Media is full of ‘expert’ advice on the best foods, super foods and super supplements to boost our immune system and keep ourselves safe from anything from flu to cancer. But, although each advice talks about ‘secret’ foods and ingredients, the truth is much simpler: according to the Academy of Nutrition and Dietetics, the secret to strong immune system is healthy, balanced nutrition and good hygiene.
What is immune system?
The immune system is, well, a system, which consists of organs, tissues, cells and chemicals which have the job of protecting our entire body and all bodily functions from agents causing diseases. To do that, immune system has to be capable of detecting all potential dangers, which we call pathogens, such as bacteria, viruses, fungus or parasites. Then, once the danger is detected, the immune system has to neutralize the danger.
It is not always easy distinguishing real attackers from those that are good for us, such as intestinal bacteria, or even from our own tissue. On top of that, pathogens change and adapt very fast, so the elements of our immune system have to be able to adapt fast too.
There are two types of protectors: immune system that is non-specific and non-adaptable and is always there (called innate) and adaptable immune system, which is specific to each pathogen. Skin is our first line of defense and it protects most of our body and organs. Many pathogens reach our internal organs from the skin, especially hands, which got in contact with pathogens. That is why washing hands is so important at times of epidemics, or even to keep healthy in general. We have other mechanical mechanisms of getting rid of attackers: sneezing keeps lungs clean, and tears clean our eyes of debris and pathogens.
But, at times, our mechanical line of defense fails and the pathogens enter the body. Then the other part of the immune system response takes over, on cellular level: our white blood cells or leukocytes.
Leukocytes are created in lymphoid organs such as spleen, the thymus and bone marrow. They circulate between our organs and lymph nodes, which store them, through blood vessels and lymphatic vessels, constantly on the lookout for pathogens.
Leukocytes can be phagocytes, chewing up invaders, and lymphocytes, cells which remember invaders they met before and know how to destroy them: they make antibodies for each specific pathogen.
How can we help our immune system?
Mostly, all elements of our immune system work together remarkably well to keep us protected from disease-causing pathogens. When they work in harmony, all is well and we are strongly protected. But, things go wrong, some germ invades our system and we get sick. How to prevent that from happening is a subject of a huge number of research studies. Whether we, with some lifestyle changes, can make a difference in this process is not conclusively proven. But, one thing is sure: strong, healthy body is more resistant to any disease than one that has any health issue. Staying strong and healthy is very much a matter of right nutrition and healthy lifestyle.
But, sometimes it is enough that our diet is missing some important nutrient or micronutrient in order to lower our immunity and get sick.
Selenium is a component of selenoprotein involved in all aspects of cell function and biochemistry. One study found the strong association between selenium deficiency and gastrointestinal and prostatic cancers. Selenium-rich foods are Brazil nuts, other nuts, mushrooms, meant, fish and eggs. Healthy people are almost never deficient in selenium.
Vitamin E: Studies show that even a very small deficiency in vitamin E negatively affects our immune response. Vitamin E maintains mucosal surfaces by affecting some types of T and B cells as well as cytokines. The most important sources of vitamin E are nuts, seeds, vegetable oils, green leafy vegetables and some fortified cereals.
Vitamin B6. Several studies show that a vitamin B6 deficiency strongly affects the immune response, to the extent that it impairs the ability of lymphocytes to mature and develop into T and B cells. The best natural sources of vitamin B6 are salmon, avocado, herring, sunflower seeds and walnuts.
Vitamin C. Although all of us grew up popping vitamin C to keep us from getting colds and flu, scientists do not agree on the role of vitamin C in our immune response. Some studies on animals show strong correlation, others are extremely positive. One study found that vitamin C supplements improve forms of our immune system response such as antimicrobial as well as natural killer cell function, lymphocyte proliferation , delayed-type hypersensitivity and chemotaxis. The sources of vitamin C are fruits, vegetables like peppers and leafy greens, and herbs like thyme and parsley.
Zinc is a trace element essential for the functioning of the immune system. Zinc deficiency affects the ability of T and other immune cells to function. Sources of zinc are oysters, some types of mushrooms, calf’s liver, spinach, venison and other red meats.
Herbal supplements are very popular immunity boosting aids. Health food stores and drugstores are full of supplements claiming to keep us from getting flu, cancer, infections and just about anything else. While different people have different experience with various herbs, there are very few well done studies on the way herbal supplements support immunity response. Herbs such as aloe vera, ginseng, garlic and Echinacea have been used in different cultures for millennia to cure different health issues and boost our natural resistance. The lack of sufficient scientific support does not mean that they are not useful, but suggests that we should be careful.
People who lead healthy lifestyle and eat balanced nutrition are almost never suffering from nutrients, vitamins or mineral deficiencies. The more diverse our nutrition is, the better our chances are of having all we need to keep our immune system functioning well without the need for supplements.
Other aspects of healthy lifestyle work together with balanced nutrition:
- No smoking
- Regular exercise
- Healthy weight.
- Blood pressure