By feeding the good bacteria in your digestive tract, a plant-based diet can improve health and prevent disease. In your digestive tract, trillions of bacteria live and play an important role in your health. However, among the thousands of species of gut microbes that live in your gut, some are beneficial to your health and others are not.
Researchers discovered that feeding young pigs a tomato-rich diet for two weeks increased the diversity of gut microbes and shifted gut bacteria toward a more favorable profile. Following the observation of these results with a short-term intervention, the research team intends to move on to human studies to look for health-related links between tomato consumption and changes in the human gut microbiome – the community of microorganisms living in the gastrointestinal tract.
“It’s possible that tomatoes provide benefits by modulating the gut microbiome,” said senior author Jessica Cooperstone, an assistant professor of horticulture and crop science as well as food science and technology at The Ohio State University.
“Overall dietary patterns have been linked to differences in microbiome composition, but food-specific effects have received little attention,” Cooperstone explained. “Ultimately, we’d like to determine what role these specific microorganisms play in humans and how they might contribute to potential health outcomes.”
The research is published in the journal Microbiology Spectrum.
Overall dietary patterns have been linked to differences in microbiome composition, but food-specific effects have received little attention. Ultimately, we’d like to determine what role these specific microorganisms play in humans and how they might contribute to potential health outcomes.
Jessica Cooperstone
The tomatoes used in the study were developed by David Francis, an Ohio State plant breeder, tomato geneticist, and co-author, and are the type commonly found in canned tomato products. Ten recently weaned control pigs were fed a standard diet, and ten pigs were fed the standard diet with 10% of the food made up of a freeze-dried tomato powder.
Both diets had the same amount of fiber, sugar, protein, fat, and calories. The control and study pig populations lived apart, and the researchers who ran the study spent as little time as possible with the pigs – a series of precautions designed to ensure that any microbiome changes observed with the study diet could be attributed to chemical compounds in the tomatoes.
Microbial communities in the pigs’ guts were detected in fecal samples taken before the study began and then seven and 14 days after the diet was introduced.
To sequence all of the microbial DNA in the samples, the researchers used a technique known as shotgun metagenomics. The results revealed two major changes in the microbiomes of pigs fed a tomato-heavy diet: the diversity of microbe species in their guts increased, and the concentrations of two types of bacteria common in the mammalian microbiome shifted to a more favorable profile.
This higher ratio of the phyla Bacteroidota (formerly known as Bacteriodetes) to Bacillota (formerly known as Firmicutes) present in the microbiome has been linked with positive health outcomes, while other studies have linked this ratio in reverse, of higher Bacillota compared to Bacteroidota, to obesity.
Tomatoes account for about 22% of vegetable intake in Western diets, and previous research has associated consumption of tomatoes with reduced risk for the development of various conditions that include cardiovascular disease and some cancers.
But tomatoes’ impact on the gut microbiome is still a mystery, and Cooperstone said these findings in pigs — whose gastrointestinal tract is more similar than rodents’ to the human GI system — suggest it’s an avenue worth exploring.
“This was our first investigation into how tomato consumption might affect the microbiome, and we’ve characterized which microbes are present, as well as how their relative abundance has changed as a result of the tomato intervention,” she explained.
“We need to do more of this type of work in humans over time to truly understand the mechanisms. We also want to understand the complex interplay: how does eating these foods change the composition of what microbes are present, and what effect does that have functionally? More knowledge could lead to more evidence-based dietary recommendations for long-term health.”
