“You are what you eat” is an old saying originally penned in 1826 by the gastronomic food-wizard Anthelme Brillat-Savarin in his essay on the physiology of gout. He wrote, “Dis-moi ce que tu manges, je te dirai ce que tu es” [Tell me what you eat, and I will tell you what you are]. The same could be said for the trillions of bacteria in your guts: You are what they eat.

Researchers have known for a while that the gut biome needs to be fed soluble fiber found in grains, veggies and fruits for heart health. Now they may know (we’d like to see two more human studies) that your biome also needs insoluble fiber; it adds bulk to the stool and helps food pass more quickly through the stomach and intestines, helping to protect your heart from any effects of high blood pressure.

The bacteria that gobble up insoluble fiber produce a fatty acid called propionate. According to a study in the journal Circulation, this (at least in mice) reduces cardio problems associated with high blood pressure such as abnormal enlargement of the heart, an irregular heartbeat and atherosclerosis.

Insoluble fiber comes from eating foods such as beans, 100 percent whole wheat or bran products, green beans, potatoes, cauliflower and nuts. So, if you have high blood pressure (75 million Americans do) feed the little guys insoluble fiber — and you may get unbelievably big rewards. Not only may insoluble fiber protect your cardio system, it’s part of a brain-boosting diet as well!

Mehmet Oz, M.D. is host of “The Dr. Oz Show,” and Mike Roizen, M.D. is Chief Wellness Officer and Chair of Wellness Institute at Cleveland Clinic. To live your healthiest, tune into “The Dr. Oz Show” or visit www.sharecare.com.