Home » Health and Nutrition » Zinc: Vegetarian Nutrient of Concern #5

Zinc: Vegetarian Nutrient of Concern #5

Jennifer Hanes MS, RDN, LD

Zinc is a nutrient that you probably never think of.  We don’t learn about it in health class. There’s not a zinc section on MyPlate. This is because deficiency of this mineral is relatively rare. 

However, major sources of zinc come from animal sources, mostly meat, so vegetarians and vegans can be at risk of deficiency if they’re not careful.

This is the 5th in my series of nutrients of concern for vegetarians, based on my blog post Are You an Unhealthy Vegetarian?

pumpkin soup in blue patterned bowl topped with pumpkin seeds and parsley
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Function

Like many of the other nutrients in our series, zinc serves a number of functions for us. 

It is required in over 100 enzymatic activities in our cells.  

Other roles include wound healing, immune system function (this is why you always see it added to cough drops), protein and DNA synthesis, and cell division.

Zinc maintains the structure of some proteins and can affect the expression of some genes.

For children and pregnant women, it promotes normal growth.

Finally, zinc is required for you to smell and taste!

Newer research has linked zinc deficiency to worsening symptoms of major depressive disorder and ADHD, as well as increased aggression and violence!

This is interesting information in light of some research that suggests vegans (and sometimes vegetarians) may have higher rates of depression than other populations. We’re getting off-topic, but this can be a focus on a future blog post!

Unfortunately, you don’t have a zinc storage system in your body, so you have to have a regular, daily intake to meet your needs.

Unfortunately for vegetarians, the most prominent sources of zinc come from animal sources. In fact, 7 of the top 10 sources of zinc are animal flesh, but more on that later!

seasoned Cashews in blue bowl
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Recommended intake

Men and pregnant women need 11 mg per day. Lactation adds another 1mg to your daily needs. Women that are not pregnant or breastfeeding only need about 8mg per day.

Zinc Sources

Vegetarian sources include fortified cereals, whole grains, beans, nuts and seeds, yogurt, cheese, oatmeal, and peas.

Phytates, discussed in our article on calcium can also bind zinc, potentially increasing the amount a vegetarian should eat in a day.

Certain preparation methods can improve zinc bioavailability. Soaking beans and leavening or fermenting grains, most notably. Whole grain bread > whole-grain crackers in terms of zinc intake.

beet, pea, and microgreen salad on white plate.
Photo by Jonathan Farber on Unsplash

Symptoms of Deficiency

Mild deficiency causes loss of appetite, poor immune system function, and delayed growth in children.

As deficiency continues you can develop hair loss, diarrhea, impotence, hypogonadism in males, lesions on the eyes or skin, unintended weight loss, delayed wound healing, difficulty tasting your food, and fatigue.

Zinc deficiency can be difficult to diagnose, as there are no stores, meaning that the zinc in your body is tied up within your cells, rather than floating in your blood or chilling in your liver and muscles.

Infants that are exclusively breastfed past 4-6 months may not get enough zinc to continue growing normally. Introduce some age-appropriate sources in the child’s diet.

Causes of Secondary Deficiency

A common theme in this series, gastrointestinal malfunction can lead to deficiency due to both poor absorption and increased loss. Chronic liver disease, chronic kidney disease, sickle cell anemia, diabetes, cancer, and chronic diarrhea can lead to increased losses of dietary zinc.

salad topped with chickpeas in a black bowl.
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Conditions that increase zinc needs

Vegetarian sources of zinc are not as bioavailable, meaning we don’t absorb as much of it. Because of this, a vegetarian may need more total intake compared to an omnivore. Some estimates actually recommend 50% more zinc intake in this population!

However, other sources indicate that vegetarians may adapt to this zinc binding by becoming more efficient at absorption than their omnivorous counterparts. And some studies have found similar serum zinc levels in vegetarians and omnivores. However, we must remember that there isn’t much in our blood so a deficiency cannot be diagnosed based on blood levels.

Pregnancy – due to its role in growth women that are pregnant or lactating have higher zinc needs than normal. 

Treatments for Deficiency

Treatment for deficiency is dietary modification. Or supplementation if symptoms are severe.

Thankfully, vegetarian sources of zinc are also common foods in the vegetarian diet, such as beans (including tofu and tempeh), peas, yogurt, and nuts and seeds. 

oatmeal with almonds and raisins in a white bowl.
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Symptoms of zinc toxicity

Short-term toxic levels of zinc can cause nausea, vomiting, loss of appetite, abdominal cramps, diarrhea, and headaches.

Long-term zinc toxicity can lead to copper deficiency (weakness/fatigue, poor memory, sensitivity to cold, premature grey hair, and vision loss), poor iron function, poor immune system function, and reduced HDL (“good” cholesterol) levels.

Treatment for toxicity

Toxicity from dietary intake is rare. Look at your supplements and make sure you’re not taking in more than ~30mg /day from that source.

Another unusual source of zinc is denture adhesives. Normal, recommended use will not cause toxicity. However regular excessive use can.  Toxicity has been reported when an individual uses 2+ 2.4oz tubes of denture adhesive per week.

Variety of cheeses on display
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Should I take a zinc supplement?

Not usually.  There is some evidence that taking zinc supplements at the first sign of a cold may decrease the severity and length of your illness.

Children with sickle cell disease may have better growth and learning capabilities when supplemented with zinc.

What supplementation won’t do

No amount of supplementation will outperform a well-planned diet.  Obsessively taking supplements is a drain on your pocket and promotes a false feeling of health or wellness.

Any concern for the omnivores?

Not really at all. This one is all ours….

References

National Institutes of Health

Healthline

Medical Journal of Australia

Psychology Today

Psychology Today, part 2

More on Dietitian Jenn

My review of the Mediterranean Diet.

Vitamin B12 and the vegetarian diet.

Should you get nutrition advice from your doctor?

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