Zinc

Why zinc is good for you

• Zinc is needed for proper growth and reproduction
  Zinc is especially required for the synthesis of DNA and RNA (the nucleic acids that exist in cells that assist with cell division, reproduction and repair). Many studies have shown that low zinc levels in pregnancy can be associated with a higher risk of complications such as miscarriage and birth defects.
• Zinc is very important for children
  Zinc is a vital nutrient for children, as it helps them grow and develop normally, while low levels of zinc cause stunted and suboptimal growth, loss of taste, behavioural problems, lethargy and poor appetite (which further exacerbates the suboptimal growth and development in children).
• Zinc is important for eye health
  The eyes have very high concentrations of zinc (especially the iris and retina). The eyes need adequate levels of zinc to maintain healthy eyesight. Zinc helps to activate vitamin A (a vitamin essential for eye health and which has high concentrations in the eye) in the eye and prevent conditions such as cataracts, optic neuritis, inflammation of the eye and impaired colour discrimination.
• Zinc is required to make many hormones
  The body relies on zinc to help create many hormones, including hormones that control growth, the important male hormone testosterone and hormones that instruct the immune system on what action to take when the body is under attack from bacteria, fungi or viruses.
• Zinc limits excessive prolactin levels
  Studies show that zinc limits the productions of the female hormone prolactin, which if too high, can cause secretion of breast milk in women who are not pregnant, enlarged breasts and sexual dysfunction. Studies show that zinc supplements reduce these problems when used in people with elevated prolactin levels.

There is some zinc in every one of the cells in the body, but most of it is in the skin, hair, nails and eyes (and in the prostate gland, for males).

Important zinc facts

• Zinc is a trace mineral
  Zinc is a trace mineral, which means only very small amounts of this mineral are required to enable the proper functioning of the body and to enable good health. Zinc is the second most abundant trace mineral in the body.
• Zinc is needed to enable over 200 enzymes to work properly
  Over 200 important enzymes in the body rely largely on sufficient levels of zinc to activate them and enable them to function correctly.
• Zinc is part of superoxide dismutase
  The body produces its own natural antioxidant, superoxide dismutase (SOD), to neutralise any free radicals that may occur through any natural oxidative processes in the body. Zinc is an essential part of the SOD molecule and helps this antioxidant perform its duties more effectively.
• Long term zinc supplements should be taken with copper
  People who take zinc supplements over the longer term, should also be taking copper supplements too, as high levels of zinc can cause a decrease in the blood levels of copper and decrease the absorption of any copper in the blood. These two minerals need to be taken together so that blood levels of both remain in a healthy range.
• Zinc is an antioxidant
  Zinc is an antioxidant, which means that it protects the body from oxidative damage caused by free radicals. Oxidative damage from environmental toxins (such as ultraviolet light, radiation, cigarette smoking and air pollution) can cause premature ageing, damage to the DNA of cells and damage to cells and body tissues; it can even allow conditions such as heart disease and cancer to manifest through the various body systems. Zinc antioxidant properties also helps to stabilise the cell membranes and protects the cells DNA and RNA through its antioxidant properties.
• Zinc ensures taste and smell are normal
  Interestingly, zinc works to ensure that the two senses – taste and smell – are normal. Zinc’s importance in body system that go through a rapid amount of cells are especially reliant on zinc (such as the taste buds in the tongue and the olfactory nerves in the nose) and need it to stay healthy.
• Zinc protects against damage from toxic substances
  Zinc has a known effect on detoxifying the body from the toxic effects of a number of poisonous substances, by protecting the liver through the detoxification and elimination process in the liver. Zinc protects the body against damage from many environmental toxins such as carbon tetrachloride (a cleaning solvent), lead (in old paint, pollution and leaded petrol) and cadmium (in exhaust fumes, drinking water and pollution).
• Zinc exists in all cells of the body
  There is some zinc in all the cells of the body, but it is especially concentrated in the skin, hair, nails and eyes (and in the prostate gland in men).
• Zinc is available in various supplement forms
  There are a number of forms of zinc supplements. Zinc sulfate is the most frequently used supplement but it is not very well absorbed and can cause stomach upset. Better forms of zinc include: zinc picolinate, zinc citrate, zinc acetate, zinc glycerate, zinc gluconate and zinc monomethionine. The form of zinc that is the best and most absorbed is zinc gluconate.

Zinc works best with

• Vitamin A – zinc helps with the absorption of vitamin A and increases its effectiveness.
• Vitamin B6 (pyridoxine)
• Vitamin D
• Vitamin E (tocopherol)
• Cysteine
• Glucose
• Glutathione
• Insulin
• Magnesium
• Manganese

Zinc and health

• Zinc is important for a healthy immune system
  Zinc is vitally important for a healthy immune system, as it helps to create healthy white blood cells, helps to create the antibodies (which provide immunity to a number of pathogens) and provides a protective and enhancing effect on the immune system as a whole. It seems to give a real boost to the thymus gland, especially in people over 40. By then, the thymus gland may have naturally shrunk quite a bit, so its not producing the hormones that stimulate the body to produce infection-fighting white blood cells it used to. Getting a little extra zinc may get the thymus working better again and help fight off illness faster. Studies show that people who have lower than optimal zinc levels, often experience more frequent infections which are of a longer duration. Other studies on both animals and humans have shown that people (or animals) with low zinc levels experience abnormalities and shrinking of the spleen, thymus and lymph nodes (which are all involved in immunity) as well as a decreased production amount of the antibodies and T cells. Other research has shown that people with lowered zinc levels (especially if accompanied with high copper levels) are associated with many types of cancers and in fact if people with lung cancer have a higher blood levels of zinc, they tend to have a longer survival rate.
• Zinc helps the body fight off colds and flu
  Many studies have shown that zinc helps the body fight fight the effects of colds and flu more quickly and lessens the effects and duration of any viral or bacterial infection that does progress into a cold or flu. Zinc helps to reduce the symptoms of a cold or flu, such as a runny nose, coughing and sore throat. The best way to get the most out of zinc is to start taking it at the first sign of a cold or flu (such as slightly sore throat, sneezing), before it takes hold and develops more debilitating symptoms, when the infection can be a lot harder to stop. Zinc lozenges are a great way to take zinc, as they can relieve the upper respiratory symptoms quite well. Zinc lozenges are usually in the form of zinc gluconate and should be taken as directed on the packet.
• Zinc is important for prostate gland health
  Zinc is required for a healthy prostate gland, which naturally contains very high levels of zinc. Low levels of zinc in the prostate gland generally signify that the prostate gland is unhealthy and not functioning properly. Studies show that men who have benign prostatic hyperplasia (non-cancerous prostate condition where the prostate enlarges), find significant relief from the symptoms of this condition (the prostate size decreases) if they are given zinc supplements. Research also shows that zinc stops certain male hormones from attaching to cells in the prostate gland and reducing the risk of prostate cancer and other diseases of the prostate gland.
• Zinc is important for male fertility
  Men need zinc to produce testosterone and other male hormones, as well as healthy sperm and semen, so more zinc in the diet could help solve male infertility. Many studies have shown that zinc is very vital for healthy male fertility, although the researchers have suggested that the mechanism of the actual activity of zinc is not clear, there is a definite link between blood levels of zinc and fertility. Studies show that low levels of zinc in men are linked to lower levels of sperm and lower quality of sperm, while high healthy levels of zinc are linked to normal and healthy sperm. In one study, men with low sperm counts took zinc supplements for 6 weeks after which their testosterone and sperm counts went up and nearly half of them had pregnant wives before the study was over
• Zinc helps the body heal wounds quickly
  Zinc is needed to help the body recover from any type of wound or injury (even surgery) because it helps to stimulate the healing process. When there is injury to the body, all the stores of zinc are used to help with the healing of the wound and more is needed to make sure healing occurs quickly as quite a lot of the zinc in the body can be lost when the body is injured.
• Zinc is important for healthy skin, hair and nails
  Zinc is especially vital for the health of skin, hair and nails. Studies show that low zinc levels can be attributed to minor skin rashes and irritations that clear up once zinc has been supplemented. These often clear up when patients start eating a diet higher in zinc or take zinc supplements. Zinc also helps to clear up psoriasis on the skin. If there is a major zinc deficiency, it presents as white spots on the fingernails or nails that are weak and break easily. Supplementation with zinc or adding more foods high in zinc can help to alleviate deficiency and resolve the nail health problems.
• Healing wounds – zinc is essential for healing wounds. Several studies show that patients recover from surgery faster if they get enough zinc. The effect is dramatic if the patient was low on zinc to begin with – it did not seem to work as well on patients who had good zinc levels prior to surgery. People who are scheduled for surgery should talk to their doctor about taking zinc supplements for a few weeks before and after the surgery
• Zinc is important for a healthy thymus gland
  Zinc is important in the health of the thymus gland, which is where the special white blood cells that fight infection are sent from the bone marrow (where they are created) to mature and enable their infection fighting abilities. These special white blood cells that are sent to the thymus gland are called T lymphocytes (or T cells) and they carry out the immune response in reaction to an invading pathogen (bacteria, fungi, virus) to prevent it from causing infection and illness and the T cells have a lot of zinc inside them.
• Zinc is needed for a healthy pancreas
  Zinc is necessary for the health of the pancreas, as it forms part of essential coenzyme constituents which enable the pancreas to function properly when it releases the hormones insulin or glucagon.

People who wish to take a zinc supplement should talk to a medical professional before taking it.

Current research

• Diabetes – some diabetics may be low on zinc because they do not absorb it well and also excrete it too quickly. Zinc supplements could help. Zinc might also help with the other problems diabetics often have – slow wound healing and frequent infections
• Macular degeneration – this serious eye problem is the leading cause of blindness in the elderly. The eyes naturally contain a lot of zinc and a lot of it is concentrated in the retina, the part of your eye affected by macular degeneration. Zinc supplements could help prevent or slow down vision loss from macular degeneration
• Memory – people who get the recommended daily intake of zinc do better on memory tests than those who do not

People who wish to take a zinc supplement should talk to a medical professional before taking it.

Groups at risk of zinc deficiency

Almost a century ago in Egypt, doctors noticed that poor, young boys who ate almost nothing but unleavened bread were very short and underdeveloped. It turned out that their diets had very little zinc. Once they started getting more zinc in their diet, they started growing normally again.

In modern society, such a serious zinc deficiency is very rare, although a slight zinc deficiency is quite common. Surveys show that many women only get about half the RDA. The groups at most at risk of zinc deficiency are:

• Strict vegetarians or vegans – animal foods such as meat and fish are the best dietary sources of zinc. Fruits have virtually none. Children who do not eat animal foods are most at risk for zinc deficiency
• People eating a very high fibre diet – the fibre, especially from whole grains, binds up the zinc in the diet and keeps it from being absorbed
• Pregnant or breastfeeding mothers – much of the nutrients eaten are passed onto the child and extra may be needed each day to top up supplies of zinc
• People over 50 years – the ability to absorb zinc from food drops as we age
• People who abuse alcohol – alcohol abusers do not eat very well in general and even moderate amounts of alcohol flush out the zinc stored in your liver and make you excrete it.
• People taking oral contraceptives – oral contraceptives can lower blood levels of zinc, so women who take this type of contraceptive medication should have their zinc levels tested for deficiency
• People taking penicillamine – this drug is used to treat Wilson’s disease (excessive levels of copper in the body) and rheumatoid arthritis, decreases zinc levels, so supplementation may be required
• Diuretics – these medications can cause low blood levels of zinc as a side effect, so zinc supplementation may be required to avoid zinc deficiency
• ACE inhibitors – such as captopril and enalpril may cause low blood levels of zinc as a side effect, so zinc supplementation may be required to avoid zinc deficiency

People in these groups at risk of deficiency should talk to a medical professional about zinc supplements before taking them.

Symptoms of zinc deficiency

Zinc deficiency has a number of symptoms such as:

• slowed growth in children
• slow wound healing
• frequent infections
• skin irritation
• hair loss
• loss of sense of taste

Generally speaking, most people do not have to worry much about being deficient in this mineral. Anyone who eats a reasonably well-balanced diet will get plenty of zinc, but some people are more prone to being deficient and should seek medical advice about supplementation.

Zinc in food

Zinc recommended daily intake (RDI)

The tolerable upper limits should only be taken for short periods and only under medical supervision.

Toxic levels of zinc

Zinc is toxic at doses greater than 1000mg per day, but can produce some toxicity symptoms such as nausea and vomiting at levels higher than 150mg per day.

Overdosage and toxicity symptoms – acute

Acute toxicity from taking too much in zinc supplements – over 1000mg can cause the following symptoms:

• Abdominal pain
• Abnormal intestinal bleeding
• Gastric ulceration

Overdosage and toxicity symptoms – chronic

Chronic toxicity of zinc from taking higher than the therapeutic dose of supplements (over 150mg) for a long time can cause the following symptoms:

• Diarrhoea
• Nausea
• Vomiting

Precautions

Certain people should consult their doctor before taking zinc supplements:

• People taking certain medications – the zinc will keep the medications from being absorbed into the bloodstream and reduce its effectiveness or the medication may increate blood levels of zinc which can be toxic
• People with severe stomach or duodenal ulcers – may have an exacerbation of their gastrointestinal symptoms, such as nausea, vomiting, abdominal pain and abdominal bleeding
• Women who are pregnant – high levels of zinc should not be taken as they can cause premature labour or stillbirth. Consult your doctor about suitable supplemental levels of zinc to prevent any adverse effects on the growing foetus
• People taking any type of medication – always consult your doctor before adding any supplements to your regime, as there can be serious interactions

Interactions with medications and supplements – adverse

The following are the medications and supplements that are more likely to cause an adverse reaction with zinc supplements:

• Antibiotics
  Antibiotics should not be taken at the same time as zinc supplements as the zinc can decrease the absorption of the antibiotics and inactive some of their effectiveness. It is advisable to take zinc at least 2 hours before or after the intake of the antibiotic. It’s preferable to not take the zinc supplements at all until the course of the antibiotic is completed.
• Blood pressure medications
  Blood pressure medications may cause low blood levels of zinc as a side effect, so zinc supplementation may be required to avoid zinc deficiency
• Calcium
  Zinc supplements can interfere with the absorption of calcium from foods or supplements, especially if the zinc supplements are at very high levels. If calcium supplements need to be taken, it may be advisable to omit the high zinc supplements and take lower levels
• Copper
  Zinc supplements can decrease the absorption of copper from foods or supplements, especially if the zinc supplements are at high levels. High or long-term levels of zinc supplements must be taken with a copper supplement to prevent deficiency of copper and the adverse health effects associated with it
• Cortisone medications
  Cortisone medications could cause any lab tests measuring zinc levels to be inaccurate. Cortisone medications should be stopped before measuring zinc levels, but only under medical supervision, as the dose of the cortisone has to be tapered off gradually – this medication cannot be stopped suddenly as it can cause very severe side effects if this happens
• Hormone replacement therapy (HRT)
  Hormone replacement therapy (HRT) drugs, which are a combination of synthetic oestrogen and progesterone for women that are menopausal, may reduce zinc excretion and cause higher than normal levels of zinc in the body. Zinc supplements should not be taken by women on HRT medications
• Hydralazine
  Hydralazine medication is used to treat high blood pressure. There has been at least one report of an interaction between zinc and hydralazine which resulted in a lupus-erythematosus-like syndrome (characterized by a facial butterfly rash, fever, leg and mouth ulcers, and abdominal distress)
• Iron
  If zinc supplements are taken at the same time as iron supplements, the zinc may decrease the body’s ability to absorb the iron, especially if the zinc supplements are at very high levels
• Immunosuppressant medications
  Immunosuppressant medications such as corticosteroids and cyclosporine should not be taken with zinc supplements, as zinc has immune enhancing effects and the immunosuppressant medications are used to suppress immunity. Avoid zinc supplements if taking these types of medications
• Non-steroidal anti-inflammatory drugs (NSAIDs)
  NSAIDs such as ibuprofen can have reduced absorption and effectiveness if zinc supplements are taken at the same time. It is advisable to avoid taking zinc if taking NSAIDs
• Penicillin
  Penicillin, an antibiotic should not be taken at the same time as zinc supplements as the zinc can decrease the absorption of penicillin and inactive some of its effectiveness. It is advisable to take zinc at least 2 hours before or after the intake of penicillin. It is better to not take the zinc supplements at all until the course of penicillin is completed
• Progesterone
  Progesterone may reduce zinc excretion and cause higher than normal levels of zinc in the body. Zinc supplements should not be taken by women taking progesterone
• Steroids
  Steroids could cause any lab tests measuring zinc levels to be inaccurate. Steroids should be stopped at least three days before taking a blood test to measure zinc levels
• Tetracycline
  If zinc supplements are taken at the same times as Tetracycline, an antibiotic, the zinc may decrease the amount of the Tetracycline that is absorbed and negate some of the effectiveness of the medication. If possible, take the course of Tetracycline medication without taking zinc supplements, but the zinc needs to be taken, then it should be taken at least 2 hours before or after the Tetracycline to reduce the effects of interaction

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Last updated: 5 May 2024