A-Z Library
Zinc
Zinc is an essential mineral. Its chemical names include zinc aspartate, zinc gluconate and zinc picolinate.
How it works
This essential mineral is important in prostate gland function, the growth of reproductive organs and is especially important for the production of healthy sperm. It helps promote a healthy immune system and is necessary for the healing of wounds. It plays a vital role in the proper action of over 70 enzymes involved in a wide range of activities. It is involved in keeping sight, smell, and taste in good working order. It is also vital for the release of insulin. It is an anti-oxidant and so helps fight against the damage that can be caused by excess free radicals.
Scientific studies have shown that some people who suffer from acne and eczema can have reduced levels of zinc. Research has also shown that the symptoms of benign prostatic hyperplasia, such as a frequent need to pass urine, may be improved by increasing the dietary intake of zinc. Good intakes of zinc may also improve male fertility as it is needed for dampening down sperm activity until in the female tract.
Fibre in cereals and phytates in pulses and spinach can reduce zinc absorption, as can too much phosphorus. The oral contraceptive pill can lower levels of zinc.
People with acne, eczema, those who have recently undergone surgery or been badly burnt, people over 55, men with a non-cancerous swelling of the prostate gland (benign prostatic hyperplasia) those suffering from a cold, and anyone on a restricted diet may benefit from zinc supplements.
Natural food sources
Zinc can be found in the following foods: calves' liver, oysters, sardines, wheatgerm.
Taking zinc supplements
Optimum nutritionists suggest intakes of 15-20mg a day, rising to 50mg for therapeutic uses. The suggested safe upper level of supplements is 15mg for long-term usage and 50mg for short-term usage. The body seems to tolerate zinc supplements in the form of zinc gluconate with ease. All types of zinc should be taken with food in order to avoid any nausea.
Precautions
Daily intakes of 50-300mg of zinc over long periods of time can interfere with the absorption of iron and copper, leading to deficiencies in both. Symptoms such as nausea, vomiting, abdominal pain, and fever may occur after intakes of 2000mg (2g) or more. Anyone suffering from liver or intestinal damage should consult a doctor before taking supplements.
Therapeutic uses
- Top sources of zinc mg/100g of food
- Oysters59.2mg/100g
- Wheatgerm17mg/100g
- Calves' liver 7.8mg/100g
- Pumpkin seeds6.6mg/100g
- Canned corned beef5.6mg/100g
- Roast beef5.5mg/100g
- Lean roast lamb5.3mg/100g
- Canned crab5.0mg/100g
- Pork loin 3.5mg/100g
- Sardines in oil3.0mg/100g
Recommended Daily Amounts (RDA)/ Safe Upper Levels (SUL) - Adult intake
The RDA is 15mg. The SUL for Zinc has been set at 25mg from long-term use of dietary supplements and no more than 42mg from all dietary sources.
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