As the mercury drops, cold and flu outbreaks soar. Its tempting to believe the marketing claims that this pill or that herbal remedy can protect you, but the science says theres simply no magic bullet to boost your immune system. Eating a healthy diet, however, is even more important during cold and flu season. Experts may not fully understand how specific nutrients aid the immune system, and tests of individual vitamins and minerals against colds and flu do not always produce positive results. But its clear that the combination found in healthy foods can build your bodys ability to fight infections.
Researchers at Tufts Nutritional Immunology Laboratory are looking for new ways in which diet might affect the immune system. Simin Nikbin Meydani, DVM, PhD, laboratory director and head of Tufts Jean Mayer USDA Human Nutrition Research Center on Aging, says, Several ongoing animal and human studies are designed to determine the impact of other dietary components and functional foods on immune response and resistance to infection. These projects include the effects of wolfberry and pre- and pro-biotics on resistance to influenza infection and immune response, and the effect of olive oil on immune and inflammatory responses. Other research is investigating whether white button mushrooms could improve resistance to viral and bacterial infection by enhancing the bodys immune response.
KEEPING THE DOCTOR AWAY: Two studies published in late 2012 helped demonstrate the connection between healthy eating and immune function (see the May 2013 newsletter). In one, older adults who increased their fruit and vegetable consumption to at least five servings a day responded significantly better to a pneumonia vaccine than those in a control group. (One serving was defined as 80 grams of fruit-about one apple, orange or banana-or three-quarter cup of fruit juice, or three heaping tablespoons of vegetables.)
The second study tested both a dietary intervention and a supplement, finding that both groups needed fewer doctor and hospital visits than a control group. Those in the dietary group ate at least five servings of fruits and vegetables daily, fish twice a week, nuts at least weekly and only whole-grain bread. The supplement given a second group was designed to approximate the same increase in nutrients: 1,500 micrograms of beta-carotene, 2 milligrams vitamin E, 80 milligrams vitamin C, 2 milligrams zinc and 25 micrograms selenium.
Whole-grain bread and other whole-grain foods, while not a specific nutrient, may improve gut health by promoting good bacteria. This in turn may have a beneficial impact on the immune system. A 2009 review, for example, found that the beta-glucan fiber in oats improves the defenses of the immune system. At Tufts, the HNRCA is currently recruiting participants for a study of the effects of a diet rich in whole grains on intestinal health and immune response in adults ages 40-65