Your body’s immune system fights off foreign invaders — bacteria, viruses and fungi — that cause infection. Even if you do get sick, a healthy immune system helps you recover faster. The immune system includes these interconnected parts:
— Innate immune system. This is the part you’re born with, which immediately responds to invaders using white blood cells.
— Adaptive immune system. Also called the acquired immune system, it develops antibodies after a first exposure from a disease-causing invader. Antibodies can then recognize and defend against future exposures.
— Bone marrow. This spongy tissue within bones contains stem cells, some of which mature into infection-fighting white blood cells.
— Lymphatic system. Lymph fluid, vessels and lymph nodes help clear away infections.
— Spleen. This abdominal organ can detect and produce cells to defend against unwanted invaders.
— Skin. Your skin acts as an all-over, first-line barrier against germs and other invaders. In addition, dendritic cells help trigger the body’s immune response to viruses, bacteria and fungi.
Organs such as your heart, lungs and brain also play a supporting role by keeping you — and therefore your immune system — healthy.
Healthy habits and a strong immune system work together to help keep you disease- and infection-free. Experts offer tips for shoring up your immune system with these approaches:
— Stress reduction.
— Sleep sufficiency.
— Avoiding infection.
— Social connection.
Keeping up with recommended immunizations — such as flu shots and shingles vaccines — provides a powerful assist to your immune system. Ask your doctor about the HPV vaccine or any vaccines you’ll need before you travel.
“Vaccinations impart immunity by exposing our bodies to small dose of the microbe — virus or bacteria — which leads to production of the antibodies against that microbe,” says Dr. Yufang Lin, an integrative medicine physician at Cleveland Clinic. “When we are exposed to the same microbe in real life, our bodies can produce antibodies to fight it off quickly, thus avoiding a full-blown illness,” she says. “Vaccinations thus increase the body’s ability to fight off infection.”
Your body’s response to stress can affect your immune system both directly and indirectly, says Lindsay Jernigan, a licensed clinical psychologist in private practice in Vermont.
“When we are under stress, our bodies release a cascade of hormones that are designed to help us survive the stressful moment, particularly adrenaline, cortisol and glucosamine,” she says. “This is a healthy and adaptive response,” explains Jernigan, who is also a writer for Psychology Today. However, excess levels of these fight-or-flight hormones build up and increase systemic inflammation and decrease the body’s white blood cell response.
Chronic stress increases depression and anxiety, which in turn further promote inflammation and the release of corticosteroids, Jernigan says. “To add salt to the wound, emotional distress also impacts our health-related choices,” she says, which indirectly affects the immune system.
For instance, Jernigan notes that while under stress, you may be more prone to engage in unhealthy coping mechanisms such as substance abuse, social isolation and physical stagnation.
According to the Holmes-Rahe Stress Life Stress Inventory, a well-known scale created by two psychiatrists, these are the top five stress-inducing events:
— Death of a spouse.
— Marital separation.
— Detention in jail or other institution.
— Death of a close family member.
Marriage, job loss and pregnancy are also major life stressors.
In general, consuming a well-balanced diet with at least five daily servings of fruits and vegetables will help promote a healthy immune system, says Tiana Carey, a registered dietitian with UC Davis Health in Sacramento, California.
In particular, Carey recommends foods rich in the following nutrients for their healthful effects:
— Vitamin A (beta carotene). Assists with the health of your intestines and respiratory system. Vitamin A-rich foods include carrots, sweet potato, spinach, broccoli and red bell peppers.
— Vitamin C. Helps stimulate antibody formation. Vitamin C-rich foods include citrus fruits, strawberries, red bell pepper and kiwi.
— Vitamin E. Promotes the neutralization of free radicals by working as an antioxidant. Vitamin E-rich foods include vegetable oils, nuts, seeds and avocado.
— Zinc. “There are many zinc-dependent enzymes in our body and deficiency has been linked with immune dysfunction,” Carey says. Zinc-rich foods include beans, seeds, nuts, meat, poultry and seafood.
— Protein. Specific amino acids found in protein are essential for T-cell functions. Protein-rich foods include meats, poultry, seafood, eggs, beans, nuts and seeds.
“These nutrients have been shown to help your immune system work most efficiently and effectively, but too much of a good thing can be harmful,” Carey says. “Eat these nutrients in moderation and don’t go overboard — if you eat too many carrots, you may just turn orange.”
Tweak your diet as needed. “Diets high in highly processed food, sugar, trans fat and salt have been associated with an increased risk of inflammation and chronic illness,” says Lin, who points to familiar spices with helpful antimicrobial properties such as ginger, garlic, rosemary, thyme, oregano, sage, peppermint and lemon balm.
Staying hydrated helps your immune system stay healthy. “Water comprises 70% of our body weight and is involved in most of the metabolic process in the body, including energy generation and detoxification,” Lin says. “When we don’t drink enough water, these processes can become sluggish and function poorly.”
[See: The Best Plant-Based Diets.]
“Exercise is our superpower when it comes to stress management,” Jernigan says. Any form of physical movement can be helpful, including:
Getting the right amount of exercise can bolster your immune system by strengthening physical health, increasing flexibility and coordination and improving mental health, Lin explains. Just don’t overdo it.
“Excessive exercise — beyond one’s ability in duration or intensity — can suppress and weaken immunity,” Lin says. “Proper exercise has been shown to improve the immune system; however, strenuous exercise outside of one’s comfort zone can weaken (it).”
Adequate sleep at the right time is critical for a healthy immune system, Lin emphasizes. “At night, our bodies rest, recover and regenerate,” she says. “Chronic sleep deprivation is associated with increased risk of diabetes, heart disease, anxiety, depression and chronic pain via increased chronic inflammation and a suppressed immune system.”
Sleep timing is important, Lin adds. “Our body functions based on circadian rhythm, which is a natural, internal biology clock that regulates the sleep-wake cycle, hormone regulation, digestion and immune response.”
Unhealthy Habits to Lose
Some habits can sabotage your immune system. Changing behaviors like these will also improve your overall health:
— Eating a lot of processed, sugary or junk foods.
— Sitting too much (being sedentary).
— Staying indoors continually.
— Substance abuse.
— Social isolation.
Overreliance on over-the-counter supplements also can be unhealthy. Although many over-the-counter supplements claim to have positive effects in combating illness, be aware that not all claims are regulated or true, Carey advises.
When contagious illness is rampant, whether it’s the COVID-19 pandemic or flu season, take extra precautions to stave off infectious organisms (and protect others around you). Avoid sick people when possible.
“In general, when a person is infected with a viral illness, such as a cold, they are most likely to be infectious to others in the first few days of illness, as their body is in the early phases of mounting an immune response to fight off infection,” Lin says.
— Use barriers like face masks. If contaminated air is filtered through a mask, infection risk is much lower, Lin says.
— Keep up with hand hygiene. Consistent hand-washing and hand sanitizing clearly help.
— Seek fresh air. “Risk is also lower in a well-ventilated, outdoor environment,” Lin says.
— Disinfect frequently touched surfaces at home and work. “Another way the microbe can be transmitted is through shared working space,” Lin cautions. “As someone coughs or sneezes into their hand and then touches a tabletop, that tabletop now has the virus or the bacteria.”
— Brush your teeth regularly. Avoiding oral infections is important.
— Follow respiratory etiquette. Cough into your sleeve or a tissue — not into the air or your hand.
— Maintain physical distance. Respect distancing guidelines during disease outbreaks.
Shower or bathe at night instead of — or in addition to — morning bathing or showering, Lin suggests. “As we move about during the day, we pick up dirt and germs, dusts, pollens and other allergens, which can cling to our clothes, skin and hair,” she says. “We spend one-third of our life in bed. Without washing these off, we may have prolonged exposure to these particles while we sleep and an increased risk of developing illness or allergic symptoms, which can increase risk of sinus infections.”
Tend to Your Emotional Well-Being
Make the body-mind connection and take positive steps to further support your immune system:
— Stay connected with family and friends. “Studies show resiliency is in part dependent on social connections with others,” Lin says. “Isolation and loneliness have been connected with increased risk of chronic diseases.”
— Have a purpose in life. A sense of purpose is critical for emotional well-being, Lin says.
— Have fun. “Our emotions are intimately connected to our physical health,” Lin notes. “Having fun brings about happiness, recharges our emotional batteries and supports a healthy immune system.”
— Be grateful. Gratitude for what you have is another positive emotion that reduces stress and supports emotional well-being.
— Help others. “Altruism boosts emotional wellness, thereby boosting physical wellness,” Jernigan says. “Helping others releases feel-good hormones that counter the effects of stress hormones.”
— Spend time outdoors. “Right-size your stressors by spending time outdoors,” Jernigan advises. “Mother Nature is a master at stress reduction.”
Don’t wait until you get sick to get started. “Promoting a healthy immune system at baseline is key,” Carey says. “Unfortunately, most research shows that there is not much you can do once you are already sick, but having a healthy immune system can help prevent becoming sick in the first place.”
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