Plant-based diets shine when looking at the gut microbiome

September 7, 2020

A recent study investigating how foods impact gut health in children points to plant-based proteins, fresh fruits and vegetables, and grains as key to a diverse and healthy microbiome.

There has been a wealth of evidence collected on how important the gut microbiome is for health maintenance, but little research has been done on how diet habits are related to gut health in prepubescent children. A recent study took a closer look.

The study,1 published in the Journal of the Academy of Nutrition and Dietetics, reveals that gut health in young children and pre-pubescent teenagers is both dynamic and diverse, and is particularly responsive to certain food groups.

“The gut microbiome remains dynamic for children past 3 years of age and responds to dietary differences,” says lead author Dena Herman, PhD, MPH, RD, professor at California State University, Northridge and director of the MCH Nutrition Leadership Training Program at the UCLA Fielding School of Public Health. “This represents an opportunity to learn healthy habits early in life so that they can be sustained over the life course to maximize health.”

The health of the gut plays a vital role in maintaining health and supporting immune functions, the study notes. The microbiome is impacted by a number of factors, with individualized diets being one of the most important determinants of a diverse gut environment.

The microbiome of the gut is created at birth, the study notes, but continues to develop throughout infancy and is significantly affected throughout childhood by diet. There is a large shift in the composition of the gut as infants are weaned and begin consuming solid foods, with the makeup of the gut resembling that of adults by about age 3 years. Little research has been done on the makeup of the childhood gut between 3 years of age and the adolescent years, the study notes, but dietary patterns have been associated with significant differences in the guts of children in the age range of 4 to 8 years. As diets have shifted more toward a Western diet, heavily featuring highly processed foods and high-fat animal products, more and more diseases have been attributed to an imbalance in the microbial composition of the gut, the study reveals.

To examine how diet influenced gut health in the study group, researchers asked parents to collect fecal samples and quantitative 24-hour diet recalls, investigating each 3 times, each time about 6 days apart. The team examined how diet impacted gut health by splitting children into groups based on the types of food they consumed. Protein consumption—both animal- and plant-based—was the only food group that was associated with gut diversity. Total grain and vegetable consumption, on the other hand, heavily influenced the community makeup of the microbiome, the study notes. The research team noted some surprise here, in that yogurt was the only animal-derived food that was associated with the membership and structure of the microbiome. Instead, proteins were more closely linked to higher levels of diversity in the types of microorganisms found in the gut, the study states. The most abundant microorganisms found in the study groups were Bacteroides and Prevotella. The first was tied to Western diets, and the latter to fiber-rich diets.

Adequate diversity in the microbiome samples was noted, with results appropriate for the cohort’s age group. The research team found that older children in the study group had more diversity in their gut microbiomes, and that gender had no impact on the results. There were a number of trends noted with different food groups, such as lower diversity with a high non- whole-food grain consumption, and abundance of certain bacteria groups with higher consumption of fruit and fiber.

Overall, the study revealed that fresh fruits and vegetable consumption led to increased variation in the structure of the microbiome—with citrus, melon, and berries contributing most to gut diversity. Whole and non-whole grains were key to maintaining gut health, immune health, and glucose regulation, Herman stated. B-vitamins also played a big role in gut health, contributing to microbiome structure and composition, she says.

The 2- to 9-year-old group studied in this report is significant, because this represents a time when diets are becoming more diverse, and children begin to explore and become more independent in their eating habits. The study highlights the need to make this time count, the study notes, with guidance from adults on healthy eating habits to help promote good health and disease prevention in adulthood.

“Early and middle childhood may represent a crucial window when the gut microbiome might still be amenable to lasting manipulations through diet,” the study reveals.

The study emphasizes the importance of diet in the development of a healthy microbiome during the childhood years, with non-whole-grain foods enriched with vitamins and minerals being perhaps one of the largest contributors to gut health in this pilot sample.

“There are many benefits of a healthy gut for children. First and foremost, is an enhanced immune response. Young children are often more susceptible to upper respiratory tract infections and ear infections, especially if they are in childcare and as they enter school,” Herman explains. “By maintaining a diverse diet, children have a better chance of maximizing the healthy bacteria that can support immune health.”

The benefits of a healthy gut don’t end with physical health, she adds. Mental health effects were not the focus of the study, Herman says, but there has been prior research drawing a strong connection between gut health and brain health.

“For children this could translate into better focus in school allowing them to reach their academic potential. Unlike other studies, this study showed that children past 3 years of age are still able to change the structure and membership of their microbiome through the foods that they eat,” she says. “This is exciting and helps us extend the findings from studies in adults to children. The benefits described for children are similar for adults. However, as we age we have increased risk for inflammation, which can lead to higher rates of chronic diseases including cancers. That is why it is important to start healthy habits as early in life as possible.”

Although the study was small, it was more detailed than most previously conducted research examining gut health in children, she says. It highlights the benefits of plant-based diets, which Herman says she hopes will convince parents and clinicians to make changes—both for their children and themselves.

“I would hope that the results we have shared provide further support for the promotion of a plant-based diet—not only for young children, but also for adults. Parents are role models for their children’s eating habits and this study shows that we can actively engage in making positive changes to our gut health and overall health starting at a young age,” Herman says. “As a pediatric dietitian myself, I would hope that we could work together with the medical community, particularly pediatricians, to promote healthy habits including healthful eating habits and regular exercise through anticipatory guidance at all well-child visits. With the high rates of obesity in the United States, having children consume foods that support reduced risk for obesity may translate into lower risks for obesity-related diseases in adulthood such as cardiovascular disease and diabetes. Starting this practice as early as possible will ensure the most benefit for these children and generations to come.”

Reference

1. Herman D, Rhoades N, Mercado J, Argueta P, Lopez U, Flores G. Dietary habits of 2- to 9-year-old american children are associated with gut microbiome composition. J Acad Nutr Diet. 2020;120(4):517-534. doi:10.1016/j.jand.2019.07.024