Zinc is a nutrient that plays many vital roles in your body. Because your body doesnt naturally produce zinc, you must obtain it through food or supplements. This article explains everything you need to know about zinc, including its functions, health benefits, dosage recommendations and potential side effects.
What Is Zinc?
Zinc is considered an essential nutrient, meaning that your body cant produce or store it. For this reason, you must get a constant supply through your diet. Zinc is required for numerous processes in your body, including:
- Gene expression
- Enzymatic reactions
- Immune function
- Protein synthesis
- DNA synthesis
- Wound healing
- Growth and development
Zinc is naturally found in a wide variety of both plant and animal foods. Foods that dont naturally contain this mineral, such as breakfast cereals, snack bars and baking flour, are often fortified with synthetic forms of zinc. You can also take zinc supplements or multi-nutrient supplements that provide zinc. Because of its role in immune function, zinc is likewise added to some nasal sprays, lozenges and other natural cold treatments.
Role in Your Body
Zinc is a vital mineral that your body uses in countless ways. In fact, zinc is the second-most-abundant trace mineral in your body after iron and is present in every cell. Zinc is necessary for the activity of over 300 enzymes that aid in metabolism, digestion, nerve function and many other processes. In addition, its critical for the development and function of immune cells. This mineral is also fundamental to skin health, DNA synthesis and protein production. Whats more, body growth and development relies on zinc because of its role in cell growth and division. Zinc is also needed for your senses of taste and smell. Because one of the enzymes crucial for proper taste and smell is dependent on this nutrient, a zinc deficiency can reduce your ability to taste or smell.
Research shows that zinc has numerous health benefits.
Boosts Your Immune System: Zinc helps keep your immune system strong. Because it is necessary for immune cell function and cell signalling, a deficiency can lead to a weakened immune response. Zinc supplements stimulate particular immune cells and reduce oxidative stress. For example, a review of seven studies demonstrated that 8092 mg per day of zinc may reduce the length of the common cold by up to 33%. Whats more, zinc supplements significantly reduce the risk of infections and promote immune response in older adults.
Accelerates Wound Healing: Zinc is commonly used in hospitals as a treatment for burns, certain ulcers and other skin injuries. Because this mineral plays critical roles in collagen synthesis, immune function and inflammatory response, it is necessary for proper healing. In fact, your skin holds a relatively high amount about 5% of your body’s zinc content. While a zinc deficiency can slow wound healing, supplementing with zinc can speed recovery in people with wounds. For example, in a 12-week study in 60 people with diabetic foot ulcers, those treated with 200 mg of zinc per day experienced significant reductions in ulcer size compared to a placebo group.
May Reduce the Risk of Certain Age-Related Diseases: Zinc may significantly reduce your risk of age-related diseases, such as pneumonia, infection and age-related macular degeneration (AMD). Zinc may relieve oxidative stress and improve immune response by boosting the activity of T-cells and natural killer cells, which help protect your body from infection. Older adults who supplement with zinc experience improved influenza vaccination response, reduced risk of pneumonia and boosted mental performance. In fact, one study determined that 45 mg per day of zinc may decrease infection rates in older adults by nearly 66%. Additionally, in a large study in over 4,200 people, taking daily antioxidant supplements vitamin E, vitamin C and beta-carotene plus 80 mg of zinc decreased vision loss and significantly reduced the risk of advanced AMD.
May Help Treat Acne: Acne is a common skin disease that is estimated to affect up to 9.4% of the global population. Acne is driven by obstruction of oil-producing glands, bacteria and inflammation. Studies suggest that both topical and oral zinc treatments can effectively treat acne by reducing inflammation, inhibiting the growth of P. acnes bacteria and suppressing oily gland activity. People with acne tend to have lower levels of zinc. Therefore, supplements may help reduce symptoms.
Decreases Inflammation: Zinc decreases oxidative stress and reduces levels of certain inflammatory proteins in your body. Oxidative stress leads to chronic inflammation, a contributing factor in a wide array of chronic illnesses, such as heart disease, cancer and mental decline. In a study in 40 older adults, those who took 45 mg of zinc per day experienced greater reductions in inflammatory markers than a placebo group.
Although severe zinc deficiency is rare, it can occur in people with rare genetic mutations, breastfeeding infants whose mothers dont have enough zinc, people with alcohol addictions and anyone taking certain immune-suppressing medications. Symptoms of severe zinc deficiency include impaired growth and development, delayed sexual maturity, skin rashes, chronic diarrhea, impaired wound healing and behavioural issues. Milder forms of zinc deficiency are more common, especially in children in developing countries where diets are often lacking in important nutrients. It is estimated that around 2 billion people worldwide are deficient in zinc due to inadequate dietary intake. Since zinc deficiency impairs your immune system increasing the chances of infection zinc deficiency is thought to cause over 450,000 deaths in children under 5 every year. Those at risk of zinc deficiency include (29):
- People with gastrointestinal diseases like Crohns disease
- Vegetarians and vegans
- Pregnant and breastfeeding women
- Older infants who are exclusively breastfed
- People with sickle cell anaemia
- People who are malnourished, including those with anorexia or bulimia
- People with chronic kidney disease
- Those who abuse alcohol
Symptoms of mild zinc deficiency include diarrhoea, decreased immunity, thinning hair, decreased appetite, mood disturbances, dry skin, fertility issues and impaired wound healing. Zinc deficiency is difficult to detect using laboratory tests due to your bodys tight control over zinc levels. Thus, you may still be deficient even if tests indicate normal levels. Doctors consider other risk factors such as poor dietary intake and genetics alongside blood results when determining whether you need supplements.
Many animal and plant foods are naturally rich in zinc, making it easy for most people to consume adequate amounts. Foods highest in zinc include:
- Shellfish: Oysters, crab, mussels, lobster and clams
- Meat: Beef, pork, lamb and bison
- Poultry: Turkey and chicken
- Fish: Flounder, sardines, salmon and sole
- Legumes: Chickpeas, lentils, black beans, kidney beans, etc.
- Nuts and seeds: Pumpkin seeds, cashews, hemp seeds, etc.
- Dairy products: Milk, yogurt and cheese
- Whole grains: Oats, quinoa, brown rice, etc.
- Certain vegetables: Mushrooms, kale, peas, asparagus and beet greens
- Animal products, such as meat and shellfish, contain high amounts of zinc in a form that your body easily absorbs.
Keep in mind that zinc found in plant-based sources like legumes and whole grains is absorbed less efficiently because of other plant compounds that inhibit absorption. While many foods are naturally high in zinc, certain foods such as ready-to-eat breakfast cereals, snack bars and baking flours are fortified with zinc.
Toxicity and Dosage Recommendations
Just as a deficiency in zinc can cause health complications, excessive intake can also lead to negative side effects. The most common cause of zinc toxicity is too much supplemental zinc, which can cause both acute and chronic symptoms. Symptoms of toxicity include:
- Nausea and vomiting
- Loss of appetite
- Abdominal cramps
- Reduced immune function
- Decreased good HDL cholesterol levels
Ingesting too much zinc can also cause deficiencies in other nutrients. For example, chronic high zinc ingestion can interfere with your absorption of copper and iron. Reductions in copper levels have even been reported in people consuming only moderately high doses of zinc 60 mg per day for 10 weeks.
In order to avoid overconsumption, stay away from high-dose zinc supplements unless recommended by a doctor. The recommended daily intake (RDI) is 11 mg for adult men and 8 mg for adult women. Pregnant and breastfeeding women should consume 11 and 12 mg per day, respectively. Unless a medical condition is hindering absorption, you should easily reach the RDI for zinc through diet alone. The tolerable upper level for zinc is 40 mg per day. However, this does not apply to people with zinc deficiencies, who may need to take high-dose supplements. If you take supplements, choose absorbable forms such as zinc citrate or zinc gluconate. Stay away from zinc oxide, which is poorly absorbed.
The Bottom Line
Zinc is needed for DNA synthesis, immune function, metabolism and growth. It may reduce inflammation and your risk of some age-related diseases. Most people meet the RDI of 11 mg for men and 8 mg for women through diet, but older adults and people with diseases that inhibit zinc absorption may need to supplement. Because high-dose zinc supplements can lead to dangerous side effects, its important to stick to recommendations and only take supplements when necessary.
Healthline, 14 November 2018 ; http://www.healthline.com.org