Health Benefits of Zinc

Diseases and Conditions It Can Prevent or Treat

Senior Asian woman reading vitamin label

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Zinc is one of several essential trace minerals that your body needs to sustain good health. Since the body is unable to store zinc, we must obtain it through either the foods we eat or dietary supplement.

Zinc is needed for a multitude of biological functions. It acts as a catalyst for over 300 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.

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.

Health Benefits

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:

Disease Prevention

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.

A zinc deficiency impairs the immune system and leaves you vulnerable to diseases your body could otherwise neutralize. Zinc supplementation can sometimes help "boost" the immune response and shorten the duration of colds, flu, recurrent ear infections, upper respiratory tract infections, and bladder infections.

A 2018 study from the University of Texas has even suggested that zinc supplements can halt the growth of esophageal cancer cells. Similar studies have hinted at the same effect for colorectal cancer, stomach cancer, brain cancer, and non-Hodgkin's lymphoma.

While zinc supplements can neither stop nor treat cancer, research suggests they may have a protective effect since most people with cancer are zinc deficient.

Child Development

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. 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). There is even evidence that a dietary zinc deficiency may predispose a child to autism spectrum disorders.

Zinc supplementation not only helps avoid developmental delays in children, it is reported to improve symptoms of attention deficit-hyperactivity disorder (ADHD), according to a 2011 study from Ohio State University.

Skin Conditions

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.

While zinc supplements can help prevent the certain skin disorders, topical zinc oxide can be used to accelerate wound healing or treat conditions like acne, diabetic foot ulcers, diaper rash, herpes simplex infections, and hemorrhoidal rectal pain.

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).

Gastrointestinal Problems

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.

Macular Degeneration

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.

study in the Archives of Ophthalmology reported that zinc eye drops delayed the progression of macular degeneration in 75 percent of users, reducing the five-year risk to a 1.3 percent.

Psychological Disorders

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 anorexia nervosa, obsessive-compulsive disorder (OCD), depression, post-partum depression, and dementia.

While zinc supplement won't necessarily reverse these conditions, it can help increase the availability of serotonin and dopamine (the so-called "feel good" neurotransmitters) in the brain. This can not only help ease depression, but it may also improve memory and mental sharpness.

Male Infertility

Zinc deficiency in men is linked to poor sperm motility and quality. 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 of studies concluded that zinc supplements increased the semen volume, sperm motility, and percentage of healthy sperm in infertile men compared to a group provided a placebo.

Side Effects

Taking zinc supplements in excess of 40 milligrams (mg) per day may not be safe over the long term. At doses this high, zinc can cause diarrhea, vomiting, cramps, and a metallic taste in the mouth (dysgeusia).

At doses exceeding 100 mg per day, zinc supplement can also block the absorption of copper, leading to anemia, and reduce the amount of "good" high-density lipoprotein (HDL) cholesterol circulating in the blood. Kidney and stomach damage can also occur.

Although zinc may suppress tumor growth in the prostate gland, exceptionally high doses can actually aggravate prostate cancer as well as non-cancerous prostate enlargement (benign prostatic hyperplasia).

When applied to broken skin, zinc oxide may cause burning, itching, and tingling sensations.

Drug Interactions

Zinc can interfere with the activity of certain drugs or alter the concentration of zinc in the body. Before taking a zinc supplement, speak with your doctor if you are taking any of the following medications:

  • ACE Inhibitors used to treat high blood pressure, including Capoten (captopril), Lotensin (benazepril), and Vasotec (enalapril)
  • Corticosteroids, such as prednisone and Medrol (methylprednisolone)
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) such as Advil (ibuprofen) and Aleve (naproxen)
  • Platinol (cisplatin) used to treat certain cancers
  • Thiazide diuretics ("water pills"), such as Diuril (chlorothiazide), Hygroton (chlorthalidone), and Lozol (indapamide)
  • Quinolone and tetracycline antibiotics, including Avelox (moxifloxacin), Cipro (ciprofloxacin), and Levaquin (levofloxacin)

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 percent to 98 percent 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.

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.

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.

Overdosing on supplements is not the only concern. Oysters, for example, are extremely high in zinc, especially those from polluted waters. Some oyster varieties can contain as much as 10 mg of zinc per shellfish. Denture creams also contain high concentrations of zinc that can enter the bloodstream through your gums.

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.

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