In the previous blog, we discussed ways to reduce stress in order to boost immunity. Today, I am introducing ways to optimize immune function by making simple changes to your diet.
The relationship of the digestive and the immune systems is becoming more apparent, with a deepening understanding of the human microbiome. The interdependence of these systems is important, as the gut houses about 70% of our immune system. The digestive system of the average person harbors more than 500 distinct species of bacteria. Referred to as the microbiome or gut flora, these trillions of useful bacteria provide dozens of various functions and capabilities and mostly reside in the colon (large intestine) and ileum. The human gut flora is critical to the vitality of the host and plays a fundamental role in nutrient absorption, metabolism, pathogen resistance, and regulation of the immune response. The composition and distribution of this microbiome varies according to age, state of health, and even geographic region.
Excessive antibiotic use poses probably the single most deleterious effect on gut health, as it decimates healthy gut flora, allowing pathogenic bacteria the opportunity to populate. This effect is highlighted in one study where after just one single course of ciprofloxacin, presence of the harmful bacterium clostridium difficile was found in the subjects’ digestive tracts in higher than normal amounts. This, in addition to other factors like chronic stress, can lead to a cascade of harmful events such as intestinal hyper-permeability, systemic inflammation, and insulin insensitivity.
In past blog entries, I have introduced the Chinese medicine view of the Spleen. Here I will delve a bit deeper into it, focusing on its primary function: digestion. According to TCM, the Spleen is responsible for the transformation and transportation of food essences into blood and Qi in the body. This means that the quality of food we eat is directly proportional to the quality of our blood and Qi. This view relates almost identically to the western medical view of the digestive system, in that its primary function is to receive food, extract minerals and nutrients, and turn it into useful energy for the body. One common condition we see in the clinic, especially in the United States, is called Spleen Qi deficiency. This manifests as fatigue, reduced energy, loose stools, gas and bloating, undigested food in the stools, and in advanced cases, prolapse or blood loss. The major contributor to this condition (in addition to overwork and chronic stress as we learned in the previous blog post) is improper eating habits. This includes excessively damp-forming foods such as greasy, fried, alcohol, dairy, and too much eating of cold or raw foods, as well as eating at irregular intervals or times, or eating while emotionally upset. Also, as seen above, antibiotics have a destructive effect on the gut (which we now know is equal to the concept of the Spleen in TCM)
Spleen Qi deficiency. This manifests as fatigue, reduced energy, loose stools, gas and bloating, and undigested food in the stools.
Now that we have a basic understanding of the human microbiome and the TCM view of the Spleen, let’s discuss ways to improve it. Gut health will invariably involve a 3 fold approach: healing what has been damaged, digestive and immune maintenance, and then finally prevention. For this I suggest visiting a practitioner who is well versed in the area of nutrition, so that he/she may guide you in the process of reconstructing your gut.
What can you do to address and improve gut health on your own? Here is a list of some foods that have been shown to benefit the immune system either directly or indirectly via the digestive system, and I highly recommend eating them as often as possible. Integrating them slowly into your diet, as well as eliminating some of the harmful foods I have listed here, will help improve your overall health.
Mushrooms, such as shiitake: Shiitake, a Japanese mushroom that has been cultivated for over 1000 years, contains strong immune system regulating properties, along with antibacterial and antiviral properties, including that of stimulation of macrophage activity (macrophages are one form of white blood cells responsible for the body’s first response to infection).
Eat a diet that is very high in antioxidant rich foods: From vegetables, fruits (especially berries), and beans
Probiotics: Fermented food sources such as kimchi, kefir, sauerkraut, kvass – all of these contain high levels of probiotics which are helpful in replenishing healthy gut bacteria/flora. You may also simply take a probiotic supplement. There are several high-probiotic yogurts as well.
Prebiotic foods: Such as asparagus, and the night shade family (onion, garlic)
Omega-3 fatty acids to control inflammation: High quality fish oil or fresh wild-caught fatty fish like salmon is a great source for this
Dark leafy greens and micro-algae: Such as spirulina and chlorella offer immune-enhancing properties and a high dose of B-12, an immune superstar vitamin.
Quercetin: A powerful antioxidant found in green tea, tomatoes, and…is found to be a strong immunostimulant as well.
Yellow and orange foods: The color that benefits the Spleen. Eat foods of these colors (in addition to other colors of course) such as peppers, yams, and Japanese potato to strengthen the Spleen.
Avoid sugar, refined carbohydrates, fried foods, excessive alcohol, dairy, and cold foods: all which promote inflammation and deplete healthy gut bacteria and allow unhealthy bacteria to flourish as well as overgrowth of Candida albicans (yeast).
Written by: Lauren Phillips, L.Ac.
Healing with Whole foods: Asian Traditions and Modern Nutrition. Paul Pitchford. North Atlantic Books. 2002.