How a high fiber diet improves one’s overall health


Is leaky gut syndrome real? Formerly thought of as an imaginary disease, leaky gut syndrome is increasingly accepted by mainstream medical science. The condition involves the gradual damaging of the gut lining by the diet a person eats, eventually leading to low overall health, with everything from diabetes to cardiovascular disease all being linked to problems with the health of the gut. According to microbiologist Justin Sonnenburg, those who do not eat anything resembling the modern western diet have a completely different mix of bacteria in their digestive systems, and this makes them mostly immune to many of the diseases that plague much of the world today.

His group of Italian microbiologists compared the gut bacteria of people in Italy to people in rural Burkina Faso and found an enormous difference between the two populations. The villagers in Burkina Faso ate mostly millet and sorghum, and therefore had a large amount of microbial diversity compared to those who ate less fiber and more refined foods in Europe. The Italians had microbes that were intended to help digest sugars, fats, and proteins, in Burkina Faso the microbes were mostly capable of digesting fiber and complex carbohydrates. It is well known that one’s gut microbiome is intended to absorb adapts to what one eats – but does this affect a person’s health?

According to Sonnenburg, almost all westerners have an unhealthy microbiome. We do not even recognize it as a health problem. Because it is nearly universal, it is thought of as usual, when it is actually a health issue. The diet that prevailed through most of human evolution was radically different from the menu that is normal today, and the microbes that are in our digestive systems are not those we evolved to benefit from. When Sonnenburg published his study, in 2010, what gut microbes were good for health was only beginning to be understood, but it was known that a diversity of bacteria is essential. The study proved that fiber, which was eaten in much higher quantity in West Africa, encouraged a variety of microbes to grow in the gut.


Another study that Sonnenburg was involved in was conducted on mice, which were split into groups that fed on higher and lower quantities of fiber, with their gut bacteria being compared afterward. The mice fed a high fiber diet ended up with a much greater microbial diversity. Thankfully, the damage is not permanent – after a few weeks of switching from one diet to the other, the microbes of the low fiber mice adjusted to their new high fiber diet. On another level, there is evidence that one inherits the microbiome of one’s mother, and that these changes may, therefore, take generations to entirely correct. While antibiotics greatly increased the average life expectancy, and have done much more good than harm so far, they may also be overused, as they destroy healthy gut bacteria.

The idea that gut bacteria have a significant effect on health has only recently stopped being considered unscientific and has a long way to go before it is well understood. We do not usually know whether or not a specific bacteria is positive, harmful, or neutral. Sonnenburg envisions that, although this is not likely to occur soon, many medical treatments could involve replacing a persons’ digestive bacteria with a healthier microbiome and using a high fiber diet to maintain it. While this is still a long way away, the days in which it was considered close to quackery to place a lot of importance on gut bacteria are now over.