic if consumed at too high a dosage for a prolonged period. While ingesting a lot of garlic won’t harm you, taking more than the recommended dose of zinc can have serious side effects. There is a very small difference with trace elements between what is the optimal dose and what is a toxic dose, and these differences need to be understood. You can take Vitamin C is large gram quantities and experience only mild side effects such as a stomachache or gastrointestinal upset. But taking too much zinc in supplement form can trigger adverse effects that can include:

  1. Upset stomach and nausea
  2. Loss of appetite
  3. Gastrointestinal upset, cramps, and diarrhea
  4. Headaches
  5. Lower blood levels of “good” HDL
  6. Alteration of the body’s copper status and iron function.

If you decide you want to take a zinc supplement, pleases remember that the upper intake level for zinc is 30-40 mg per day for adults and that includes both the supplement and the zinc you are getting in your food. A long-term intake above this recommended level increases the risk of adverse health effects unless you have a health condition and your physician is prescribing a high daily dose.

Zinc Interference with Certain Pharmaceuticals

There are many supplements that can interfere with the effectiveness of both prescription and over-the-counter drugs. Zinc is one of those supplements that should be regarded with caution and listed with your doctor if you are on certain medications. For example you may be taking zinc to bolster your immune system, but if you are also taking immunosuppressant medication such as corticosteroids then zinc can interfere with the drugs ability to decrease the immune response. This article from St. Luke’s (Missouri) Complementary and Alternative Medicine Department gives a list of pharmaceuticals, including antibiotics, where zinc supplementation can have negative side effects when combined with these drugs.

Check You Multivitamin for Zinc

Many people find it easiest to take a multivitamin each day rather than 6 or 7 individual supplements. Zinc is commonly added to multivitamins to be sure that your basic biological functions and immune system are supported. When choosing a multivitamin, look for one with the recommended daily dose of zinc, but not one that has more than 30 mg of zinc per serving. Multivitamins such as Garden of Life, Mega Food, Pure Encapsulation Nutrient 950, and Nature Made are a full-spectrum supplement without overdoing it on the zinc component.

Cold and flu protection supplements and powders always contain zinc for boosting the immune system. Products such as Emergen-C Immune Plus increases the amount of zinc in this product compared to their regular Emergen-C fizzy powders. The immune boosting product contains 10mg of zinc and you would not want to take more than 3 of these powder packs per day. I have seen people who will sip all day on water that contains these immune-boosting powders. While doing this for a few days will not cause a problem, constant over-use of cold and flu remedies can lead to ingesting more zinc than is probably safe.

Getting Enough Zinc from Your Food

The best way to ensure you’re getting enough zinc for optimal health is to focus on food sources. People that aren’t on any restrictive diet who eat a wide variety of plant and animal foods should be getting sufficient zinc such that supplementation is not necessary. Grass-fed beef, poultry, lamb, fish, and eggs are all good sources of zinc. Nuts such as pumpkin seeds, cashews, and chickpeas are also greats sources for getting a dose of zinc. Whole grain cereals and legumes also round out the list of zinc-containing foods.

Individuals who prefer a vegetarian or vegan diet plan will need to zero in on top plant sources of zinc and make sure they eat these often. Examples to include in a non-meat diet would be mushrooms, wheat germ, fortified cereals, beans and legumes, seeds, nuts, oatmeal, tofu, spinach, mushrooms, asparagus, broccoli, and zucchini.

If you’re concerned about not getting enough zinc from your regular diet due to dislikes or dietary restrictions, talk to your doctor or dietitian for guidance and whether zinc supplements might be appropriate for you. Zinc is one of the most important nutrients for optimal wellness, but striking the right balance is vital for reaping its benefits.

When to Supplement with Zinc

Dietary restrictions or being a “picky eater” may cause you to have too limited a daily zinc intake and in these cases a zinc supplement might be appropriate to maintain good health. Please remember, if you are on any kind of medication to check in with your primary care physician first to make sure a zinc supplement will not interact with your medication.

Zinc can be taken as a supplement on its own in either capsule or lozenge form or can be a part of a general supplement mix. As with many supplements such as magnesium, calcium, and potassium, there are many different forms of zinc to make it readily absorbable to the body. Here is a list of the most common forms of zinc found in supplements:

Zinc gluconate: This form of zinc is most common in over-the-counter supplements and often used in cold and flu season remedies.

Zinc acetate: Like zinc gluconate, zinc acetate is often added to cold lozenges to reduce symptoms and speed up the rate of recovery.

Zinc picolinate: The picolinate form of minerals may be absorbed better than other formulations.

Zinc orotate: This form is bound to orotic acid and one of the most common types of zinc supplements on the market.

Zinc citrate: Published research showed that this type of zinc formulation is well-absorbed and has a less bitter aftertaste than zinc gluconate.

The biometal zinc packs quite a punch for such a minimal amount that the body needs. The take-home message is that you should be very careful with using zinc both due to potential drug interactions and toxicity side effects. When in doubt, always talk to your healthcare provider to get their input on whether a zinc supplement is right for you.

The information contained in this article is for educational and informational purposes only. It is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.