BOOSTING IMMUNITY THE HEALTH PROMOTION BOARD WAY

The Health Promotion Board (HPB) is concerned that some members of the public are consuming vitamin C tablets and other health supplements indiscriminately in the hope of boosting their immunity against SARS. Our recommendations on boosting immunity against diseases, centring around the four pillars of a healthy lifestyle, are given below:

1. Eat a balanced diet

The recommended dietary allowance (RDA) for vitamin C for healthy adults is 30 mg per day. Consuming a varied and balanced diet based on the Healthy Diet Pyramid will provide the recommended levels of nutrients, including vitamin C, needed to boost the immune system. Individuals should avoid consuming more than 1000 mg (1g) of vitamin C a day (conventional effervescent tablets on the market contain 1000mg of vitamin C per tablet). This includes the combined levels of vitamin C from supplements and foods. As oxalate is an end product of vitamin C metabolism, excessive vitamin C intake can lead to increased risk of kidney stone formation.

It is important to consume a balanced and varied diet as the components of different foods often work in synergy to provide different types of protection e.g. protein provides building blocks for antibodies; minerals like zinc, selenium and iron are needed for optimal functioning of the various types of immune cells; and vitamins C and E are antioxidants which help to reduce damage to cells. Plant-based foods such as fruit, vegetables and wholegrains are not only rich in vitamins and minerals but also phytochemicals, which function as antioxidants.

Dietary supplements have been found to be beneficial among individuals who are consuming below the recommended levels of nutrients but the effect is negligible among those already consuming a balanced diet. Supplements may be useful among the elderly who are usually at higher risk of nutrient inadequacy. Megadoses of vitamins e.g. in excess of 1000 mg of vitamin E and 3000 mg of vitamin A should be avoided as they can be harmful to health.

For a list of the RDAs of the various nutrients, please log on to HPB Online at www.hpb.gov.sg

2. Exercise regularly

Aim to engage in moderate intensity exercises for at least 30 minutes per day at least 5 times a week (you may engage in physical activity in accumulated blocks of 10 minutes). It has been shown that regular exercise makes you less susceptible to infections and diseases.

3. Stay smoke-free

Smokers should try to quit smoking as it weakens the body's immune system, thus rendering them more susceptible to lung infections.

4. Reduce stress and have adequate rest

Stress and inadequate rest will lower the body's immune capabilities. If you are suffering from stress:

a. identify the source of stress
b. keep your body healthy by exercising regularly, eating wisely and getting enough sleep
c. do not turn to cigarettes or alcohol to relieve your stress - smoking and drinking will not solve your problem and will cause more problems for your health
d. learn relaxation techniques. Deep breathing exercises, meditation, massage and muscle relaxation techniques can be helpful in relieving stress

If you have problems sleeping:

a. identify the contributing factors (eg. too much caffeine, excessive worrying, sleeping at irregular hours, exercising just before sleep etc) and deal with the problem accordingly
b. establish a regular sleeping schedule
c. maintain a proper bedroom environment for sleep
d. consult a doctor if the problem persist