Immunity-boosting vitamins and minerals are on everyone’s minds these days. (Read more: Vitamin D deficiency linked to poorer outcomes in COVID-19)

Ironically, you seldom hear about zinc in these discussions. This, despite the fact that zinc is often added in lozenges as a way to treat common colds (a viral infection) quickly.

Zinc is important for our immunity and various bodily functions at the cellular level: research has found that about 300 enzymes in the body depend on zinc. These enzymes do jobs like healing wounds and synthesizing DNA.

Indeed zinc deficiency has been linked to a host of health problems. Severe zinc deficiency can cause:

  • Bullous pustular dermatosis, in which pus-filled blisters or pimples form on the skin
  • Alopecia (hair loss)
  • Diarrhoeal diseases: Researchers say zinc deficiency impairs the immune function, which in turn may leave children more susceptible to infections that cause diarrhoea.
  • Emotional disorders
  • Abnormal weight loss
  • Immune system problems and infections
  • Male hypogonadism: Smaller than normal testes and low testosterone production are the main characteristics of male hypogonadism. It is also linked to low libido and infertility in some men.
  • Neurosensory disorders
  • Delay in the healing of ulcers and wounds
  • In extreme cases, death

Even in mild to moderate cases, zinc deficiency is linked to growth retardation, hypogonadism, rough skin and poor immunity.

Researchers estimate that about two billion people in the world may have a zinc deficiency. However, inadequate testing of blood for zinc deficiency (zinc serum test) means that it is difficult to gauge the nationwide prevalence of this condition. Indeed, most people may not even realise if they have a mild to moderate zinc deficiency.

Though healthy individuals can get their daily required values of zinc from food, this is harder to do with an entirely vegetarian diet as plant-based foods often contain phytates that interfere with the absorption of zinc. Zinc absorption may also be affected in people with certain underlying conditions like ulcerative colitis.

Here's everything you should know about zinc, its health benefits, how much zinc you need and zinc side-effects.

  1. How much zinc do we need?
  2. Benefits of zinc
  3. Sources of zinc and zinc supplements
  4. Zinc side-effects
  5. Takeaways

We all know that we need minerals in our diet to stay healthy. But how much we need of each is less known. Well, minerals are divided into two categories:

  • Macrominerals: We need more than 100 milligrams a day of calcium, magnesium, phosphorus, sodium, potassium, sulfur and chloride—these are known as macrominerals.
  • Microminerals: We need smaller quantities of iron, zinc, manganese, copper, selenium, cobalt and fluoride on a day-to-day basis—these are known as microminerals or trace minerals.

The difference between macro and micro or trace minerals is mainly the quantities we need, not how important they are for our health. After all, we all know how important iron is for the body to avoid anaemia.

According to the National Institutes of Health Office of Dietary Supplements, US, the amount of zinc we need daily is:

Age Male Female Pregnancy Lactation
0–6 months 2 mg 2 mg - -
7–36 months 3 mg 3 mg - -
4–8 years 5 mg 5 mg - -
9–13 years 8 mg 8 mg - -
14–18 years 11 mg 9 mg 12 mg 13 mg
19 years and above  11 mg 8 mg 11 mg 12 mg

Researchers began looking into the importance of zinc for humans in the 1960s, in West Asia where they were able to link short stature (dwarfism) and smaller testicular development (hypogonadism) in adolescents with zinc deficiency.

Subsequently, researchers were able to reduce these symptoms through zinc supplementation in prepubescent boys in Egypt and Iran. Similar efforts in the US in the 1970s showed that zinc supplementation could improve growth metrics (length and weight) in boys up to six months of age.

Since then, scientists have uncovered the many uses of zinc for the body. For example, our immune cells use zinc as a messenger.

Today, according to an article published in 2013 in Advances in Nutrition—a peer-reviewed journal published by Oxford University Press—doctors use zinc in the “management of acute diarrhoea in children, Wilson's disease, the common cold and for the prevention of blindness in patients with an age-related dry type of macular degeneration and...decreasing the incidence of infection in the elderly. Zinc not only modulates cell-mediated immunity but is also an antioxidant and anti-inflammatory agent”.

To quickly recap, these are some of the most important benefits of zinc for humans:

Zinc for immunity

Research shows that zinc is important for controlling T-cells that are a part of our adaptive immunity (the immunity we gain from fighting an infection or disease).

T-cells identify any bacteria, virus or other pathogens that attack the body. Killer T-cells then destroy infected cells while helper T-cells send out a message to the body to create antibodies against the pathogen. T-cells use cytokines as a messenger—the phrase cytokine storm has, of course, become better known after researchers uncovered their role in COVID-19 related deaths.

Recent research by scientists across Oxford University, the University of Newcastle, Durham, Imperial College, the Netherlands and the USA, has also found that zinc is crucial to the development of B-cells which form the antibodies against a pathogen.

The findings were published in Nature Immunology in February 2019, in an article titled "An essential role for the Zn2+ transporter ZIP7 in B cell development".

Our body also uses zinc and copper to make superoxide dismutase, a powerful antioxidant which helps the body clear away the superoxides that are normally created when the body uses oxygen.

Zinc for baby development and young children

In addition to bodily growth, zinc is important for brain development in babies. They need this trace mineral especially during periods of great growth spurts.

While formula-fed babies can get their requisite 2 mg a day easily, breastfed babies who are older than six months must be given zinc-rich foods or supplements to make up for any deficit. You could, for example, give your baby mashed and pureed avocado for zinc. (Read more: Best foods to wean your six-month-old).

For young children, zinc is important to fight infections, including respiratory infections and diarrhoea-causing infections. Zinc supplementation can help to prevent these, and doctors also use zinc to treat acute diarrhoea.

Adequate zinc intake has also been linked to proper cognitive function, better focus and memorising skills in adolescents.

Zinc helps to prevent and manage diarrhoea

Diarrhoea is one of the biggest causes of death in children under five in developing countries. Researchers have been arguing for wide-scale measurement of zinc status in these populations. In cases where zinc deficiency in children is suspected, diagnosed and treated early enough, doctors are able to prevent serious illness and death.

Zinc for cold and pneumonia prevention

Studies show that zinc can reduce the chances of respiratory tract infection, especially in children and in people over 60 years old.

Researchers have shown that zinc supplementation in the elderly (those with low zinc serum levels to begin with) prevents pneumonia. It also shortens the recovery time and reduces the need for antibiotics in older pneumonia patients.

Zinc for healing wounds and skin problems

We have all heard of the use of zinc oxide as a sunscreen. We also know that calamine—a zinc preparation—can help in the treatment of rashes and acne. Zinc pyrithione based shampoos have antibacterial and antifungal properties that help in fighting dandruff. Of late, dermatologists have also started using zinc-based preparations for the treatment of:

  • Infections, including cutaneous leishmaniasis which presents as skin lesions
  • Inflammatory skin conditions like acne vulgaris and rosacea
  • Pigment disorders like melasma (dark spots on the face, also known as the mask of pregnancy)
  • Neoplasias or basal cell carcinoma
  • Acrodermatitis enteropathica: A rare genetic disorder in which the body is unable to absorb zinc from the food.
  • Topical creams with zinc in them are used in the treatment of diaper rashes and leg ulcers.

Zinc is used in the treatment of Wilson's disease

A genetic disorder, Wilson's disease is a condition in which there is an excess build-up of copper in the body. Zinc acetate has been shown to be effective in managing copper toxicity in patients.

Zinc in body enzymes

Scientists first discovered zinc-linked enzymes in the body in 1940—the enzyme they found, carbonic anhydrase II, plays a role in maintaining electrolyte balance in the body and bone reabsorption.

Today, we know that zinc plays a role in the functioning of some 300 enzymes (zinc metalloenzymes) in the body that are responsible for metabolism, immunity and more.

Zinc prevents osteoporosis

Research shows that while zinc deficiency is linked to loss of bone density, adequate amounts of zinc in the bones actually slow down ageing and reduce some effects of menopause, including osteoporosis.

According to an article published in the Molecular and Cellular Biochemistry journal, the mechanism of how zinc promotes bone growth has multiple layers:

  • It stimulates osteoblastic bone formation and mineralization
  • It activates an enzyme called aminoacyl-tRNA synthetase, which helps in protein synthesis at the cellular level and helps in bone growth.
  • Zinc prevents osteoclastic bone resorption.
  • Adequate dietary zinc can increase bone mass.

All of these factors help to improve bone health and avoid osteoporosis (a degenerative disease in which the bones starts to lose their density, become more brittle and prone to fractures).

Zinc for sexual health

We know that zinc deficiency can cause hypogonadism and low testosterone. Conversely, adequate zinc and zinc supplementation can improve the production of sex hormones testosterone and prolactin.

Zinc is also involved in the development of sexual organs. Though more studies need to be done on this, some researchers have suggested that zinc may help to manage premature ejaculation.

Healthy individuals can get their daily zinc requirements from non-vegetarian foods such as oysters, lobsters, chicken and pork.

It is harder to meet all your zinc requirements with a purely vegetarian diet but it is possible—you should soak, sprout, ferment or leaven these foods to increase the availability of the zinc present in them. The vegetarian sources of zinc include:

Zinc supplements

Research is divided on whether you should take zinc supplements. For example, a study in which South Asian children were given zinc supplements showed improved health outcomes. However, another study on protein metabolism in middle-aged men showed that zinc supplements did not make a significant difference among the participants.

Your age and the desired outcome are just two of the many things you should consider before taking zinc supplements. Ideally, you should talk to your doctor before taking any supplements. In this case be sure to also ask about the dosage, as an excess of zinc can also produce some side-effects.

That said, zinc supplements are available in six main forms:

  • Zinc gluconate
  • Zinc acetate
  • Zinc sulphate
  • Zinc picolinate
  • Zinc orotate
  • Zinc citrate

They vary slightly in terms of taste and bioavailability of zinc. Zinc gluconate is most often used in nasal sprays and lozenges to treat the symptoms of a cold. Zinc sulphate oral solution is sometimes prescribed for the treatment of diarrhoea in children.

Though rare, taking too much zinc can cause some side-effects such as:

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Zinc is important for proper development, immune function, protein synthesis and a myriad other functions in the body.

Though we need only trace amounts of this mineral, zinc deficiency is very common. It can lead to a host of problems like growth retardation, male hypogonadism, cognitive problems, alopecia and several skin problems.

Oysters and animal proteins are the best food sources of zinc. That said, vegetarians and vegans can also get adequate zinc through large amounts of rajma, pumpkin seeds, cashew nuts and tofu. It's important to remember that phytates (plant compounds) in many plant-based diets inhibit the absorption of zinc in the body. Try soaking, sprouting, fermenting, leavening any vegetarian sources of zinc, to increase the bioavailability of the mineral (the extent to which it can be absorbed in the body).

References

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