Zinc is an important mineral required for a wide range of reactions and functions in the body, including healthy growth, immune function, DNA synthesis, and cell division.
The highest concentrations of zinc in the body are found in the liver, pancreas, kidney, bones, muscles, and eyes. Zinc also contributes to a person’s sense of smell and taste.
However, the body cannot store zinc. Supplementation is often necessary to maintain a healthy zinc balance.
The World Health Organization (WHO) has identified zinc deficiency as a widespread global health burden.
Zinc has demonstrated the following benefits during studies.
It is important to bear in mind, however, that further research is required in all cases to confirm the effects of zinc. The vital mineral shows action in many different parts of the body, and not all of its mechanisms are confirmed.
1) Supports growth and development
Zinc deficiency has been linked to poor growth. Several studies have confirmed that zinc supplementation led to small but notable increases in a child’s rate of growth.
More research is needed to confirm the growth benefits of zinc.
The slight enhancement of growth when zinc is taken as a supplement suggests that zinc may be more effective as part of a wider effort to improve the nutritional status of children around the world.
2) Decreased risk of age-related chronic disease and infection
The effects of zinc on infection may be linked to the reduction of cytokines in the body. Cytokines are substances secreted by the immune system as part of the body’s response to an infection.
3) Fighting age-related macular degeneration (AMD)
AMD is an age-related disease that gradually deteriorates the part of the eye responsible for clear central vision. This significantly decreases reading ability and facial recognition.
Zinc supplementation has been shown to the decrease risk of developing advanced AMD by 25 percent when taken with high levels of antioxidants.
4) Common cold
Zinc is present in many remedies and lozenges available to treat the common cold. However, it is not always effective, and data has not been reliable to confirm the impact of zinc on the common cold.
While zinc has not consistently shown the ability to clear the virus, a dosage of more than 75 milligrams (mg) per day during a case of the common cold shows a significant reduction in the severity of symptoms.
5) Wound healing
Zinc plays a role in maintaining skin integrity and structure. Deficiency can often contribute to chronic wounds, such as leg ulcers. Many people with chronic leg ulcers are less able to efficiently absorb zinc into the body, and have lower levels of zinc in the blood.
While studies have not demonstrated significant effects on wound healing, supplementation has accelerated the healing process in people who do not usually consume enough zinc.
Zinc sulfate is sometimes applied to treat wounds, but it has only shown positive effects in patients who do not have enough zinc. It has not been confirmed effective for the general treatment of wounds.
“Zinc supplementation could significantly increase the sperm quality of infertile males. However, further studies are needed to better elucidate the correlation between seminal plasma zinc and male infertility.”
In children with zinc deficiency, immune responses are often insufficient to deal with incoming threats, such as infections. The WHO advises that children in countries with fewer resources are often prone to zinc deficiency.
Zinc supplementation could significantly increase the sperm quality of infertile males. However, further studies are needed to better elucidate the correlation between seminal plasma zinc and male infertility.
The Recommended Daily Intake for zinc is 8 mg per day for adult females and 11 mg per day for adult males.
Consuming an adequate zinc intake is important for children. Even mild zinc deficiency can impede growth, increase the risk of infection, and increase risk of diarrhea and respiratory disease.
The recommended daily amount changes with age. The following table clarifies a few key life stages and their corresponding zinc requirements.
|Life stage||Recommended amount|
|Infants under 12 months||2 mg until 6 months, 3 mg from 6 to 12 months|
|Male aged over 14 years||11 mg|
|Female teens aged over 14 years||9 mg until 18 years, 8 mg from 18 years onward|
|Pregnant and breastfeeding women||Between 11 and 13 mg depending on age|
A more comprehensive list is available here.
Falling short of the required zinc intake poses a health risk.
Zinc deficiency can cause:
- delayed wound healing
- slow growth and sexual development
- impotence in men
- decreased taste perception
- eye and skin lesions
- night blindness
- hair loss
Zinc supplements are available, but it is best to obtain any vitamin or mineral through consuming food. It is not the individual vitamin or mineral that makes certain foods an important part of the diet but the synergy of nutrients working together.
Focus on obtaining the daily zinc requirement from foods, then use supplements as a backup if necessary.
The best sources of zinc are beans, animal meats, nuts, whole grain or fortified cereals, and dairy products. Fish and other seafood are also a superior source of zinc.
The typical western diet allows for adequate zinc intake, at an average range of between 10 and 15 mg per day.
However, several dietary factors can decrease zinc absorption. Phytates, copper, calcium, and folic acid may all interrupt the ability of the body to absorb zinc. Zinc absorption is increased when consumed with red wine, glucose, lactose, or soy protein.
The zinc requirement for vegetarians may be 50 percent higher than the recommended intake of zinc because of low bioavailability of zinc from plant-based foods.
Here is how much zinc is contained the following foods:
- 1 cup of canned eastern oyster: 147.34 mg
- 3 oz boneless, lean chuck eye steak: 8.96 mg
- 1 cup of canned, plain baked beans: 5.79
- 3 oz of raw King Alaskan crab: 5.06 mg
- 1 cup of cooked northern lobster: 5.87 mg
- 1 cup of cooked wild rice: 2.20 mg
- 1 cup of cooked green peas: 1.9 mg
The upper limit for zinc in adults is 40 mg per day. It is rare to consume toxic amounts of zinc, but this can cause gastrointenstinal irritation and vomiting. High levels of zinc supplementation are known to cause copper deficiency and impair iron absorption.
Zinc deficiency is far more common. It is important to consume enough zinc to avoid the negative effects of zinc deficiency.