Year-after-year nutritionists keep teaching us to eat varieties of foods to get the most nutrients. Who would argue this concept? The more diverse foods are consumed the greater chance we have of getting different nutrients from the different sources. When we think about health of our microflora we think of addition of probiotics or prebiotics to our diet. Probiotics are live bacteria that we consume from yogurt, kefir or probiotic supplements. Prebiotics are simply foods for our bacteria. So far we know they like fruit and vegetable residues (fiber) that comes to our large intestine. It makes sense to think the more diverse foods we consume the happier is our microflora. Or is it?
Scientists from the University of Texas at Austin and five other institutions hypothesized that fish consuming more diverse foods will feed diverse varieties of bacteria that would lead to higher diversity of colonies in the gut. To test this hypothesis they conducted a study.
Scientists caught 398 stickleback and 255 perch, they divided them into 3 feeding groups. The first group was fed with some frozen insect larvae, others with tiny crustaceans, and a third group had an equal mixture of the two foods. Also, the aquaria had the same microbes in the water as the water in their lake.
To everyone’s surprise, the results showed that the opposite is true: The fish that favored one type of food item had more bacterial diversity in their guts than fish that ate a mixture of prey.
How can this be explained? Researchers have two theories that have not been proven yet. The first theory is that the large diversity of food gives an advantage to some stronger bacteria that may not thrived otherwise, which may cause death of more specialized but weaker bacteria. Second theory is that the diverse foods may mean diverse inhibitory chemicals that may suppress more diverse bacteria.
Although this is the first study that suggests that eating variety of foods maybe not the healthiest thing for microbiota, this is the first study that examined the question of the effect of the variation of foods on microbiota. Certainly we don’t have enough research on this topic to make a conclusion how human microbiota is affected by variety of foods in our diet. There are more studies that have to be done using human subjects to answer this question. This study should not be used as a guide but just as a question to further research this subject.