Vegetarian Information Sheet

Zinc Introduction -- Functions -- Dietary Sources -- Required Intakes -- Meal Plan Introduction The mineral zinc is present in every part of the body and has a wide range of functions. It helps with the healing of wounds and is a vital component of many enzyme reactions. Zinc is vital for the healthy working of many of the body's systems. It is particularly important for healthy skin and is essential for a healthy immune system and resistance to infection. Functions Zinc has a range of functions. It plays a crucial role in growth and cell division where it is required for protein and DNA synthesis, in insulin activity, in the metabolism of the ovaries and testes, and in liver function. As a component of many enzymes, zinc is involved in the metabolism of proteins, carbohydrates, lipids and energy. Our body contains about 2-3g of zinc. There are no specific storage sites known for zinc and so a regular supply in the diet is required. Zinc is found in all parts of our body, 60% is found in muscle, 30% in bone and about 5% in our skin. Particularly high concentrations are in the prostate gland and semen. Men need more zinc than women because male semen contains 100 times more zinc than is found in the blood. The more sexually active a man the more zinc he will require. The recommended amounts of zinc for adult men are 1/3 higher than those for women. The first signs of zinc deficiency are impairment of taste, a poor immune response and skin problems. Other symptoms of zinc deficiency can include hair loss, diarrhoea, fatigue, delayed wound healing, and decreased growth rate and mental development in infants. It is thought that zinc supplementation can help skin conditions such as acne and eczema, prostate problems, anorexia nervosa, alcoholics and those suffering from trauma or post-surgery. It is always better to seek the advice of an expert before dosing yourself with supplements. If you choose to take a zinc supplement you should not need more than the daily recommended amount unless medical advice says otherwise. Dietary Sources Zinc is present in a wide variety of foods, particularly in association with protein foods. A vegetarian diet often contains less zinc than a meat based diet and so it is important for vegetarians to eat plenty of foods that are rich in this vital mineral. Good sources for vegetarians include dairy products, beans and lentils, yeast, nuts, seeds and wholegrain cereals. Pumpkin seeds provide one of the most concentrated vegetarian food sources of zinc. Only 20% of the zinc present in the diet is actually absorbed by the body. Dietary fibre and phytic acid, found in bran, wholegrain cereals, pulses and nuts, inhibit zinc absorption. Phytic acid forms a highly insoluble complex with zinc which the body cannot absorb. Cooking processes can reduce the adverse effects of both phytic acid and dietary fibre on zinc absorption. Baking can destroy over half the phytic acid in wholemeal bread. Zinc deficiency occurs where a large part of the diet consists of unleavened bread, such as Iran and other Middle East countries. High levels of the toxic mineral cadmium can also prevent zinc absorption because these two minerals compete for absorption. Conversely high levels of zinc in the diet can prevent the absorption of cadmium. Various chemicals added to many processed foods can also reduce zinc absorption eg phosphates, EDTA. A deficiency of zinc in the diet means zinc absorption is improved. Zinc is lost via the faeces, urine, hair, skin, sweat, semen and also menstruation.

Required Intakes The old Recommended Daily Amounts (RDAs) have now been replaced by the term Reference Nutrient Intake (RNI). The RNI is the amount of nutrient which is enough for at least 97% of the population.

Pregnant women do need extra zinc, but it is thought that demands are met by increased absorption from the gut. Breast feeding mothers need extra zinc in their diet. Breast milk contains over 2mg of zinc in the first four months and women need an extra 6mg a day to cover these demands. Breast feeding women must include a generous serving of at least one good source of zinc in their diet each day. The iron supplements routinely prescribed for pregnant women when there is no sign of anaemia may compromise zinc status. This is because the interactions between essential minerals are complex and too much of one may cause an imbalance of another. Excess zinc is toxic. Too much zinc will interfere with the metabolism of other minerals in the body, particularly iron and copper. Symptoms of zinc toxicity occur after ingestion of 2g of or more and include nausea, vomiting and fever.

Meal Plan