Zinc is a unique element with antioxidant properties necessary for the activity of over 100 enzymes and a wide range of critical functions in your body. These include cellular metabolism, protein synthesis, the creation of DNA, immune function, vision, and your senses of taste and smell, to name a few. Zinc also supports a healthy pregnancy and key features of growth and development. Because your body can’t make zinc, you need to get it in adequate amounts from the foods you eat. Adult women need at least 8 milligrams of zinc per day, while men need 11 milligrams. Daily zinc requirements increase to 11 to 12 milligrams during pregnancy and lactation, respectively. Since zinc is a known nutrient gap1 in many diets (conservative estimate: 15% of Americans consume inadequate zinc), supplemental zinc can be a prudent strategy. In fact, zinc is critical for the development and function of many immune cells in our innate (neutrophils, macrophages, and natural killer cells) and adaptive immune (B-cells and T-cells) responses. Inadequate zinc can weaken these immune defenses. One meta-analysis that was published in JRSM Open2 found that supplementing with zinc lozenges at a dose of at least 75 milligrams per day reduced the duration of the common cold by an average of 33%. “The research on the role of zinc in immune function is particularly important and relevant now due to COVID-19,” says Kylie Ivanir, M.S., R.D., of Within Nutrition. “Zinc is necessary for maintenance and development of immune cells; zinc deficiency can result in increased susceptibility to disease.” As an added bonus, this clinical trial demonstrated that zinc supplementation also improved several metabolic health parameters (including blood glucose, insulin, insulin sensitivity, and HDL [or “good”] cholesterol), antioxidant status and glutathione levels, and key biomarkers of chronic inflammation. What about other skin health conditions? In one small study published in the International Journal of Dermatology5, participants with rosacea were given either 300 milligrams of zinc sulfate (which equates to approximately 70 milligrams of zinc) or a placebo for three months. After the treatment period, the group taking zinc experienced significant improvements in rosacea, with minimal side effects. In fact, zinc deficiency over time can contribute to systemic inflammation7 and is thought to be linked to impaired immune function often seen in older adults. In fact, clinical studies using zinc supplementation in elderly adults have shown that zinc can decrease the production of inflammatory cytokines8, reduce oxidative stress, and decrease the incidence and severity of infections. AMD is a degenerative disease that affects the macula, and it’s the leading cause of vision loss in the U.S. The macula is the central part of the retina, where zinc happens to be very highly concentrated10. In a clinical trial published in Current Eye Research11 in 2008, participants with AMD were given either 25 milligrams of zinc twice daily or a placebo. After six months, the zinc group had significant improvements in visual acuity, contrast sensitivity, and flash recovery time. And zinc was a key component of the AREDS/AREDS2 formulas, which have shown promise for improving intermediate and late-stage AMD. These seminal eye health clinical trial interventions also included antioxidant micronutrients copper; vitamins C and E; and carotenoids beta-carotene, lutein, and zeaxanthin. Amino acid chelate forms of this mineral (e.g., zinc bisglycinate chelate) are unique, and research shows they’re gentle, premium, and well-absorbed14 forms of zinc. While there aren’t plentiful side-by-side clinical trials in humans, to inform bioavailability of different forms of this mineral, a few do exist. For example, zinc oxide absorption has been shown to be lower15 than zinc citrate and gluconate forms. And zinc bisglycinate14 has been shown to have superior absorption over zinc gluconate. In addition to choosing the right form of zinc, dose is important. Taking too much can interfere with another essential mineral: copper. “Zinc reduces the amount of copper the body is able to absorb, so high doses of zinc can result in copper deficiency,” explains Ivanir. Specifically, total daily intakes (i.e., food plus supplements) of zinc greater than 60 milligrams, over time, have been tied to copper deficiency. Experts also agree that when choosing a supplement, make sure it’s tested for purity and potency. While you can take zinc every day, make sure you’re not overdoing it. The upper limit for zinc (meaning the most you should get in a day) is 40 milligrams. If you take more than this regularly, you may experience mild gastrointestinal distress. But acute zinc toxicity (typically seen with single zinc doses16 of 225 milligrams and higher) may involve more serious symptoms like abdominal pain, nausea, vomiting, diarrhea, and lethargy. You should also be careful about when you’re taking your zinc supplements in relation to other vitamins and minerals. According to Ivanar, “Taking large amounts of supplemental iron (over 25 mg) may decrease zinc absorption, so these two mineral supplements should be taken separately.” That’s because iron and zinc compete for the same absorption transporter in the small intestine. If you take medications, make sure to discuss any possible drug-nutrient interactions with your health care provider. As Ivanar explains, “Zinc supplements can interact with certain medications such as specific antibiotics, the drug penicillamine, and certain diuretics.” She has written twelve books and has had more than 2,000 articles published across various websites. Lindsay currently works full time as a freelance health writer. She truly believes that you can transform your life through food, proper mindset and shared experiences. That’s why it’s her goal to educate others, while also being open and vulnerable to create real connections with her clients and readers.
