Why do you need Zinc? (SQ-118)
When you think of minerals, iron and calcium and magnesium generally top the list. It is well-known that your body needs iron to make red blood cells and prevent anemia. Calcium is required for strong bones, healthy nerve transmission and muscle contraction. Magnesium relaxes body and mind and is known for its ability to reduces stress and muscle cramps. What about zinc? Chances are this essential trace mineral isn’t always on the top of your mind.
Did you know that more than 300 enzyme systems in the body depend on zinc to function properly? It plays a vital role in supporting your immune function and you need zinc for healthy metabolism and making new cells. It also supports prostate health in men and maintains hormone levels. In fact, zinc deficiency has been associated with thyroid disorders as you need zinc and other trace minerals like selenium and copper to make thyroid hormones. Low zinc levels also affect fertility and testosterone levels in men.
Clearly, zinc is important, and its deficiency can impair a lot of important functions in the body, putting you at a risk of many health complications. Let’s discuss why zinc is absolutely important for your overall health.
Role of zinc in the body
Your body can’t make zinc on its own, so it is important to get this essential trace mineral from food (shellfish and meat are a couple of the best sources as are nuts, seeds and legumes) or from supplements.
Zinc is present in every cell and it is a critical part of various enzymes that support biological processes. It is required for:
- Cell formation and division
- DNA and protein synthesis
- Growth and development in all stages of life
- Healthy immune function
- Wound healing
- Sensory function (taste, smell and vision)
- Proper digestion and healthy gut
1. Essential co-factor in enzyme function
More than 3000 proteins in your body contain zinc and this accounts for nearly 10% of the total proteins in the body.
Zinc works as an important co-factor for over 300 enzymes, proteins that help speed up bio-chemical reactions in the body. It is also important for the structure and stabilization of proteins and cell membranes. For example, zinc is crucial for enzymes that are involved in metabolism and maintaining acid-base (pH) balance in the body. It is also an essential co-factor in proteins involved in cellular signaling and gene expression.
2. DNA synthesis and repair
Zinc plays a vital role in DNA synthesis and repair. Studies suggest that just a modest boost in zinc intake can reduce DNA damage. A 2016 study showed that increasing dietary zinc: 
- Decreased DNA strand breaks in leukocytes
- Restored the levels of proteins involved in DNA repair
- Restored antioxidant and immune functions
Zinc is important for building healthy immunity. Since it is required for DNA synthesis and making new cells, zinc plays a vital role in the production, growth and function of different types of immune cells that help fight infections and keep diseases at bay.
Zinc is important for the normal development and functions of cells like T cells, B cells, macrophages and neutrophils. The essential mineral also reduces oxidative damage and inflammation. Even a mild zinc deficiency can impair your immune function, increasing your risk of infectious diseases such as influenza and pneumonia.
Studies show that boosting your zinc intake within 24 hours of onset of symptoms reduces the severity and duration of common cold. It also reduces the risk of acute lower respiratory tract infections in children. 
In fact, there is very high-quality evidence that proves properly formulated zinc lozenges may reduce the duration of colds by nearly 33%. This meta-analysis of randomized, double-blind, and placebo-controlled clinical trials found that “the current evidence of efficacy for zinc lozenges, in particular zinc acetate lozenges, is so strong that common cold patients may be encouraged to try them for treating their colds.” 
Your immune system weakens with age, leading to increased risk of infectious diseases such as pneumonia, inflammation and chronic diseases. Studies show that oral zinc supplements may help improve immunity, reduce inflammation, prevent pneumonia and lowers the rate of respiratory infections in the elderly.  
4. Growth and development
Zinc is important for growth and development, as it is involved in cell growth and division. Healthy intake of zinc is especially important in children  and even a slightly low zinc status can impair proper growth and increase the risk of infectious diseases and diarrhea in children.
5. Gut health and diarrhoea
Zinc plays several roles in maintaining your gut health. For example, this mineral:
- Maintains gut-barrier function: Zinc supports a healthy gut barrier function. Its deficiency weakens the tight junctions across the intestinal lining, leading to leaky gut. This gives rise to food allergies, absorption issues, inflammatory bowel diseases, diarrhea and celiac disease.  A healthy zinc intake helps improve gut barrier function, repair a leaky gut and regenerate gut mucosa, the highly resilient innermost lining of the gastrointestinal tract that is damaged by inflammatory bowel diseases.
- Healthy metabolism and digestion: You need zinc for healthy metabolism of proteins, fats, and carbohydrates. In addition, the mineral also helps in proper function of digestive enzymes, improving digestion and absorption of nutrients.
- In Diarrhoea: Zinc supplements reduce the duration and symptoms of diarrhoea in zinc-deficient children. The World Health Organization recommends taking zinc supplements along with oral rehydration solutions, for treating diarrhoea in children. It is believed that zinc improves the absorption of fluids from the intestines, restores the mucosal integrity and supports immune function.
6. Sensory function
Zinc is required for sensory functions such as taste and smell. Low zinc levels can cause taste and smell dysfunction, which also affects appetite, nutritional status and overall quality of life. Older adults are especially affected by taste dysfunction because of age, use of medications, and zinc deficiency.
7. Eye health
Zinc plays a huge role in keeping your eyes and vision healthy. In fact, a large concentration of zinc is stored in the retina and choroid (thin layer of tissue under retina that contains blood vessels that carry oxygen and nutrition to the eye).
Basically, zinc is involved in various stages of vitamin A metabolism, such as its absorption, transportation and conversion in the body. It also protects eyes from oxidative damage that comes with age and other external actors.
For example, you need zinc dependent enzyme retinol dehydrogenase to convert retinol to retinal, which is critical to the synthesis of rhodopsin. Rhodopsin is a protein present in the rod cells of the retina, and it enables you to adapt to and see in low-light conditions.
Zinc plays a vital role in transporting vitamin A from liver to the retina of the eye, where it is used to produce melanin, a pigment that gives your eyes their color. Melanin works as a sunscreen for the eyes as it protects the eyes from the oxidative damage induced by UV rays.  Zinc is also an important component of various enzyme systems and it is also present in superoxide dismutase, an enzyme that helps prevent oxidative damage in cells and tissues, including those of eyes.
Some studies suggest that zinc supplements can help delay the development of age-related macular degeneration (AMD). People who are at high risk of AMD or those already with early symptoms can reduce their risk of moving to advanced AMD, by increasing their zinc intake. And it is found that zinc works best when used along with other powerful antioxidants and nutrients.
8. Helps in skin health and wound healing
Considering your skin contains a high concentration of zinc, it is no surprise that the trace mineral is important for your skin health. In fact, low zinc levels have been associated with a severe type of acne lesions.  Zinc deficiency is also linked with chronic wounds. In fact, one of the typical signs of zinc deficiency is wounds that don’t heal quickly. Taking a zinc supplement can accelerate wound healing and repair.
Zinc is commonly used in the treatment of burns, wounds and skin conditions like acne. Emerging research shows zinc is also helpful for dermatitis, psoriasis and diabetic foot ulcers. 
Zinc is helpful in inflammatory skin conditions, faster wound healing and general skin health, as the mineral:
- Plays a vital role in DNA synthesis and production of new skin cells
- Helps in protein synthesis (you need protein, vitamin C and zinc for healthy wound healing)
- Maintains skin structure and integrity
- Plays an important role in collagen synthesis
- Boosts immune function, prevents infections and reduces inflammation
Other functions of Zinc
- Maintains healthy levels of hormones such as testosterone, progesterone, estrogen and thyroid hormones
- Supports prostate health and may reduce the risk of enlarged prostate and inflammation in prostate (the prostate gland requires higher amounts of zinc than most cells for proper functioning).
- Supports hair growth and makes your hair strong (you need zinc keratin synthesis)
- Regulates sugar levels
- Supports reproductive health
- Supports cognitive function, such as learning and memory
Your body is not able to store zinc, so it is important that you get healthy amounts of mineral from foods or supplements. Ideally, you should be able to get all the zinc you need from a healthy, well-balanced diet, which also reduces your risk of zinc overdose or zinc toxicity that is possible when you take supplements above the recommended dosages.
Some of the best sources of zinc include shellfish (oysters, crabs and lobsters), meat (beef and pork), poultry, milk and cheese, yogurt, nuts and seeds (pumpkin seeds, almonds, cashews nuts), chickpeas, black beans, lentils and kale.
Not getting enough zinc through food is the most common reason for developing zinc deficiency. However, many other factors such as absorption issues and certain health conditions put you at a higher risk.
What increases your risk for zinc deficiency?
- Insufficient consumption of foods that contain zinc
- Gastrointestinal diseases like Crohn’s disease and celiac disease
- Pregnancy and breastfeeding
- Condition such as diabetes, sickle cell anemia, liver disease, kidney dysfunction
Symptoms of Zinc deficiencySince zinc is required for hundreds of enzyme functions, protein synthesis, sensory functions new cells formation and healthy immune system, its deficiency can manifest into a number of symptoms such as:
- Reduced sense of taste and smell
- Loss of appetite
- Slower healing of wounds
- Bleeding gums
- Acne or dry scaly skin
- Reduced growth and development
- Loss of hair and alopecia
- White spots or ridges on your fingernails
Too much of zinc can be harmful
Zinc is a trace mineral, meaning you need it very small amounts. Too much of zinc intake, that usually happens when you take a high-dose zinc supplement, can be damaging.
What can excessive intake of zinc can do?
- Reduces your body’s ability to absorb copper, causing copper deficiency. This can lead to neutropenia, abnormally low levels of neutrophils in the body. Neutrophils are a type of white blood cells that help fights all kinds of bacterial and viral infections. Copper deficiency, due to excessive zinc, increases the risk of infections. Low levels of copper in the body also results in other complications such as weak bones and osteoporosis and loss of skin pigmentation.
- Reduces absorption of iron, leading to anemia
- Low levels of HDL cholesterol
Symptoms of zinc toxicity
- Pain or cramps in stomach
- Loss of appetite
- Nausea and vomiting
- Headache and dizziness
- Metallic taste in mouth
- Frequent bouts of infections
- Zyba et al. A moderate increase in dietary zinc reduces DNA strand breaks in leukocytes and alters plasma proteins without changing plasma zinc concentrations. The American Journal of Clinical Nutrition. 2017.
- Brown KH et al. Preventive zinc supplementation among infants, preschoolers, and older prepubertal children. Food Nutr Bull. 2009
- Harri Hemilä et al. Zinc lozenges and the common cold: a meta-analysis comparing zinc acetate and zinc gluconate, and the role of zinc dosage. JRSM Open. 2017
- Barnett et al. Effect of zinc supplementation on serum zinc concentration and T cell proliferation in nursing home elderly: a randomized, double-blind, placebo-controlled trial. The American Journal of Clinical Nutrition. 2016.
- Hajo Haase and Lothar Rink. The immune system and the impact of zinc during aging. Immun Ageing. 2009
- Liu et al. Effect of Zinc Supplementation on Growth Outcomes in Children under 5 Years of Age. Nutrients. 2018
- Skrovanek et al. Zinc and gastrointestinal disease. World J Gastrointest Pathophysiol. 2014
- Le at al. The role of melanin in protecting the skin and the retina from light damage: A comparative biological framework for Age-Related Macular Degeneration. Investigative Ophthalmology & Visual Science. 2014
- Majid Rostami Mogaddam et al. Correlation between the Severity and Type of Acne Lesions with Serum Zinc Levels in Patients with Acne Vulgaris. Biomed Res Int. 2014
- Momen-Heravi M et al. The effects of zinc supplementation on wound healing and metabolic status in patients with diabetic foot ulcer: A randomized, double-blind, placebo-controlled trial. Wound Repair Regen. 2017