How are diet and the immune system related?

When you think about ‘immune reactions’ and eating, allergies or spoiled food are probably top of mind. This is your body trying to keep you from eating things it thinks are going to kill you.

However, the type of foods you eat and your nutritional status is also deeply linked with your ability to resist a host of diseases more generally.

A link between undernutrition and famine, and an inability to fight off various infections like tuberculosis and measles has been known for some time. More recently though, overnutrition and obesity have been shown to be associated with an overactive immune system.

The #1 cause of death in the U.S. is cardiovascular disease, which is caused by narrowing of the arteries due to the accumulation of plaques (atherosclerosis). These plaques are quite literally made up of immune cells (macrophages), cholesterol, and fats. The signals that cause this deadly buildup are increased in people and animals that are obese.

Interestingly, these same signals also cause your cells to stop responding to insulin (insulin resistance), the hallmark of Type-2 diabetes.

How do you reduce these signals? If you’re following along, you might’ve already guessed the answer. Fiber!

When the good microbes in your gut break down fiber, they create anti-inflammatory molecules (Short Chain Fatty Acids), contributing to a reversal of the negative effects we mentioned above. These molecules can also affect your appetite, leaving you fuller and less prone to overeating.

Remember this:

1. Obesity and overnutrition contribute to an overactive immune system

2. An overactive immune system contributes to atherosclerosis and cardiovascular disease

3. Fiber eaten by microbes in your gut turns into signals that reverse this overactivation.