Diet and immune function. Accessed May 13, Western diet and the immune system: an inflammatory connection. Physical Activity Guidelines for Americans , 2nd edition [PDF Washington, DC: US Department of Health and Human Services; J Sport Health Sci.

Exercise, immunity, and illness. In: Zoladz JA, ed. Muscle and Exercise Physiology. Academic Press. T lymphopaenia in relation to body mass index and TNF—alpha in human obesity: adequate weight reduction can be corrective.

Clin Endocrinol Oxf. Changes in nutritional status impact immune cell metabolism and function. Front Immunol. Increased risk of influenza among vaccinated adults who are obese.

Int J Obes Lond. Obesity as a predictor of poor antibody response to hepatitis B plasma vaccine. Hepatitis B vaccine immunoresponsiveness in adolescents: a revaccination proposal after primary vaccination.

Comparison of a triple antigen and a single antigen recombinant vaccine for adult hepatitis B vaccination. J Med Virol. Reduced tetanus antibody titers in overweight children.

Swindt, Christina [corrected to Schwindt, Christina]]. Sleep and health: Everywhere and in both directions. Arch Intern Med. Skip directly to site content Skip directly to search. Español Other Languages. Six Tips to Enhance Immunity Español Spanish. Minus Related Pages.

Food Assistance. Reduced Risk of Death. For More Information Healthy habits to protect against flu. MyPlate Plan. Physical activity basics. Healthy eating for a healthy weight. Tips to get more sleep.

Support for quitting smoking Preventing excess alcohol use. References 1 Childs CE, Calder PC, Miles EA. Connect with Nutrition, Physical Activity, and Obesity. fb icon twitter icon youtube icon alert icon. Last Reviewed: September 5, Source: Division of Nutrition, Physical Activity, and Obesity , National Center for Chronic Disease Prevention and Health Promotion.

Facebook Twitter LinkedIn Syndicate. So, what can you do? If you suspect your diet is not providing you with all your micronutrient needs — maybe, for instance, you don't like vegetables — taking a daily multivitamin and mineral supplement may bring other health benefits, beyond any possibly beneficial effects on the immune system.

Taking megadoses of a single vitamin does not. More is not necessarily better. Walk into a store, and you will find bottles of pills and herbal preparations that claim to "support immunity" or otherwise boost the health of your immune system.

Although some preparations have been found to alter some components of immune function, thus far there is no evidence that they actually bolster immunity to the point where you are better protected against infection and disease. Demonstrating whether an herb — or any substance, for that matter — can enhance immunity is, as yet, a highly complicated matter.

Scientists don't know, for example, whether an herb that seems to raise the levels of antibodies in the blood is actually doing anything beneficial for overall immunity.

Modern medicine has come to appreciate the closely linked relationship of mind and body. A wide variety of maladies, including stomach upset, hives, and even heart disease, are linked to the effects of emotional stress. Despite the challenges, scientists are actively studying the relationship between stress and immune function.

For one thing, stress is difficult to define. What may appear to be a stressful situation for one person is not for another. When people are exposed to situations they regard as stressful, it is difficult for them to measure how much stress they feel, and difficult for the scientist to know if a person's subjective impression of the amount of stress is accurate.

The scientist can only measure things that may reflect stress, such as the number of times the heart beats each minute, but such measures also may reflect other factors. Most scientists studying the relationship of stress and immune function, however, do not study a sudden, short-lived stressor; rather, they try to study more constant and frequent stressors known as chronic stress, such as that caused by relationships with family, friends, and co-workers, or sustained challenges to perform well at one's work.

Some scientists are investigating whether ongoing stress takes a toll on the immune system. But it is hard to perform what scientists call "controlled experiments" in human beings.

In a controlled experiment, the scientist can change one and only one factor, such as the amount of a particular chemical, and then measure the effect of that change on some other measurable phenomenon, such as the amount of antibodies produced by a particular type of immune system cell when it is exposed to the chemical.

In a living animal, and especially in a human being, that kind of control is just not possible, since there are so many other things happening to the animal or person at the time that measurements are being taken. Despite these inevitable difficulties in measuring the relationship of stress to immunity, scientists are making progress.

Almost every mother has said it: "Wear a jacket or you'll catch a cold! Probably not, exposure to moderate cold temperatures doesn't increase your susceptibility to infection. There are two reasons why winter is "cold and flu season. Also the influenza virus stays airborne longer when air is cold and less humid.

But researchers remain interested in this question in different populations. Some experiments with mice suggest that cold exposure might reduce the ability to cope with infection. But what about humans? Scientists have performed experiments in which volunteers were briefly dunked in cold water or spent short periods of time naked in subfreezing temperatures.

They've studied people who lived in Antarctica and those on expeditions in the Canadian Rockies. The results have been mixed. For example, researchers documented an increase in upper respiratory infections in competitive cross-country skiers who exercise vigorously in the cold, but whether these infections are due to the cold or other factors — such as the intense exercise or the dryness of the air — is not known.

A group of Canadian researchers that has reviewed hundreds of medical studies on the subject and conducted some of its own research concludes that there's no need to worry about moderate cold exposure — it has no detrimental effect on the human immune system. Should you bundle up when it's cold outside?

The answer is "yes" if you're uncomfortable, or if you're going to be outdoors for an extended period where such problems as frostbite and hypothermia are a risk. But don't worry about immunity. Regular exercise is one of the pillars of healthy living.

It improves cardiovascular health, lowers blood pressure, helps control body weight, and protects against a variety of diseases. But does it help to boost your immune system naturally and keep it healthy? Just like a healthy diet, exercise can contribute to general good health and therefore to a healthy immune system.

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February 15, Helpful ways to strengthen your immune system and fight off disease How can you improve your immune system? What can you do to boost your immune system? Photos courtesy of Michael N. Starnbach, Ph. Every part of your body, including your immune system, functions better when protected from environmental assaults and bolstered by healthy-living strategies such as these: Don't smoke.

Eat a diet high in fruits and vegetables. Exercise regularly. Maintain a healthy weight. If you drink alcohol, drink only in moderation. Get adequate sleep. Take steps to avoid infection , such as washing your hands frequently and cooking meats thoroughly. Try to minimize stress. Keep current with all recommended vaccines.

Vaccines prime your immune system to fight off infections before they take hold in your body. Increase immunity the healthy way Many products on store shelves claim to boost or support immunity.

These barriers include:. Adaptive or acquired immunity is a system that learns to recognize a pathogen. It is regulated by cells and organs in our body like the spleen, thymus, bone marrow, and lymph nodes.

When a foreign substance enters the body, these cells and organs create antibodies and lead to multiplication of immune cells including different types of white blood cells that are specific to that harmful substance and attack and destroy it.

Our immune system then adapts by remembering the foreign substance so that if it enters again, these antibodies and cells are even more efficient and quick to destroy it. Antigens are substances that the body labels as foreign and harmful, which triggers immune cell activity.

Allergens are one type of antigen and include grass pollen, dust, food components, or pet hair. Antigens can cause a hyper-reactive response in which too many white cells are released. For example, an allergy to mold triggers symptoms of wheezing and coughing in a sensitive individual but does not trigger a reaction in other people.

When pathogens attack healthy cells and tissue, a type of immune cell called mast cells counterattack and release proteins called histamines, which cause inflammation. Inflammation may generate pain, swelling, and a release of fluids to help flush out the pathogens.

The histamines also send signals to discharge even more white blood cells to fight pathogens. However, prolonged inflammation can lead to tissue damage and may overwhelm the immune system. Autoimmune disorders like lupus, rheumatoid arthritis, or type 1 diabetes are partly hereditary and cause hypersensitivity in which immune cells attack and destroy healthy cells.

Immunodeficiency disorders can depress or completely disable the immune system, and may be genetic or acquired. Acquired forms are more common and include AIDS and cancers like leukemia and multiple myeloma.

Eating enough nutrients as part of a varied diet is required for the health and function of all cells, including immune cells.

Certain dietary patterns may better prepare the body for microbial attacks and excess inflammation, but it is unlikely that individual foods offer special protection. Examples of nutrients that have been identified as critical for the growth and function of immune cells include vitamin C, vitamin D, zinc, selenium, iron, and protein including the amino acid glutamine.

Diets that are limited in variety and lower in nutrients, such as consisting primarily of ultra-processed foods and lacking in minimally processed foods, can negatively affect a healthy immune system.

It is also believed that a Western diet high in refined sugar and red meat and low in fruits and vegetables can promote disturbances in healthy intestinal microorganisms, resulting in chronic inflammation of the gut, and associated suppressed immunity.

The microbiome is an internal metropolis of trillions of microorganisms or microbes that live in our bodies, mostly in the intestines. It is an area of intense and active research, as scientists are finding that the microbiome plays a key role in immune function.

The gut is a major site of immune activity and the production of antimicrobial proteins. A high-fiber plant-rich diet with plenty of fruits, vegetables, whole grains, and legumes appear to support the growth and maintenance of beneficial microbes.

Certain helpful microbes break down fibers into short chain fatty acids, which have been shown to stimulate immune cell activity.

These fibers are sometimes called prebiotics because they feed microbes. Therefore, a diet containing probiotic and prebiotic foods may be beneficial. Probiotic foods contain live helpful bacteria, and prebiotic foods contain fiber and oligosaccharides that feed and maintain healthy colonies of those bacteria.

Animal studies have found that deficiencies in zinc , selenium , iron , copper, folic acid , and vitamins A , B6 , C , D , and E can alter immune responses. Epidemiological studies find that those who are poorly nourished are at greater risk of bacterial, viral, and other infections.

Eating a good quality diet, as depicted by the Healthy Eating Plate, can prevent deficiencies in these nutrients. However, there are certain populations and situations in which one cannot always eat a variety of nutritious foods, or who have increased nutrient needs.

In these cases a vitamin and mineral supplement may help to fill nutritional gaps. Studies have shown that vitamin supplementation can improve immune responses in these groups. The elderly are a particularly high-risk group. The immune response generally declines with increasing age as the number and quality of immune cells decreases.

This causes a higher risk of poorer outcomes if the elderly develop chronic or acute diseases. In addition, about one-third of elderly in industrialized countries have nutrient deficiencies. Diet variety may also be limited due to budget constraints or lower interest in cooking for one person; poor dentition; mental impairment; or lack of transportation and community resources to obtain healthy food.

Megadose supplements many times the RDA do not appear justified, and can sometimes be harmful or even suppress the immune system e.

Remember that vitamin supplements should not be considered a substitute for a good diet because no supplements contain all the benefits of healthful foods. Several herbal supplements have been suggested to boost immune function.

What does the research say? Diet Review: Anti-Inflammatory Diet. Food Safety, Nutrition, and Wellness during COVID Ask the Expert: The role of diet and nutritional supplements during COVID The contents of this website are for educational purposes and are not intended to offer personal medical advice.

You should seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. The Nutrition Source does not recommend or endorse any products.

Skip to content The Nutrition Source. The Nutrition Source Menu. Search for:. Home Nutrition News What Should I Eat? What Is Our Immune System? These barriers include: Skin that keeps out the majority of pathogens Mucus that traps pathogens Stomach acid that destroys pathogens Enzymes in our sweat and tears that help create anti-bacterial compounds Immune system cells that attack all foreign cells entering the body Adaptive or acquired immunity is a system that learns to recognize a pathogen.

Other conditions that trigger an immune response Antigens are substances that the body labels as foreign and harmful, which triggers immune cell activity.

What factors can depress our immune system? Feeding your body certain foods may help keep your immune system strong. Plan your meals to include these 15 powerful immune system boosters.

No supplement will cure or prevent disease, and no supplement or diet can protect you from COVID Currently, no research supports the use of any supplement to protect against COVID specifically. Vitamin C is thought to increase the production of white blood cells , which are key to fighting infections.

Most citrus fruits are high in vitamin C. The recommended daily amount for most adults is:. Ounce for ounce, red bell peppers contain almost 3 times as much vitamin C mg as a Florida orange 45 mg. Besides boosting your immune system, vitamin C may help you maintain healthy skin.

Beta-carotene, which your body converts into vitamin A , helps keep your eyes and skin healthy. Broccoli is supercharged with vitamins and minerals. Packed with vitamins A, C, and E, as well as fiber and many other antioxidants , broccoli is one of the healthiest vegetables you can put on your plate.

The key to keeping its power intact is to cook it as little as possible — or better yet, not at all. Research has shown that steaming or microwaving are the best ways to keep more nutrients in the food. Garlic adds flavor to food and has long been used for medicinal purposes. Early civilizations recognized its value in fighting infections.

Garlic may also slow down hardening of the arteries, and people use it to treat high blood pressure. Ginger is another ingredient many turn to after getting sick. Ginger may help decrease inflammation, which can help reduce a sore throat and inflammatory illnesses. It may also help with nausea.

Ginger may also decrease chronic pain and might even possess cholesterol-lowering properties. Similar to broccoli, spinach is healthiest when cooked as little as possible so that it retains its nutrients. However, light cooking makes it easier to absorb the vitamin A and allows other nutrients to be released from oxalic acid , an antinutrient.

Check out some spinach recipes here. These cultures may stimulate your immune system to help fight diseases. Try to get plain yogurts rather than the kind that are flavored and loaded with sugar.

You can sweeten plain yogurt yourself with healthy fruits and a drizzle of honey instead. Yogurt can also be a great source of vitamin D , so try to select brands fortified with this vitamin. Clinical trials are even in the works to study its possible effects on COVID Research so far suggests that vitamin D deficiency may increase the risk for COVID19 and the severity of disease progression in people with the infection.

Experts therefore believe supplementation may protect people with a vitamin D deficiency. However, there is no evidence that vitamin D can treat a COVID19 infection.

When it comes to preventing and fighting off colds, vitamin E tends to take a backseat to vitamin C. However, this powerful antioxidant is key to a healthy immune system. Nuts, such as almonds , are packed with the vitamin and also have healthy fats.

Adults only need about 15 mg of vitamin E each day. Sunflower seeds are full of nutrients, including phosphorous , magnesium , and vitamins B6 and E. Vitamin E is important in regulating and maintaining immune system function. Other foods with high amounts of vitamin E include avocados and dark leafy greens.

Sunflower seeds are also high in selenium. Just 1 ounce contains nearly half the selenium that the average adult needs daily. A variety of studies , mostly performed on animals, have looked at its potential to combat viral infections such as swine flu H1N1.

You may know turmeric as a key ingredient in many curries. This bright yellow, bitter spice has also been used for years as an anti-inflammatory in treating both osteoarthritis and rheumatoid arthritis.

Research shows that high concentrations of curcumin , which gives turmeric its distinctive color, can help decrease exercise-induced muscle damage. Curcumin has promise as an immune booster based on findings from animal studies with antimicrobial properties. More research is needed.

Both green and black teas are packed with flavonoids , a type of antioxidant. Where green tea really excels is in its levels of epigallocatechin gallate EGCG , another powerful antioxidant.

Research has suggested that EGCG may have antiviral properties that support the immune system. The fermentation process black tea goes through destroys a lot of the EGCG.

Green tea, on the other hand, is steamed and not fermented, so the EGCG is preserved. Papayas also have a digestive enzyme called papain that has anti-inflammatory effects.

Papayas have decent amounts of potassium , magnesium, and folate , all of which are beneficial to your overall health. Like papayas, kiwis are a rich source of essential nutrients, including folate, potassium, vitamin K , and vitamin C.

The soup may help lower inflammation, which could improve symptoms of a cold. Poultry, such as chicken and turkey, is high in vitamin B6. About 3 ounces of light turkey or chicken meat contains nearly one-third of your daily recommended amount of B6.

Vitamin B6 is an important player in many of the chemical reactions that happen in the body. Stock or broth made by boiling chicken bones contains gelatin , chondroitin, and other nutrients helpful for gut healing and immunity.