Immunity refers to the ability of your immune system to fight against various infections and prevent illnesses. If you’ve noticed that you’re often sick, feel fatigued, or have other nagging symptoms, it may mean that your immune system is weakened.

Your immune system is a wide network of cells and tissues that are always on the lookout for invaders (foreign substances such as microbes that include bacteria, viruses, or parasites) and are ready to attack (launch an immune response) when they find one. 

The primary organs of the immune system include the bone marrow and the thymus. 

  • The bone marrow produces your new blood cells (including the one that provides immunity).

  • The thymus produces the hormone ‘thymosin’, which in turn aids in the production of immunity cells (primarily T-cells and B-cells).

Basic Functioning of Your Immune System

When your white blood cells (WBCs), also called leukocytes, find a target, they multiply and send signals to other cells to do so. There are two main types of leukocytes - Phagocytes and Lymphocytes.

The phagocytes absorb pathogens and break them down, effectively eating them. The lymphocytes help the body to remember previous invaders (targets) and recognize them if they come back to attack again, by releasing antibodies. The B-lymphocytes produce antibodies and the T- lymphocytes destroy compromised cells in the body.

Thus, when your body is attacked by the same invader again, your immune system generates the same immune response that it did the first time when your body was attacked.

While bolstering your immunity is easier said than done, several dietary and lifestyle changes may strengthen your body’s natural defenses and help you fight harmful pathogens or disease-causing organisms.

9 Tips to Strengthen Your Immunity Naturally

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. Sleep is considered an important modulator of the immune response. Your immune system releases proteins called cytokines (proteins secreted by specific immune cells) when you are asleep, which helps regulate innate immune responses. 

It is important for adults to sleep for 7 - 8 hours each night, while teenagers need 9 - 10 hours, younger children need about 12 hours and infants need up to 16 hours of sleep every night.

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.

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.

2. Eat more whole plant foods. Plant foods like fruits, vegetables, nuts, seeds, and legumes are rich in 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 at high levels. 

The fiber in plant foods feeds your gut microbiome or the community of healthy bacteria in your gut (a group of organs that includes the mouth, esophagus, stomach, pancreas, liver, gallbladder, small intestine, colon, and rectum). A robust gut microbiome can improve your immunity and help keep harmful pathogens from entering your body through your digestive tract. 

Remember that whole plant foods have essential nutrients that you cannot get from other foods. The vitamins and minerals, and phytochemicals in these foods help keep your immune system cells functioning at their best.

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, and injury, chronic inflammation can suppress your immune system.

Olive oil, which is highly anti-inflammatory, is linked to a decreased risk of chronic diseases like heart diseases and type 2 diabetes [presence of excess glucose (sugar) in your blood)]; and may help your body fight off harmful disease-causing bacteria and viruses. It is advisable to look for extra-virgin olive oil, the first press of the olives with the highest concentration of antioxidants.

Fatty acids are known to play diverse roles in the functioning of your immune cells. Fatty acids such as omega-3 fatty acids, found in salmon and chia seeds, can fight inflammation as well. 

4. Eat more fermented foods or take a probiotic supplement. Fermented foods are rich in beneficial bacteria called probiotics, which populate your digestive tract. Fermentation in food processing is the process of converting carbohydrates to alcohol or organic acids using microorganisms—yeasts or bacteria—under anaerobic conditions. 

Fermented foods include:

  • Yogurt
  • Sauerkraut (finely cut raw cabbage that has been fermented by various lactic acid bacteria)
  • Kimchi (a Korean dish which is a combination of vegetables, garlic, ginger, chili peppers, salt, and fish sauce)
  • Kefir (fermented drink, traditionally made using cow's milk or goat's milk), and 
  • Natto (a traditional Japanese dish consisting of fermented soybeans). 

Research suggests that a flourishing network of gut bacteria can help your immune cells differentiate between normal, healthy cells and harmful invader organisms.

If you don’t regularly eat fermented foods, probiotic supplements are another option. Several probiotic supplements in the form of tablets or capsules are available in the market. Consult your doctor before starting these supplements.  

5. Limit added sugars. When there is a spike in your sugar intake, your immune system is compromised, and you are more likely to get sick. 

Curbing your sugar intake can decrease inflammation and aid weight loss, thus reducing your risk of chronic health conditions like obesity (a disorder involving excessive body fat), type 2 diabetes, and heart disease.

Given that obesity, type 2 diabetes, and heart disease can weaken your immune system, limiting added sugars is an important part of an immune-boosting diet.

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. Instead of sugary juices and drinks, eat more natural fruits, vegetables, and yogurt to satisfy your sweet cravings.

6. Engage in moderate exercise regularly. Prolonged intense exercise can suppress your immune system; moderate exercise can give it a boost. Regular, moderate exercise may reduce inflammation and help your immune cells regenerate regularly.

Examples of moderate exercise include brisk walking, steady bicycling, jogging, swimming, and light hiking. You should aim for at least 150 minutes of moderate exercise per week.

7. Stay hydrated. Hydration doesn’t necessarily protect you from germs and viruses, but preventing dehydration is important to your overall health. Increasing your fluid intake can help flush out toxins, ward off illness and help us reset your system.

Dehydration (a condition on which there is an excess loss of fluids from your body) can cause headaches and hinder your physical performance, focus, mood, digestion, and heart and kidney function. These complications can increase your susceptibility to illness.

To prevent dehydration, you should drink enough fluids daily. Water is recommended because it’s free of calories, additives, and sugar.

While tea and juice are also hydrating, it's best to limit your intake of fruit juices and sweetened tea because of their high sugar content.

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. It is recommended to drink a minimum of 2 liters of water per day. 

Note that older adults begin to lose the urge to drink, as their bodies do not signal thirst adequately. Older adults need to drink water regularly even if they do not feel thirsty.

8. Manage your stress levels. Relieving stress and anxiety is key to stronger immune health. If stress drags on for a long time, it makes you more vulnerable to illness, from colds to serious diseases. 

Long-term stress or chronic stress promotes inflammation, as well as imbalances in your immune cell function. In particular, prolonged psychological stress can suppress the immune response in children.

Activities that may help you manage your stress include meditation, exercise, journaling (writing or drawing your thoughts in a book), yoga, and other mindfulness (being completely aware of your present) practices. 

You may also benefit from seeing a licensed counselor or therapist in case of chronic stress which is leading to depression or anxiety, whether virtually or in person.

9. Eat supplements wisely. It’s easy to turn to supplements if you hear claims about their ability to treat or prevent infections. However, these assertions are unfounded and untrue.

However, some studies indicate that the following supplements may strengthen your body’s general immune response:

  • Vitamin C. Vitamin C, also known as ascorbic acid, is necessary for the growth, development, and repair of all your body tissues. It's involved in many body functions, including the proper functioning of your immune system. Vitamin C supplements can help prevent colds, keep your eyes and skin healthy and boost your overall immunity.

  • Vitamin D. Vitamin D is responsible for the intestinal absorption of other minerals like calcium, magnesium, and phosphate.  It keeps your bones and teeth healthy and is necessary for the proper functioning of your immune system. You can take a Vitamin D supplement of about 20 micrograms a day or 500 micrograms once a month.

  • Zinc. Zinc is needed for your body's immune system to properly work. It plays a role in cell division, cell growth, wound healing, and the breakdown of carbohydrates. Zinc supplements stimulate particular immune cells and it is recommended to take no more than 40mg a day. 

  • Garlic. Garlic’s antibacterial and antiviral properties resist or destroy viruses and other microorganisms. Garlic supplements contain antioxidants that can boost your immune system. You can consume dried garlic powder in your milk or add it while cooking. In the case of garlic pills or supplements, check with your doctor about the recommended daily dose. 

Take supplements only after consulting your general physician.

The key takeaway is that several lifestyles and dietary changes can strengthen your immune system. Eat healthily, sleep well and stay stress-free to keep illness and infections away. 

If you fall sick too frequently, consult your doctor to understand ways to boost your immune system.

Disclaimer: This article is written by the Practitioner for informational and educational purposes only. The content presented on this page should not be considered as a substitute for medical expertise. Please "DO NOT SELF-MEDICATE" and seek professional help regarding any health conditions or concerns. Practo will not be responsible for any act or omission arising from the interpretation of the content present on this page.