We’ve all heard the old adage “you are what you eat.” But what if you’re also what you ate as a child? Can children’s diets continue to affect them throughout the rest of their lives? Is it possible that excess fat and sugar in a child’s diet can change their microbiome for the worse?
Those are the findings being suggested by a new study in mice. Carried out by researchers at the University of California – Riverside, this study is one of the first to show a drastic reduction in the diversity and total number of gut bacteria in mature mice who were fed a high-fat and high-sugar diet as juveniles.
“We studied mice, but the effect we observed is equivalent to kids having a Western diet, high in fat and sugar and their gut microbiome still being affected up to six years after puberty,” explained UCR evolutionary physiologist Theodore Garland. The UCR paper was published in the Journal of Experimental Biology.
What is your microbiome? On a large scale, it refers to the total community of bacteria, fungi, viruses and parasites that are living on and inside of you right now. Before you panic and reach for the bug spray, many of these are helpful, most of them living in your gut. They do things like break down food, synthesize vitamins and nutrients and stimulate the immune system.
In case you’re wondering, yes, there are some pathogenic critters in there, too. When you’re healthy, there is a balance between “good and evil.” That balance can be disturbed, however. Antibiotic use is one way. Illness and poor diet can also throw things off and make you more susceptible to disease.
Garland’s team divided the mice into four intersecting groups in order to assess the impact of diet on the microbiome. Half the mice were fed a standard, healthier diet, half were fed a “Western” diet, higher in fat and sugar. Across these two groups, half the mice had access to an exercise wheel, half did not.
This pattern was maintained for three weeks. The mice were then returned to a condition wherein they received a standard, healthier diet and did no exercise. This is how laboratory mice are normally kept. At 14 weeks, the researchers examined the abundance of gut bacteria and the diversity of the microbiome in the mice.
They discovered something interesting in the Western diet group. The quantity of bacteria such as Muribaculum intestinale was much lower in this group. M. intestinale is a gut bacteria that plays a role in carbohydrate metabolism.
According to the study, exercise matters, too. Muribaculum bacteria counts went up in mice on the standard diet who had access to exercise. For those on the Western diet, however, it didn’t matter whether they exercised or not. Muribaculum bacteria counts decreased in both exercise and non-exercise groups fed the Western diet.
While research is ongoing into the full range of functions this family of bacteria have, researchers believe one important function of Muribaculum intestinale and it’s associated family of bacteria is that it influences how much energy is available to its host.
In another study, researchers noted that a very similar species of bacteria increased in number after five weeks of treadmill training. This suggests that exercise alone is enough to increase this bacteria’s numbers in the gut. In another study from Finland, endurance exercise was found to improve gut health by improving the numbers and quality of bacteria involved in metabolism. (See Endurance Exercise Can Give You A Healthier Gut.)
The strongest finding in the UCR study, however, was that consuming a Western diet early in life had more lasting negative effects on the microbiome than the positive ones from early-life exercise.
In order to assess and understand when the changes in the mouse microbiomes begin and whether they continue into later phases of life, Garland’s team hope to repeat their experiment, with additional samples taken at other points in time.
The most significant finding overall, say the researchers, is that the negative effects of the Western diet were noted so long after changing the diet and persisted even after changing it back.
The takeaway, Garland said, is essentially, “You are not only what you eat, but what you ate as a child!”
While more research in this area is sure to come, it seems safe to say that the gut health benefits of good diet and exercise for children will be long-lasting. The more we learn, the more obvious this becomes. Perhaps it’s time we start giving more than lip service and casual attention to what our kids eat and how much they move!
Keep the faith and keep after it!
Journal Reference – Monica P. McNamara, Jennifer M. Singleton, Marcell D. Cadney, Paul M. Ruegger, James Borneman, Theodore Garland. Early-life effects of juvenile Western diet and exercise on adult gut microbiome composition in mice. The Journal of Experimental Biology, 2021; jeb.239699 DOI: 10.1242/jeb.239699