Why should you be concerned about gut health? A healthy gut helps you absorb more nutrients from the food you eat. Yet, a healthy gut does more than that. Research shows that 70% of your immune system lies in your intestinal tract. What’s more, this portion influences the activity of your immune system. Therefore, the health of your gut may play a key role in protecting against infection and in preventing the overreaction of the immune system that triggers chronic inflammation. In addition, some studies link a healthy gut to better weight control and brain health.
Your gut is colonized by trillions of bacteria. Bacteria have the reputation of being harmful because some cause disease, but the bacteria that populate a healthy gut are not only harmless but offer health benefits. For one, they protect against the invasion of harmful bacteria, viruses, and yeast by competing for their resources. When the gut is full of healthful bacteria, there’s less space or resources for bad bacteria to lay down roots.
Each person has a population of bacteria residing in their gut and it’s almost like a unique signature, so much so that it’s come to be called the gut microbiome. What’s more, lifestyle habits and the foods we eat can modify these bacteria and alter their composition for better or worse. This, in turn, can impact health in a positive or negative way. What should you eat and not eat to protect your gut microbiome and keep it healthy? First, let’s look at some foods to avoid.
Did you know processed foods make up more than 60% of the offerings you find at the average supermarket? They’re everywhere and people love them because of their convenience. Yet, more highly processed ones may harm your gut. These foods are high in sugar and some research suggests that sugar may contribute to a less favorable gut microbiome – but there’s another reason.
Most ultra-processed foods contain emulsifiers, food additives that give the product texture and extend the life of the product. Research in mice shows that carboxymethylcellulose and polysorbate 80, two common emulsifiers in processed foods, triggered inflammation, weight gain, and metabolic changes in the mice. Since emulsifiers have detergent-like properties, researchers believe these common additives in foods like ice cream and salad dressings could damage the gut lining and harm the gut-friendly bacteria that live there. One concern is that these changes might increase the risk of colon cancer. Another reason to avoid ultra-processed foods and eat foods in their whole, unaltered state.
Artificial sweeteners provide sweetness without supplying significant calories or causing a rise in blood sugar. This makes them popular with diabetics. However, recent studies question whether these sweeteners are safe. In a 2018 study, researchers tested 6 of the most popular artificial sweeteners and their impact on the gut microbiome. They found that even low concentrations of 1 mg/ml of these artificial sweeteners were harmful to the healthy bacteria that reside in the gut.
An occasional glass of wine may not harm you, but excessive use of alcohol could be harmful to your gut. Preliminary research finds that long-term use of alcohol alters the composition of the gut microbiome in people in a way that may trigger inflammation. In fact, this may explain some complications associated with long-term alcohol use, such as liver disease. If you drink alcohol, stick to no more than a single glass of wine daily.
Excessive Amounts of Red Meat
A diet high in red meat can negatively impact your gut microbiome in two ways. For one, the red meat you eat may contain antibiotic residues that harm healthy gut bacteria. Eating an occasional piece of red meat probably won’t have a big impact on your gut microbiome, but eating it every day is a different story. According to the World Health Organization, 80% of the antibiotics purchased are for use in animal agriculture. If antibiotics destroy bacteria when we take them for an infection, why wouldn’t the traces of antibiotics in red meat do the same?
But that’s not the only way a diet heavy in red meat may damage the gut microbiome. Studies show that people who eat a diet high in red meat have higher levels of a chemical called TMAO in their bloodstream. Where does TMAO come from? When bacteria in the gut feed on nutrients in red meat, they produce this chemical. The reason TMAO is so problematic is that it changes the activity of blood-clotting cells called platelets in a way that increases the risk of a blood clot forming in a blood vessel. Interestingly, a red meat diet also makes it harder for the kidneys to flush TMAO out of the body.
Foods that Support Gut Health
Now, you know what to avoid. What should you eat to enhance the health of your gut? Plant-based foods are rich in a type of fiber called prebiotics. Even though we can’t break this fiber down, bacteria can. When they do, they produce short-chain fatty acids that support a healthy gut lining. Some preliminary research suggests that short-chain fatty acids, such as butyric acid, may lower the risk of colon cancer, possibly by reducing inflammation. Some good sources of prebiotic fiber are legumes, asparagus, oats, apples, garlic, onions, leeks, nuts, almonds, flaxseed, and more.
Probiotic foods support gut health in a different way. These foods supply your gut with healthy bacteria. Why not take a supplement? Recent studies question the merits of doing this since supplements contain varying types of bacteria and we don’t yet know which ones are protective. Plus, some probiotic supplements have quality control issues or lack enough bacteria to make a difference. In addition, recent research shows that probiotic supplements are linked with digestive upset in some people. Also, there have been cases of people with weakened immune systems developing severe side effects and infection from taking probiotic supplements. Get your probiotics from food by choosing more prebiotic and probiotic-rich choices. You’ll get the additional benefits these foods offer too!
· Am J Physiol Gastrointest Liver Physiol. 2012 May 1; 302(9): G966–G978.
· Food and Nutrition. “Food Additives: Emulsifiers”
· Advances in Nutrition, Volume 10, Issue suppl_1, January 2019, Pages S31–S48.
· Science Daily. “Artificial sweeteners have toxic effects on gut microbes”
· Molecules 2018, 23, 2454.
· Am J Public Health. 2015 December; 105(12): 2409–2410.
· National Center for Complementary and Integrative Medicine. “Probiotics: In Depth”
· Medical News Today. “Red meat raises heart disease risk through gut bacteria”