Zinc is one of several essential trace minerals that your body needs to sustain good health. Since the body is unable to make zinc, we must obtain it through either the foods we eat or dietary supplements.
Zinc is needed for a multitude of biological functions. It acts as a catalyst for over 100 different enzymes and the transcription of DNA. Without a sufficient supply of zinc, our bodies would be unable to develop normally, ward off infection, or heal properly.1
Roughly 2 to 4 grams of zinc are distributed throughout a healthy human body, primarily in the bones, muscles, brain, liver, kidneys, eyes, and prostate gland. To ensure we sustain this level, we need to eat foods rich in zinc, including meat, fish, shellfish, poultry, eggs, dairy, and nuts.
Zinc supplements may be used if you don’t get enough from your diet. On the other hand, the overuse of supplements can lead to side effects and toxicity.
Zinc is essential for human development and the promotion of a healthy immune system. It not only helps prevent a host of common and uncommon illnesses, but it can also treat certain health conditions. Here are some of the benefits you should know about:
Zinc is responsible for activating a type of white blood cell called a T lymphocyte (T-cell). These cells are central to your body’s immune defense. Some are “killer” T-cells that neutralize pathogens like bacteria, viruses, or fungi. Others are “helper” T-cells that direct the assault of an infection or cancer.2
A zinc deficiency impairs the immune system and leaves you vulnerable to diseases your body could otherwise neutralize. Zinc supplementation may help support the immune response and shorten the duration of colds.3
Globally, over half a million deaths in children under five are directly attributed to zinc deficiency, according to research from the University of Colorado School of Medicine.4 Even a mild deficiency in children can lead to growth delays and an increased vulnerability to infection.
A zinc deficiency in early childhood can result in short stature, cognitive and motor delays, and significant behavioral problems (including irritability, lethargy, and depression). However, a review published in 2012 found no evidence that taking zinc supplements would improve mental or motor development in children.5
Zinc helps maintain the integrity and structure of the skin. A moderate to severe zinc deficiency will commonly manifest with skin problems, including lesions, ulcers, and slow-healing wounds.6
While zinc supplements can help prevent certain skin disorders, topical zinc oxide can be used to accelerate wound healing or treat conditions like acne, ulcers, diaper rash, and herpes simplex infections.7
In addition to its anti-inflammatory and antibacterial properties, topical zinc can promote re-epithelialization (the migration of healthy epithelial skin cells into a wound or ulcer).
Even moderate zinc deficiency can interfere with the absorption of food in the intestines. This has a knock-on effect in which the body is robbed of not one but several essential nutrients.
Diarrhea is a characteristic symptom of zinc deficiency and one that can be especially devastating in infants and toddlers. According to the World Health Organization, a 10- to 14-day course of zinc supplements can effectively treat diarrhea in children with a known deficiency and prevent recurrence.8
Macular degeneration is an aging-related disorder in which a part of the retina called the macula is damaged over time. As with the skin, zinc plays a central role in maintaining the integrity of the macula.
Zinc plays an important role in the transmission of nerve signals and the rate by which neurotransmitters are absorbed in nerve cells. Deficiencies are commonly associated with psychological disorders such as depression and certain forms of psychosis.9
Zinc deficiency in men is linked to poor sperm motility and quality.10 To this end, zinc supplements are often prescribed when treating male infertility as it enhances the production of the male sex hormone testosterone. The same effect can potentially aid in the treatment of erectile dysfunction.
A 2016 review and reanalysis of studies concluded that zinc levels were lower in men with fertility problems when compared to men without fertility issues.11
Possible Side Effects
Taking zinc supplements in excess of 40 milligrams (mg) per day may not be safe over the long term. At high doses, zinc can cause diarrhea, vomiting, cramps, and a metallic taste in the mouth (dysgeusia). In addition, excessive zinc consumption can block the absorption of copper, leading to anemia and neurological problems.1
When applied to broken skin, zinc oxide may cause burning, itching, and tingling sensations.
Zinc can interfere with the activity of certain drugs or alter the concentration of zinc in the body. If you’re currently taking any medications, speak with your healthcare provider before taking zinc supplements.
Dosage and Preparation
The recommended daily allowance (RDA) of nutrients determined in the United States by the Food and Nutrition Board of the Institute of Medicine. The RDA is average daily intake considered sufficient to meet the nutritional needs of 97% to 98% of healthy people.
The RDA for zinc from all sources varies by age, sex, and pregnancy status:
Infants up to 6 months: 2 mg/day
Children 7 months to 3 years: 3 mg/day
Children 4 to 8 : 5 mg/day
Children 9 to 13: 8 mg/day
Girls and women 14 to 18: 9 mg/day
Boys and men age 14 to older: 11 mg/day
Women 19 and older: 8 mg/day
Pregnant women 14 to 18: 13 mg/day
Pregnant women 19 and older: 11 mg/day
Lactating women 14 to 18: 14 mg/day
Lactating women 19 and older: 12 mg/day
In terms of supplementation, you need to be aware of the tolerable upper intake limit (UL) you should consume from all sources in the course of a day. For zinc, the UL is 40 mg per day.1
The appropriate use of zinc ointments, creams, or eyedrops can vary by the strength of the product. Always ensure that you use a product as directed, carefully reading the prescribing information on the package insert or label. If you are uncertain what an instruction means, speak with your doctor or pharmacist.
What to Look For
Without question, the best source of zinc is real foods. These include beef, lamb, pork, shellfish, legumes, seeds, nuts, milk, cheese, eggs, whole grains, potatoes, and sweet potatoes.1
If you decide to use a daily supplement, either on its own or as part of a multivitamin formulation, try not to exceed the daily value (DV) listed on the product label unless your doctor tells you otherwise. The DV is described as a percentage of what you typically need each day.
When buying a supplement, always choose those that have been tested and approved by a recognized certifying body like the U.S. Pharmacopeia (USP). Never use expired supplements, eye drops, or topical ointments.
Zinc poisoning is rare from naturally occurring zinc in foods. With that being said, the overuse of supplements can be especially problematic if combined with foods or products high in zinc.
One ounce of oyster meat, for example, provides 39 mg of zinc, which is all you need for one day.12 Denture creams also contain high concentrations of zinc that can enter the bloodstream through your gums, while zinc lozenges used to treat the common cold may expose you to as much as 100 mg of zinc per day.