Zinc: Essential for Human Health
Zinc is an essential trace element for humans, animals and plants. It is vital for many biological functions and plays a crucial role in more than 300 enzymes in the human body. The adult body contains about 2-3 grams of zinc. Zinc is found in all parts of the body: it is in organs, tissues, bones, fluids and cells. Muscles and bones contain most of the body’s zinc (90%). Particularly high concentrations of zinc are in the prostate gland and semen.
Zinc – vital for growth and cell division
Zinc is especially important during pregnancy, for the growing fetus whose cells are rapidly dividing. Zinc also helps to avoid congenital abnormalities and pre-term delivery. Zinc is vital in activating growth – height, weight and bone development – in infants, children and teenagers.
Zinc – vital for fertility
Zinc plays a vital role in fertility. In males, zinc protects the prostate gland from infection (prostatitis) and ultimately from enlargement (prostatic hypertrophy). Zinc helps maintain sperm count and mobility and normal levels of serum testosterone.
In females, zinc can help treat menstrual problems and alleviate symptoms associated with premenstrual syndrome (PMS).
Zinc – vital for the immune system
Among all the vitamins and minerals, zinc shows the strongest effect on our all-important immune system. Zinc plays a unique role in the T-cells. Low zinc levels lead to reduced and weakened T-cells which are not able to recognize and fight off certain infections. An increase of the zinc level has proven effective in fighting pneumonia and diarrhea and other infections. Zinc can also reduce the duration and severity of a common cold.
Zinc – vital for taste, smell and appetite
Zinc activates areas of the brain that receive and process information from taste and smell sensors. Levels of zinc in plasma and zinc’s effect on other nutrients, like copper and manganese, influence appetite and taste preference. Zinc is also used in the treatment of anorexia.
Zinc – vital for skin, hair and nails
Zinc accelerates the renewal of the skin cells. Zinc creams are used for babies to soothe diaper rash and to heal cuts and wounds. Zinc has also proven effective in treating acne, a problem that affects especially adolescents, and zinc has been reported to have a positive effect on psoriasis and neurodermitis.
Zinc is also used as an anti-inflammatory agent and can help sooth the skin tissue, particularly in cases of poison ivy, sunburn, blisters and certain gum diseases.
Zinc is important for healthy hair. Insufficient zinc levels may result in loss of hair, hair that looks thin and dull and that goes grey early. There are also a number of shampoos which contain zinc to help prevent dandruff.
Zinc – vital for vision
High concentrations of zinc are found in the retina. With age the retinal zinc declines which seems to play a role in the development of age-related macular degeneration (AMD), which leads to partial or complete loss of vision. Zinc may also protect from night blindness and prevent the development of cataracts.
Who needs zinc?
Everyone needs zinc. Children need zinc to grow, adults need zinc for health. Growing infants, children and adolescents, pregnant women and lactating mothers, athletes, vegetarians and the elderly often require more zinc.
Where do we get zinc from?
We get zinc primarily from our food. The major sources of zinc are (red) meat, poultry, fish and seafood, whole cereals and dairy products. Zinc is most available to the body from meat. The bioavailability of plant-based foods is generally lower due to dietary fibre and phytic acid which inhibit the absorption of zinc.
A balanced diet is the best way to provide your body with zinc. A zinc supplement or a daily multi-vitamin/multi-mineral supplement may be taken if your nutritional intake is insufficient.*
*Large doses of zinc should not be taken over a prolonged period of time without your physician’s direction.
Dietary Sources of Zinc & their Average Zinc Content (mg/100g)
Meat (especially red meat) 5.2
Milk products 1.2
Sugars & preserves 0.6
Canned vegetables 0.4
Green vegetables 0.4
Fresh fruits 0.09
Pregnant women and lactating mothers require more zinc to ensure optimal development of the fetus and newborn baby.
What if we don’t get enough zinc?
Zinc deficiency is a serious problem in many developing countries. Zinc deficiency is ranked as the 5th leading risk factor in causing disease, especially diarrhea and pneumonia in children, which can lead to high mortality rates in these underdeveloped regions. Other severe deficiency symptoms include stunted growth and impaired development of infants, children and adolescents. Early zinc deficiency also leads to impaired cognitive function, behavioral problems, memory impairment and problems with spatial learning and neuronal atrophy. Public health programs involving zinc supplementation and food fortification could help overcome these problems.
In industrialized countries cases of mild zinc deficiency can be observed. The most common symptoms include dry and rough skin, dull looking hair, brittle finger nails, white spots on nails, reduced taste and smell, loss of appetite, mood swings, reduced adaptation to darkness, frequent infections, delayed wound healing, dermatitis and acne.
Mild zinc deficiency symptoms can usually be corrected by supplying the body with the right amount of zinc each day. Supplemental zinc not exceeding the recommended daily allowance might be taken. Therapies involving larger doses of zinc should always be discussed with your physician. Therapeutical doses typically range from 20 mg – 30 mg, in some rare cases doses might be higher.
Are there any adverse reactions?
The tolerable upper limit for zinc was set at 40 mg per day for adults over 19. Doses up to 30 mg per day are generally well tolerated. Higher doses may cause gastrointestinal reactions including nausea, vomiting, cramps and discomfort. Other adverse reactions include a metallic taste in the mouth, headache and drowsiness. High doses of zinc might also impair the status of other nutrients especially copper, calcium and iron.