All About Zinc: How to Fit It into a Gluten-Free Diet


This trace mineral is essential to good health.

Photo by thinkstock/istock/vroeva

“Well, he’s low in zinc,” the doctor said as he thumbed through the overstuffed binder holding my son’s medical records. I had consulted this doctor, known as a medical detective, for help with my son’s numerous health issues—food allergies, developmental delays, slow growth, picky eating and more. “His zinc level definitely needs to be corrected first thing,” he said.

It turned out that both my children were deficient in zinc, a trace mineral critical for healthy growth and development, skin integrity, attention, immunity and appetite. “There’s a clear link between low zinc levels and growth hormone deficiency,” the doctor added, touching on one of the problems my too-small-for-her-age daughter had been struggling with for years.

An Essential Mineral

“Zinc is involved in numerous pathways responsible for cell structure and regulation. It’s needed for normal growth, taste acuity, wound healing and for immune, neurological and reproductive health. It also protects again excess free radical formation and inflammation,” says registered dietitian Geri Brewster, RD, MPH, CDN of Mount Kisco, New York. “Studies show that zinc can reduce the duration of colds and prevent upper respiratory infections. Zinc supplementation in people with cirrhosis helps liver function and glucose tolerance. It’s important for prostate health and thyroid support.” It’s also critical for overall gut health.

“Zinc is important to the integrity of the gastrointestinal tract. If you’re low in zinc, you have increased intestinal permeability, called leaky gut, which increases gut inflammation and compromises the immune system,” Brewster says.

Eat Your Zinc

The best way to get zinc, of course, is through your diet. However, there’s so little zinc in any single food that a varied menu is essential to obtaining adequate amounts. Best food sources include beef, chicken, turkey, oysters, shellfish, shrimp, cashews, quinoa and fortified foods (conventional breakfast cereals, breads and baked goods). Most gluten-free products aren’t fortified, which puts those who eat gluten-free at greater risk for zinc deficiency, especially if they have absorption issues like celiac disease. Vegetarians and vegans are also at risk—foods richest in zinc are meat and seafood, and many plant sources contain phytates, which inhibit zinc absorption. Others at risk are those with stressed immune, neurological or reproductive systems, those with poor circulation and those with impaired wound healing.

All this makes zinc an excellent candidate for supplementation. A physician who specializes in nutrition or a savvy dietitian-nutritionist can test your blood level and assess your diet to determine your need for a zinc supplement and the proper dosage.

“Zinc is considered safe in amounts that don’t exceed 40mg a day for adults. Higher doses for extended periods might decrease copper levels and lead to anemia,” says Brewster.

I learned the hard way that you can be deficient in this key nutrient even when you’re eating adequate food sources. Both my kids are gluten sensitive and have malabsorption issues, a set up for zinc deficiency. Although “just go gluten-free” is the sole prescription for celiac disease and gluten sensitivity, nutritional deficiencies should always be assessed and addressed.

A few months into giving my children zinc supplements and making sure they were eating adequate food sources of zinc, I could no longer call them picky eaters. They were fighting over octopus sushi and my son was asking me to take him to the salad place for a salad. At her six-month visit to the endocrinologist, my daughter’s growth hormone level had increased—and more importantly, she had actually grown.

Consult a knowledgeable dietitian or physician about supplements and proper dosages.

Freelance writer Kirstin Boncher blogs at and