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Dietary Indoles May Help Extend Lifespan

bowl of sprouts

Researchers are continually learning about micronutrients that help improve lifespan. Sometimes we achieve the nutrients directly, such as through the food we eat. And sometimes indirectly, such as through metabolism of our intestinal bacteria.


The microbiome in our bodies is fascinating. We may not be aware of the colony of bacteria that live within our digestive tracts, but they can do wonderful things for our health. For example, we have recently learned that this bacteria plays a role in supporting our immune system.

Those little creatures inside of us may also play a role in helping us live longer and healthier lives.

Researchers with Emory University School of Medicine have found that intestinal bacteria produce a nutrient class called indoles. These micronutrients may help us maintain mobility and resilience throughout our lifespan. Senior author Daniel Kalman PhD calls this a “healthspan”, as it doesn’t necessarily mean you are adding years to your life, but you are definitely adding life to your years.

"With medical advances, people are living longer; but you might not really want to live longer if it means spending those extra years frail and infirm," says Dr. Kalman.

Indoles are produced by many types of bacteria, including E.Coli. Most varieties of E. Coli bacteria are harmless and normally live within the intestines of healthy people. (There are strains that you may have heard of that are harmful to health such as E.Coli 0157:H7, but that isn’t the strain we are talking about here.)

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In an animal study, indoles appeared to increase mobility in older age and improved resistance to stress.

A lot of new research about gut microbiome and health shows that certain foods contribute to a positive balance of the strains of bacteria we find in our digestive tracts. Too much of the wrong foods can upset the balance and lead to systemic inflammation. These include refined carbohydrate (including added sugar), animal foods and trans fats.

Foods that positively impact our microbiota include plants, especially those with anti-oxidant and anti-inflammatory properties such as colorful fruits and vegetables.

Some of these plants also contain direct sources of indoles – cruciferous vegetables like broccoli and kale. These specifically contain Indole-3-carbinol or I3C which is thought to have anti-cancer activity.

Journal Reference:
Robert Sonowal, Daniel Kalman et al. Indoles from commensal bacteria extend healthspan. PNAS, August 21, 2017 DOI: 10.1073/pnas.1706464114

Additional Resource:
Oregon State University – Linus Pauling Institute

Photo Credit: Wikimedia Commons