How to Make Your Immune System Stronger
How to boost your immune system
What can you do?
On the whole, your immune system does a remarkable job of defending you against disease-causing microorganisms. But sometimes it fails: A germ invades successfully and makes you sick. Is it possible to intervene in this process and make your immune system stronger? What if you improve your diet? Take certain vitamins or herbal preparations? Make other lifestyle changes in the hope of producing a near-perfect immune response?
The idea of boosting your immunity is enticing, but the ability to do so has proved elusive for several reasons. The immune system is precisely that — a system, not a single entity. To function well, it requires balance and harmony. There is still much that researchers don’t know about the intricacies and interconnectedness of the immune response. For now, there are no scientifically proven direct links between lifestyle and enhanced immune function.
But that doesn’t mean the effects of lifestyle on the immune system aren’t intriguing and shouldn’t be studied. Quite a number of researchers are exploring the effects of diet, exercise, age, psychological stress, herbal supplements, and other factors on the immune response, both in animals and in humans. Although interesting results are emerging, thus far they can only be considered preliminary. That’s because researchers are still trying to understand how the immune system works and how to interpret measurements of immune function. The following sections summarize some of the most active areas of research into these topics. In the meantime, general healthy-living strategies are a good way to start giving your immune system the upper hand.
Immunity in action. A healthy immune system can defeat invading pathogens as shown above, where two bacteria that cause gonorrhea are no match for the large phagocyte, called a neutrophil, that engulfs and kills them (see arrows).
Photos courtesy of Michael N. Starnbach, Ph.D., Harvard Medical School
Adopt healthy-living strategies
Your first line of defense is to choose a healthy lifestyle. Following general good-health guidelines is the single best step you can take toward keeping your immune system strong and healthy. 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, vegetables, and whole grains, and low in saturated fat.
- Exercise regularly.
- Maintain a healthy weight.
- Control your blood pressure.
- 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.
- Get regular medical screening tests for people in your age group and risk category.
Many products on store shelves claim to boost or support immunity. But the concept of boosting immunity actually makes little sense scientifically. In fact, boosting the number of cells in your body — immune cells or others — is not necessarily a good thing. For example, athletes who engage in “blood doping” — pumping blood into their systems to boost their number of blood cells and enhance their performance — run the risk of strokes.
Attempting to boost the cells of the immune system is especially complicated because there are so many different kinds of cells in the immune system that respond to so many different microbes in so many ways. Which cells should you boost, and to what number? So far, scientists do not know the answer. What is known is that the body is continually generating immune cells. Certainly it produces many more lymphocytes than it can possibly use. The extra cells remove themselves through a natural process of cell death called apoptosis — some before they see any action, some after the battle is won. No one knows how many cells or what kinds of cells the immune system needs to function at its optimum level.
Scientists do know more about the low end of the scale. When the number of T cells in an HIV/AIDS patient drops below a certain level, the patient gets sick because the immune system doesn’t have enough T cells to fight off infection. So there is a bottom number below which the immune system can’t do its job. But how many T cells is comfortably enough, and beyond that point, is more better? We don’t know.
Many researchers are trying to explore the effects of a variety of factors — from foods and herbal supplements to exercise and stress — on immunity. Some take measures of certain blood components like lymphocytes or cytokines. But thus far, no one really knows what these measurements mean in terms of your body’s ability to fight disease. They provide a way of detecting whether something is going on, but science isn’t yet sufficiently advanced to understand how this translates into success in warding off disease.
A different scientific approach looks at the effect of certain lifestyle modifications on the incidence of disease. If a study shows significantly less disease, researchers consider whether the immune system is being strengthened in some way. Based on these studies, there is now evidence that even though we may not be able to prove a direct link between a certain lifestyle and an improved immune response, we can at least show that some links are likely.
Age and immunity
Earlier in this report (see “Cancer: Missed cues”), we noted that one active area of research is how the immune system functions as the body ages. Researchers believe that the aging process somehow leads to a reduction of immune response capability, which in turn contributes to more infections, more inflammatory diseases, and more cancer. As life expectancy in developed countries has increased, so too has the incidence of age-related conditions. Happily, investigation into the aging process can benefit us all — no matter what our age.
While some people age healthily, the conclusion of many studies is that, compared with younger people, the elderly are far more likely to contract infectious diseases. Respiratory infections, influenza, and particularly pneumonia are a leading cause of death in people over 65 worldwide. No one knows for sure why this happens, but some scientists observe that this increased risk correlates with a decrease in T cells, possibly from the thymus atrophying with age and producing fewer T cells to fight off infection. Thymus function declines beginning at age 1; whether this decrease in thymus function explains the drop in T cells or whether other changes play a role is not fully understood. Others are interested in whether the bone marrow becomes less efficient at producing the stem cells that give rise to the cells of the immune system.
Researchers at the University of Arkansas are looking at another aspect of why the immune system seems to weaken with age. They studied cell death in mice. They conducted an experiment to compare the lifespan of memory T lymphocytes in older mice with those of younger mice and found that the lymphocytes in older mice die sooner. This suggests that as the lymphocytes die off, the elderly immune system loses its memory for the microbes it is intended to fight and fails to recognize the microbes when they reappear. The body thus becomes less able to mount a vigorous immune response.
A reduction in immune response to infections has been demonstrated by older people’s response to vaccines. For example, studies of influenza vaccines have shown that for people over age 65, vaccine effectiveness was 23%, whereas for healthy children (over age 2), it was 38%. But despite the reduction in efficacy, vaccinations for influenza and S. pneumoniae have significantly lowered the rates of sickness and death in older people when compared with non vaccination.
Yet other researchers are looking at the connection between nutrition and immunity in the elderly. A form of malnutrition that is surprisingly common even in affluent countries is known as “micronutrient malnutrition.” Micronutrient malnutrition, in which a person is deficient in some essential vitamins and trace minerals that are obtained from or supplemented by diet, can be common in the elderly. Older people tend to eat less and often have less variety in their diets. One important question is whether dietary supplements may help older people maintain a healthier immune system. Older people should discuss this question with a physician who is well versed in geriatric nutrition, because while some dietary supplementation may be beneficial for older people, even small changes can have serious repercussions in this age group.
What about diet?
Like any fighting force, the immune system army marches on its stomach. Immune system warriors need good, regular nourishment. Scientists have long recognized that people who live in poverty and are malnourished are more vulnerable to infectious diseases. Whether the increased rate of disease is caused by malnutrition’s effect on the immune system, however, is not certain. There are still relatively few studies of the effects of nutrition on the immune system of humans, and even fewer studies that tie the effects of nutrition directly to the development (versus the treatment) of diseases.
There are studies of the effects of nutritional changes on the immune systems of animals, but again there are few studies that address the development of diseases in animals as a result of changes in immunity. For example, one group of investigators has found that in mice, diets deficient in protein reduce both the numbers and function of T cells and macrophages and also reduce the production of immunoglobulin A (IgA) antibody.
There is some evidence that various micronutrient deficiencies — for example, deficiencies of zinc, selenium, iron, copper, folic acid, and vitamins A, B6, C, and E — alter immune responses in animals, as measured in the test tube. However, the impact of these immune system changes on the health of animals is less clear, and the effect of similar deficiencies on the human immune response has yet to be assessed. But the research at this stage is promising, at least for some of the micronutrients.
So what can you do? If you suspect your diet is not providing you with all your micronutrient needs — maybe you don’t like vegetables or you choose white bread over whole grains — taking a daily multivitamin and mineral supplement brings health benefits of many types, beyond any possibly beneficial effects on the immune system. Taking megadoses of a single vitamin does not. More is not necessarily better. Researchers are investigating the immune boosting potential of a number of different nutrients.
Selenium. Some studies have suggested that people with low selenium levels are at greater risk of bladder, breast, colon, rectum, lung, and prostate cancers. A large-scale, multiyear study is currently in progress to look at the effects of combining selenium and vitamin E on prostate cancer prevention.
Vitamin A. Experts have long known that vitamin A plays a role in infection and maintaining mucosal surfaces by influencing certain subcategories of T cells and B cells and cytokines. Vitamin A deficiency is associated with impaired immunity and increased risk of infectious disease. On the other hand, according to one study, supplementation in the absence of a deficiency didn’t enhance or suppress T cell immunity in a group of healthy seniors.
Vitamin B2. There is some evidence that vitamin B2 enhances resistance to bacterial infections in mice, but what that means in terms of enhancing immune response is unclear.
Vitamin B6. Several studies have suggested that a vitamin B6 deficiency can depress aspects of the immune response, such as lymphocytes’ ability to mature and spin off into various types of T and B cells. Supplementing with moderate doses to address the deficiency restores immune function, but megadoses don’t produce additional benefits. And B6 may promote the growth of tumors.
Vitamin C. The jury is still out on vitamin C and the immune system. Many studies have looked at vitamin C in general; unfortunately, many of them were not well designed. Vitamin C may work in concert with other micronutrients rather than providing benefits alone.
Vitamin D. For many years doctors have known that people afflicted with tuberculosis responded well to sunlight. An explanation may now be at hand. Researchers have found that vitamin D, which is produced by the skin when exposed to sunlight, signals an antimicrobial response to the bacterium responsible for tuberculosis, Mycobacterium tuberculosis. Whether vitamin D has similar ability to fight off other diseases and whether taking vitamin D in supplement form is beneficial are questions that need to be resolved with further study.
Vitamin E. A study involving healthy subjects over age 65 has shown that increasing the daily dose of vitamin E from the recommended dietary allowance (RDA) of 30 mg to 200 mg increased antibody responses to hepatitis B and tetanus after vaccination. But these increased responses didn’t happen following administration of diphtheria and pneumococcal vaccines.
Zinc. Zinc is a trace element essential for cells of the immune system, and zinc deficiency affects the ability of T cells and other immune cells to function as they should. Caution: While it’s important to have sufficient zinc in your diet (15–25 mg per day), too much zinc can inhibit the function of the immune system.
Herbs and other supplements
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.
But that doesn’t mean we should discount the benefits of all herbal preparations. Everyone’s immune system is unique. Each person’s physiology responds to active substances differently. So if your grandmother says she’s been using an herbal preparation for years that protects her from illness, who’s to say that it doesn’t? The problem arises when scientists try to study such a preparation among large numbers of people. The fact that it works for one person won’t show up in the research data if it’s not doing the same for a larger group.
Scientists have looked at a number of herbs and vitamins in terms of their potential to influence the immune system in some way. Much of this research has focused on the elderly, children, or people with compromised immune systems, such as AIDS patients. And many of the studies have had design flaws, which means further studies are needed to confirm or disprove the results. Consequently, these findings should not be considered universally applicable.
Some of the supplements that have drawn attention from researchers are these:
Aloe vera. For now, there’s no evidence that aloe vera can modulate immune response. Because many different formulations and compounds have been used in studies, comparing the results is difficult. However, there is some evidence that topical aloe vera is helpful for minor burns, wounds, or frostbite, and also for skin inflammations when combined with hydrocortisone. Studies have found aloe vera is not the best option for treating breast tissue after radiation therapy.
Astragalus membranes. The astragalus product, which is derived from the root of the plant, is marketed as an immune-system stimulant, but the quality of the studies demonstrating the immune-stimulating properties of astragalus are poor. Furthermore, it may be dangerous.
Echinacea. An ocean of ink has been spilled extolling echinacea as an “immune stimulant,” usually in terms of its purported ability to prevent or limit the severity of colds. Most experts don’t recommend taking echinacea on a long-term basis to prevent colds. A group of physicians from Harvard Medical School notes that studies looking at the cold prevention capabilities of echinacea have not been well designed, and other claims regarding echinacea are as yet not proven. Echinacea can also cause potentially serious side effects. People with ragweed allergies are more likely to have a reaction to echinacea, and there have been cases of anaphylactic shock. Injected echinacea in particular has caused severe reactions. A well-designed study by pediatricians at the University of Washington in Seattle found echinacea didn’t help with the duration and severity of cold symptoms in a group of children. A large 2005 study of 437 volunteers also found that echinacea didn’t affect the rate of cold infections or the progress and severity of a cold.
Garlic. Garlic may have some infection-fighting capability. In laboratory tests, researchers have seen garlic work against bacteria, viruses, and fungi. Although this is promising, there haven’t been enough well-designed human studies conducted to know whether this translates into human benefits. One 2006 study that looked at rates for certain cancers and garlic and onion consumption in southern European populations found an association between the frequency of use of garlic and onions and a lower risk of some common cancers. Until more is known, however, it’s too early to recommend garlic as a way of treating or preventing infections or controlling cancer.
Ginseng. It’s not clear how the root of the ginseng plant works, but claims on behalf of Asian ginseng are many, including its ability to stimulate immune function. Despite the claims of a number of mainly small studies, the National Center for Complementary and Alternative Medicine (NCCAM) considers there have been insufficient large studies of a high enough quality to support the claims. NCCAM is currently supporting research to understand Asian ginseng more fully.
Glycyrrhiza glabra (licorice root). Licorice root is used in Chinese medicine to treat a variety of illnesses. Most studies of licorice root have been done in combination with other herbs, so it’s not possible to verify whether any effects were attributable to licorice root per se. Because of the potential side effects of taking licorice and how little is known about its benefits — if any — for stimulating immune function, this is an herb to avoid.
Probiotics. There are hundreds of different species of bacteria in your digestive tract, which do a bang-up job helping you digest your food. Now researchers, including some at Harvard Medical School, are finding evidence of a relationship between such “good” bacteria and the immune system. For instance, it is now known that certain bacteria in the gut influence the development of aspects of the immune system, such as correcting deficiencies and increasing the numbers of certain T cells. Precisely how the bacteria interact with the immune system components isn’t known. As more and more intriguing evidence comes in to support the link that intestinal bacteria bolster the immune system, it’s tempting to think that more good bacteria would be better. At least, this is what many marketers would like you to believe as they tout their probiotic products.
Probiotics are good bacteria, such as Lactobacillus and Bifidobacterium, that can safely dwell in your digestive tract. You’ll now find probiotics listed on the labels of dairy products, drinks, cereals, energy bars, and other foods. Ingredients touted as “prebiotics,” which claim to be nutrients that feed the good bacteria, are also cropping up in commercially marketed foods. Unfortunately, the direct connection between taking these products and improving immune function has not yet been made. Nor has science shown whether taking probiotics will replenish the good bacteria that get knocked out together with “bad” bacteria when you take antibiotics.
Another caution is that the quality of probiotic products is not consistent. Some contain what they say they do; some do not. In a 2006 report, the American Academy of Microbiology said that “at present, the quality of probiotics available to consumers in food products around the world is unreliable.” In the same vein, the FDA monitors food packages to make sure they don’t carry labels that claim the products can cure diseases unless the companies have scientific evidence to support the claims. Does this mean taking probiotics is useless? No. It means the jury is still out on the expansive health claims. In the meantime, if you choose to take a probiotic in moderation, it probably won’t hurt, and the scientific evidence may ultimately show some benefit.
The stress connection
Modern medicine, which once treated the connection between emotions and physical health with skepticism, 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. But although the relationship between stress and immune function is being studied by a number of different types of scientists, so far it is not a major area of research for immunologists.
Studying the relationship between stress and the immune system presents difficult challenges. 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 who repeat the same experiment many times with many different animals or human beings, and who get the same result most of the time, hope that they can draw reasonable conclusions.
Some researchers place animals into stressful situations, such as being trapped in a small space or being placed near an aggressive animal. Different functions of their immune systems, and their health, are then measured under such stressful conditions. On the basis of such experiments, some published studies have made the following claims:
- Experimentally created “stressful” situations delayed the production of antibodies in mice infected with influenza virus and suppressed the activity of T cells in animals inoculated with herpes simplex virus.
- Social stress can be even more damaging than physical stress. For example, some mice were put into a cage with a highly aggressive mouse two hours a day for six days and repeatedly threatened, but not injured, by the aggressive mouse — a “social stress.” Other mice were kept in tiny cages without food and water for long periods — a “physical stress.” Both groups of mice were exposed to a bacterial toxin, and the socially stressed animals were twice as likely to die.
- Isolation can also suppress immune function. Infant monkeys separated from their mothers, especially if they are caged alone rather than in groups, generate fewer lymphocytes in response to antigens and fewer antibodies in response to viruses.
- Many researchers report that stressful situations can reduce various aspects of the cellular immune response. A research team from Ohio State University that has long worked in this field suggests that psychological stress affects the immune system by disrupting communication between the nervous system, the endocrine (hormonal) system, and the immune system. These three systems “talk” to one another using natural chemical messages, and must work in close coordination to be effective. The Ohio State research team speculates that long-term stress releases a long-term trickle of stress hormones — mainly glucocorticoids. These hormones affect the thymus, where lymphocytes are produced, and inhibit the production of cytokines and interleukins, which stimulate and coordinate white blood cell activity. This team and others have reported the following results:
- Elderly people caring for relatives with Alzheimer’s disease have higher than average levels of cortisol, a hormone secreted by the adrenal glands and, perhaps because of the higher levels of cortisol, make fewer antibodies in response to influenza vaccine.
- Some measures of T cell activity have been found to be lower in depressed patients compared with nondepressed patients, and in men who are separated or divorced compared with men who are married.
- In a year-long study of people caring for husbands or wives with Alzheimer’s disease, changes in T cell function were greatest in those who had the fewest friends and least outside help.
- Four months after the passage of Hurricane Andrew in Florida, people in the most heavily damaged neighborhoods showed reduced activity in several immune system measurements. Similar results were found in a study of hospital employees after an earthquake in Los Angeles.
- In all of these studies, however, there was no proof that the immune system changes measured had any clear adverse effects on health in these individuals.
Does being cold make you sick?
Almost every mother has said it: “Wear a jacket or you’ll catch a cold!” Is she right? So far, researchers who are studying this question think that normal exposure to moderate cold doesn’t increase your susceptibility to infection. Most health experts agree that the reason winter is “cold and flu season” is not that people are cold, but that they spend more time indoors, in closer contact with other people who can pass on their germs.
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 dunked people in cold water and made others sit nude 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. They’ve found that exposure to cold does increase levels of some cytokines, the proteins and hormones that act as messengers in the immune system, but how this affects health isn’t clear.
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.
Exercise: Good or bad for 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 maintain a healthy immune system? Just like a healthy diet, exercise can contribute to general good health and therefore to a healthy immune system. It may contribute even more directly by promoting good circulation, which allows the cells and substances of the immune system to move through the body freely and do their job efficiently.
Some scientists are trying to take the next step to determine whether exercise directly affects a person’s susceptibility to infection. For example, some researchers are looking at whether extreme amounts of intensive exercise can cause athletes to get sick more often or somehow impairs their immune function. To do this sort of research, exercise scientists typically ask athletes to exercise intensively; the scientists test their blood and urine before and after the exercise to detect any changes in immune system components such as cytokines, white blood cells, and certain antibodies. While some changes have been recorded, immunologists do not yet know what these changes mean in terms of human immune response. No one yet knows, for example, whether an increase in cytokines is helpful or has any true effect on immune response. Similarly, no one knows whether a general increase in white cell count is a good thing or a bad thing.
But these subjects are elite athletes undergoing intense physical exertion. What about moderate exercise for average people? Does it help keep the immune system healthy? For now, even though a direct beneficial link hasn’t been established, it’s reasonable to consider moderate regular exercise to be a beneficial arrow in the quiver of healthy living, a potentially important means for keeping your immune system healthy along with the rest of your body.
One approach that could help researchers get more complete answers about whether lifestyle factors such as exercise help improve immunity takes advantage of the sequencing of the human genome. This opportunity for research based on updated biomedical technology can be employed to give a more complete answer to this and similar questions about the immune system. For example, microarrays or “gene chips” based on the human genome allow scientists to look simultaneously at how thousands of gene sequences are turned on or off in response to specific physiological conditions — for example, blood cells from athletes before and after exercise. Researchers hope to use these tools to analyze patterns in order to better understand how the many pathways involved act at once.
5 Natural Tips to Keep Your Immune System Strong During Fall and Winter
You know your immune system plays a role in warding off infectious disease, but you may not realize just how important an ally this system really is in protecting you from foreign invaders like bacteria, parasites, fungi, viruses and other pathogenic microbes.
If you’re one of the many thousands who get sick without fail every fall and winter, this article is for you. Because as you are probably aware, getting sick is NOT an inevitable part of the change in seasons. You surely know a handful of people who seemingly never get sick -- maybe they work in your office or even share your home. These people are able to avoid illness not because they aren’t exposed to germs, but because their immune system is able to keep them healthy.
You Don’t Get Sick Just Because You’re Exposed to Germs
There’s a common misconception that if you get the flu it’s because you were exposed to a flu virus, whereas if your officemate stays healthy it’s because he was not. But the truth is germs are literally everywhere, and while taking commonsense measures to avoid them, like washing your hands regularly, is smart, it’s naïve to think you can avoid them entirely.
But this isn’t really a big deal if you’re healthy, because your body is built to deal with these pathogen exposures and will keep you from getting sick as long as your immune system is strong.
In fact, new research in PLoS Genetics revealed that when 17 healthy people were exposed to a flu virus, only half of them got sick. All of them had an active immune response, but the responses yielded different outcomes, with some avoiding illness and others manifesting symptoms like sniffles, sneezing and fever. The researchers therefore concluded that your immune system’s response to the flu virus is an important factor in whether or not you get sick, likely an even more important one than virus exposure. They state:
“Exposure to influenza viruses is necessary, but not sufficient, for healthy human hosts to develop symptomatic illness. The host response is an important determinant of disease progression.”
Knowing this, what can you do to ramp up your immune system and get it into top working condition just in time for winter? Plenty!
1. Eat Antioxidant-Rich Foods
Eating an antioxidant-rich diet is one of the best ways to curb free radical damage in your body while also optimizing your immune system. Ideally, try to include a wide range of fruits and vegetables in your diet, as this will give you an equally wide range of antioxidants, which is important since each antioxidant has a slightly different impact on your immune health.
For example, glutathione, found in whey protein, asparagus, avocado and parsley, has been described as the "most important antioxidant" because it empowers your immune system to exert its full potential by quenching free radicals, recycling vitamins C and E into their biologically active forms and regulating DNA synthesis and repair.
Carotenoids in sweet potatoes, cantaloupe, peaches, pumpkin and other orange, red, yellow and dark green fruits and veggies are said to enhance many aspects of immune function, and selenium, found in Brazil nuts, tuna, beef, poultry, oats, brown rice, sunflower seeds and wheat germ, helps prevent cellular damage from free radicals and plays a role in your immune system health as well.
2. Check Your Vitamin D Levels
Vitamin D helps activate your immune system. In fact, research published last year revealed that when your body is exposed to a pathogen, your T cells (a type of white blood cell that is key to your immune system function) extend a vitamin D receptor to search for vitamin D. If you don’t have enough vitamin D, the T cell will not be able to activate and your immune system will not be able to take action appropriately.
Many Americans are vitamin D deficient, so it makes sense to get your levels tested to ensure you’re in a healthy range. Vitamin D can be obtained from safe sun exposure, fortified foods and/or supplementation.
A regular exercise program is about much more than weight loss and muscle strength. Physical activity, even just brisk walking, can enhance your antibody and natural T cell response. Research shows that people who exercise are about half as likely to catch a cold as those who do not, and even if they do catch a cold, their symptoms tend to be much less severe.
It’s a good idea to regard exercise like you do eating, breathing and sleeping -- as an essential, immovable part of your day. Schedule your day around your exercise, instead of vice versa, and you’ll enjoy better health -- and fewer sick days -- because of it.
4. Keep Stress in Check
Taking a stroll through a nature preserve, curling up in your favorite chair with a good book, having lunch with a dear friend … all of these are ways to help keep your immune system in top working order because they help you relieve stress.
Chronic stress impacts your body’s ability to fight infections in a number of ways, including altering the number of T cells that regulate an immune response and greatly reducing the effectiveness of your immune system. When you’re under stress, you’re also more likely to eat poorly, have trouble sleeping and resort to other unhealthy behaviors, like drinking excess alcohol, which can all further dampen your immune response. Cell-mediated immunity actually increases along with a person’s level of optimism, so it’s essential that you have a handful of tricks up your sleeve to pull out when you’re feeling anxious, overwhelmed, or worried -- and do so on a regular basis to keep chronic stress at a very low level (as opposed to waiting until you’re approaching burn-out levels). Yoga, journaling, prayer, knitting, woodworking -- you know better than anyone what makes you feel good, just be sure you give yourself permission to do those things on a regular, ideally daily, basis.
A lack of sleep will weaken your immune system, not only reducing T cells but also impacting levels of proteins called cytokines. Research shows that your risk rises significantly if you sleep for under seven hours a night, and the less you sleep, the more likely you are to weaken immune function.
The hormone melatonin is also secreted while you sleep, and since insufficient melatonin production is linked to decreased immune function, this is another route by which your sleeping habits influence your immune health. You should know that exposure to light at night will also interfere with your production of melatonin, so it’s important to keep your bedroom very dark, and also keep the light off if you wake up at night to use the bathroom.
If you’re having trouble sleeping, you can find 11 sleep tips here. In addition, some people find that supplements such as melatonin and valerian help them achieve a more restful night’s sleep.
If you implement the lifestyle changes above now, there’s a good chance your immune system will have no problem warding off invaders this fall and winter. Remember to keep these healthy habits up come spring and summer, though, as this will help you stay well throughout the entire year.
Say Goodbye to Sickness
If you're prone to sickness, consider taking larch regularly. A new study found that larch can help reduce the number of colds by 23%! You can purchase larch supplements at the pharmacy or health food store. Just be sure to look for the ingredient "larch resist-aid."
Cleanse Your Gut
Oregano oil can help you improve your gut health and boost your immune system. It acts kind of like a weed killer by helping to eliminate some of bad bacteria that may be dominating your digestive system.
When using oregano oil to cleanse your gut, spread out your doses and take 200 mg 3 times a day.
Kick a Cold
Whatever variety you choose – enoki, shitake or oyster – Japanese mushrooms are a great immunity booster. They are also loaded with ergothioneine, a powerful antioxidant, that does not get destroyed during the cooking process.
Relieve Your Liver
You need to support your liver to make sure it's able to detoxify as much as it can and provide a good environment for immune cells that live there.
Cruciferous vegetables such as kale, broccoli, lettuce and cabbage support your liver and immune function by boosting the liver's ability to flush out toxins.
Attend to Your Adrenals
Avocados! Adding these to your diet is an easy way to support adrenal function and health and keep your immune system happy. Avocados contain essential amino acids, antioxidants and some healthy fats to help balance hormone production.
To attend to your adrenals, try having 1 serving (1/2 cup) per day!
Clear Your Lungs
According to Ayurvedic traditions, ginger warms the body and helps to break down the accumulation of toxins in the organs, particularly in the lungs and sinuses. Ayurveda also believes that ginger helps to cleanse the lymphatic system, which is our body’s sewage system. By helping keep your airways and lymphatics open, ginger may help prevent the accumulation of the toxins that may increase your risk of infection.
Improve Your Vision
A fantastic supplement for promoting healthy vision, black currants contain compound anthocyanosides, which may be helpful for promoting night vision. They are also rich in vitamin C – they contain 5 times the amount in an orange – making them a powerful immunity booster!
A little oatmeal goes a long way for your health. This super food contains soluble fiber which reduces LDL, or "bad" cholesterol.
Get Healthier Skin
The juice in pomegranate seeds contain ellagic acid and punic alagin which fight damage from free radicals and help preserve the collagen in your skin. It's also a powerful source of phytonutrients that promote healthy skin.
Reduce Heart Attack Risk
Pumpkin seeds, which are rich in magnesium, may help lower blood pressure and reduce your risk for heart attacks or stroke.
Ease a Cough
Sage extract works as an expectorant, which helps your body move mucus out of your respiratory tract and helps to calm your cough. As a good alternative to an over-the-counter expectorant, try a drop of sage extract in tea or hot water.
Strengthen Your Hair
Containing iron, biotin and vitamin B12, eggs can help strengthen hair. The iron also helps combat anemia, a reduction of red blood cells that may also cause hair loss in women.
Immunity Booster and Cancer Fighter
As a natural immunity booster, graviola has been traditionally used to kill parasites, ameliorate liver problems, reduce fevers, and help treat colds and the flu. Scientists have studied graviola since the 1940s and most research has been centered around annonaceous acetogenins, a group of natural compounds that appear to have some anti-tumor properties – meaning they may help fight various types of cancer cells and thus help boost immune function.
Prevent Antibiotic Resistance
A diet lacking in nutrients and fresh vegetables causes your body to be deficient in phytochemicals. Add green veggies, mushrooms, onions seeds and berries to build a competent and functioning immune system.
Your lifestyle can affect how well your immune system can protect you from germs, viruses, and chronic illness.
Replacing bad health habits with good ones can help keep your immune system healthy. Check this list to see where you could use some improvement.
1. You're short on sleep.
You may have noticed you’re more likely to catch a cold or other infection when you’re not getting enough sleep. A lab experiment bears this out: When students at the University of Chicago were limited to only 4 hours of sleep a night for 6 nights and then given a flu vaccine, their immune systems made only half the normal number of antibodies.
Not getting enough sleep can lead to higher levels of a stress hormone. It may also lead to more inflammation in your body.
Although researchers aren’t exactly sure how sleep boosts the immune system, it’s clear that getting enough – usually 7 to 9 hours for an adult – is key for good health.
2. You don't exercise.
Try to get regular, moderate exercise, like a daily 30-minute walk. It can help your immune system fight infection.
If you don't exercise, you're more likely to get colds, for example, than someone who exercises. Exercise can also boost your body's feel-good chemicals and help you sleep better. Both of those are good for your immune system.
3. Your diet is off.
Eating or drinking too much sugar curbs immune system cells that attack bacteria. This effect lasts for at least a few hours after downing a couple of sugary drinks.
Eat more fruits and vegetables, which are rich in nutrients like vitamins C and E, plus beta-carotene and zinc. Go for a wide variety of brightly colored fruits and vegetables, including berries, citrus fruits, kiwi, apples, red grapes, kale, onions, spinach, sweet potatoes, and carrots.
Other foods particularly good for your immune system include fresh garlic, which may help fight viruses and bacteria, and old-fashioned chicken soup. If you do come down with a cold or the flu, a bowl of chicken soup can help you get well faster, one study shows.
Some mushroom varieties -- such as reishi, maitake, and shiitake -- may also help your immune system.
4. You're always stressed.
Everyone has some stress; it's part of life. If stress drags on for a long time, it makes you more vulnerable to illness, from colds to serious diseases.
Chronic stress exposes your body to a steady stream of stress hormones that suppress the immune system.
You may not be able to get rid of your stress, but you can get better at managing it.
- Learn to meditate.
- Slow down.
- Connect with other people.
- Work out to blow off steam.
Counseling is a big help, too.
Easing stress lowers levels of a stress hormone. It also helps you sleep better, which improves immune function.
People who meditate regularly may have healthier immune system responses, some studies show. In one experiment, people who meditated over an 8-week period made more antibodies to a flu vaccine than people who didn’t meditate. And they still showed an increased immune system response 4 months later.
5. You're too isolated.
Having strong relationships and a good social network is good for you.
People who feel connected to friends – whether it’s a few close friends or a large group – have stronger immunity than those who feel alone, studies show.
In one study, lonely freshmen had a weaker immune response to a flu vaccine than those who felt connected to others.
Although there are many other things that affect your health, making meaningful connections with people is always a good idea.
6. You've lost your sense of humor.
Laughing is good for you. It curbs the levels of stress hormones in your body and boosts a type of white blood cell that fights infection.
Just anticipating a funny event can have a positive effect on your immune system. In one study, men were told 3 days in advance that they were going to watch a funny video. Their levels of stress hormones dropped.