High Blood Pressure and Colon Bacteria


The CARDIA Study shows that having certain types of bacteria in your colon is associated with having high blood pressure (Hypertension, Mar 25, 2019), and that you can lower blood pressure by improving the proportion of healthful to unhealthful bacteria in your colon.

Lifestyle changes may be more important than drugs in treating high blood pressure (BMJ, Feb 15, 2019;364:l571). More than 90 percent of North Americans will eventually develop high blood pressure, which markedly increases risk for strokes and heart attacks. You cannot cure high blood pressure by taking drugs; you can only cure it by changing the lifestyle factors that cause it. Drugs only help to control high blood pressure for as long as you continue to take them (Hypertension, 2002;40(5):612-618). Most people cannot control high blood pressure by taking just one drug; often they have to take as many as four or more drugs together.
High blood pressure is associated with:
• eating large amounts of meat, sugar and fried foods;
• not eating enough vegetables, beans, fruits and other parts of plants;
• being overweight; and
• not exercising

The CARDIA study suggests that lifestyle changes may help to lower high blood pressure because they increase the number and diversity of healthful bacteria in your colon.

Change the Foods You Eat for More Healthful Colon Bacteria
Eat more vegetables, fruits, beans, seeds and other plant parts: These nutrient-rich foods contain complex carbohydrates and fats that are not released rapidly into the bloodstream so they do not cause high rises in blood sugar and insulin, and their fiber passes to the colon where bacteria convert it to anti-inflammatory SCFAs (short chain fatty acids). A vegan diet lowers high blood pressure, even without calorie restriction or weight loss (American Journal of Medicine, March 08, 2019).
Restrict meat and other animal products: Many studies associate eating meat with high blood pressure (Austin J Pulm Respir Med, January 21, 2015;2(1):1019). Mammal meat can cause high blood pressure (J Hypertens, 2008; 26: 215-222) because it contains carnitine that is converted by colon bacteria to a chemical called TMAO that stiffens arteries and causes high blood pressure and arteriosclerosis (Nat Med, 2013; 19: 576-585).
Restrict sugar-added foods: People who take in 10-25 percent of their calories from sugared beverages and foods are at increased risk for high blood pressure and suffer a 30 percent higher risk for heart attacks, compared with people who take less than ten percent of calories from added sugars (British Medical Journal: Open Heart, Dec. 11, 2014). See Excess Sugar Favors Growth of Harmful Gut Bacteria
Avoid excess salt: Many doctors believe that a high-salt diet is a major cause of high blood pressure, but low-salt diets reduce systolic blood pressure by less than 5 mm Hg in most adults with hypertension (JAMA Intern Med, 2014;174(4):516-524).

In a recent study, researchers put 158 people with high blood pressure on one of three heart-healthy diets that were planned to be 1)high carbohydrate, 2)high protein, or 3)high monounsaturated fats (The American Journal of Clinical Nutrition, March 1, 2018). All three of the diets were low in the foods that are most often associated with high blood pressure: meat, added sugars and fried foods. All of the “healthful” diets lowered high blood pressure in more than 60 percent of the participants, and all three diets caused similar lowering of blood and urine markers of cell damage and inflammation. The people who had their high blood pressure lowered had significant favorable changes of six urinary metabolites that bacteria in your colon make from the food that you eat. These urinary components are associated with a drop in high blood pressure and a reduction in heart attacks. The authors believe that these changes occurred because the participants ate foods that reduced the unhealthful bacteria and increased the healthful bacteria in their colons.

Who is Likely to Develop High Blood Pressure?
A report in the Journal of Hypertension lists indicators of risk for developing high blood pressure:
• high resting heart rate (>70)
• overweight (BMI>25)
• high LDL cholesterol (>100)
• high uric acid level (>6.0 mg/dL)
• high blood sugar (>145 one hour after a meal)
• low glomerular filtration rate (a test of kidney function)
Having two of these factors doubles your chances of suffering high blood pressure and having three almost triples your chances (J of Hypertension, March 5, 2019).

Other risk factors for high blood pressure include:
• not exercising
• eating an unhealthful diet
• drinking alcohol
• smoking or exposure to smoke
• having sleep apnea
• being diabetic

You are considered to have high blood pressure if your systolic blood pressure is greater than 120 before you go to bed at night or just after you wake in the morning (when your blood pressure is at its lowest level). You may also have high blood pressure if your systolic pressure is greater than 140 after resting for 5 to 10 minutes during the day.

My Recommendations
All of the lifestyle changes that help to prevent and treat high blood pressure will also help to protect you from heart attacks, dementia, diabetes and many other life-shortening diseases, so these recommendations apply to virtually all North American adults.
• Restrict sugared drinks and sugar-added foods, and limit other refined carbohydrates such as foods made from flour
• Restrict mammal meat and limit other animal products
• Eat large amounts of vegetables, beans, nuts, unground whole grains, fruits and other plant parts
• Exercise
• Avoid being overweight
• Restrict alcohol; even moderate amounts of alcohol raise risk for high blood pressure (American College of Cardiology’s 68th Annual Scientific Session, Sunday, March 17, 2019)
• Avoid smoking

Checked 1/27/23