Diet, Disease, and the Microbiome: Harvard Health Blog


There is a growing interest in the microbiome of the human body and its connection to chronic diseases. A new study examines this connection, along with how the foods we eat influence the composition of our microbiome.

The microbiome protects the host and plays a role in the risk of disease

The microbiome consists of genes from tiny organisms (bacteria, viruses, and other microbes) that are found in the gastrointestinal tract, primarily the small and large intestine. The normal intestinal flora – another term for the microbiome – protects its human host. For the microbiome to thrive, there must be the right balance, dominating the least healthy healthy species.

Scientists do not fully understand how the microbiome affects the risk of developing chronic diseases, such as heart disease, obesity and type 2 diabetes. Many factors, including differences between individuals and individual diets, have made this a difficult area. to investigate.

The study investigates the relationships between diet, microbiome, and disease risk

But a new study, published in Nature medicine, explains these factors and sheds light on how our diets shape our microbiome and how our microbiome, in turn, influences the risk of disease.

The researchers studied more than 1,100 people enrolled in PREDICT 1, a large trial that examines individual responses to food. They used a technique called metagenomic sequencing to identify, classify, measure, and analyze genetic material from the microbiomes of study participants. They also collected detailed and long-term information about the dietary intake of all these people, so that they could analyze their dietary patterns, including the intake of different food groups, foods, and nutrients. In addition, they collected information from study participants on several factors that are known to influence metabolism and risk of disease, including measurements of blood sugar (glucose), cholesterol, and inflammation, before and after meals. . Finally, they measured the personal health attributes of the study participants, including age, weight, body mass index (BMI), body fat, and blood pressure.

Diet influences the microbiome and the microbiome influences the risk of disease

The study found that the health of the microbiome is influenced by diet and that the composition of the microbiome influences the risk of health outcomes. The results showed that specific intestinal microbes were associated with specific 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 the most affected by diet-influenced microbiome changes.

For example, less healthy dietary patterns (dairy desserts, unhealthy meats, processed foods) supported intestinal species associated with measures of blood sugar, cholesterol, and inflammation that are significantly associated with an increased risk of heart events, accidents. cerebrovascular and type 2 diabetes.

In contrast, a more diverse intestinal microbiome was linked to healthy dietary patterns (high-fiber vegetables such as spinach and broccoli, nuts, and heathy foods such as fish and eggs) and was linked to measures related to a lower risk of certain diseases. chronicles. . In addition, the study found that polyunsaturated fats (found in fish, nuts, pumpkin seeds, flax and chia, sunflower, safflower, and non-hydrogenated soybean oils) produce healthy intestinal species associated with a reduced risk. of chronic disease.

A minimally processed plant-based diet is good for the microbiome and to reduce the risk of disease

So what do these findings mean? First, the study showed that eating more unprocessed plant foods (fruits, vegetables, nuts, seeds, and whole grains) allows the gut microbiome to thrive. Some foods of animal origin, such as fish and eggs, are also favorable. Avoiding certain foods of animal origin, such as red meat and bacon, dairy and highly processed foods (even processed plant foods such as sauces, baked beans, juices or sugary drinks and desserts) prevents unhealthy intestinal spices colonize the gut.

It is important to keep in mind that food quality is important; processed o ultraprocessed plant foods they were not associated with clusters of intestinal microbes. When choosing foods, consider whether they are processed or unprocessed, as well as whether they are a plant or animal food.

It can also be helpful to think in terms of dietary patterns, rather than individual foods or food groups. Food patterns that emphasize foods that are beneficial to the microbiome are plant-based dietary patterns. They include vegan diets (no animal products) and ovo-vegetarians (vegetarians plus eggs). The fish-eating pattern, in which fatty, white fish are the preferred meats, is also good for the microbiome.

Emphasizing minimally processed plant foods allows the intestinal microbiome to thrive, providing protection against or decreasing the risk of chronic diseases such as heart disease, diabetes, metabolic diseases, and obesity.

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