Prevent Cold, Flu, and Allergy: Boost Your Immune Systems

How can you boost your immune system?

Boosting your immune system

Everyone feels run down from time to time. How can you make sure your immune system is in the best condition to fight infection?

Many things affect the immune system, including your mood, stress level, nutrition, and the amount of sleep you get. It is important that you support your immune system, so that it can protect you.

Top tips

  • Keep your life as stress-free as possible
  • Get the right amount of sleep
  • Eat a balanced diet containing plenty of Vitamin C, E, B6 and zinc
  • Try alternative remedies, like Echinacea and garlic

Stress and mood

Keeping your life as stress-free as possible will help you keep your immune system healthy.

Being happy and optimistic helps your immune system function better. When you are depressed, your immune system tends to be depressed1. Stress and depression have both been shown to affect how the immune system functions, either causing suppression of usual activity, or an over-reaction2.

Stress increases the levels of some hormones, including adrenaline and corticosteroids. Corticosteroids suppress the immune system, leaving you open to infection3. Also, the level of immune suppression is proportional to the level of stress: the more stressed you are, the more the immune system is affected1.


Lack of sleep will affect the immune system and make you more likely to become susceptible to infection.

Parts of the immune system regulate sleep and in turn are altered by sleep and sleep deprivation. The normal sleep-wake cycle regulates the functioning of the immune system4. Significant detrimental effects on immune functioning can be seen after a few days of total sleep deprivation, or after several days of partial sleep deprivation4. Shift-workers frequently get less sleep than their non shift-working counterparts5. If you are getting less sleep than you need to keep your immune system working efficiently, take extra care of the other areas that affect your health.


What you eat has a great effect on your immune system. A healthy, well-balanced diet is important to ensure that you have all the nutrients you need to keep your body functioning properly.

It is important to have sufficient amounts of all vitamins and minerals. But to keep your immune system functioning properly, pay special attention to the following:

Vitamin C: Helps white blood cells fight infection and is essential for healing wounds. It is also an antioxidant that neutralizes potentially damaging free radicals6. It is found in most fresh fruit (especially citrus fruits), vegetables and fruit juices.

Vitamin E: An antioxidant that neutralizes free radicals in the body. It is also important for the protection of cell membranes and maintaining healthy skin, heart and circulation, nerves, muscles and red blood cells6. Vitamin E can be found in seed oils, olive oil, avocadoes, nuts, leafy green vegetables, egg yolks, wholegrain bread, and cereals.

Vitamin B6: Important in the formation of antibodies that help fight infection. It is also important for protein metabolism, the functioning of many enzymes, for the formation of hemoglobin in red blood cells, and for maintaining a healthy nervous system. Vitamin B6 can be found in wholegrain bread, meat, fish, bananas, wheat bran, and fortified breakfast cereals6.
Deficiencies in a number of vitamins, including vitamin A and B12, pyridoxine (B6) and folic acid, can also cause immune system dysfunction7.

Zinc: Aids the growth of immune cells7 and inhibits the growth of several viruses1. Some studies have shown that zinc promotes the destruction of foreign particles and micro-organisms1. It works in conjunction with a powerful antioxidant, and is also important for the maintenance of hair, skin and nails. Zinc can be found in red meat, liver, shellfish, egg yolks, dairy products, and wholegrain cereals.

Alternative remedies

Many products claim to boost the immune system, but which ones actually work?

Echinacea: Used to strengthen the immune system6. It is generally used to treat upper respiratory tract infections and studies have found it effective at relieving cold symptoms8. It reportedly works by stimulating white blood cell activity. It is thought to be useful as a wound-healing agent for abscesses, burns, eczema, varicose ulcers of the leg, and other skin wounds9. It can be taken in either liquid or tablets form, and can be bought from pharmacies or health-food stores. Women who are pregnant or breast-feeding women should not take this supplement.

Garlic: Has antibacterial and antiviral properties and is traditionally used to treat a range of diseases and ailments6, 10. It is thought to prevent common colds and flu. Garlic can be eaten raw or taken as a supplement. Consult your doctor before taking these supplements if you are taking drugs to prevent blood clots or to reduce high blood pressure6.

Selenium: Required for the proper functioning of the immune system. Brazil nuts are the best sources of selenium. Other sources include liver, shellfish, crab and fish. Plant foods such as wheat are a good source because of the selenium-rich soil in many parts of the US11. Be careful not to overdose on selenium, as it is toxic in high concentrations. A deficiency of selenium has been linked to bad moods12.

Chicken soup: What your mother told you is true - chicken soup can help you feel better! A study in the journal Chest has shown that it has a mild anti-inflammatory effect, which can help in relieving the symptoms of upper respiratory tract infections13.


  1. Murray M, Pizzorno J. encyclopedia of Natural Medicine. 2nd Edn. Little, Brown and Company. 2000
  2. Raison CL, Miller AH. The neuroimmunology of stress and depression. Seminars in clinical neuropsychiatry. 2001; 6: 277-94
  3. Youngson R. Royal Society of Medicine, Health Encyclopedia. 2nd Edn 2000
  4. Rogers NL, Szuba MP, Staab JP, Evans DL, Dinges DF. Neuroimmunologic aspects of sleep and sleep loss. Seminars in clinical neuropsychiatry. 2001; 6: 295-307
  5. Shift work. British Sleep Foundation.
  6. Factsheets. Health Supplements Information Servise.
  7. Beisel WR, Edelman R, Nauss K, Suskind RM. Single-nutrient effects on immunological functions. Report of a workshop sponsored by the Department of Food and Nutrition and its nutrition advisory group of the American Medical Association. Journal of the American Medical Association. 1981; 245: 53-8
  8. Schulten B, Bulitta M, Ballering-Bruhl B, Koster U, Schafer M. Efficacy of Echinacea purpurea in patients with a common cold. A placebo-controlled, randomised, double-blind clinical trial. Arzneimittel-Forschung. 2001;m 51: 563-8
  9. Fetrow CW, Avila JR. Professional's Handbook of Complementary and Alternative Medicines. 2nd Edn. Springhouse. 2001
  10. Alternative Common Cold Medications. From the Common Cold center, Cardiff University.
  11. National Institutes of Health, Office of Dietary Supplements. Health Information, Vitamin and Mineral Supplements Fact Sheets.
  12. Rayman MP. The importance of selenium to human health. The Lancet. 2000; 356: 233-41
  13. Rennard BO, Ertl RF, Gossman GL, Robbins RA, Rennard SI. Chicken soup inhibits neutrophil chemotaxis in vitro. Chest. 2000; 118: 1150-7

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