What is zinc?
Zinc Zinc Deficiency Zinc deficiency has many causes, including various disorders, alcohol use disorder, and use of diuretics. People lose their appetite and hair and may feel sluggish and lose their sense of taste... read more , a mineral, is required in small quantities for many metabolic processes. Dietary sources include oysters, beef, and fortified cereals. Zinc supplements are available in capsule, tablet, lozenge, and nasal spray form.
What claims are made about zinc?
People most often take zinc in the form of lozenges to reduce the duration of cold symptoms. Some people take zinc to fight acne or improve heart health. Some people take zinc to slow the progression of age-related macular degeneration Age-Related Macular Degeneration (AMD or ARMD) Age-related macular degeneration (AMD) causes progressive damage to the macula, the central and most vital area of the retina, resulting in gradual loss of central vision. Central vision becomes... read more , which is an eye disease, or to help heal wounds because zinc deficiency delays wound healing.
Mild zinc deficiency impairs growth in children and can be corrected with zinc supplementation.
Studies suggest that zinc supplementation helps people with prediabetes or diabetes control their blood sugar levels.
Does zinc work?
Scientific studies are inconsistent, but if zinc has an effect on the common cold, it probably is small and occurs only when it is taken very soon after cold symptoms develop.
Strong evidence indicates that zinc supplements, when combined with certain other supplements into a standardized preparation, slow progression of moderate to severe atrophic (dry form) age-related macular degeneration Age-Related Macular Degeneration (AMD or ARMD) Age-related macular degeneration (AMD) causes progressive damage to the macula, the central and most vital area of the retina, resulting in gradual loss of central vision. Central vision becomes... read more . Evidence also shows that zinc may help people with diabetes and prediabetes control their blood sugar levels.
A 2016 study found that zinc supplementation may help relieve diarrhea in zinc-deficient or undernourished children (usually in low-resource countries) who are over 6 months old. There is evidence that, in low-resource countries, once-weekly supplements containing zinc and iron during the first year of life may decrease mortality due to diarrhea and respiratory infections.
What are the possible side effects of zinc?
Zinc is generally safe, but zinc toxicity Zinc Excess Zinc excess occurs when the body has too much of the mineral zinc. Zinc is widely distributed in the body—in bones, teeth, hair, skin, liver, muscle, white blood cells, and testes. It is a component... read more can develop if high doses are taken. The common side effects of zinc lozenges include the following:
Symptoms such as fever, coughing, headache, and fatigue
Because zinc is a trace metal and can remove other necessary metals from the body, intake of zinc lozenges should be limited (for example, to no more than 14 days). Zinc sprays may irritate the nose and throat and should be avoided.
Doses greater than 40 mg daily may cause toxicity, sometimes resulting in deficiency of copper Copper Deficiency Copper deficiency is rare among healthy people and occurs most commonly among infants who have other health problems or inherit a genetic abnormality. Most of the copper in the body is located... read more in the body and decreases in iron levels, often resulting in anemia Iron Deficiency Anemia Iron deficiency anemia results from low or depleted stores of iron, which is needed to produce red blood cells. Excessive bleeding is the most common cause. People may be weak, short of breath... read more . At daily doses greater than 50 mg, levels of the high-density lipoprotein (the "good cholesterol") may decrease. Also, prostate disorders, such as benign prostatic hyperplasia Benign Prostatic Hyperplasia (BPH) Benign prostatic hyperplasia (BPH) is a noncancerous (benign) enlargement of the prostate gland that can make urination difficult. The prostate gland enlarges as men age. Men may have difficulty... read more , may worsen with consumption at high doses for several years. Whether several years of high-dose use can cause or contribute to prostate cancer in unknown.
What drug interactions occur with zinc?
The absorption and effectiveness of certain antibiotics in treating infection may be lowered if zinc supplements are taken at the same time; therefore, zinc should be taken at least 3 hours after these antibiotics.
Some drugs may decrease zinc levels. Examples include proton pump inhibitors such as omeprazole (which reduce the amount of stomach acid), the antihypertensive lisinopril (which brings blood pressure down by relaxing the blood vessels), corticosteroids, estrogens, and some antiseizure drugs.
Zinc supplements are not recommended for people in high-resource countries because most people in such countries get enough zinc through their diet without taking zinc supplements and taking too much zinc can lead to toxic levels with serious side effects. However, zinc supplements can decrease deaths due to common infections among children in low-resource countries.
High-dose zinc supplements should not be taken unless recommended by a doctor to treat a zinc deficiency Zinc Deficiency Zinc deficiency has many causes, including various disorders, alcohol use disorder, and use of diuretics. People lose their appetite and hair and may feel sluggish and lose their sense of taste... read more .
It is not clear whether zinc supplements reduce the duration of common colds, but any such effect is unlikely to be anything more than minimal.
Zinc may also help control blood sugar levels in people with diabetes or prediabetes.