What should you eat to build up your natural defences?
Our immune system is the first line of defence when it comes to maintaining good health. It defends us against a billion different invaders – bacteria, viruses and parasites – producing millions of antibodies and guarding against serious diseases. Whenever we have a cold or feel run-down it is because our immune system isn’t working as well as it should. The good news is that with simple changes to our diet and lifestyle, we can enhance our immune health. Give your system a boost with the following vitamins and foods:
Zinc
Zinc is one of the most important minerals for a healthy immune system. It increases the production of T-cells, white blood cells produced by the thymus gland, which are important in fighting infection. Zinc helps ward off colds and flu and by upping your intake during an infection it can speed your recovery.
Eat: Oysters, which contain more per serving than any other food, other shellfish are also good sources, lean red meat and poultry, dairy products, nuts and seeds, fortified breakfast cereals, wholewheat, oats and rye. The recommended daily amount (RDA) is 15mg, which you can get from 225g (8oz) steak, 100g (4oz) wheatgerm or 225g (8oz) seeds and nuts. Do not take excessive amounts as this can inhibit the absorption of iron and copper, which can lower immune function.
B vitamins
B vitamins are important for white blood cell activity and any deficiency can weaken your immune health. B6 is vital for the production of antibodies, while B12 and folate are essential for immune function. While the RDA for B6 is 2mg, nutritionists recommend between 50 and 100mg to boost immune power.
Eat: Wheatgerm, turkey, cod, beef, nuts (especially walnuts), leafy green vegetables (especially Brussels sprouts and cabbage) and fortified breakfast cereals.
Selenium
Selenium, a powerful antioxidant, works with vitamin E to stimulate and protect the immune system. Low levels allow otherwise harmless viruses to become active. Selenium also helps to bind and eliminate heavy metals, which can be toxic to the body. The RDA is 75mcg although up to 100mcg may be needed for immune-boosting power.
Eat: Brazil nuts (just four or five will give you your daily requirements), seaweed, lean meat, fish (especially tuna), shellfish, cashew nuts, walnuts, sunflower seeds, wholewheat, cheese and eggs.
Vitamin A
Even a mild deficiency in this important antioxidant can lead to increased susceptibility to infections. Vitamin A increases the number of infection-fighting cells, natural killer cells and T-cells. It is anti-viral and helps maintain the thymus gland. It is found in liver, dairy foods, eggs and oily fish. It is also present in brightly coloured fruits and vegetables in the form of betacarotene, which the body converts to vitamin A. Over-consumption of vitamin A can be toxic, however over-consumption of beta-carotene is not, as the body regulates how much is converted into vitamin A. The RDA for vitamin A is 800mcg – eat just 3g of liver or a couple of carrots.
Eat (for beta-carotene): Green leafy vegetables, carrots, sweet potatoes and yams, apricots, cantaloupe melon, broccoli, pumpkin and squashes.
Vitamin C
Vitamin C tops the league in helping to support your immune system. It is strongly anti-viral and antibacterial. It also boosts white blood cells and antibodies, and acts as an antioxidant by destroying harmful free radicals. Vitamin C is not stored in the body, so an adequate supply is required throughout the day. The current RDA is 60mg but most nutritionists suggest taking between 1-2g daily.
Eat: Kiwi fruit, citrus fruits, strawberries, guava, blackcurrants, sweet potatoes, peppers and green leafy vegetables.
Vitamin E
This is an important antioxidant that enhances white blood cell function and stimulates the production of T-cells and B-cells. It is needed to maintain healthy skin and protect the body from harmful free radicals. The RDA is 10mg, which can be obtained by eating 30g (1oz) sunflower seeds.
Eat: Wholegrains, nuts, pumpkin seeds, avocado, wheatgerm and leafy green vegetables.
Avoid the following:
Sugar and alcohol
High intakes of sugar can suppress the white blood cells’ ability to fight against infection. Alcohol has a similar effect. Smoking also damages immune health.
Heavy, rich foods
When you’re feeling under the weather, eat lightly, relying on wholefoods and plenty of fruit and vegetables. Avoid mucus-forming and fatty foods such as meat, eggs and dairy products.
Stress
There are many studies showing that if we can’t cope with stress it suppresses the immune function. Learn how to deal with stress through rest and relaxation.
Lack of sleep
During our deepest level of sleep, immune-enhancing compounds are released, so getting a good night’s sleep is vital.