Extensive research shows that high blood pressure is associated with having specific harmful bacteria in your colon (Circulation Research, Apr 2021;128(7):934–950), and that reducing harmful colon bacteria and increasing healthful ones can help to control high blood pressure. You can do this primarily by eating an anti-inflammatory diet, as well as by exercising regularly, losing excess weight, and avoiding smoke and alcohol. The American Heart Association reports that more than 100 million North American adults suffer from high blood pressure, the leading modifiable risk factor for heart attacks and strokes that cause more than 400,000 deaths each year (Curr Opin Cardiol, 2017 Jul;32(4):389-396). High blood pressure is defined as greater than 130 mm Hg systolic or 80 diastolic.
Colon Bacteria and High Blood Pressure
Many people who have high blood pressure have been found to have low amounts of the types of colon bacteria that can convert soluble fiber into short chain fatty acids (SCFAs) that are absorbed into the bloodstream and help to lower high blood pressure.
• A review of 41 studies found that eating lots of plants helps to control high blood pressure (J Hypertens, Jan 2021;39(1):23-37). Plants contain soluble fiber that cannot be absorbed until it reaches the colon, where healthful bacteria convert soluble fiber to SCFAs that are absorbed into the bloodstream. SCFAs stimulate their receptors in the kidneys and blood vessels to help lower high blood pressure (Curr Opin Nephrol Hypertens, Sept 2016;25(5):379-83). Plants are also full of flavonoids, chemicals that help to lower high blood pressure (Front Pharmacol, Jun 16, 2021;12:651926).
• A study from China found that the colons of more than 150 people with high blood pressure contained a far narrower variety of different types of bacteria and a marked increase in the bacteria, Prevotella and Klebsiella (Microbiome, Feb 1, 2017;5(1):14), that are associated with increased risk for having high blood pressure (Antioxidants & Redox Signaling, Mar 4, 2021;34(10)). In the same study, researchers transplanted stool from hypertensive humans into germ-free mice and the mice developed high blood pressure.
• A review of 17 studies enrolling 9,085 participants found that people who suffer from high blood pressure have reduced diversity of the more than 1000 different bacteria in their colons, reduced numbers of Firmicutes bacteria that make SCFAs from soluble fiber, and increased numbers of Bacterioides bacteria that do not make SCFAs (Front Cardiovasc Med, May 14, 2021; Environ Microbiol, 2017;19:95–105).
• A high salt diet can change your colony of colon bacteria to increase those that are associated with high blood pressure (Biomedicine Pharmacotherapy, Feb 2021;134:111156), and deplete the colon of healthful bacteria that help to reduce high blood pressure (Nature, Nov 15, 2017;551:585–589; Nutrients, Sept 2018;10(9):1154).
• High dietary sugar changes colon bacteria by decreasing bacterial diversity and increasing the harmful Proteobacteria (Nutrients, Jun 13, 2018;10(6)). Simple sugars that are not absorbed in the intestines and reach the colon promote the growth of harmful colon bacteria that are associated with increased risk for obesity and high blood pressure in mice (PNAS, January 2, 2019;116(1):233-238).
• A study of 205 obese pregnant women, who were at high risk for high blood pressure, found that they had extremely low levels of a healthful bacteria called Odoribacter in their colons. Those with the lowest levels of Odoribacter had the highest blood pressures (Hypertension, 2016;68:974-981).
How to Improve Your Colon Bacteria to Lower Blood Pressure
• Eat lots of plants — vegetables, fruits, beans, whole grains, nuts and other seeds.
• Try to restrict salt.
• Try to restrict foods and drinks with added sugars.
• Try to restrict mammal meat.
• Try to exercise at least half an hour every day.