Eating too much fat and sugar as a child can alter your microbiome for life, even if you follow a healthy diet when you're older, according to new research.
The study from the University of California, Riverside is one of the first to show a significant decrease in the total number and diversity of gut bacteria in mature mice fed an unhealthy diet when they were 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. "You are not only what you eat, but what you ate as a child!"
Garland's team looked for impacts on the microbiome, which refers to all the bacteria as well as fungi, parasites, and viruses that live on and inside a human or animal, after splitting the mice into four groups - one group was fed the standard 'healthy' diet, another was fed the less healthy 'Western' diet, while one group had access to a running wheel for exercise, and the other didn't.
After three weeks, all of the mice were returned to a standard diet and no exercise, and at the 14-week mark, the team examined the diversity and abundance of bacteria in their microbiome.
They found that eating a Western diet early in life had more long-lasting effects on the microbiome than early-life exercise.
The researchers plan to repeat the experiment and take samples at extra points to help get a better understanding of when the microbiome changes first appear and whether they continue much further in life.
However, regardless of when the effects first appear, the researchers believe it's significant that they were observed so long after changing the diet, and then changing it back.