What is zinc?
Zinc is an essential element required to produce hundreds of enzymes that control functions as diverse as your eyesight, the health of your skin, hair, nails, connective tissue, hearing, sexual functions, digestion, immune response, protein synthesis and more. Without sufficient zinc, good health is impossible. (1)
Zinc works closely with several other minerals in your body, and it is important that they are all in balance with each other. Chromium, copper, iron, manganese, selenium and other minerals compete with each other for uptake in your digestive system, and if any are taken in excess they can inhibit the digestion of the others. Sulphur is another element that works with zinc, playing a crucial role in the digestive and immune systems.
Zinc generally has an anti-inflammatory effect, especially when it is in balance with copper and other more pro-inflammatory substances in the body.
Most people are low in zinc or zinc-deficient. The American Dietary Reference Intake for zinc is 8 mg / day for women and 11 mg / day for men. It is likely that this level is too low for optimal health. One in three Americans get less than this low amount. (2) If you are a vegetarian, you are even more at risk.
If you live in an area with zinc-rich soils, or you are getting plenty of seafood or organic meat, you will probably be getting sufficient zinc. However, most soils today are zinc and mineral-deficient, especially in West Australia where I live.
Most people are zinc-deficient
- Most of the world's foods are zinc-deficient. Nearly all farm produce is exported from the farm rather than being recycled, as in early agricultural times. Each year, less and less zinc remains in the soil. Zinc sulphate is easily added to agricultural soil and taken up by most crops, which benefit from the zinc. However, farmers seldom replace zinc in the soil because it is too expensive and not critical for a healthy-looking crop.
- Today's cereal, vegetable and fruit crops are highly bred for characteristics such as sweetness, tough skins and large size. High mineral content is not a concern of most consumers. Today each head of wheat harvested and each apple in the supermarket has much less zinc than in earlier times when hybrids were not used.
- Zinc and other trace elements are removed when wheat, rice, corn, sugar cane and even salt are refined. Refined flour, sugars and salts are all totally mineral-deficient. Processed foods made from these refined products contain almost no zinc or other essential trace elements.
- Stress depletes zinc levels very quickly. The body's hormonal response to a new high stress event can have an effect on zinc levels within minutes. Chronic long-term stress has an equally debilitating effect on zinc levels.
- Chemicals. Some foods (especially frozen vegetables and sometimes meats) are sprayed with EDTA to retain their colour. EDTA removes zinc and other trace minerals from the food.
- Most babies are born low in zinc because their mothers tend to be low in zinc. As infants, they start their lives on a low-zinc diet.
- Vegetarian or near vegetarian diets are much lower in zinc. Many people today, for ethical reasons, seem to be moving in this direction.
- Chronic illness, stress, fighting infections, puberty, pregnancy, breast feeding, childhood and old age all require additional zinc. Most people in these situations are not getting it.
Symptoms of zinc deficiency
- White spots on finger nails (though there can be other causes of this symptom).
- Hair loss.
- Deteriorating senses of taste and smell.
- Inflammation, chronic and systemic.
- Slow healing of wounds. Supplemental zinc may speed healing and reduce scarring. Taking extra zinc before surgery can be most helpful to prevent complications such as infections and adhesions.
- Skin. A wide variety of persistent skin problems such as stretch marks, rashes, seborrheic dermatitis, eczema, psoriasis, fine varicose veins, boils, vitiligo and skin infections. Acne is common, and girls experience more acne at certain times of the month because their period regulates zinc and copper levels. Lesions and wounds on the skin tend to heal slowly.
- Immune system. Zinc is critical for a good immune response, as is a correct balance with copper. A healthy immune system protects against infections of the skin, from wounds, from food and water, and in the air and surroundings. People who already have an infection often benefit from zinc supplementation. Zinc may be given for colds, flu and even acute infections like AIDS. Vegetarians are often prone to infections because their zinc level tends to be lower.
- Yeast and fungal conditions. Zinc is a key nutrient required by fungi, bacteria, protozoa and other micro-organisms. Zinc seems to be the most important of all minerals in promoting fungal growth. (4) You need a healthy level of zinc to support your immune system to protect against pathogens. However, an excessive level of zinc may promote the growth of pathogens in your body, particularly fungi such as athlete's foot, candida, jock itch, nail fungus and thrush. In summary, a healthy zinc balance is required, along with sufficient copper.
- Cardiovascular system. Zinc deficiency causes a loss of flexibility in the arteries and veins, causing hardening of the arteries, high blood pressure, aneurysms, strokes, heart attacks and other cardiovascular problems. It is also associated with atherosclerosis. (3)
- Vision. The retina requires and stores plenty of zinc. Zinc deficiency is involved in many problems with eyesight, such as deteriorating eyesight, night blindness, macular degeneration, retinitis pigmentosa, iritis and other infections.
- Digestive system. Sufficient zinc is critical, because it is required for all digestive enzyme production. Zinc is also required to produce fast-growing intestinal tissues which need daily replacement, and for the production of bile, liver and pancreatic secretions. Symptoms of zinc deficiency include poor digestion of proteins, weak stomach acid, poor appetite, diarrhoea, ulcers, irritable bowel syndrome, yeast infections (candida), colitis, and many other digestive problems.
- Hormones. Zinc is involved in the production of a wide variety of hormones, not only the reproductive hormones mentioned elsewhere in this article. For example, zinc is required for a good insulin response, and zinc supplementation is helpful for diabetics.
- Connective tissue. Zinc imbalance or deficiency can cause inflammatory problems with tendons and ligaments such as tendonitis and bursitis.
- Brain, psychology. Zinc is required for the production of many hormones, but it may also be a calming neurotransmitter in its own right, effectively acting as a kind of sedative mineral on the central nervous system. Zinc deficiency or imbalance with other minerals (especially iodine) is associated with hyperactivity, ADD and ADHD, anxiety, cognitive decline, depression, irritability, nervousness, emotional instability, memory problems, mood swings, bipolar disorder, abnormal behaviour and many other mental and emotional symptoms. Conditions such as epilepsy, seizures, schizophrenia and other severe emotional disturbances are often associated with a zinc deficiency.
- Female reproductive system. Zinc and copper are maintained in a delicate balance and an upset can cause a variety of menstrual and reproductive problems. Zinc affects testosterone, progesterone and estrogen levels and balances. Getting your zinc level right can heal many cases of premenstrual syndrome, dysmenorrhea (dysmenorrhoea) pain during menstruation, cramping associated with menstruation, menopausal symptoms, and symptoms associated with estrogen dominance.
Zinc deficiency can cause cessation of periods in younger women who should still have menstrual cycles, and some cases of infertility.
It is possible to over-supplement with zinc during pregnancy, with an extreme and rare outcome being a miscarriage. Generally you should not exceed 50 mg of elemental zinc daily.
- Male Reproductive System. The prostate gland is a man's biggest store of zinc, and semen is rich in zinc. Zinc deficiency is the root cause of most male reproductive and prostate problems, including prostatitis, enlarged prostate and prostate cancer. With zinc being essential for the production of testosterone and other male hormones, a deficiency is often related to male infertility. Less commonly, it can also be a cause of erectile dysfunction.
- Children. Zinc is critical is for the growth and development of the foetus during pregnancy and after birth. With zinc being required in the production of reproductive hormones, a deficiency can cause low birth weight, short stature, delayed testicular development, undescended testicles and generally poor mental and physical development in children.
Boys need extra zinc around the age of puberty to develop their prostate gland and testicles. If there is insufficient zinc, their sexual development will take priority and other physical growth and development will suffer. This is one reason boys do not grow tall as fast as the girls at that age, though later the boys catch up.
- Long term chronic zinc deficiency causes dwarfism, delayed sexual maturation, and often being gaunt and wasted.
In the natural world, excessive zinc in the body is most unusual. Monkeys locked in galvanised cages can suffer from zinc overload when they hold on to the zinc-galvanised bars for week after week. They lose fur, and have a variety of digestive, skin, eyesight and other problems (white monkey syndrome).
A zinc excess can occur if you take too much zinc supplement. When using the zinc taste test, it will taste unpleasant. Over a longer period, symptoms that appear similar to zinc deficiency will often occur, as the overload will often affect the same enzymes.
Symptoms of zinc overdose may include prostatitis, vision problems, skin problems and more. Emotional symptoms can also occur, though less frequently. Yeast and fungal ailments may worsen, because zinc seems to be the most important of all minerals in promoting fungal growth.
Zinc may be toxic in excess of 40 mg elemental zinc per day. (2) One reason is that high levels of zinc induce copper deficiency. Zinc and copper are needed together, but are also antagonists to each other.
Tests for zinc deficiency
The quickest and easiest test for zinc sufficiency is a zinc taste test. For an adult, mix 50 mg of zinc sulphate in half a glass of water. If it tastes sweet, pleasant, or like water, then your body needs it. If it has a strong metallic or unpleasant taste, you don't need it and are not zinc-deficient.
Blood serum blood tests for zinc are generally useless because zinc does not accumulate in the blood.
A test for white blood cell zinc levels is not very reliable.
Zinc in urine and faeces shows what was consumed in the last few meals rather than zinc levels in the body.
A hair test for zinc is not very reliable, and needs an expert to interpret the results.
Sodium and potassium levels in the hair, copper sufficiency and the body type of the patient all need to be taken into account.
Food sources of zinc
The best way to get zinc is through your food.
Oysters are by far the richest source of zinc. Next comes red meat - beef, lamb, game meat and other red meats. Other molluscs like mussels are also a good source. Zinc is also found in pork, crustaceans (lobster, shrimp etc), poultry (chicken, turkey etc), fish, strong cheese (like parmesan) and egg yolks. Most animal-based foods contain some level of zinc.
Plants generally do not need much zinc for their own growth and health, so plant-based foods generally contain very little zinc. Pumpkin seeds and sea vegetables such as kelp and dulse are the best plant sources. Most tree nuts also contain some zinc, depending upon the mineral quality of the soil in which they are grown. A few legumes, headed by aduki beans, also contain a small amount of zinc.
Vegetarians are even more deficient in zinc than most other people, because it is difficult to obtain sufficient zinc from vegetables, fruits, nuts, pulses, seeds and other vegetarian foods.
How to supplement zinc
Buy zinc sulphate as a liquid. It should simply be zinc sulphate, not zinc compounds in other forms. It is acceptable to have a small quantity of magnesium chloride added, and possibly pyridoxine hydrochloride, but preferably nothing else.
Follow the supplier's instructions, or for an adult, mix 50 mg of zinc sulphate in half a glass of water, and take it before going to bed. It will help you sleep well and have lucid, pleasant dreams.
50 mg of zinc sulphate is the equivalent of 11 mg of elemental zinc. Most people who regularly eat red meat get 10-20 mg of elemental zinc per day from their food. If you need to supplement, experience of many users has shown that approximately 10-15 mg of elemental zinc per day is suitable for the average adult. Experiment, varying the dose slightly for a week at a time, to find what suits you for your particular body and conditions.
Zinc sulphate is stable, it should not have a short use-by date.
My experience is that zinc sulphate in liquid form is much more effective than zinc tablets which are often useless.
Zinc as a remedy / treatment
Ensuring zinc sufficiency can be the key to treating many of the ailments discussed on this page.
Pyroluria. About 10 - 15% of adults suffer from this condition, in which zinc and vitamin B6 are excreted in the urine. Pyroluriacs need to supplement with zinc and B6 for the rest of their lives, and need higher levels of supplementation than other people. This treatment is usually dramatically successful.
Gilbert's syndrome. I have found that zinc sulphate is helpful in controlling the symptoms of Gilbert's syndrome.
1. Hambidge M.
Human zinc deficiency.
J Nutr. May 2000; 130(5S Suppl):1344S-9S.
2. Zinc, Dietary Reference Intakes for vitamin A, vitamin K, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium and zinc. Food and Nutrition Board, Institute of Medicine. Washington DC, National Academy Press; 2001:442-501.
3. Alissa EM et al. The effects of coadministration of dietary copper and zinc supplements on atherosclerosis, antioxidant enzymes and indices of lipid peroxidation in the cholesterol fed rabbit. Int J Exp Pathol. Oct 2004; 85(5):265-75.
4. Lulloff SJ et al. Fungal susceptability to zinc deprivation. J Lab Clin Med. Oct 2004; 144(4):208-14.