The immune system consists of a complex and finely orchestrated collection of tissues and cells that protect your body from allergens, bacteria, viruses, and other potentially harmful organisms, collectively known as antigens. The skin and the membranes that line the entrances to the body (nasal passages, eyes, and respiratory and digestive tracts) are the first line of defense and provide a physical barrier against invaders. Internally, specialized white blood cells fight antigens that manage to get through the skin: T-lymphocytes continually patrol the body for antigens; B lymphocytes make antibodies, special blood proteins that neutralize or destroy germs; and neutrophils and macrophages remove antigens from the blood to send them to the lymphatic system, which removes them. To function smoothly, these cells depend on you to keep your body in tip-top shape.
“There is no question that the immune system is fundamentally influenced by overall health, and a balanced diet is key,” says David Katz, MD, MPH, director of the Yale Prevention Research Center in New Haven, Connecticut. “Essential nutrients are not only critical for the production and maintenance of key germ-fighting cells in the immune system, but a balanced diet also has a strong effect on vascular function, and the immune system relies on blood flow.” Katz says. The bloodstream is the route by which infection-fighting cells travel throughout the body to where they are needed.
Given the complexity of the immune system, there is no specific food that will magically repel cold germs and flu viruses. Instead, eating a healthy, balanced diet is your best investment in immunity.
Fill your plate with fruits and vegetables
Vitamins (especially A and C) and phytochemicals that give fruits and vegetables their color serve as antioxidants that promote immune function, says Charles Stephensen, Ph.D., a research scientist at the USDA’s Western Human Nutrition Research Center. at the University of California, Davis. “These nutrients help ensure that lymphocytes can divide and reproduce properly in response to a virus and that the neutrophils and macrophages that engulf and kill invading bacteria can do their jobs,” says Stephensen.
What to do: Eat five to nine servings of fruits and vegetables a day. To maximize the variety of vitamins, minerals and antioxidants, try to eat two different colors of vegetables and fruits with each meal, suggests Blackburn. “Cover two-thirds of your plate with vegetables, fruits, whole grains, and beans, and one-third with lean protein,” he says.
Choose lean protein sources
The amino acids found in protein make up the building blocks of every cell in your body, including the cells that fuel your immune system. If you don’t eat enough protein, you’ll make fewer white blood cells to fight off antigens. “One of the ways that immune cells fight pathogens is by increasing their numbers,” says Simin Nikbin Meydani, Ph.D., associate director of the Jean Mayer Research Center on Aging at Tufts University in Boston, Massachusetts. . “To increase the proliferation of immune cells, proteins and amino acids are needed.”
What to do: Consume 0.8 to 1 gram of protein per kilogram (kg) of your body weight. That means if you weigh 130 pounds, which works out to about 59 kg, eat at least 47 grams of protein per day. But remember, quality counts: To avoid saturated fat, choose three- to four-ounce servings of lean protein like fish, shellfish, poultry (without skin), eggs, lentils, beans, and soy products.
Focus on healthy fats
High-fat diets appear to affect the immune system by decreasing the function of T-lymphocytes.
Reducing fat, on the other hand, can boost immune function by improving T cell function. However, the type of fat you eat is just as important as the amount. Trans fats (found in margarines and many commercial baked goods) can contribute to chronic low-grade inflammation in the body. “The immune system can be tied to dealing with inflammation, and the resulting damage to cells and tissues, rather than defending the body,” says Katz.
What to do: Limit your total fat intake to 30 percent of daily calories, with 5 to 10 percent saturated fat. For the remaining 20 to 25 percent, look for sources of unsaturated fats, such as canola oil, olive oil, nuts, avocados, and seeds. And increase your intake of omega-3 fatty acids (from fatty fish like salmon, halibut, and sardines), which help fight inflammation and free up your immune system to defend against antigens.
make time for tea
Green tea is a rich source of a type of antioxidant called catechin, and preliminary research has found that a specific catechin, epigallocatechin gallate (eggc), may give the beverage antigen-fighting abilities. When researchers at the University of Sherbrooke in Canada added green tea to laboratory samples of adenovirus (one of many viruses that cause colds), they found that egcg inhibited the ability of the virus to replicate. Similarly, researchers in South Korea found that EGCG can also stop influenza virus replication. While these studies were done in petri dishes rather than human subjects, some researchers believe you can be reasonably confident of the benefits of green tea, particularly when consumed in place of colas or other sugary beverages with little nutritional benefit. “Green tea catechins can enhance lymphocyte responses and appear to have anti-inflammatory effects,” says Stephensen.
What to do: Swap at least one cup of coffee a day for green tea. To get the optimal amounts of catechins from your tea, steep the bag for at least three minutes in hot water.
Maintain a proper energy balance.
Eat enough, but not too many or too few, calories each day. “Considerable evidence shows that crash dieting, anorexia, or nutrient deficiencies increase a person’s susceptibility to infection, but excessive calorie consumption can also have deleterious effects on cell production in the immune system,” says Meydani. . “This could be because excessive calorie consumption leads to increased production of compounds called prostaglandins, which have a suppressive effect on T cell production.” Fewer T cells patrolling the body increase the chances that an antigen will take hold.
What to do: To find the right amount of calories for you, go to www.mypyramid.gov, which makes recommendations based on age, gender, and activity level.
Take the only supplement that works
Although the researchers we spoke with criticized most of the supplements, they all agreed that a multivitamin is worth taking. If you are even marginally deficient in certain nutrients, particularly vitamins B, A, C, E, selenium, iron, and zinc, your immune system function may be affected. “This can happen without seeing any obvious signs of deficiency, until you get sick with a virus or bacterial infection,” says Meydani.
What to do: Choose a multivitamin formulated specifically for your gender or age. For example, multivitamins made for men and postmenopausal women contain less iron than those made for younger women. And always look for the US Pharmacopeia seal, says Douglas Heimburger, MD, professor of nutritional sciences and medicine at the University of Alabama at Birmingham. “He tells you that certain pharmaceutical standards have been met and tested,” says Heimburger.
CookingLight.com: How to choose the right multivitamin for you:
Consume friendly bacteria
A drink of yogurt or kefir a day might help keep infections at bay. That’s because these foods contain probiotics, bacteria that stimulate immune cells in the gastrointestinal tract. “The normal, healthy bacteria that colonize the gastrointestinal tract help it resist harmful bacteria and detoxify harmful substances,” explains Susanna Cunningham-Rundles, Ph.D., professor of immunology at Cornell University’s Weill Medical College in New York City. In addition to their protective effect on the GI tract, probiotics can also help stimulate immune cell production throughout the system. In a recent study of 33 women at the University of Vienna, Austria, those who ate plain yogurt every day for two weeks increased their T cell count by nearly 30 percent.
What to do: Look for yogurt or kefir that contains “live active cultures,” indicating helpful bacteria. CookingLight.com: Add live cultures to your diet with these tips and recipes
How exercise helps
“Immune system cells don’t function normally when a person is overweight or has high cholesterol and triglyceride levels,” says Gabriel Fernandes, Ph.D., professor of medicine at the University of Texas Health Science Center at San Antony. “Immune cells cannot recognize bacteria or viruses and destroy them,” says Fernandes. Along with diet, exercise is key to losing extra pounds.
What to do: “Increase your physical activity from 30 minutes a day to 60 to burn more calories,” says Fernandes. In a yearlong study of 550 men and women, researchers at the University of South Carolina found that those who exercised moderately were 25 percent less likely to develop a cold compared to those who rarely exercised. exercise. (Subjects simply walked briskly.) As with diet, moderation is essential; too much exercise or exercising to exhaustion can increase the body’s production of adrenaline and cortisol, two hormones that temporarily suppress immune function.
Research has shown that people who have low glutathione levels are susceptible to chronic disease. Research shows that GSH levels decline by 8-12% per decade, starting in your 20s. Glutathione levels are further depleted by ongoing stress on the immune system, such as illness, infection, and environmental toxins. As we now know, a weakened immune system can lead to illness and disease. This is a fierce cycle. While you need glutathione for a productive immune system, a weakened immune system makes it harder to produce glutathione.