Did you know that 70% to 80% of your immune system is located in your gut? Particularly, over 10,000 species and 100 trillion live microorganisms. In fact, humans have 10 times more bacterial cells than human cells.
Bacteria live on the ears, nose, skin, nose, and mostly in the gastrointestinal (GU) tract. They help with digestion, protect the body against infections, regulate appetite and metabolism and strengthen the immune system by releasing enormous quantities of antibodies or ‘fighters’ into the gut. They also influence mood, memory, concentration, and brain functioning.
Let us dive deeper into the interplay between the gut and immunity!
In the gut, the immune cells are in constant battle with antigens or ‘attackers’ and harmful bacteria that can enter your body from intestinal microbes and from foods you consume.
How does the immune system work in your gut?
The immune system strengthens the lining of the gut to maintain tolerance to the unhealthy foods we consume. This system is located in the wall of the gut and usually demonstrates two kinds of responses: Pro-inflammatory, which supports inflammation and Anti-inflammatory, which strengthens the immune system to fight the inflammation. The former is produced by harmful or ‘bad’ bacteria and the latter by the resident or ‘good’ bacteria present in your intestine in normal conditions.
Therefore, the type of bacteria that inhabits the gut becomes critical. When we discuss gut health, we are basically talking about preserving a healthy intestinal flora i.e., maintaining the number and health of good bacteria in the gut. The more of good bacteria, the better the protection against harmful or bad bacteria and disease.
So, how to take care of our gut and strengthen immunity?
The most important way to do this is by taking care of what we consume.
Diets rich in carbohydrates, processed foods and low in fibre reduce the number of good bacteria, cause thinning and breakdown of the gut lining, and lower anti-inflammatory responses in the gut.
Low-carbohydrate and high-fibre diets are important for gut health. Consume foods rich in anthocyanins, tannins, and flavonoids (anti-inflammatory agents) to help retain the ability of your gut to ward off bad bacteria and nourish the good bacteria.
Plant-based foods such as asparagus, onions, garlic, leeks, whole grains, and legumes (peas, green beans, chickpeas, and lentils) affect the composition and diversity of bacteria in the gut and strengthen the immune system.
The gut bugs are healthiest and support robust immunity when we consume high-fibre foods such as raspberries, broccoli, apples, green peas, lentils, artichokes, chickpeas, zucchini, whole grains and beans. Fruits such as papaya are also a rich source of natural fibre that’s key in maintaining good gut health, and guava prevents constipation.
On the contrary, the typical Western diet, which is high in animal proteins, processed foods, saturated fat and sugar, reduces gut microbial diversity and promotes chronic inflammation and medical conditions such as diabetes, obesity and cardiovascular diseases.
Prebiotics and probiotics: The gut ‘booster’ foods
Supplements formulated with prebiotics and probiotics help to maintain gut ecology. Plant-based diets are rich in prebiotic fibres and can increase gut biodiversity.
Probiotics are living microorganisms that can improve gut health. They strengthen the connection between the cells lining your gut. The gut lining is delicate, and when weakened, increases your vulnerability in the face of harmful stimuli or ‘invaders’.
Probiotic-rich foods are usually fermented foods such as yogurt, kefir, kimchi, aged cheddar cheese, Swiss cheese like gouda, and cottage cheese. Probiotics can restore the microbiome composition and reintroduce good microbes, allowing for more efficient immune functions.
Manage weight to improve gut flora and immunity
Excessive body weight also influences immune function. Fat stores initially considered inert tissues, actually release chemicals and hormones that stimulate inflammation. Medically termed adipose tissue, fats are now considered metabolically active endocrine organs.
Obesity or adiposity has direct effects on the immune system and triggers inflammatory responses. Maintain a healthy weight by following plant-based diets to boost gut health and the immune system.
Apart from high-fibre and low-carb foods, here are a few dietary tips to maintain a healthy weight:
Consume healthy fats that support your immune function. You can cook with olive oil, canola oil, or avocado oil or add avocado slices to salad dressings to improve healthy fat intake, which must comprise 20% to 40% of your daily calorie intake.
Non-vegetarians must prefer wild-caught fish to farmed fish varieties. Eating fish three times per week is recommended. Fish could also be consumed as daily fish-oil supplements of 1,200 milligrams.
Protein must be present in every meal: The immune system performs well with regular protein servings. Similar to fat, muscle is also an endocrine organ with direct impacts on the immune system, muscle is built from protein. Dietary protein may be obtained from animal foods, but good bacteria prefer plant-origin sources.
High-protein foods include almonds, oats, cottage cheese, quinoa, broccoli, Greek yogurt, lentils, pumpkin seeds, soy, brussels sprouts, beans, chickpeas, and Chinese cabbage. Fruits such as guava also contain proteins.
Use natural herbs and spices in food preparations: Not only do spices and herbs add flavour to foods, but are also rich in phytochemicals that may increase gut-bug biodiversity. Herbal remedies such as mulethi stimulate bowel movements.
Triphala prevents the growth of harmful bacteria and promotes the growth of good bacteria, cumin seeds can activate digestive enzymes and remove toxins from our body. Ashoka root and Ginger strengthen digestive health!
Gut bacteria, irritable bowel syndrome and immunity
The gut microbiome and immune cells are critically interconnected. What’s present in your gut would determine what education the cells of the immune system receive.
The weakening of the gut firewall protection by good bacteria allows bad bacteria to enter our bodies resulting in infections and nutritional disorders. In the majority of cases, this results in ‘irritable bowel syndrome’ (IBS), which is caused primarily by a faulty immune system and an inflamed gut than an external infection. IBS patients have defects in the lining of the gut, the barrier that prevents bacteria from interacting with the host (that’s us).
It, thus, becomes essential that we protect the good bacteria and gut immunity. Nutrition is a major modulator of immunological function which means that what we eat initiates the release of a metabolic byproduct from specific gut bacteria that, in turn, modulates gut immunity. “You are what you eat” is true!
Gut, immune diseases, autoimmunity and cancer
The gut bacteria (and other microbes) act as gatekeepers as well as trainers. They teach immune cells to discriminate between foreign substances and our tissues.
There are two types of immunity-humoral immunity (antibody-based) and cell-mediated immunity (cell-based). B cells release antibodies or ‘fighters’ that can destroy harmful bacteria and prevent them (and foreign substances) from entering the gut. This is known as humoral immunity.
When antibodies are unable to access the invaders that have attacked our cells, T-cells mediate the scenario and destroy the infected cells. This is known as cell-mediated immunity.
When everything is running smoothly, the gut sends signals that enable the development of healthy immune functions and modulate immune responses. In return, the immune system helps to populate the gut microbiome with good bacteria.
A shift in the makeup of the bacterial community, tilting the balance between good and bad bacteria toward the bad bacteria results in inflammation and disease. If these bacteria release toxins that have carcinogenic potential, cancer may develop.
When the good and bad bacteria are in good relations, the human body is equipped to respond to pathogens and tolerate harmless bacteria, preventing an autoimmune response and ensuring overall health.
When the immune system is weak or misfunctioning, it confuses our own healthy body cells with antigens or ‘attackers’ of the immune system. In autoimmune diseases, the immune cells wrongly think that our own cells are foreign invaders or antigens – which is called an autoimmune response.
Interestingly, tuberculosis manifests in the lungs, but bacterial imbalances show up in the gut! The immune system sends signals about infection from the lungs to the gut, which appears to respond by killing off particular bacteria.
Good bacteria-reducing factors such as poor diet, surgeries, antibiotic use, chemotherapy, and heavy metals lower your intestinal flora, which can snowball into lower immunity.
Hence, if you want to improve your immunity, you must look at the gut!