Zinc is vital for health and growth and is an essential mineral in the body. It is found in high concentrations and has important functions in the prostate gland, sperm and the eye.
WHO IS AT RISK
Zinc is the one mineral that is consistently low in the Australian diet in comparison to the recommended dietary intakes. Women and the elderly are most at risk of a zinc deficiency. People with IBS, inflammatory bowel disease, diverticulitis, short bowel syndrome or anyone with chronic diarrhoea should take extra care to ensure that adequate is consumed from diet or supplementation. Vegans and vegetarians have an increased need for zinc in their diets. It is widely distributed in foods of animal origin, but less is found in plants and it is more difficult to absorb. The fibre and phytates in wholegrain breads and cereals bind the zinc, making it less available. Vegetarians should aim to consume the higher recommended limit.
SYMPTOMS OF ZINC DEFICIENCY
Symptoms of zinc deficiency in adults can include slow or poor wound healing, weakness, white flecks in fingernails, impaired senses of sight, taste, smell, loss of appetite, decreased immunity, dermatitis and impotence in men. In children, zinc deficiency results in failure to grow and develop sexually. FUNCTIONS Zinc helps maintain the body’s immune system and therefore to resist infection. It enhances bone growth in the young and preserves bone in the older adult. Zinc is essential for normal growth and sexual development. It is also required for wound healing and the maintenance of a strong immune system. Zinc is a component of many of the body’s enzyme systems. It is necessary for normal taste sensations and the functioning of the eyes.
THE RECOMMENDED INTAKE OF ZINC
An over consumption of zinc is not known to cause any medical problems. However, high levels of zinc in the diet can inhibit the absorption of other minerals, such as copper.
RECOMMENDED DAILY INTAKE OF ZINC IN AUSTRALIA
|Infants||3 – 4.5 milligrams|
|Children 1-3 years||4.5 milligrams|
|Children 4 -7 years||6 mg milligrams|
|Children 12 –18 years||12 milligrams|
|Adults||12- 16 milligrams|
|Pregnancy||16- 18 milligrams|
|Lactation||18- 21 milligrams|
SOURCES OF ZINC
Zinc is found in most foods of animal origin. Liver, oysters, crayfish and scallops are excellent sources. In general it is high in meat and seafood and also found in eggs, milk and cheese. Zinc is less concentrated in plant foods, and is more difficult to absorb than from animal sources. Good sources are whole meal cereals, barley, yeast, and nuts such as almonds and pulses such as white beans. Wheat bran is very high in zinc but not readily available to the body. Consuming more than 1 - 2 tablespoons of unprocessed bran per day could interfere with zinc absorption. Zinc is usually found in foods rich in iron. Vegetarians can look to white bean and nuts but may need to consider a supplement if they don’t eat eggs or dairy.
FOOD SOURCES OF ZINC
|Oysters- 6 only||19.4|
|Egg - one||0.4|
|Liver- 1 slice||4.0|
|Lamb - 100g||3.0-4.0|
|Chicken - 100g||1.0-2.0|
|Crayfish, crab- ½ cup||3.0- 6.0|
|Milk - regular or skim - 250ml||0.9|
|LEGUMES & NUTS|
|Nuts- ¼ cup||2.0-1.5|
|Beans - 100g dry weight||2.8|
|Lentils- ½ cup - cooked||1.0|
|BREADS & CEREALS|
|Rolled oats - 100g raw weight||1.9|
|Unprocessed Bran- 2 tablespoons||0.8|
|Breakfast Cereal - average bowl||0.8|
|Wholemeal bread - 2 slices||1.0|
|White bread - 2 slices||0.4|
|Barley- 1 cup cooked||0.8|
|Potato - 1 medium||0.4|
|Other vegetables average serve||0.2|
Added to site on : Sunday, 25 August 2002