Nutrition page 6

Vitamin E

Possibly the most potent antioxidant, vitamin E is present in large amounts in our retina, especially in the macula, where it protects the retinal cells against free radical damage. Vitamin E supplements have been found to reduce the risk of macula degeneration, cataracts, and retinal problems in people with diabetes.

Vitamin E can also improve our immunity by enhancing the function of immune cells, and protects cell structure from damage as immune cells use free radicals against invading microbes. Studies have shown that elderly people taking daily supplements of vitamin E improved their resistance to flu, and reduced their risk of contracting upper respiratory infections. It has been suggested that these benefits may be seen in adults and children as well.

The major sources of vitamin E include vegetable oils (canola, sunflower, safflower), nuts (almonds, hazelnuts), whole grains, seeds (especially soybean), avocado, and green leafy vegetables.

Iodine

Iodine is a component of thyroid hormones. The thyroid gland, which is located at the bottom of the neck, controls our growth, development, and metabolism by secreting thyroid hormones. The most important function of the thyroid however is that it controls brain development and myelination during infancy. Iodine deficiency during pregnancy and childhood can cause permanent brain damage and mental retardation. The good thing is that a deficiency in iodine is easily prevented by using iodised salt, and eating seafoods such as seaweed and kelp.

To find out more about the critical role of iodine during pregnancy, visit the Procare website. Also, have a look at our feature article on iodine deficiency and pregnancy.

Iron

Most of us are aware of the fact that iron is needed for oxygen delivery by our red blood cells, but iron is also responsible for energy generation by cells, including our immune cells like T and B cells. Without sufficient iron, our immune system does not work so well, making us more prone to infections.

Getting enough iron from your diet is not just about eating iron-rich foods, because all the iron you eat amounts to little if they are not absorbed by your body. Iron found in red meat and other animal products are the best source of iron as these are easier to absorb. As a rule of thumb, the darker the meat, the higher the iron content. Iron derived from plant sources is more difficult to absorb, but can be enhanced by vitamin C. For best results, try to make sure you include iron- and vitamin C-containing foods in the same meal.

Interestingly, micro-organisms also need iron to survive, and our immune system has developed ways to deal with them by producing an anti-microbial molecule called lactoferrin, which cuts off the iron supply to micro-organisms. Lactoferrin is found within the secretions from many of our body openings, including tears and saliva. However by far the richest source of lactoferrin is human colostrum, which is the breast milk produced shortly after a baby is born. Colostrum from cows also contains a substantial amount of lactoferrin.

Zinc

Being an antioxidant, zinc is required for the healthy function of cells throughout the body. This is particularly so in the immune system, where it is required for T, B and natural killer cell function.

Zinc affects the thymus gland, which is involved in the maturation and development of T cells. A deficiency in zinc results in a smaller thymus and slower development of T cells, in turn lowering immunity.

Zinc has been shown to block viral replication. When a virus attaches itself to a cell, it integrates its own genetic code with that of the cell. In doing so, the virus hijacks the cell, using it as a factory for its own multiplication. Eventually the cell becomes completely loaded with the virus and bursts, releasing the virus from within, and this cycle continues. The presence of zinc is able to hamper or prevent this process from occurring, effectively preventing the virus from spreading.

Zinc is a critical component of the body’s defence against free radical damage. Free radicals are chemically reactive molecules capable of damaging our genetic and cellular materials. Our immune cells take advantage of the damaging effects of free radicals and use them as a means to kill invading microbes. To protect our own tissues against the power of free radicals, we have evolved some protective mechanisms, one of which is zinc-dependent. So if you are zinc-deficient, your own tissues may be prone to free radical attack, causing irreversible tissue damage which in turn reduces your immunity.

Good sources of zinc includes lean meat, nuts, eggs, pulse, some seafood, and hard cheese. Generally, plant-derived zinc is more difficult to absorb, although refining and cooking can substantially increase the ease of zinc absorption from plant foods. To maximise your intake of dietary zinc, try the following:

Avoid cola (fizzy drinks)
Avoid tea or cocoa with meals
Cook all legumes until soft before eating
Avoid eating raw bran and wheat germ. Instead, add them to baking mixtures

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