9 Power Foods That Boost Immunity and The Top 10 Immune Busters

9 Power Foods That Boost Immunity

You’re washing your hands, using Purell like crazy, and sneezing into your elbow. Now add these superfoods to your diet for an extra flu-fighting punch.

Flu-fighting foods

 

9 Power Foods That Boost Immunity

You’re washing your hands, using Purell like crazy, and sneezing into your elbow. Now add these superfoods to your diet for an extra flu-fighting punch.

By Amanda MacMillan and Tamara Schryver, RD
Flu-fighting foods

Flu-fighting foods

It takes more than an apple a day to keep the doctor away. It turns out that eating some pretty surprising nutrients will help keep your immune system on guard.

You can ensure your body and immunity run smoothly by rounding out your plate with plenty of colorful servings of fruits and veggies, plus 8 to 10 glasses of water a day, at the very least. The following ingredients can add extra flu-fighting punch to your winter meal plan.

More from Prevention: Everything You Need To Know About Cold & Flu

1. Yogurt

Probiotics, or the “live active cultures” found in yogurt, are healthy bacteria that keep the gut and intestinal tract free of disease-causing germs. Although they’re available in supplement form, a study from the University of Vienna in Austria found that a daily 7-ounce dose of yogurt was just as effective in boosting immunity as popping pills. In an 80-day Swedish study of 181 factory employees, those who drank a daily supplement of Lactobacillus reuteri—a specific probiotic that appears to stimulate white blood cells—took 33% fewer sick days than those given a placebo. Any yogurt with a “Live and Active Cultures” seal contains some beneficial bugs, but Stonyfield Farm is the only US brand that contains this specific strain.

Your optimal dose: Two 6-ounce servings a day.

More from Prevention: 25 Tasty Things You Can Do With Yogurt

2. Oats and Barley

These grains contain beta-glucan, a type of fiber with antimicrobial and antioxidant capabilities more potent than echinacea, reports a Norwegian study. When animals eat this compound, they’re less likely to contract influenza, herpes, even anthrax; in humans, it boosts immunity, speeds wound healing, and may help antibiotics work better.

Your optimal dose: At least one in your three daily servings of whole grains.

3. Garlic

This potent onion relative contains the active ingredient allicin, which fights infection and bacteria. British researchers gave 146 people either a placebo or a garlic extract for 12 weeks; the garlic takers were two-thirds less likely to catch a cold. Other studies suggest that garlic lovers who chow more than six cloves a week have a 30% lower rate of colorectal cancer and a 50% lower rate of stomach cancer.

Your optimal dose: Two raw cloves a day and add crushed garlic to your cooking several times a week. (Here’s what to do about garlic breath.)

4. Shellfish

Selenium, plentiful in shellfish such as oysters, lobsters, crabs, and clams, helps white blood cells produce cytokines—proteins that help clear flu viruses out of the body. Salmon, mackerel, and herring are rich in omega-3 fats, which reduce inflammation, increasing airflow and protecting lungs from colds and respiratory infections.

Your optimal dose: Two servings a week (unless you’re pregnant or planning to be).

5. Chicken Soup

When University of Nebraska researchers tested 13 brands, they found that all but one (chicken-flavored ramen noodles) blocked the migration of inflammatory white cells—an important finding, because cold symptoms are a response to the cells’ accumulation in the bronchial tubes. The amino acid cysteine, released from chicken during cooking, chemically resembles the bronchitis drug acetylcysteine, which may explain the results. The soup’s salty broth keeps mucus thin the same way cough medicines do. Added spices, such as garlic and onions, can increase soup’s immune-boosting power.

Your optimal dose: Have a bowl when feeling crummy. (Give this delicious recipe a try!)

6. Tea

People who drank 5 cups a day of black tea for 2 weeks had 10 times more virus-fighting interferon in their blood than others who drank a placebo hot drink, in a Harvard study. The amino acid that’s responsible for this immune boost, L-theanine, is abundant in both black and green tea—decaf versions have it, too.

Your optimal dose: Several cups daily. To get up to five times more antioxidants from your tea bags, bob them up and down while you brew.

7. Beef

Zinc deficiency is one of the most common nutritional shortfalls among American adults, especially for vegetarians and those who’ve cut back on beef, a prime source of this immunity-bolstering mineral. And that’s unfortunate, because even mild zinc deficiency can increase your risk of infection. Zinc in your diet is very important for the development of white blood cells, the intrepid immune system cells that recognize and destroy invading bacteria, viruses, and assorted other bad guys, says William Boisvert, PhD, an expert in nutrition and immunity at The Scripps Research Institute in La Jolla, CA.

Your optimal dose: A 3-oz serving of lean beef provides about 30% of the Daily Value (DV) for zinc. That’s often enough to make the difference between deficient and sufficient. Not a beef person? Try zinc-rich oysters, fortified cereals, pork, poultry, yogurt, or milk.

8. Sweet Potatoes

You may not think of skin as part of your immune system. But this crucial organ, covering an impressive 16 square feet, serves as a first-line fortress against bacteria, viruses, and other undesirables. To stay strong and healthy, your skin needs vitamin A. “Vitamin A plays a major role in the production of connective tissue, a key component of skin,” explains Prevention advisor David Katz, MD, director of the Yale-Griffin Prevention Research Center in Derby, CT. One of the best ways to get vitamin A into your diet is from foods containing beta-carotene (like sweet potatoes), which your body turns into vitamin A.

Your optimal dose: A half-cup serving, which delivers only 170 calories but 40% of the DV of vitamin A as beta-carotene. They’re so good, you might want to save them for dessert! Think orange when looking for other foods rich in beta-carotene: carrots, squash, canned pumpkin, and cantaloupe.

9. Mushrooms

For centuries, people around the world have turned to mushrooms for a healthy immune system. Contemporary researchers now know why. “Studies show that mushrooms increase the production and activity of white blood cells, making them more aggressive. This is a good thing when you have an infection,” says Douglas Schar, DipPhyt, MCPP, MNIMH, director of the Institute of Herbal Medicine in Washington, DC.

Your optimal dose: Shiitake, maitake, and reishi mushrooms appear to pack the biggest immunity punch; experts recommend at least ¼ ounce to 1 ounce a few times a day for maximum immune benefits. Add a handful to pasta sauce, sauté with a little oil and add to eggs, or heap triple-decker style on a frozen pizza.

More from Prevention: Top 10 Immune-Boosting Tips

The Top 10 Immune Busters

Strengthen your immune system by kicking these defense-impairing habits

By Ellen Mazo and The Editors of Prevention Health Books
The same way that our 20 immune boosters can kick your immune system into high gear, these 10 habits can make it shut down. Follow this advice, and your body will thank you.

1. Stop Smoking

Smoking, and breathing in secondhand smoke, are terrible for your entire body. Cigarette smoke contains more than 4,000 chemical compounds. Of these, at least 43 are known carcinogens.

Here are just some of the ways it wreaks havoc: Smoking causes heart disease, lung and esophageal cancer, and chronic lung disease. It contributes to cancer of the bladder, pancreas, and kidneys. Women who smoke during pregnancy are more likely to have problems, including babies with low birth weights, which is a leading cause of infant death.

In fact, smoking kills more than two times as many people as AIDS, alcohol abuse, motor vehicle accidents, homicides, drugs, and suicide combined. One out of every five deaths in America is smoking-related. On average, smokers die nearly 7 years earlier than nonsmokers!

Secondhand smoke is almost as deadly. Each year, because of exposure to tobacco smoke, an estimated 3,000 nonsmoking Americans die of lung cancer and 300,000 children suffer from lower respiratory tract infections. Secondhand smoke can trigger an asthma attack and aggravate symptoms in people with allergies. In addition, tobacco smoke has been shown to make asthma worse in preschool children and may even cause it.

2. Dodge Those PCBs

It takes just one exposure of less than one-millionth of a gram for immunotoxic contaminants such as polychlorinated biphenyls (PCBs), mercury, certain pesticides, and dioxin-like substances to disrupt the immune function of innocent wildlife. Since these chemicals can stay in the environment for decades, vulnerable wildlife species have no escape from their devastation. Moreover, not only do these toxins become more concentrated as they move their way up the food chain, they can also cause life-threatening autoimmune reactions–the immune system’s inability to tell the difference between the body’s own tissues and foreign invaders.

So, what does this have to do with your immune system? A lot. Evidence suggests that some of these same chemicals may be putting us at risk. A few examples: In Aberdeen, N.C.—home of the Aberdeen pesticides dump—scientists found that young adults were two times more likely than nonresidents to have shingles, a painful condition caused by a herpes virus. In another study, researchers found that chlordane, a termite-killing substance, caused weaker immune responses in people who had been exposed.

So what can you do? Reduce your exposure as much as possible to unnecessary toxins. Stay away from cigarette smoke, excess alcohol, and illicit drugs. Buy organic produce when possible. Rinse your fruits and vegetables thoroughly to remove pesticides. Switch to natural gardening methods and stay indoors or go away when your neighbors are using pesticides. Choose cleansers, paper goods, and other products that are made with less toxic materials. Read food labels vigilantly and avoid products that contain unnecessary chemicals.

3. Avoid Sleep Deprivation

Sleep deprivation has a powerfully detrimental effect on your immune system. The perfect example is college students who get sick after pulling all-nighters cramming for exams.

If you’re tired when you wake up in the morning, you’re not getting enough sleep, or maybe not enough quality sleep. Either way, your immunity is probably compromised. Poor sleep is associated with lower immune system function and reduced numbers of killer cells that fight germs. Killer cells are also the part of the immune system that combats cells that divide too rapidly, as they do in cancer. Lower their numbers and you may be at greater risk for illness.

Studies have shown that chronic sleep deprivation also contributes to heart disease, gastrointestinal problems, and other medical illnesses. One study on the effects of sleep deprivation showed that a group of men restricted to 4 to 6 hours of sleep per night experienced changes in hormone function and carbohydrate metabolism that mimic aging changes; the lack of sleep was making them older faster.

The Top 10 Immune Busters

Strengthen your immune system by kicking these defense-impairing habits

By Ellen Mazo and The Editors of Prevention Health Books

4. Release Yourself from the Stress Trap

No doubt about it, stress is an Immune Buster.

The loss of a job, the death of a spouse, the breakup of a marriage—these are all examples of situations that can trigger a vigorous stress response in the body.

There is compelling scientific evidence that chronic stress causes a measurable decline in the immune system’s ability to fight disease. Severe and chronic stress have a direct impact on the immune system that can cause disease or change the course of a preexisting disease. For example, studies have indicated that higher levels of stress hormones lead to more rapid cancer progression.

Other research has shown that people who are stressed are more prone to developing cardiovascular disease. Studies show that women with cardiovascular disease who are better able to manage their stress live longer and remain healthier than women with cardiovascular disease who undergo a lot of stress and don’t know how to manage it.

Periods of extreme stress can result in lower natural killer cell count, sluggish “killer T” cells, and diminished macrophage activity that can amplify the immune response. In fact, widows and widowers are much more likely to get sick during the first year following the death of their spouse than their peers who have not experienced a major loss.

More from Prevention: How The Pros Cope With Stress

5. Adopt an Optimistic Outlook

Even subtle shades of sadness can weaken your immune system. Here’s why:

Studies show that pessimists who look at a half-glass of water and think that it’s half-empty don’t live as long as optimists, who see the same glass as half-full. When pessimists put a more positive spin on the calamities in their lives, they have less stress and better health. One reason for this could be that optimists take better care of themselves. It could also be due to less stress-related damage to your immune system, such as killer cells that suddenly become pacifists. In one study, cancer patients who completed a special course designed to make them more optimistic had stronger immune systems than those who maintained their woesome ways.

Other research supports the idea that having a negative outlook when under stress can make you and your immune system miss out. A 1998 study at UCLA found that law students who began their first semester optimistic about the experience had more helper T cells midsemester, which can amplify the immune response, and more powerful natural killer cells. The reason? They experienced events such as their grueling first year as less stressful than did their more pessimistic classmates. Researchers say that this establishes the possibility that a person’s outlook and mood when stressed might affect responses to common immune challenges such as exposure to cold viruses.

More from Prevention: Optimism For Pessimists

6. Avoid Sedentary Lifestyles

One in four American women doesn’t exercise at all, making sedentary lifestyles even more common in women than in men. Sedentary ways have a tremendous impact on health. The benefits of exercise are so great that choosing not to exercise is like throwing away a winning lottery ticket. Millions of Americans suffer from illnesses that can be prevented or treated through exercise, including 50 million people with high blood pressure, 13.5 million with coronary heart disease, and 8 million with type 2 diabetes.

Studies show the dangers of a sedentary life. One study compared inactive people with those who walked briskly almost every day. Researchers found that those who didn’t walk took twice as many sick days in 4 months as those who walked.

Over time, you should work up to the standard recommendation of five times a week for at least 30 minutes. Experts say that it takes a half-hour of aerobic exercise to sweep white blood cells, key immune system components that are stuck on the blood vessel walls, back into circulation.

Moderate exercise is the key. If your exercise is too intense, it can actually suppress your immune system, which is why marathon runners often get colds after a race. What defines overexertion depends on your fitness level. Consult with your doctor to determine yours before starting an exercise program.

7. Avoid Social Isolation

The cost of social isolation may be higher than we think. Studies show that the fewer human connections we have at home, at work, and in the community, the more likely we are to get sick, flood our brains with anxiety-causing chemicals, and die prematurely.

One study in Sweden showed that those who frequented cultural events such as concerts, museum exhibits, and even ball games tended to live longer than their stay-at-home peers. The key factors could be increased social contact and reduced stress. Other studies have found that people who are isolated may live only half as long as those who have a lot of human contact. Love seems to be an immune system nutrient.

The good news is that these same studies also show that the more human connections we have, the more likely we are to live longer and healthier. Connectedness is the unacknowledged key to emotional and physical health. The more ties you have, the more likely you are to stay well in the first place. Researchers who monitored 276 people between the ages of 18 and 55 found that those who had six or more connections were four times better at fighting off the viruses that cause colds.

More from Prevention: How To Keep Your Friends Close

The Top 10 Immune Busters

Strengthen your immune system by kicking these defense-impairing habits

By Ellen Mazo and The Editors of Prevention Health Books

8. Junk the Junk Food

Combined with sedentary lives, a poor diet is estimated to kill between 310,000 and 580,000 Americans each year.

So, how bad is junk food for your immune system?

Experts have known for some time that when a person is malnourished, her immune system is weakened. When you restore the person to normal nutrition, her immune system improves, which is no surprise. But what they’re just learning is that when you continue to improve nutrition beyond mere adequacy, the immune system continues to improve, even in healthy people.

One thing that a lot of junk food has in common is excess fat. Fats, especially polyunsaturated fats, tend to suppress the immune system. Cut your total fat intake to no more than 25% of daily calories.

Another bad component of junk food is excess sugar. Sugar inhibits phagocytosis, the process by which viruses and bacteria are engulfed and then literally chewed up by white blood cells.

9. Arm Yourself Against Too Many Antibiotics

The cost of antibiotic resistance is high, both literally and from a health perspective. Literally, while it costs only $12,000 to treat a patient who has tuberculosis that responds to antibiotics, the cost soars to $180,000 for a patient with a multidrug-resistant strain.

From a health perspective, the cost of antibiotic resistance is an increase in the seriousness of disease. For example, treating a person with tuberculosis caused by a strain that is killed by antibiotics is highly effective. In contrast, between 40 and 60% of people who get antibiotic-resistant tuberculosis die.

The cost of misuse of antibiotics can be a weakened immune system. Researchers found that certain patients taking antibiotics had reduced levels of cytokines, the hormone messengers of the immune system. When your immune system is suppressed, you’re more likely to develop resistant bacteria or to become sick in the future.

Here are steps to take to use antibiotics properly:

Take antibiotics only for bacterial infections.
Take antibiotics the right way. If you are prescribed an antibiotic, it’s crucial that you take the entire course.
Don’t use antibiotics to try to prevent infection.
Don’t save or share antibiotics.
Avoid antibacterial hand soaps and lotions.
10. Use Laughter to Beat Stress

Researchers have found that the positive emotions associated with laughter decrease stress hormones and increase certain immune cells while activating others. In one study conducted at Loma Linda University School of Medicine in California, 10 healthy men who watched a funny video for an hour had significant increases in one particular hormone of the immune system that activates other components of the immune system.

So how can you add a little humor to your life? Simply find reasons to laugh. Rent a funny video; read a book of jokes. Have lunch with a friend known for her sense of humor. Lightening up can really light up your immune system.

 



 

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