About 22% of the vegetables consumed in Western diets are tomatoes – though whether tomatoes should even be classed as vegetables is a debate for another time. Given how abundant they are in our diets, how are tomatoes benefiting our health? A recent study, published in Microbiology Spectrum, revealed that a tomato-rich diet may be the key to a healthier lifestyle.
Tomatoes – good for you and your gut bacteria
The gut microbiota (the community of microorganisms in the gastrointestinal tract) consists of around one hundred trillion microorganisms. The microbiome (the collection of genomes of the microorganisms) consists of over three million genes. It is thought of as another “organ of the body.” Diet has a significant impact on this “organ,” but food-specific effects on gut microbe profiles have not been studied extensively.
Researchers from the Ohio State University and the Pennsylvania State University found that tomatoes have a positive effect on the gut microbiota of piglets: diversity of bacterial species increased and a healthier bacteria profile was favoured.
Jessica Cooperstone, senior author of the paper and Assistant Professor of Horticulture and Crop Science and Food Science and Technology at Ohio State University said, “It’s possible that tomatoes impart benefits through their modulation of the gut microbiome. Ultimately, we’d like to identify in humans what the role is of these particular microorganisms and how they might be contributing to potential health outcomes.”
The experimental approach
The researchers set up a controlled experiment. Ten piglets were fed a standard diet and another ten piglets were fed the same standard diet that was supplemented with a freeze-dried tomato powder. Piglets were used because their GI tracts are similar to those of humans. There was minimal interaction with the researchers and additional measures were taken to guarantee that any observed changes could be solely attributed to diet.
Faecal samples were taken before the experiment, at 1 week and then at 2 weeks. All the microbial DNA in the samples was sequenced using shotgun metagenomic sequencing (untargeted sequencing of all the DNA present in a sample). This allowed the researchers to determine what the different proportions of bacteria were at the phylum level. This gave a broad and global overview of the gut microbiome.
They found that not only was there greater bacterial diversity with a tomato-supplemented diet, but a higher Bacteroidota to Bacillota ratio. This particular bacterial ratio is associated with a lower risk of obesity and cardiovascular disease.
Evidence-based dietary recommendations
These early findings have shown the positive effects of a tomato-rich diet in piglets. The research offers a strong foundation for future human studies.
“This was our first investigation as to how tomato consumption might affect the microbiome, and we’ve characterized which microbes are present, and how their relative abundance has changed with this tomato intervention,” said Professor Cooperstone. “To really understand the mechanisms, we need to do more of this kind of work in humans in the long term. A better understanding could lead to more evidence-based dietary recommendations for long-term health.”