The Immune System
When making decisions about our health it is always best to have an understanding of how the body works. The immune system is complex and differs from others in that it is comprised of many organs, tissues, and cell types that exist throughout the entire body rather than in one localized area. There are three broad levels of immune system defense. First, barriers act to prevent foreign invaders from entering our system to begin with; skin and mucous membranes as well as stomach acid, enzymes, and bacteria within our intestinal tract provide our main physical barriers. Our second level of immune defense is the innate immunity, which provides general defense against any invader that makes it into the system. Specific types of white blood cells (neutrophils and macrophages) work here to engulf and destroy foreign invaders and damaged cells. The acquired immunity, which provides defense against recognized invader types, is the third level of immune defense. At this level white blood cells, called lymphocytes, produce antibodies to target and destroy infected cells.
The immune system continuously produces functioning cells on a daily basis for system maintenance but when an invader is encountered it ramps up this production. In order to produce the many cells needed to mount an effective immune response there is a requirement for energy and building block nutrients. Several specific micronutrients are essential to the proliferation and function of immune cells including vitamin D, folate, vitamin B6, vitamin B12, iron, and zinc.
In fighting infection immune cells produce a concentrated burst of reactive oxygen species (ROS), otherwise known as free radicals, which act to kill the foreign invaders. While free radicals are efficient in killing the unwanted ‘bugs’ in our system, they are also well known to cause damage to human cells. In fact, prolonged exposure to these ROS can lead to many diseases. In order to protect our own cells and tissues it is crucial that we keep this oxidative burst in check. Antioxidant nutrients are responsible for protecting our systems from the free radicals that are produced in immunity defense. Examples of some antioxidant nutrients include vitamin C, vitamin E, vitamin A, and zinc.
Inflammation is commonly referred to in a negative context; however, our immune system uses inflammation to isolate an infected area and appropriately deliver immune cells and antibodies to the site of infection or injury. However, inappropriate or prolonged activation of inflammation can lead to tissue damage and chronic disease. Omega-3 fatty acids function to decrease inflammation in the system and should be consumed regularly. Check out this article on anti-inflammatory eating for more information on inflammation and diet.
Diet and Immune Health
The most basic (but also the most important) strategy that we can adopt in supporting our immune system is to continue to eat nutrient dense foods.
Eating a balanced diet composed of high fiber carbohydrates, lean meats and proteins, healthy fats, and many fruits and vegetables will go a long way in supporting each and every cell in the body, the immune cells being no different.
In choosing whole foods to support nutrient needs we are assured we’re getting a wide variety of essential nutrients rather than just one specific nutrient- as is the case with supplementation. While a ‘food first’ approach is always best (in my humble opinion), if there is concern that certain vitamins or minerals are lacking from the diet, a high quality multivitamin-mineral can provide the extra support your immune system may need. Additionally, some specific nutrients may be beneficial at higher doses for immune boosting power. With a general understanding of immune system function we are better able to address what specific nutrients, foods, and supplements may be helpful in boosting the immune system.
Probiotics & Prebiotics
Because the gut offers our first line of defense against invaders it is very important to be supporting your gastrointestinal system when considering immunity. Feeding the micro-biome with consistent intake of probiotics is an excellent way to ensure immune health. Probiotics are live bacteria that live within us in symbiosis and promote health. Rather than supplementing, I recommend choosing fermented food regularly or on a daily basis; examples include kimchi, tofu, tempeh, sour kraut, kombucha, kefir, and yogurt. Perhaps even more important than probiotics are prebiotic foods, think of prebiotics as the food for our probiotic bacteria in the gut. Prebiotic foods include whole grains, legumes, and starchy or fibrous vegetables and fruits. Make sure that these foods comprise the majority of your diet.
Beyond food and multivitamin therapy, a couple of micronutrients deserve extra attention. Zinc, in particular, is important in supporting immune function through cell proliferation as well as through antioxidant action. Zinc supplementation has shown promise in reducing the duration of the common cold and may be a something to add when symptoms of illness initially appear. Foods high in zinc include oysters, meats, seeds, green vegetables and mushrooms. For an immune boost you may consider supplementing with zinc at higher levels as symptoms of illness initially arise and only through the duration of said illness.
Today most Americans are deficient in vitamin D. As could be predicted, if we’re deficient in a micronutrient its functions may be working at less than optimal levels- the same goes for vitamin D and immunity. I recommend a daily low dose vitamin D3 supplement (2,000IUs) be added to your routine to support adequate vitamin D levels. Spending 15-30 minutes in direct sunlight with arms and face exposed and sunscreen free can also support adequate vitamin D levels. For those who are deficient (based on a prescribed blood test) a higher dose (5,000-10,000IU) of vitamin D3 can be taken until that deficiency has been corrected. Vitamin D is found in fatty fish like sardine, salmon, and tuna as well as in fortified dairy products and some mushrooms.
Vitamin C is an antioxidant vitamin and contributes to immune defense by neutralizing free radicals and supporting cellular functions in both innate and adaptive immunity. Research on supplementing with vitamin C to fight illness is mixed, with most data indicates that it is only marginally beneficial in individuals who are not deficient. The general consensus seems to be that, if you want the benefits of vitamin C, you need to be eating it every day, not just at the onset of illness. Vitamin C rich foods include citrus, peppers, tomatoes, strawberries, and green vegetables. A mega-dose of vitamin C at the beginning of an illness may or may not be effective in decreasing illness duration but the good news is that it will not hurt- if this is your go to, continue that practice.
Echinacea is the name used for a group of flowering plants related to daisies. The herb has been used for centuries in treating a variety of ailments including the common cold or flu. While clinical research is not conclusive, some studies have found an ability of Echinacea to stimulate both innate and adaptive immunity, suggesting that the plant has immunological potential. Echinacea contains a variety of active compounds that have antioxidant and anti-inflammatory properties. Tablets, tinctures, extract, and teas made from Echinacea may offer a natural immune boost.
Elderberry is another plant that has been used for a long span of time in supporting immune function during illness. Elderberries are naturally high in antioxidants and vitamin C so, given what we know about immunity, it makes a lot of sense that this old remedy would have some merit. In fact, in studies elderberry extracts have shown to decrease the duration of sickness in individuals who become ill.
Garlic is famous for its use in cooking, however this plant has also been proclaimed to support health for many decades. In recent years, however, this claim has gained some scientific backing. Garlic produces a variety of compounds possessing interesting pharmacological properties. Notably, these compounds exhibit a broad spectrum of beneficial effects against microbial infections and provide anti-inflammatory activity. They also seem to regulate certain aspects of the immune system while directly stimulating immune cells. Garlic can be found in supplemental form or eaten raw; I recommend mincing it into tiny pieces and swallowing with water-not on an empty stomach.
Ginger is another plant that is used widely in cooking that can promote immune health. Ginger has antioxidant and anti-inflammatory properties. In large doses ginger has been shown to stimulate respiratory cells to secrete a specific anti-viral protein. Ginger may also inhibit the production of mucous and can thereby clear congestion in the respiratory tract. Interestingly ginger, when used in combination with garlic and lime, seems to provide antibacterial benefits against some bacteria types- this effect is not seen when these plants are used individually. Ginger can be found in supplements and teas or the root itself can be added to homemade juice (or even chewed).
Mushrooms have complex medicinal properties that vary from species to species and this bullet really deserves its own article (to come!). Despite their differences, most mushrooms are similar in that they boost the immune system. Mushrooms contain a high level of an active compound called Beta-glucan. This compound is able to bind to receptors in the immune system and have immunomodulation effects- meaning that the result may be either immune-stimulating or immune-suppressing depending on the needs of the system. You may find mushrooms in capsules, powders, and tinctures for supplementation. Species commonly found in immune specific formulas include (but are not limited to) maitake, shiitake, chaga, reishi, and turkey tail. I recommend supplementing with a high quality tincture or powder for health maintenance.
As with every single system in the body, hydration is key to immune health. The immune system relies on the blood supply to receive important nutrients as well as to send communicating molecules throughout the body. Our blood is almost entirely made up of water and requires our consistent intake of fluid. A complementary system to our immune defense is the lymphatic system. The lymphatic system can be thought of as the body’s sewage system, it is responsible for draining and removing waste from the body. The lymphatic does this by carrying the waste material in a fluid called lymph; when dehydrated this system cannot work as efficiently because there is less lymph fluid to be used as the exit vehicle for waste. The lymphatic system also acts to transport white blood cells throughout the body. This means that when we’re dehydrated there is less lymph, slower transportation of the illness fighting white blood cells, and slower exit of invaders. I recommend choosing calorie free beverages like water or unsweetened tea to best hydrate. Drink a full glass of water first thing in the morning and shoot for 11-15 8oz. cups today. Keep an eye on the color of your urine to ensure that you remain hydrated.
Other Important Factors for Immune Health
Aside form what we put into our body, there are a few additional considerations to make to best support your immune system. These include getting adequate sleep, reducing stress and/or participating in stress reduction practices-such as yoga or meditation, and continuing to be active as able.