Diet and Immune Health: A Robust Digestive System Reflects a Strong Immune System

By Angela Soeon Park, L.Ac.

When boosting the immune system, we often think about Superfoods as a quick fix. However, the immune system is complicated and a barometer of our overall health. Hence, we need to see whole-body interactions. The immune system defends the body against infection. Although it works most of the time effectively, if the immune system fails, we become sick due to our bodies being taxed by stress, sleep deprivation, illness, or poor nutrition.

In Chinese Medicine theory, immunity depends on several factors:

• The kidney organ network supplies the fuel for all our metabolic functions and reproductive system.
• The spleen network, including the digestive system, absorbs and distributes nutrients.
• The lung network governs defensive energy that protects us from external pathogens.
• The liver network manages neurological responses and facilitates the smooth flow of detoxification.

These organ networks must function correctly and work harmoniously to support healthy immunity.

In Chinese Medicine, the focus is not always on strengthening the immune system specifically but rather on strengthening the whole body to allow the immune system to function optimally. As a result of enhancing the entire body's health, there will be natural daily detoxification and proper circulation of Qi (energy), blood, and body fluid (including lymph) without blockages.

Even though the immune system is complex, the foundation of a robust immune system starts with a healthy digestive system. All immune cells require adequate and appropriate nutrition to function optimally. Seventy percent of the immune system makes up the digestive system. Good digestion and proper nutrition are critical modulators of immune function, with probiotics and prebiotics playing a significant role in the immune system.

Probiotics are found in fermented foods like kombucha, sauerkraut, kimchi, miso, tempeh, pickles, and yogurt. These gut bacteria (probiotics) are the healthiest and support strong immunity when we consume high-fiber plant foods (prebiotics). The microbiome in the gut interacts with immune cells in the digestive system - the diverse array of bacteria and fungi that live in the gastrointestinal tract and are directly influenced by an individual's diet and lifestyle.

You may have experienced being often sick or lethargic with digestive issues such as bloating, gas, indigestion, stomach pain, constipation, and diarrhea after overconsuming unhealthy foods such as alcohol, spicy, oily, processed, or fast foods. This example can explain how the foods we eat affect the diversity and composition of bacteria in the gut, affecting the immune system.

A few essential micronutrients have been identified as critical for the growth and function of immune cells, including:

• Iron is a component of enzymes critical for immune cell function. Sources include red meat, beans, nuts, and fortified breakfast cereals
• Vitamin A helps protect against infections by keeping skin and tissues in the mouth, stomach, intestines, and respiratory system healthy. Sources include orange and red fruits and vegetables like carrots, apricots, and bell peppers.
• Vitamin C stimulates the formation of antibodies and the production, function, and movement of white blood cells. Sources include citrus fruits like oranges, grapefruit, strawberries, and tomatoes.
• Vitamin D helps regulate antimicrobial proteins that can kill pathogens. Sources include sunlight, fatty fish, like salmon, egg yolks, and fortified dairy.
• Vitamin E works as an antioxidant to protect the integrity of cell membranes from damage caused by free radicals. Sources include seeds, nuts, vegetable oils, and peanut butter.
• Zinc is needed for wound healing and supports immune response. Sources include meats, whole grains, milk, seeds, and nuts.

The above nutrients should be ingested from food rather than supplements, as foods contain health-promoting benefits. For most, a balanced diet will supply adequate nutrition to maintain a robust immune system. However, specific populations, like pregnant people, older adults, and those with digestive issues, cannot eat nutritious foods or have increased nutrient needs. In these cases, vitamin and mineral supplements help fill nutritional gaps.

From a TCM viewpoint, there is no one-size-fits-all label for foods (herbs). We must consider the food's (herbs) natural properties and functions. However, certain foods (herbs) stand out with unique attributes, often consumed to maintain good health. These foods include:

• Ginseng strengthens and replenishes Qi (vital energy), essential to the body, relieving fatigue and improving immunity. Due to medicinal potency, consult an acupuncturist or TCM nutritionist before consumption.
• Astragalus is known for strengthening the immune system and helping the body fight infections. It is an adaptogen that increases the body's ability to handle stress and contains anti-aging properties.
• Eating walnuts can sharpen the mind and boost concentration and memory. In addition to helping the brain, walnuts can support the kidney's Qi and aid digestion by lubricating the intestine
• Also known as wolfberries, goji berries have been used as an herbal remedy for over 3,000 years. They nourish the kidney essence that underpins human vitality. Goji berries are commonly eaten to improve eyesight.
• A warming food, the jujube date helps to strengthen the spleen and stomach's Qi. It also nourishes the blood.
• Ginger is a warming spice that supports the digestive and immune systems as one of the most famous antibacterial, antiviral, and antifungal herbs
• Mushrooms like Shiitake, Reishi, Maitake, Cordyceps, Lion's Mane, Chaga, and Turkey Tail contain beta-glucans and other immunomodulating compounds that have been shown to support the immune system. Our Natural Immunity Plus supplement contains various medicinal mushrooms.