While hunger might be the most obvious effect of dieting or fasting, dropping the amount you eat can have broader effects on your body than just feeling the need to eat more. Researchers had observed that fasting for long periods of time and exercising could both drop inflammation in a person’s body as measured by blood markers. While some research had shown some of the reasons for this lowering of inflammation, new research out this week has found that the body’s switch in fuel source when calories are scarce may also play a major role.
What does the body normally use for fuel?
The body has several types of fuel it can burn for energy, but it mainly uses the sugar glucose. Glucose is taken in as an ingredient in the food you eat, but it can also be made from some other compounds. Some amino acids that come from protein, for example, can be converted into sugar if food is scarce and the body needs more sugar. That only happens after the body has exhausted its stores, though. The liver is the main storage house for glucose and it stores that sugar in a long molecule called glycogen that’s similar to the starch you find in potatoes. That glycogen can be broken down during short fasts or brief bouts of exercise and can be released into the blood to keep blood sugar up between meals.
What happens when that fuel runs out?
This store is limited. Once it runs out, fat stores have to be used to keep the body going. While sugar is used to make fats, the process can’t be run exactly in reverse the way it can be for glycogen because making fat requires a permanent change in the form of the sugar used to make it. As a result, the body makes something called ketone bodies from the fat that can circulate in the body and be used as an alternative fuel. There are several types of ketone bodies. This research looked at a number of them, but their major finding was with a molecule called β-hydroxybutyrate (BHB) that seemed to reduce inflammation used as fuel during fasting, other diets that reduce sugar intake and exercise.
How did BHB lower inflammation?
There are several chemicals the body uses to trigger immune cells and cause inflammation when it thinks defense is needed. The researchers started out by looking at genes they knew were involved in triggering this inflammatory reaction. They exposed immune cells to signals that would normally trigger inflammation and then added BHB to the mix. They found that BHB acted on a protein called NLRP3 that helped to manufacture inflammatory hormones that were normally released by these cells. With this protein blocked by BHB, hormones were made in smaller amounts and the amount of inflammation decreased. Notably, the effect was specific to NLRP3 and didn’t influence other branches of inflammation. Other ketone bodies they tested didn’t seem to drop inflammation the way BHB did.
Did they test this in animals as well?
The researchers then repeated the experiments using mice. They injected a compound into the mice that would cause inflammation and then injected some with a special type of BHB that would stick around in the body of the mice. Sure enough, mice that had gotten BHB had fewer immune cells in the area of inflammation, indicating fewer inflammatory hormones had been released.
How does this apply to me?
Many diseases have been tied to increased inflammation including heart disease; type 2 diabetes, bone loss, gout, multiple sclerosis and Alzheimer’s disease. Giving BHB is unlikely to reverse or cure these diseases. But doing things that increase it, like dieting, exercising or even giving it as a medication may help decrease how severe a disease is and buy a person time while they try to fix the underlying problem causing the disease.