The immune system is the body’s defence against infections. It is made of a complex network of cells and proteins that protects the body against infections. The immune system fights various germs – bacteria, viruses, protozoa and fungi. The immune system keeps records of every pathogen (germ) it has ‘overpowered’ so that when that same infection comes again another time, it can easily identify it and destroy it quickly. Studies at Stanford University have shown that the immune system is also able to keep a memory of pathogens it has not even encountered yet.
There are a variety of factors that influence the proper function of the immune system. Some of these factors are how much sleep you get, stress level, personal hygiene, lifestyle and diet. The food you eat and the nutrients in these foods have an effect on the strength of your immune system.
It is important to note that presently, no expert health organization has endorsed any food, nutrient, supplement or food claim that prevents a person from being infected by COVID-19 by boosting the immune system. Nonetheless, making the right food choice should be a habit that is not dictated entirely by circumstances. Here, in this article, are immune-boosting nutrients and the foods that provide them as well as some foods that have shown some antiviral activity in laboratory tests.
The joint effect of various nutrients has a strong influence on the ability of the immune system to fight against infections.Making poor food choices will most likely result in a weak immune system, which then leaves you exposed to various infections. To paint a simplified picture, this can be likened to an army that goes to battle with clubs and stones to fight an enemy that has the latest weaponry. The army with the clubs and stones will most certainly lose the battle. Hence, making intelligent food choices should be a regular habit, equipping your immune system with all the nutrients needed to protect you against infections, even infections caused by those germs the immune system has not been exposed to before.
1. Vitamin A
In the early twentieth century, vitamin A was referred to as the anti-infective vitamin when scientists observed that its deficiency increased the severity of infections. Research has shown that organs and tissues that form part of the immune system need constant supply of vitamin A to maintain the amounts of vitamin A needed for them to perform their function well. Further, studies have found that carotenoids (vitamin A from plant sources) aid in the production of proteins (immunoglobulins). These immunoglobulins neutralize toxic substances, halt the activity of certain microorganisms and neutralize the activity of viruses. Foods that supply adequate amounts of carotenoids/vitamin A include dark leafy green leaves like spinach, ademe and cocoyam leaves (kontomire), maize, carrots, pawpaw (papaya), mango, orange and tangerine.
2. Vitamin C
Vitamin C, popularly known to be obtained from citrus fruits, plays a crucial role in boosting the immune system. Vitamin C contributes to the immune system by accumulating in white blood cells, enhancing their potency and enabling them to kill microorganisms. Studies conducted in New Zealand found that vitamin C deficiency results in impaired immunity, making you more prone to infections. Findings from another study in Switzerland revealed that the quantity of vitamin C in the blood rapidly reduces during infections and stress, and intake of vitamin C was observed to improve the immune system’s ability to defend the body against infections. Some of the rich sources of vitamin C are bell peppers (red, green, yellow, orange), pineapple, orange, lemon, tangerine, guava, cauliflower, pawpaw (papaya), strawberries, kiwi fruit, African star fruit (alasa) and black velvet tamarind (yooyi).
3. Vitamin D
A 2019 review of studies involving over 11,000 people indicated that vitamin D intake reduces the risk of respiratory infections (infections in the respiratory system, which may cause coughing or impair your breathing). Some scientific findings point out that vitamin D is able to do this by improving the response of the immune system to pathogens, enabling it to better fight against the infections. Food sources of vitamin D include mackerel, salmon, tuna, cheese, egg yolk, beef liver and herrings.
4. Vitamin E
Similar to vitamin C, vitamin E is a potent antioxidant. Also, it has the ability to control the function of the immune system. Multiple studies indicate that vitamin E plays an important role in boosting the immune system. Different experiments involving people of different age groups show that intake of vitamin E has a direct positive effect on the immune system. Some of the studies found that people who were prone to having pneumonia and common cold had a reduced chance of infection following a regular intake of vitamin E. Vitamin E can be obtained from foods like coconut, palm fruit, groundnuts, soybeans, maize, sunflower, almonds, shrimps, avocado, mango, snails, octopus, and green leafy vegetables.
Zinc is a mineral that is naturally present in both plant- and animal-source foods. It is involved in various activities of cells (the basic units of living organisms). Zinc is involved in the formation of protein in the body to repair worn out cells and tissue, it helps wounds to heal and promotes the proper function of the immune system. In the immune system, zinc works together with vitamin C to enhance the immune system’s ability to defend the body against infections. Zinc reduces the risk, severity, and duration of infectious diseases (diseases caused by bacteria, viruses or other pathogens and can be easily spread from one person to another like common cold, COVID-19, hantavirus pulmonary syndrome, etc.). Dietary sources of zinc include eggs, milk and milk products, beans, groundnuts, crab, lobster, oysters, beef, breakfast cereals, chicken, whole grains and others. Daily intake of zinc is necessary to maintain normal levels because the body does not have any specialized storage system for zinc.
In some studies, some foods and herbs have shown antiviral properties. The potent natural components these foods have enable them to inactivate some viruses. Curcumin, an extract from turmeric, has been found to inhibit many viruses. Further, tea and tea products, due to their epigallocatechin gallate contents, have been observed to have an antiviral effect on several viruses including coronavirus, adenovirus, influenza virus, rotavirus and herpes simplex virus. Though there is limited validated evidence to support antiviral foods, the list of such foods includes hibiscus tea (sobolo or zobo), basil, garlic, rosemary, ginger, ginseng, dandelion, sage, oregano and fennel.
These nutrient, vitamins A, C, D and E and zinc, are only the main nutrients known to boost the immune system. The body needs all other nutrients in addition to these to ensure optimum immune function. Other foods such as mushrooms and green tea have also been found to affect the immune system positively and protect the body against viruses and infections.
Wash your hands regularly, sanitize your hands and practice social distancing to help in the fight against COVID-19. Share this post with friends and family, and feel free to leave a comment below.
PS: The term “Corona” is of a Latin root, meaning crown. In these times when the Coronavirus, COVID-19, is affecting all aspects of our civilization, who are you going to crown in your life? I recommend Jesus – we need Him now more than ever. Seek Him and He will keep you safe.