We need to build a strong immune system to stay healthy. We can build immunity from vitamins and minerals through variety of foods and sunlight. The COVID-19 has put the spotlight on the role of nutrition in boosting or strengthening the immune system.
The immune system is made up of different organs, cells, and chemicals that fight infection (microbes), and protects your body from outside invaders, like bacteria, virus, fungi, and toxins. To build a strong immune system include the following foods in your diet, keeping in mind that it is better to avoid supplements.
- Vitamin C– Leafy green vegetables such as spinach and kale, bell peppers, sprouts, broccoli, papaya, citrus fruits like orange, grapes, lemons, etc.
- Vitamin E– Spinach & broccoli, peanuts, hazelnuts, sunflower seeds, etc.
- Vitamin A– Carrots, sweet potatoes, pumpkin, and squash, contains carotenoids which are converted into vitamin A by the body. They contain antioxidants which fight free radicals, cell damage, and inflammation, and vitamin C which strengthens the immune system.
- Vitamin D– Known as the sunshine vitamin, vitamin D is produced by the body when the skin is exposed to sunlight. It occurs naturally in foods such as fatty fish, fish liver oils, egg yolks, canned tuna, fortified milks, fortified cereal, and some mushrooms.
- Folic acid– Peas, beans, leafy green vegetables and in some fortified foods.
- Iron– Dried fruits, raspberries, asparagus, dark leafy vegetables, chicken liver, etc.
- Selenium– Garlic, broccoli, sardines, tuna, beef, poultry and grain products.
- Zinc– Oysters, crab, poultry, baked beans (w/o sugar), yoghurt and chickpeas.
- Omega-3 fatty acids– Walnuts, flax seeds, fatty fish, etc.
All these are needed to build a healthy immune system, but here, we highlight two critical nutrients that are vital to boost immunity – vitamin D and Omega-3 fatty acids.
Vitamin D – When exposed to sunlight, the body makes vitamin D from cholesterol. We need vitamin D to absorb calcium and phosphate, the two minerals in our diet that are essential for maintaining strong and healthy bones.
A recent teamusa.org report noted that 28.9% of U.S adults are Vitamin D deficient and another 41.1% are Vitamin D insufficient. This means that approximately two-thirds of U.S population have low levels of Vitamin D. Deficiency or insufficiency of vitamin remains extremely common due to the changes in lifestyle – most indoor workers get too little of sunshine and most people use sunscreen when they go out. Using sunscreen will protect you from skin cancer, but it can block the UV rays needed for vitamin D synthesis.
Your immune system needs Vitamin D to function properly and its deficiency make you more prone to infection and disease. That’s why it’s important to focus on foods that are good sources of vitamin D daily, including fatty fish, fish liver oils, egg yolks, canned tuna, fortified milks, fortified cereal, and some mushrooms. As Vitamin D is oil soluble and needs fat to get absorbed properly, make sure you eat some fat too.
Vitamin D promotes immune response, it has both anti-inflammatory and immunoregulatory properties and is significant for the activation of immune system defences. According to a study mentioned in a healthline.com article, vitamin D supplements decreased the risk of at least one acute respiratory infection (ARI) by 12% in both those who were deficient in vitamin D and those with adequate levels. The review found that vitamin D supplements are more effective against ARI when taken daily or weekly in small doses than when taken in larger, widely spaced doses.
Omega-3 fatty acids
Omega-3 fatty acids help boost the immune system by enhancing the functioning of immune cells. It not only prevents disease by reducing inflammation, but also enhances the activity of white blood cells. They are essential fatty acids, means the body cannot make them from other fats. The only way to get a sufficient amount of omega-3 is to consume foods high in omega-3 fats.
The main types of omega-3 fats are:
- EPA & DHA from fish and algae (which enhance the function of B immune cells)
- ALA- mainly from plants
Benefits of Omega-3 fatty acids:
- Reduced cardiovascular disease
- Fight inflammation (decrease CRP, IL-6 and TNF-α levels which are all markers of inflammation)
- Fight autoimmune disease
- Fight depression and anxiety
- Improve eye health
- Reduce symptoms of metabolic syndrome
- Improved immune system
According to the teamusa.org report, in the last 60 years, the standard American diet has shifted from being fairly balanced in Omega-3 (anti-inflammatory) and omega-6 (pro-inflammatory), to being very high in Omega-6 and very low in Omega-3 fatty acids. The immune function can suffer and the inflammatory markers can become elevated when this ratio is skewed. Aim to minimize the consumption of omega-6 rich foods such as corn, sunflower, cottonseed and soybean oils, which are also found in many processed/packaged products. Focus on consuming Omega-3 rich foods such as:
- Fatty fish
- Pastured eggs
- Hempseeds etc
Omega-3 is vital for optimal health. If you don’t eat fatty fish, talk to your physician about taking an Omega-3 supplement.
Keep in mind that a proper medication for COVID-19 is not yet available. The only way to reduce risks of this infection is to maintain social distancing and follow the recommended hand-washing advice, and boost your immune system by eating the right foods. Experts also recommend wearing a mask when outside,