05/18/2018
By Karen Angelo

The next time you pick up that donut, consider this: There’s a war for survival going on inside your gut, and you’re feeding the enemy. 

Growing evidence reveals that the benefits of healthy bacteria in the gut go well beyond fighting off pathogens and aiding digestion. A healthy composition of the gut microbiome – a vast army of microorganisms that keep us alive – could help prevent depression, obesity, arthritis and illnesses such as Parkinson’s Disease among others. 

Asst. Prof. Kelsey Mangano in the Department of Biomedical and Nutritional Sciences conducts research on the effects of nutrition on bones, muscle and inflammation. Her most recent project examines the role of yogurt intake on the composition of the gut microbiome. 

Mangano, who joined the Zuckerberg College of Health Sciences in 2015, is a member of the Center for Population Health and holds an adjunct faculty appointment at the Institute for Aging Research at Hebrew Senior Life, a Harvard Medical School affiliate. She shares her expertise on the new medical frontier of the gut microbiome and what it means for health outcomes. 

Q: Why is the gut microbiome important? 

A: Think of your gut as a house that contains 100 trillion bacteria that live or die, depending on what you feed it. Healthy bacteria are fighting for a home and are less likely to survive on diets of junk food and refined sugars. 

Q: How does a healthy gut compare to an unhealthy gut? 

A: A healthy gut is defined by having many types of bacteria present and higher activity of healthy versus unhealthy bacteria. People who tend to eat a consistent diet low in fiber and high in refined grains, sugars and bad fats will have an unhealthy gut, with fewer bacteria. Studies show that people with less diversity in their guts have higher rates of chronic disease, obesity, diabetes, heart disease, inflammation and colon cancer. To achieve a healthy gut, individuals should consume more fruits and vegetables, whole grains and adequate healthy proteins. 

Q: What does the latest research tell us about the functions of the microbiome? 

A. We understand now that the microbiome is full of bacteria that are very much alive and functioning. These unique bacterial activities may contribute to many important functions in the body. This not only depends on the number of bacteria in the gut, but also on the types of bacteria present that demonstrate unique activity. For example, if we form a diverse gut microbiome, we better absorb minerals such as calcium and magnesium. Greater absorption of these nutrients may lower inflammation and improve bone health. 

Q: What foods promote a healthy gut? 

A: The best thing you can do is eat a balanced diet, high in fiber. Fiber feeds gut bacteria. Good bacteria especially thrive on nondigestible fibers, such as garlic, onions and leeks. Fruits, vegetables, whole grain rice and breads – all contribute fiber to a healthy diet. Fermented foods, such as yogurt, kimchee, sauerkraut and pickled foods, contain live cultures that boost health-promoting gut bacteria. These foods provide a healthy dose of bacteria that may help to prevent growth of other bacteria shown to be associated with poor health outcomes. 

Q: After switching to a healthy diet, how long does it take for the composition of the gut to improve? 

A: Amazingly, it can take less than 24 hours. Making a change to your diet will alter the gut microbiome within a day. However, these changes are not permanent. If a person goes back to their original diet, the gut bacteria will also change. Therefore, any positive changes made to the diet should be sustained long-term. 

Q: Should people take probiotic and multivitamin supplements? 

A: Getting your nutrients from food is always best. The unique interaction of nutrients in foods may have the most beneficial health effects. One reason for this is that nutrients within foods work together for greater absorption. However, some people may benefit from a probiotic supplement. For example, if a person is taking an antibiotic, which lowers the diversity of the gut bacteria, they may benefit from the healthful bacteria probiotics provide. 

Q: What does the future hold for research of the microbiome? 

A: This field of research is exploding. With new laboratory techniques, we can test the genetic makeup of gut bacteria and understand their function and activity. I expect that new approaches to prevent and treat chronic diseases will be developed based on diets that can modify the gut microbiome. Food will be medicine.