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What is zinc? A guide to your body’s second most abundant mineral

Zinc is an essential dietary mineral that is found in every cell in your body. In fact, it’s the second most abundant mineral in your body after iron. As humans we can't produce it though, so we need to get a constant supply through our diets. 

Zinc benefits

Zinc is involved in the function of every system in your body and plays a role in everything from copying genetic material to breaking down food and nutrients. It’s required for the activity of over 100 enzymes, and also plays important roles in your growth and development, skin health, immune system, sense of smell and many other vital processes. The main zinc benefits are:

Zinc supports your immune system

The most well-known benefit of zinc is its role in supporting your immune system. Zinc supports the growth and function of immune cells, which in turn helps your immune system fight off invading bacteria and viruses. It also helps to protect your cells from oxidative damage caused by exposure to environmental toxins (1).

Zinc plays a role in growth and development

Another crucial benefit of zinc is its key role in cell division and growth (2). It’s especially important during periods of rapid growth, including pregnancy, childhood, and adolescence, as well as in tissues that have quick cell changes and turnover, such as your immune system and digestive tract. In addition, it’s essential for collagen synthesis, which is crucial for the growth and maintenance of your skin, bones and other body tissues. It can also speed up wound healing as it supports cell division, allowing new tissue to be formed.

Zinc supports hormone health

A lesser known zinc benefit is its role in supporting hormone health. Zinc is involved in the metabolism and production of hormones, including thyroid, leptin, testosterone, melatonin and other sex hormones that are necessary for reproductive health. 

Zinc deficiency also alters testosterone levels. The enzyme ‘aromatase’ causes testosterone to convert oestrogen. Zinc inhibits aromatase and prevents the overactivation of the enzyme, halting the excessive conversion of testosterone to oestrogen. The depletion of testosterone through zinc deficiency results in inhibited sperm production in males (3) (4).

Zinc helps with inflammation

Another benefit of zinc is that it’s both a potent antioxidant and a cofactor to the enzymes that control the antioxidant defence system. Antioxidants help to fight the effects of free radicals in your body, protecting your cells from oxidative damage and therefore supporting the process of reducing inflammation throughout your body (5).

Zinc plays a role in taste and smell 

One of the enzymes that is critical to maintain good taste and smell function is dependent on zinc (6).

Zinc supports gene expression

Zinc can regulate genetic expression and is involved in DNA synthesis (7).

Zinc supports your hair, skin and nails

Zinc is an essential mineral critical for supporting many processes in your body. It is involved in almost every metabolic function, including hair and skin health. 

Normal hair growth and loss follow a cycle. After hair grows, it begins a phase where it starts slowing growth and enters a “resting phase”. During this phase, hair follicles start to shrink and after a few months, follicles release the hair. Zinc appears to help inhibit the follicles from shrinking that precedes hair loss, meaning you hang on to hair longer, helping it to be longer. It also helps with follicle health as new hairs grow in. 

Zinc also plays a role in keeping the oil glands in your scalp and follicles working properly, and makes sure they produce enough sebum to keep your hair moisturised and scalp hydrated. 

Although zinc won’t increase your hair growth, including zinc in your diet can help prevent hair loss. Hair loss is a common symptom of zinc deficiency.

Studies show that reversing zinc deficiency with supplementation may reduce deficiency-related hair loss. 

Zinc deficiency & depletion 

Your body can't store zinc, so it depends on a daily supply through diet. Things that can drive low zinc status and make people at risk of zinc deficiency include:  

  • Inadequate dietary intake: Vegans and vegetarians are at risk of zinc deficiency because it's less abundant in plant foods than animal protein, and plant foods are often high in a substance called phytic acid, which inhibits the absorption of minerals.

  • Poor absorption: Poor absorption of zinc is common in those with chronic digestive conditions (e.g. inflammatory bowel disease). Low stomach acid levels driven by ageing and stomach acid-lowering medications can also impair zinc absorption. 

  • High utilisation, or ‘draining’, of zinc: Factors like high stress, pregnancy, breastfeeding, high alcohol intake, tissue repair (e.g. surgery), over exercising or strenuous physical training, and chronic use of other ‘zinc-depleting’ medications such as diuretics can all increase excretion and decrease absorption of zinc. 

  • Other minerals: Zinc competes with iron and calcium for absorption and high zinc intakes can inhibit copper absorption.

Zinc deficiency symptoms

Without enough zinc in the body, hundreds of different nerve, metabolism, and digestive enzymes will stop working, and your health will decline. Low zinc status can manifest as a wide range of signs, symptoms, and conditions, including:

  • Slow growth in early years
  • Loss of sense of taste, smell, and appetite
  • Weight loss
  • Impaired immune function, recurrent and/or long lasting infections
  • Slow wound healing
  • Hair loss and skin changes (e.g. acne, psoriasis) 
  • Diarrhoea
  • Low libido
  • Impaired fertility
  • Impotence 
  • Low mood, memory and concentration
  • Lack of menstrual periods and premenstrual syndrome (PMS)
  • White spots on the fingernails

Zinc RDA

The recommended daily zinc intake for adult males in the UK is 9.5mg, and for adult females is 7mg. 

Sources of zinc 

Foods containing zinc

Zinc is found in a wide variety of foods. Zinc content is fairly high in animal sources and less so in plant foods due to their phytic acid (phytate) content. Phytates, found in whole grains, legumes, seeds and nuts bind to zinc and inhibit its absorption. The requirement for dietary zinc may be as much as 50% higher for strict vegans and vegetarians, whose major food staples are grains and legumes.

Animal sources of zinc

Oysters, red meats, eggs, poultry, cheese, fish, shrimp, crab, and other shellfish. 

Vegetarian sources of zinc

Legumes (especially beans, peas, soybeans, and peanuts), whole grains, tofu, brewer's yeast, brazil nuts, almonds, cooked greens, mushrooms, green beans, pumpkin, and sunflower seeds.

Zinc supplements

People who are unable to get enough zinc through their diet, or who can’t properly absorb it, may benefit from zinc supplements.

To maximise absorption, it’s best to take a zinc supplement on an empty stomach, at least one or two hours before or after meals. If you find that you experience stomach pains, try taking it with meals instead.

Summary

Although getting enough zinc from food is possible, it can be difficult for people who don’t eat animal products. While zinc is abundant in seafood, it isn’t very highly concentrated in plant-based foods.

We must also take into consideration lifestyle factors that can deplete zinc levels from the body, such as exercise, medication, stress, etc. which increase your daily needs. So, focus on consuming zinc-rich foods daily, and you also might want to supplement with zinc to make sure you get enough of this vital nutrient every day. 

References

  1. Zinc and the immune system

  2. The effects of severe zinc deficiency on protein turnover in muscle and thymus

  3. Review: The role of zinc in the endocrine system

  4. Zinc status and serum testosterone levels of healthy adults

  5. Zinc in Infection and Inflammation

  6. Zinc and Taste Disturbances in Older Adults

  7. Regulation of intestinal gene expression by dietary zinc

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