Hippocrates, the Greek founder of Western medicine, is famously quoted as stating 2,383 years ago “let food be thy medicine, and let medicine be thy food.” Somewhere along the way, Western medicine has lost its emphasis on the importance of food as an integral part of good health, and an integral part of good medicine.
From an evolutionary perspective, human physiology has not changed much since then, and the same principles still apply to our health as they did back then. A French author named Anthelme Brillat-Savarin in his book Physiologie du Gout, written 194 years ago, echoed the sentiments of Hippocrates.
He coined the popular phrase “You are what you eat” and “tell me what you eat, and I will tell you what you are.” To save on overall healthcare costs, an emphasis should be placed, once again, on the prevention of disease through public promotion of a healthy whole foods diet by the government in the form of economic incentives.
Evidence for this approach comes from a 2019 study in which foods like fruits, vegetables, whole grains, nuts, seeds, seafood and plant oils where incentivized financially for Medicare and Medicaid recipients.
It was found that there could be substantial health gains and that these incentives could be highly cost-effective if implemented on measures like prevention of cardiovascular disease and diabetes, health-related costs such as formal and informal health care costs, and lost productivity (Lee, Mozaffarian, Sy, Huang, Liu, et al., 2019).
It is estimated that 30 to 47 billion dollars in annual health-related costs could be saved simply by Americans adhering to a measure known as the healthy eating index (HEI) 12% more (Nutrition, 2018). Those numbers rose to 52 to 82 billion in savings annually if Americans adhere to an HEI 20% more often.
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Optimal Nutrition is Essentials for the Immune System
Robust immune function, while partially genetic, is still largely within our control. One of the most important factors in having a strong immune function are what we put in our bodies.
A whole foods diet consists of plant foods that are unprocessed and unrefined and therefore retain their fibre, phytochemicals and nutrients. Examples include vegetables, fruits, whole grains, nuts , and legumes.
Cells in our immune system, and cells of the body, in general, need specific nutrients in the appropriate amounts to function correctly (Child, Calder, & Miles, 2019). When we are sick the cells of the immune system has an increased demand for nutrients since extra energy is needed to fight off the infection.
Optimal nutrition is essential at these times for the immune system to effectively do its job in mounting a proper immune response against the pathogen. Proper nutrition also helps this immune response to turn off at the appropriate time, to avoid a smouldering underlying systemic inflammation over the long-term.
Some specific examples of nutrients being necessary for proper immune function are the amino acid arginine is needed for macrophages to produce nitric oxide, and vitamin A and zinc are needed for immune cells to rapidly divide in order to mount an effective immune response.
Foods rich in arginine include nuts and seeds, legumes, seaweed, dairy, fish, poultry , and other meats. Foods rich in
Vitamin A includes Cod liver oil, eggs, orange and yellow vegetables , and fruits and other sources of beta-carotene such as broccoli, spinach, and most dark leafy green vegetables.
Foods high in zinc include kidney beans, beef, shrimp, spinach, pumpkin seeds, watermelon seeds, flax seeds, oysters, garlic, egg yolks, salmon , and turkey.
Nutritional immunology seeks to explore the effects that nutrition has on our immune function. Wu, Lewis, Pae, & Meydani (2018) point out that to maintain the correct functioning and homeostasis of the different systems of the body and tissues that the body needs nutrients in appropriate amounts.
These nutrients can be found as components of so-called “functional foods”. Nutritional immunology research focuses on identifying the dietary components that help with immune function, and in what amounts.
Probiotics, found in various fermented foods such as kimchi, yogurt, sauerkraut, kefir, kombucha, pickles, miso, tempeh, sourdough bread , and certain cheeses, have been shown to have positive effects on innate immunity.
These effects include helping with the immunological functions of immune cells such as those lining the intestinal tract (epithelial cells), and antigen-presenting cells capable of phagocytoses such as dendritic cells and macrophages.
The epithelial cells lining the GIT help with the selective barrier function, preventing food particles and foreign microbes from getting across and entering the systemic circulation. This selective barrier function is referred to as mucosal immunity.
This type of immunity can be directly influenced by certain strains of probiotics which either directly act on the immune cells that are part of this system such as dendritic cells, or by stimulating the release of signaling molecules by the epithelial cells.
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In several studies, as cited in Wu et al. (2018), it was found that Lactobacilli strains found in fermented milk, helped speed recovery from respiratory and GI infections, and decrease the incidence of the common cold.
Similarly, shorter duration GI and respiratory infections were found versus control groups in elderly that were not in assisted-living facilities when they were given milk fermented containing the strain L. casei, along with yogurt cultures containing L. bulgaricus, and S. thermophilus (Turchet, Laurenzano, Auboiron & Antoine, 2003 as cited in Wu et al., 2018; Guillemard, Tondu, Lacoin, & Schrezenmeir, 2010, as cited in Wu et al., 2018.
One trial was a 3-week trial, while the other, done 7 years later, it lasted 3 months. The first trial did not find a difference in the overall number of illnesses.
Another study, which compared plain milk with milk with L plantarum strains added that were given to healthy elderly people who were institutionalized x 12 weeks, found a decreased incidence of infection and mortality associated with pneumonia, and an increase in B cells, Natural Killer cells, Antigen presenting cells and other immune cells (Mane, Pedrosa, Loren, Gassull, Espadaler, et al., 2011, as cited in Wu et al., 2018). This effect lasted for 12 weeks after this group stopped their probiotic.
Green Tea & The immune System
Green tea is another consumable item that has been studied extensively over the past many years that is often found as part of a healthy, whole foods diet. EGCG, contained within the green tea, is thought to be responsible for its effects.
Green tea and its active constituent have been shown to have positive effects on both innate and adaptive immunity functions (Pae & Wu, 2013, as cited in Wu et al., 2018). Fiber found in the form of complex carbohydrates in fruits and vegetables has been shown to decrease inflammation in humans (several studies, as cited in Myles, 2014).
Good fats also are known as monounsaturated and polyunsaturated fatty acids are an integral part of a healthy whole foods diet. They are found in foods like fish, avocado, nuts, seeds, eggs, and extra virgin olive oil. Foods like refined, processed, and fast foods , in contrast, contain an abundance of omega 6 fatty acids.
While omega 6 fatty acids are well-known to be pro-inflammatory, omega 3 fatty acids are known to be anti-inflammatory (several studies as cited in Myles, 2014). Omega 3s, because they can reduce inflammation can help with conditions that are thought to be associated with underlying inflammation.
These conditions include atherosclerosis, CVD, inflammatory bowel diseases , and allergic illness. A study on mother’s who had taken omega 3s during their pregnancy showed that children had a reduced risk of developing allergies and other diseases associated with inflammation (Shek, Chong, Lim, Soh, & Chong, as cited in Myles, 2014). A study where mom’s where given a high omega 6 and saturated fat diet showed the opposite of the previous study (Nwaru, Erkkola, Lumia, Kronberg-Kippila, Akonen et al., 2012 as cited in Myles, 2014).
Omega 3 fats have also been shown to be capable of down-regulating the genes responsible for inflammation (Calder, 2009 & Calder, 2010 as cited in Myles, 2014).
Two omega 3 fatty acids(1) called EPA and DHA were found to synthesize anti-inflammatory mediators known as resolvins and protectins , which further modulate the immune response (several studies, as cited in Myles, 2014).
It is believed that phytochemicals contained within fruits, vegetables and grains are responsible for their anti-cancer and anti-chronic disease properties (several studies, as cited in de Kok, Van Breda, & Manson, 2008). In vitro and in vivo studies have revealed and critically analyzed numerous compounds with biological effects that may be responsible for these effects.
About The Author:
Dr. Hayley Collinge, Naturopathic Doctor, and founder of Evolve Healthcare graduated from Boucher Institute of Naturopathic Medicine in 2013 and has been practising in Arizona since 2014.