9 Weird Facts about Zinc

By November 12, 2013Fun
zinc supernova

Zinc is one of those nutrients that doesn’t get much attention, but should.  The global prevalence of zinc deficiency is about 30%.  Even in developed countries like the US and UK, zinc deficiency rates are at 4-7%. Since plant-based sources of zinc are poorly absorbed, vegans should especially pay attention to this nutrient and know the signs of deficiency.


What is Zinc?

Zinc is a mineral which is essential for all life, including animals, plants, and even single-cell organisms.  Some zinc is used to help build proteins and cell membranes.  However, zinc mainly acts as a catalyst in the body.  This means that it helps trigger chemical reactions.  There are over 100 different human enzymes which rely on zinc to function.  Zinc is also needed to regulate cell processed like copying DNA.

In humans, high concentrations of zinc are found in the eyes and, in men, the prostate gland.  Zinc is also mostly found in the brain, muscles, bones, kidneys, and liver. The body is not capable of storing zinc, so you must have a steady daily supply in order to stay healthy.


Zinc Deficiency

Without zinc, the human body would not be able to function on any level. Even a mild deficiency in zinc can result in a vast array of symptoms.  The problem is that these symptoms can also resemble symptoms of many other conditions, so diagnosing zinc deficiency on symptoms alone is difficult.

Symptoms of Zinc Deficiency

Mild zinc deficiency might not produce very noticeable symptoms, or the symptoms (like low energy) could easily be attributed to another problem.  Plus, if you are deficient in zinc, then you likely are deficient in other nutrients as well, especially iron, since these minerals are found in the same foods.  Here are just some of the symptoms of zinc deficiency you should be on the lookout for.

  • Brittle nails with white spots on them
  • Poor immunity, frequently sick
  • Fatigue
  • Poor appetite
  • In men, symptoms of low testosterone (low libido, erectile dysfunction, poor ejaculations…)

If you think you aren’t getting enough zinc, don’t try to self-diagnose.  Go get a blood test to check your zinc levels.  Over a longer period of time, zinc deficiency could lead to some serious problems like chronic fatigue, poor mental health, and low testosterone in men.



How Much Zinc Do You Need?

The Institute of Medicine puts the RDA for zinc at 11mg/day for adult men and 8mg/day for adult women.  But, like with calcium and iron, the recommendations are a bit different for vegans because of bioavailability

Most plant-based foods which are high in zinc also contain antinutrients which block its absorption.  One group of antinutrients is phytates.  The phytates bind with the zinc, preventing it from being absorbed into the body.  Foods which are high in phytates include whole grains, seeds, and nuts. These also happen to be the foods where most vegans get their zinc.

One commonly-cited study from the WHO found that people on vegetarian and vegan diets who ate high amounts of grains absorbed only about 15% of dietary zinc.  By comparison, people eating meat and fewer grains had a zinc absorption rate of 50-55%.

Other zinc antinutrients include flavonoids (which are a type of plant pigment found in fruits, tea, chocolate, and dry beans, amongst others).  Alcohol also acts as a zinc antinutrient, so a lot of alcoholics (and I’d imagine college students also) are zinc deficient.

Because of how poorly vegan sources of zinc are absorbed, some agencies recommend that vegans (and vegetarians) consume 50% more zinc than the general RDA.  The Institute of Medicine recommends an even higher amount.  They say that vegans should consume twice the RDA of zinc. 

This would put the RDA of zinc for vegans at:

  • 12-16 mg/day for adult women
  • 16.5-22 mg/day for adult men

However, to complicate things further, there is evidence that vegans are able to adapt to the lower bioavailability of zinc by absorbing more of it and excreting less.  But a lot more research needs to be done before we can say with certainty that vegans don’t need extra zinc.  To play it safe, you might want to shoot for the higher RDA recommended for vegetarians/vegans and to eat lots of zinc superfoods.

There are also some things you can do to increase the absorption of zinc from food.  Here are some of them:

  • Eat zinc foods with foods containing yeast (such as leavened breads): The yeast destroys much of the phytic acid which would normally inhibit zinc absorption.
  • Soaking or sprouting: Soaking or sprouting beans, legumes, seeds and grains will help reduce the phytic acid content in them so more zinc is absorbed.
  • Consuming certain acids: Certain types of acids increase the absorption of zinc. These include sulphur-containing amino acids (found in garlic and onions), citric acid (found in citrus fruits like oranges), malic acid (found in apples), and tartaric acid (found in grapes).
  • Eat more protein: Consuming protein with zinc can increase zinc absorption. Here are the best vegan sources of protein.

How to Make Sure You Are Getting Enough Zinc on the Vegan Diet

There are three ways that vegans can make sure they are getting enough zinc in their diets.

1. Increase Consumption of Zinc Foods: Strive for the 150% RDA of zinc that is recommended for vegetarians and vegans by the Institute of Medicine

2. Reduce Antinutrient Consumption: You can try to avoid foods which are high in phytates and tannins (such as not drinking tea with your meals), and also avoid alcohol.  There are also several ways to reduce the phytates content in foods.  The Weston A. Price Foundation (which is rather obsessive in the issue of antinutrients) says that fermenting grains, sprouting seeds, and soaking nuts all significantly reduces phytic acid content.

3. Increase Cofactors for Zinc Absorption: Just like some substances block zinc absorption, others can help increase zinc absorption.   Consuming protein with zinc is one way to boost absorption. If you are going to take a zinc supplement, then you will want to take it with food so improve absorption.

Zinc Supplements for Vegans

Worried you aren’t getting enough zinc?  You should always aim to get nutrients from food first.  When that fails, you can use supplements as a backup.  Here are some of the top vegan supplements with zinc. You can find more vegan supplements here.

Vegan Sources of Zinc

Walnuts: 1 ounce (about 14 walnut halves) = 0.9 mg zinc

Recipe Idea:
Eat them with mashed potatoes.  The walnuts give the potatoes an exciting new texture.  Try adding walnuts and artichokes to garlicky mashed potatoes.  Or you can go the tangy route and try mashed sweet potatoes with orange juice and walnuts.


Pepitas: 1 ounce = 2.1 mg zinc

Recipe Idea:
Pepitas are great on just about any salad because they add an exciting crunch.


Tahini: 1 tablespooon = 0.7 mg zinc

Recipe Idea:
Use in an awesome dressing for a tofu and veggie salad


Peanut Butter: 2 tablespoons = 0.9 mg zinc

Recipe Idea:
Use as a tasty sauce for Asian noodles and veggies. Just mix 3 tablespoons of peanut butter with 2 tablespoons of soy sauce, 1 spoonful of lemon or lime juice, 1 tablespoon of sesame oil, and as much garlic and chili as you like.


Wild Rice: 1 cup = 2.2 mg zinc

Recipe Idea:
The nutty flavor of wild rice makes it perfect for blending up in creamy soups.


Quinoa: 1 cup = 2.0 mg zinc

Recipe Idea:
Quinoa isn’t just a good vegan source of zinc.  It is also a complete protein and loaded with minerals and vitamins.  Top it with lentils or chickpeas, or use it to make tasty veggie burgers.


Wheat Germ: 1 tablespoon = 1.7 mg zinc

Recipe Idea:
There are a lot of ways to get more wheat germ into your diet.  Consider adding a scoop to your morning smoothie, using bran instead of flour as a thickener for soups, or adding to veggie dips.

9 Weird Facts about Zinc

You probably know that zinc is a mineral which your body needs to stay alive, but do you know these weird facts about zinc??

1. Part of the reason that oysters are considered aphrodisiacs is because they have incredibly high levels of zinc. Zinc is crucial for hormone regulation (and thus improves libido).

2. Zinc deficiency can result in impotence in men.

3. Alcohol inhibits your body’s ability to absorb zinc. Chronic alcoholics often get white spots on their fingernails from zinc deficiency. Taking zinc can also help you cure a hangover!


4. Zinc can be limitlessly recycled! More than 33% of zinc used in North America is made from recycled zinc.

5. Zinc is made when stars die and explode (supernovas), causing zinc and other minerals to spew throughout space.


6.The US penny is 97.5% zinc and coated with copper. If you swallow a penny, the zinc could cause damage to the stomach lining!

7. Adults have an average of 2-3mg of zinc in their bodies.

8. The highest concentration of zinc in the body is found in the prostate and the eye.

9. Semen contains about 135micrograms of zinc. Some experts have claimed that a single ejaculation can cause a man to lose up to 5mg of zinc! Since zinc deficiency can cause vision problems, maybe there is some truth to that warning about masturbation leading to blindness!


Image credits:
Mee’s lines by Yannick Trottier is licensed under a
Creative Commons Attribution 3.0 Unported License.

About Diane Vukovic

Diane Vukovic is a vegan mom, health nut, and kitchen diva. When she's not deducing veggie nutritional facts, she's probably dancing crazily with her daughter or traveling somewhere in Europe.

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