1. Get enough sleep
Sleep and immunity are closely tied.
In fact, inadequate or poor quality sleep is linked to a higher susceptibility to sickness.
In a study in 164 healthy adults, those who slept fewer than 6 hours each night were more likely to catch a cold than those who slept 6 hours or more each night (1Trusted Source).
Getting adequate rest may strengthen your natural immunity. Also, you may sleep more when sick to allow your immune system to better fight the illness (2Trusted Source).
Adults should aim to get 7 or more hours of sleep each night, while teens need 8–10 hours and younger children and infants up to 14 hours (3Trusted Source).
If you’re having trouble sleeping, try limiting screen time for an hour before bed, as the blue light emitted from your phone, TV, and computer may disrupt your circadian rhythm, or your body’s natural wake-sleep cycle (4Trusted Source).
Other sleep hygiene tips include sleeping in a completely dark room or using a sleep mask, going to bed at the same time every night, and exercising regularly (3Trusted Source).
SUMMARY Inadequate sleep may increase your risk of getting sick. Most adults should get at least 7 hours of sleep per night.
2. Eat more whole plant foods
Whole plant foods like fruits, vegetables, nuts, seeds, and legumes are rich in nutrients and antioxidants that may give you an upper hand against harmful pathogens.
The antioxidants in these foods help decrease inflammation by combatting unstable compounds called free radicals, which can cause inflammation when they build up in your body in high levels (5Trusted Source).
Chronic inflammation is linked to numerous health conditions, including heart disease, Alzheimer’s, and certain cancers.
Meanwhile, the fiber in plant foods feeds your gut microbiome, or the community of healthy bacteria in your gut. A robust gut microbiome can improve your immunity and help keep harmful pathogens from entering your body via your digestive tract (6Trusted Source).
Furthermore, fruits and vegetables are rich in nutrients like vitamin C, which may reduce the duration of the common cold (7Trusted Source).
SUMMARY Several whole plant foods contain antioxidants, fiber, and vitamin C, all of which may lower your susceptibility to illness.
3. Eat more healthy fats
Healthy fats, like those found in olive oil and salmon, may boost your body’s immune response to pathogens by decreasing inflammation.
Although low-level inflammation is a normal response to stress or injury, chronic inflammation can suppress your immune system (8Trusted Source).
Olive oil, which is highly anti-inflammatory, is linked to a decreased risk of chronic diseases like heart disease and type 2 diabetes. Plus, its anti-inflammatory properties may help your body fight off harmful disease-causing bacteria and viruses (9Trusted Source, 10Trusted Source).
Omega-3 fatty acids, such as those in salmon and chia seeds, fight inflammation as well (11Trusted Source).
SUMMARY Healthy fats like olive oil and omega-3s are highly anti-inflammatory. Since chronic inflammation can suppress your immune system, these fats may naturally combat illnesses.
4. Eat more fermented foods or take a probiotic supplement
Fermented foods are rich in beneficial bacteria called probiotics, which populate your digestive tract (12Trusted Source).
These foods include yogurt, sauerkraut, kimchi, kefir, and natto.
Research suggests that a flourishing network of gut bacteria can help your immune cells differentiate between normal, healthy cells and harmful invader organisms (13Trusted Source).
In a 3-month study in 126 children, those who drank just 2.4 ounces (70 mL) of fermented milk daily had about 20% fewer childhood infectious diseases, compared with a control group (14Trusted Source).
If you don’t regularly eat fermented foods, probiotic supplements are another option.
In a 28-day study in 152 people infected with rhinovirus, those who supplemented with probiotic Bifidobacterium animalis had a stronger immune response and lower levels of the virus in their nasal mucus than a control group (15Trusted Source).
SUMMARY Gut health and immunity are deeply interconnected. Fermented foods and probiotics may bolster your immune system by helping it identify and target harmful pathogens.
5. Limit added sugars
Emerging research suggests that added sugars and refined carbs may contribute disproportionately to overweight and obesity (16Trusted Source, 17Trusted Source).
Obesity may likewise increase your risk of getting sick.
According to an observational study in around 1,000 people, people with obesity who were administered the flu vaccine were twice as likely to still get the flu than individuals without obesity who received the vaccine (18Trusted Source).
Curbing your sugar intake can decrease inflammation and aid weight loss, thus reducing your risk of chronic health conditions like type 2 diabetes and heart disease (19Trusted Source, 20Trusted Source).
Given that obesity, type 2 diabetes, and heart disease can all weaken your immune system, limiting added sugars is an important part of an immune-boosting diet (18Trusted Source, 21Trusted Source, 22Trusted Source).
You should strive to limit your sugar intake to less than 5% of your daily calories. This equals about 2 tablespoons (25 grams) of sugar for someone on a 2,000-calorie diet.
SUMMARY Added sugars contribute significantly to obesity, type 2 diabetes, and heart disease, all of which can suppress your immune system. Lowering your sugar intake may decrease inflammation and your risk of these conditions.
6. Engage in moderate exercise
Although prolonged intense exercise can suppress your immune system, moderate exercise can give it a boost.
Studies indicate that even a single session of moderate exercise can boost the effectiveness of vaccines in people with compromised immune systems (23Trusted Source).
What’s more, regular, moderate exercise may reduce inflammation and help your immune cells regenerate regularly (23Trusted Source).
Examples of moderate exercise include brisk walking, steady bicycling, jogging, swimming, and light hiking. Most people should aim for at least 150 minutes of moderate exercise per week (24).
SUMMARY Moderate exercise can reduce inflammation and promote the healthy turnover of immune cells. Jogging, biking, walking, swimming, and hiking are great options.
7. Stay hydrated
Hydration doesn’t necessarily protect you from germs and viruses, but preventing dehydration is important to your overall health.
Dehydration can cause headaches and hinder your physical performance, focus, mood, digestion, and heart and kidney function. These complications can increase your susceptibility to illness (25Trusted Source).
To prevent dehydration, you should drink enough fluid daily to make your urine pale yellow. Water is recommended because it’s free of calories, additives, and sugar (25Trusted Source).
While tea and juice are also hydrating, it’s best to limit your intake of fruit juice and sweetened tea because of their high sugar contents (26Trusted Source, 27Trusted Source).
As a general guideline, you should drink when you’re thirsty and stop when you’re no longer thirsty. You may need more fluids if you exercise intensely, work outside, or live in a hot climate (28Trusted Source).
It’s important to note that older adults begin to lose the urge to drink, as their bodies do not signal thirst adequately. Older adults need to drink regularly even if they do not feel thirsty.
SUMMARY Given that dehydration can make you more susceptible to illness, be sure you’re drinking plenty of water each day.
8. Manage your stress levels
Relieving stress and anxiety is key to immune health.
Long-term stress promotes inflammation, as well as imbalances in immune cell function (7Trusted Source, 9Trusted Source).
In particular, prolonged psychological stress can suppress the immune response in children (29Trusted Source).
Activities that may help you manage your stress include meditation, exercise, journaling, yoga, and other mindfulness practices. You may also benefit from seeing a licensed counselor or therapist, whether virtually or in person.
SUMMARY Lowering your stress levels through meditation, yoga, exercise, and other practices can help keep your immune system functioning properly.
9. Supplement wisely
It’s easy to turn to supplements if you hear claims about their ability to treat or prevent COVID-19.
However, these assertions are unfounded and untrue.
According to the National Institutes of Health (NIH), there’s no evidence to support the use of any supplement to prevent or treat COVID-19 (30Trusted Source).
However, some studies indicate that the following supplements may strengthen your body’s general immune response:
- Vitamin C. According to a review in over 11,000 people, taking 1,000–2,000 mg of vitamin C per day reduced the duration of colds by 8% in adults and 14% in children. Yet, supplementing did not prevent the cold to begin with (7Trusted Source).
- Vitamin D. Vitamin D deficiency may increase your chances of getting sick, so supplementing may counteract this effect. Nonetheless, taking vitamin D when you already have adequate levels doesn’t seem to provide extra benefits (31Trusted Source).
- Zinc. In a review in 575 people with the common cold, supplementing with more than 75 mg of zinc per day reduced the duration of the cold by 33% (32Trusted Source).
- Elderberry. One small review found that elderberry could reduce the symptoms of viral upper respiratory infections, but more research is needed (33Trusted Source).
- Echinacea. A study in over 700 people found that those who took echinacea recovered from colds slightly more quickly than those who received a placebo or no treatment, but the difference was insignificant (34Trusted Source).
- Garlic. A high quality, 12-week study in 146 people found that supplementing with garlic reduced the incidence of the common cold by about 30%. However, more research is needed (35Trusted Source).
While these supplements demonstrated potential in the studies mentioned above, that doesn’t mean they’re effective against COVID-19.
Furthermore, supplements are prone to mislabeling because they aren’t regulated by the Food and Drug Administration (FDA).
Thus, you should only purchase supplements that have been independently tested by third-party organizations like United States Pharmacopeia (USP), NSF International, and ConsumerLab.
SUMMARY Though some supplements may fight viral infections, none have been proven to be effective against COVID-19. If you decide to supplement, make sure to purchase products that have been tested by a third party.
The bottom line
You can make several lifestyle and dietary changes today to strengthen your immune system.
These include reducing your sugar intake, staying hydrated, working out regularly, getting adequate sleep, and managing your stress levels.
Although none of these suggestions can prevent COVID-19, they may reinforce your body’s defenses against harmful pathogens.