Impact of resistant starch diet intervention on autoimmunity

Research from Yale examined the link between diet and autoimmune diseases. The study found that a diet high in fiber, including resistant starch, reduced levels of bacteria, keeping the bacteria from moving outside of the gut and triggering autoimmune disease. Resistant starch promotes gut health by feeding the 'good bacteria' that live in our large bowel. These bacteria are called our microbiome. They can use resistant starch as food because it resists digestion in our small intestine, and moves on to the large bowel.

Could a change in diet be beneficial to people with autoimmune diseases such as lupus? A Yale-led team of researchers have revealed how a dietary intervention can help prevent the development of this autoimmune disease in susceptible mice. The study was published in Cell Host & Microbe.

For the study, led by Yale immunobiologist Martin Kriegel, the research team used mouse models of lupus. They first identified a single bacterium, Lactobacillus reuteri, in the gut of the mice that triggered an immune response leading to the disease. Specifically, in lupus-prone mice, L. reuteri stimulated immune cells known as dendritic cells, as well as immune system pathways that exacerbated disease development.

To investigate the potential impact of diet on this process, first author Daniel Zegarra-Ruiz fed the mice “resistant starch” — a diet that mimics a high-fiber diet in humans. The resistant starch is not absorbed in the small intestine but ferments in the large intestine, enriching good bacteria and causing the secretion of short-chain fatty acids. This, in turn, suppresses both the growth and movement of L. reuteri bacteria outside the gut that would otherwise lead to autoimmune disease.

While more research is needed to discern how the findings translate to humans, the study details an important link between diet, gut bacteria, and autoimmunity. “We dissected, molecularly, how diets can work on the gut microbiome,” said Kriegel. “We identified a pathway that is driving autoimmune disease and mitigated by the diet.”

 “It may have implications beyond lupus.” Kriegel noted.

The research uncovers an important link between diet, gut bacteria and autoimmunity, and can be helpful to future study. 

WHAT IS RESISTANT STARCH? FROM HEALTHLINE

• Type 1: Is found in grains, seeds and legumes and resists digestion because it’s bound within the fibrous cell walls.
• Type 2: Is found in some starchy foods, including raw potatoes and green (unripe) bananas.
• Type 3: Is formed when certain starchy foods, including potatoes and rice, are cooked and then cooled. The cooling turns some of the digestible starches into resistant starches via retrogradation.

Cookies with Oats, and Cashew Nuts both high in resistant starch

FOODS CONTAINING RESISTANT STARCH

Oats, cashew nuts, lentils, chick peas and kidney beans, peas and beans, cooked and cooled potato, sweet potato and yams, cold pasta salad, firm bananas, and wholegrain products.

THE BENEFITS OF RESISTANT STARCH

What are some of the overall benefits of resistant starch in our diets. Well, the key benefits are that we begin to make more short chain fatty acids in our body. When we have more of these, we are better able to:

• Feed good bacteria in our body
• Reduce inflammation throughout our body
• Heal our all-important intestinal tract