It was thought that arthritis and joint pain afflicting obese people was caused by overstressed joints. However, an article from Genetic Engineering and Biotechnology News titled “Obese Microbiome May be the Real Cause of ‘Wear and Tear’ Arthritis” shows that the cause of arthritis is actually from inflammation driven by the microbiomes that live in the guts of obese people. The high-fat diet many obese people have unbalances the gut microbiome which in turn causes inflammation throughout their bodies, leading to very rapid joint deterioration. To solve the issue of arthritis, Micheal Zusick and his team at the University of Rochester Medical Center conducted an experiment on mice to see if a high-fat diet’s effects might be lessened with a prebiotic, a food that is high in fiber with the intention of improving the balance of microorganisms (in this case, microbiomes).
In a healthy mouse gut, Bifidobacteria , a beneficial probiotic bacteria, is abundant. Probiotics are live microorganisms intended to provide health benefits when consumed, generally by improving or restoring the gut bacteria. However when a mice becomes obese, proinflammatory species gain in abundance. In the first part of the experiment, Michael fed mice a high-fat diet, similar to a “cheeseburger and milkshake” human diet, and after only 12 weeks of this diet, the experimental mice became obese and diabetic. They doubled their body fat percentage compared to control mice, which were fed a low-fat, healthy diet. As predicted, the colons of the obese mice were dominated by proinflammatory bacteria, and almost completely lacked Bifidobacteria. The changes in the gut microbiomes of the mice were in conjunction with signs of inflammation, as when the researchers induced osteoarthritis (OA) with a meniscal tear, a common athletic injury known to cause osteoarthritis, OA progressed much more quickly in the obese mice than in lean mice, as nearly all of the obese mice’s cartilage disappeared within 12 weeks of the tear.
Micheal then repeated the experiment but this time gave the mice the prebiotic oligofructose. What do you think is going to happen?
The results showed that the effects of obesity on gut bacteria, inflammation, and OA were completely prevented when the high-fat diet of obese mice was supplemented with the prebiotic. Prebiotics cannot be digested by rodents or humans, but they are welcomed for certain types of beneficial gut bacteria, like Bifidobacteria because colonies of those bacteria chowed down and grew, taking over the guts of obese mice and crowding out bad actors, like pro-inflammatory bacteria. This, in turn, decreased systemic inflammation and slowed cartilage breakdown in the mice’s OA knees.
Oligofructose made the obese mice less diabetic but it did not change the mice’s body weight. Obese mice who were given oligofructose remained obese. They had the same load of weight on their joints yet their joints were healthier. Reducing inflammation was enough to protect joint cartilage from degeneration. This shows that inflammation is the cause of OA and joint degeneration.
I think this topic is very interesting because arthritis can be very painful and can change a person’s physical life dramatically. Helping people to minimize the stress on their joints could allow them to get up and do activities they couldn’t before, improving their quality of life.