Interest in the microbiome of the human body and its connection to chronic diseases is growing. A new study examines this link and how the foods we eat affect the composition of our microbiome.
The microbiome protects the host and plays a role in disease risk
The microbiome consists of the genes of tiny organisms (bacteria, viruses and other microbes) that are found in the gastrointestinal tract, especially in the small and large intestines. The normal intestinal flora – another term for the microbiome – protects its human host. In order for the microbiome to thrive, there must be the right balance, with the healthy species dominating the less healthy species.
Scientists don’t fully understand how the microbiome affects the risk of developing chronic diseases like heart disease, obesity, and type 2 diabetes. Many factors, including the differences between individuals and individual diets, have made this area difficult to study.
The study examines the relationships between diet, microbiome, and disease risk
But a new study published in Natural medicine, explains these factors and provides information about how our diet shapes our microbiome and how our microbiome in turn influences our risk of disease.
The researchers looked at more than 1,100 people who participated in PREDICT 1, a large study that looked at individual reactions to food. They used a technique called metagenomic sequencing to identify, classify, measure, and analyze genetic material from study participants’ microbiomes. They also gathered detailed long-term food intake information from all of these individuals in order to analyze their eating habits, including intake of different food groups, foods, and nutrients. In addition, they gathered information from study participants on a variety of factors known to affect metabolism and disease risk, including measurements of blood sugar (glucose), cholesterol, and inflammation before and after meals. Finally, they measured the study participants’ personal health characteristics, including age, weight, body mass index (BMI), body fat, and blood pressure.
Diet affects the microbiome, and the microbiome affects the risk of disease
The study found that diet affects the health of the microbiome and that the composition of the microbiome affects the risk of health outcomes. The results showed that certain gut microbes were associated with certain nutrients, foods, food groups, and the overall composition of the diet. Health conditions such as heart disease, type 2 diabetes, obesity, and general inflammation appeared to be most affected by diet-related changes in the microbiome.
For example, less healthy eating habits (dairy desserts, unhealthy meats, processed foods) supported gut species associated with measurements of blood sugar, cholesterol, and inflammation, which are significantly linked to higher risk of heart events, stroke, and type 2 diabetes.
In contrast, a more diverse gut microbiome was tied to healthy eating habits (high-fiber vegetables like spinach and broccoli, nuts, and pagan animal feeds like fish and eggs) and measurements associated with lower risk of certain chronic diseases. Additionally, the study found that polyunsaturated fats (found in fish, walnuts, pumpkin, flaxseeds and chia seeds, sunflower, safflower, and non-hydrogenated soybean oils) produce healthy gut types that are linked to a reduced risk of chronic disease.
A minimally processed plant-based diet is good for the microbiome and for reducing the risk of disease
What do these results mean for us? First, the study showed that the gut microbiome can thrive when more unprocessed plant-based foods – fruits, vegetables, nuts, seeds, and whole grains – are eaten. Some animal foods such as fish and eggs are also inexpensive. Avoiding certain animal-based foods such as red meat and bacon, dairy products, and highly processed foods (including processed plant-based foods such as sauces, baked beans, juices, or sugary drinks and desserts) will prevent less healthy gut types from colonizing the country’s intestines.
It is important to note that the quality of the food is important. Processed or ultra-processed plant foods were not associated with pagan accumulations of gut microbes. When choosing foods, consider whether they are processed or unprocessed, and whether they are plant-based or animal-based.
It can also be helpful to think in terms of food choices rather than individual foods or food groups. Meal patterns that highlight foods that are beneficial to the microbiome are whole plant-based diet patterns. This includes vegan (no animal products) and ovo-vegetarian (vegetarians plus eggs) diets. The Pescatarian eating pattern, where greasy and white fish are the meat of choice, is also good for the microbiome.
By emphasizing minimally processed plant-based foods, the gut microbiome can thrive and protect against or reduce the risk of chronic diseases such as heart disease, diabetes, metabolic disease, and obesity.