The food you eat and the medicines you take can alter your gut bacteria in ways that either help or harm your health, two new studies suggest.
Foods like fruits, vegetables, coffee, tea, yogurt and buttermilk can increase the diversity of bacteria in a person's intestines, and that diversity can help ward off illness.
It is believed that higher diversity and richness in gut bacteria is beneficial. On the other hand, foods containing loads of simple carbohydrates appear to reduce bacterial diversity in the gut, and these include high-fat whole milk and sugar-sweetened soda.
In addition, medications can also play a part in the makeup of your gut bacteria. Antibiotics and antacids can cut down on gut bacterial diversity while smoking and heart attacks can have a negative effect.
Each person's intestines contain trillions of microorganisms, which doctors refer to as the "gut microbiome. It's the largest immune system in the body, and these bacteria have a very dramatic and prominent role in determining health and disease.
To study the effect of lifestyle on the gut microbiome, stool samples were collected from more than 1,100 people living in the northern Netherlands.
The samples were used to analyze the DNA of the bacteria and other organisms that live in the gut. In addition to stools, the study collected information on the participants' diets, medicine use and health.
In the second study, researchers with the Flemish Gut Flora Project performed a similar analysis on stool samples taken from 5,000 volunteers in Belgium.
Both studies concluded that diet has a profound effect on the diversity of gut bacteria, although, the underlying theories of these dietary factors remain largely unknown.
Researchers noted that medicines can have the same effect, and antibiotics actually can kill off some important strains of gut bacteria. One dose of an antibiotic may disrupt your gut bacteria for a year.
Both sets of researchers emphasized that their studies only help explain a fraction of gut bacteria variation -- roughly 18 percent for the Netherlands study, and about 7 percent for the Flemish study.
However, the findings from the two groups overlapped about 80 percent of the time, indicating that they are on the right track.
The Belgian researchers estimated that over 40,000 human samples will be needed to capture a complete picture of gut bacteria diversity.
Other research has shown that poor sleep, obesity, diabetes and the use of artificial sweeteners also can interfere with gut bacteria. Once researchers have a clearer understanding of the gut microbiome and its effects on health, doctors could be able to help prevent or heal illness by reading or influencing the bacteria within people's bodies. The personalized microbiome may assist in personalized nutrition, personalized medicine, disease risk stratification and treatment decision-making.
In the meantime, the general rule is a balanced diet with high fiber and low carbs tends to drive a better gut health overall.