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Foods to Stimulate the Immune System

We are constantly being attacked by disease causing organisms. They are in the food we eat, the water we drink and the air we breathe. Some of these organisms cause minor inconveniences such as the cold or the flu, but others can be life-threatening.


The immune system is the first line of defense that our bodies have to fight disease causing micro-organisms. Some of the cells lining our gastrointestinal tract have a complicated system of detectors that are able to identify foreign (harmful) bacteria. Once alerted, a chain of metabolic events occurs that produces cells and highly potent chemicals to kill off the foreign bacteria. In most cases our immune system is able to keep us healthy and disease free. People who have compromised immune systems, such as sufferers of AIDS, are not as lucky.

Probiotics are foods that contain live micro-organisms that, when taken in sufficient quantities, can produce beneficial effects. Our GI tracts contain a very large number of bacteria. This population is influenced by our age, our diet, and our state of health. When we are sick, especially in cases such as when we have diarrhea or other intestinal upsets, the number of pathogenic or disease causing bacteria in the GI tract has become too large. In a very general sense, probiotics contain good bacteria and, when they are eaten, these good bacteria can help maintain the balance of the microbial population in our GI tracts.

Many scientific publications can now be found in the literature that demonstrate the beneficial effects of consuming probiotics. Whether taken as individual bacteria in capsules or eaten in the form of yogurt or kefir, probiotics are effective as long as a sufficient number of them survive the harsh conditions of the stomach. As our understanding of how such foods exert their effects grows, it seems the immune system may be the initial site of action of probiotic bacteria.

The immune system is a complex organization of cells that directly attack and kill harmful bacteria and viruses and also cells that produce chemical substances that are toxic to harmful bacteria and viruses. It has now been shown that consumption of yogurt or live bacteria that belong to the group known as lactic acid bacteria (LAB) increase the production of IFNα , IL-10, IL-4 and IL-6. Researchers have shown that IFNα , IL-10, IL-4 and IL-6 all belong to a group of molecules called cytokines that are important members of our body’s immune response system. LAB also cause increases in the numbers and activity of natural killer (NK) cells that kill virus infected cells.

The consumption of probiotics - foods that contain live bacteria - may be an alternative to anti-biotics and anti-virals as a way of fighting disease causing bacteria and viruses

Populations Who Could Have Impaired Immune Function
  • Young children
  • Surgery patients
  • The elderly
  • People with AIDS
  • Patients after radiation treatment

Suggested Reading

EUFIC - The European Food Information Council
Nutrition and the Immune System

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