The Microbiome in Your Gut & The 12 hour Fast

 Here are some take-home messages for human health from the recent Commonweal symposium on the microbiome – the trillions of bacteria, viruses and fungi that live on and in our bodies.

*the good ones can be our friends – they want us to survive (from an

evolutionary standpoint) so they can survive.  We can work with them.  We want them to outnumber the bad bacteria that promote disease.

*good microbes in our guts eat fiber – from vegetables and fruits.  If we don’t give them plenty of fiber, they start eating the mucus lining of our intestines.  This promotes a ‘leaky gut’, allowing bacteria to enter our bloodstream.  This promotes inflammation and human disease. Eat plenty of fiber – meaning vegetables and fruits.  They have many other benefits in terms of vitamins and related nutrients. Avoid refined flours and sugars, which lack fiber and promote obesity.

*Good bacteria are found in probiotic foods, especially fermented foods, such as yogurt, kefir, kimchi, sauerkraut, miso, and also in probiotic supplements.  Have a probiotic food daily, including when you take antibiotics. Take a probiotic supplement if you don't eat these foods daily.

*Vegetables and fruits grown organically in healthy soil will be good for the earth and for you – you will benefit from their good bacteria.

More on the 12 Hour fast

Researchers from UC San Diego and the Salk Institute have done extensive work with mice  - showing that restricting food intake to an 8 to 12 hour time is beneficial.  Mice fed ad lib throughout 24 hours become obese and diabetic, whereas mice eating the same calories in an 8 to 12 hour window stay at normal weight and do not develop diabetes.

These researchers have not yet done human studies, as funding is scarce.  However, many previous studies done in mice been shown to be helpful in humans, as we share a similar metabolism.  Here is a quote from the Salk Institute – “The daily feeding-fasting cycle activates liver enzymes that breakdown cholesterol into bile acids, spurring the metabolism of brown fat -- a type of "good fat" in our body that converts extra calories to heat. Thus the body literally burns fat during fasting. The liver also shuts down glucose production for several hours, which helps lower blood glucose. The extra glucose that would have ended up in the blood -- high blood sugar is a hallmark of diabetes -- is instead used to build molecules that repair damaged cells and make new DNA. This helps prevent chronic inflammation, which has been implicated in the development of a number of diseases, including heart disease, cancer, stroke and Alzheimer's. Under the time-restricted feeding schedule studied by Panda's lab, such low-grade inflammation was also reduced.”

It’s easy and beneficial to do a 12 hour fast.  (It’s safe for most people – consult your doctor if you are taking meds for diabetes, have type 1 diabetes, or any other questions.)  Eat enough healthy food during the day, and see if it works for you.

Sadja Greenwood, MD, MPH  back issues on this blog.  Leave me a message, and I'll answer you.