Zinc (Zn) is a transition metal belonging to group 12 of the periodic table. As an "essential trace element" zinc has substantial biological importance for plants and animals.
Zinc is responsible for a number of different functions in the human body and it helps stimulate the activity of 100 different enzymes.
This Medical News Today information article highlights the potential health benefits of zinc and provides details on good sources of the nutrient, symptoms of zinc deficiency, and precautions to consider - associated with excessive zinc intake.
Only a very small intake of zinc is necessary to reap the benefits. Currently, the "Recommended Dietary Allowance" (RDA) for zinc in the US is: 8 mg/day for women and 11 mg/day for men.1
Having a low level of zinc makes a person more susceptible to disease and illness. It has been reported that zinc deficiency is responsible for over 800,000 childhood deaths in the world every year.
The element is naturally found in a number of different foods, but it is also available as a dietary supplement.
What are the possible health benefits of zinc?
Zinc is important for a healthy immune system, properly synthesizing DNA, promoting healthy growth during childhood, and healing wounds. Let's look at each of these in turn.
1) Regulating immune function
Zinc is an "essential trace element" because our
bodies only need very small amounts of it.
According to the European Journal of Immunology, the human body needs zinc to activate T lymphocytes (T cells).2
T cells help the body in two ways:
- Controlling and regulating immune responses
- Attacking infected or cancerous cells.
Zinc deficiency can severely impair immune system function.
According to a study published in the American Journal of Clinical Nutrition, "zinc-deficient persons experience increased susceptibility to a variety of pathogens."3
2) Treating diarrhea
According to the World Health Organization, diarrhea "kills an astonishing 1.6 million children under 5 every year. An article in TIME magazine said that "zinc pills appear to halt diarrhea in its tracks."
In addition, a PLoS Medicine study, which "followed a nationwide public health campaign to increase zinc use for childhood diarrhea in Bangladesh," confirmed that a 10-day course of zinc tablets is effective at treating diarrhea and also helps prevent future bouts of the condition.
3) Affecting learning and memory
Research conducted at the University of Toronto and published in the journal Neuron suggested that zinc has a crucial role in regulating how neurons communicate with one another, affecting how memories are formed and how we learn.
4) Helping treat the common cold
Zinc lozenges were found to shorten the duration of common cold episodes by up to 40% in a study published in the Open Respiratory Medicine Journal.
In addition, a Cochrane review concluded that taking "zinc (lozenges or syrup) is beneficial in reducing the duration and severity of the common cold in healthy people, when taken within 24 hours of onset of symptoms."4
5) Wound healing
Zinc plays a role in maintaining skin integrity and structure. Patients experiencing chronic wound or ulcers often have deficient zinc metabolism and lower serum zinc levels. Those with low levels should be treated with increased zinc.
A Swedish study that analyzed zinc in wound healing, concluded that "topical zinc may stimulate leg ulcer healing by enhancing re-epithelialization, decreasing inflammation and bacterial growth. When zinc is applied on wounds, it not only corrects a local zinc deficit but also acts pharmacologically."5
However, research has not consistently shown that use of zinc sulfate in patients with chronic wounds or ulcers is effective at improving healing rate.
6) Proper growth
Zinc deficiency was first discovered in adolescent boys suffering from mild anemia, short stature and delayed sexual maturation. Their diets were high in unrefined cereals and unleavened breads, both high in phytate, which competes with zinc for absorption.
Once zinc deficiencies were corrected, the boys grew as much as 5 inches per year. Infant and children's foods such as ready to eat cereals are now fortified with zinc.
7) Decreased risk of age-related chronic disease
A study from researchers at Oregon State University have found that improving zinc status through diet and supplementation may reduce the risk of inflammatory diseases.
Using cell cultures, and a mouse model, researchers were able to show that age-related reductions in zinc status may lead to impaired immune system function and systemic inflammation, both contributing factors to chronic diseases.
Adults 60 years of age and older from food-insufficient households have a significantly higher risk of zinc deficiency, reporting an intake of less than 50% of the Recommended Daily Intake for zinc compared with adults from food-sufficient households.6
8) Preventing age-related macular degeneration (AMD)
Zinc prevents cellular damage in the retina, which helps in delaying the progression of AMD and vision loss, according to a study published in the Archives of Ophthalmology.7
Several studies and trials have linked poor zinc status with low sperm quality. For example, one study in the Netherlands found that subjects had a higher sperm count after zinc sulfate and folic acid supplementation.8
In another study, researchers concluded that poor zinc intake may be a risk factor for low quality of sperm and male infertility.
On the next page, we look at other possible health benefits of zinc, foods that provide good sources of zinc, and precautions to bear in mind.