Although probiotics reside in the gut, their effects reach far beyond the digestive tract. The connection between heart and gut health is being investigated, particularly in reference to the use of probiotics for the reduction of LDL cholesterol. In a recent article published in the journal Nutrition Reviews, clinical trials evaluating the effects of probiotics on biomarkers of cardiovascular disease were reviewed.¹ Twenty-six clinical studies and two meta-analyses were reviewed, identifying four strains of probiotics effective for lowering cholesterol: Lactobacillus reuteri NCIMB 30242, Enterococcus faecium, and the combination of Lactobacillus acidophilus La5 and Bifidobacterium lactis Bb12, in addition to two synbiotic (probiotic + prebiotic) combinations: Lactobacillus acidophilus CHO-220 plus inulin and a mix of Lactobacillus acidophilus strains plus fructo-oligosaccharides (FOS).

Cardiovascular disease (CVD) is the leading cause of death worldwide. One in every three deaths in the United States is the result of cardiovascular disease, and it is rapidly increasing in low- and middle-income countries around the world. Adopting healthy lifestyle habits is an under-practiced yet crucial aspect of treating and preventing CVD. In addition to a healthy diet, maintenance of healthy body weight, regular exercise, avoidance of tobacco products, and routine medical checkups, the use of certain supplements has the potential to decrease cardiovascular risk factors. Fish oils, phytosterols, and soluble fibers are currently among those most known for beneficially affecting blood lipids. As it turns out, probiotics could be added to that prestigious list.

The study of beneficial bacteria for heart health actually begin in the 1960s when researchers investigated the link between fermented milk and low cholesterol levels and heart disease rates in the Maasai and Samburu tribes of Africa, both of which consumed a diet high in saturated fats via dairy and beef.^2,3 Since then, many studies have looked at the effects of probiotics on lowering LDL cholesterol to reduce the risk of heart disease.

Of the four probiotic strains and two synbiotic combinations studied, L. reuteri NCIMB 30242 has the most robust evidence. Two randomized, placebo-controlled, double-blind, parallel arm, multicenter studies in both yogurt (2.8 billion CFU daily)⁴ and capsules (4 billion CFU daily)⁵ found that the probiotic reduced total and LDL-cholesterol when compared to placebo. L. reuteri also had beneficial effects on lowering hs-CRP (high-sensitivity C-reactive protein) and fibrinogen levels, two more biomarkers of CVD health, and major markers of overall systemic inflammation as well.

Although it is known that probiotics have a positive effect on cholesterol levels, it is not entirely known how they work. The review article proposes several mechanisms for how probiotics may reduce circulating cholesterol levels:

1. “Binding of cholesterol by the cellular surfaces and membranes of the probiotics.
2. Assimilation of cholesterol particles into growing probiotic cells.
3. Microbial deconjugation of bile via bile salt hydrolase, resulting in increased fecal excretion of deconjugated bile salts with a compensatory increase in the use of cholesterol to produce new bile acids.
4. Short-chain fatty acid production from fermentation of carbohydrate, leading to decreased levels of blood lipids and reduced production of endogenous cholesterol by the liver.
5. A reduction in cholesterol absorption, perhaps through bile salt hydrolase activity and deconjugation of biliary salts in the small intestine.”

Statin drugs are widely prescribed for their cholesterol-lowering effects, but they come with side effects that many find intolerable. Probiotics, in addition to the healthy lifestyle habits mentioned above, are an excellent natural option with additional digestive and immune health benefits.

References

1. DiRienzo DB, “Effect of probiotics on biomarkers of cardiovascular disease: implications for heart-healthy diets.” Nutr Rev. 2014 Jan;72(1):18-29.
2. Shaper AG, Jones JW, Jones M, “Serum lipids in three nomadic tribes of Northern Kenya.” Am J Clin Nutr. 1963 Sep;13:135-46.
3. Mann GV, “Studies of a surfactant and cholesteremia in the Maasai.” Am J Clin Nutr. 1974 May;27(5):464-9.
4. Jones ML, Martoni CJ, and Prakash S, “Cholesterol lowering and inhibition of sterol absorption by Lactobacillus reuteri NCIMB 30242: a randomized controlled trial.” Eur J Clin Nutr. 2012 Nov;66(11):1234-41.
5. Jones ML, Martoni CJ, Tamber S, et al., “Evaluation of safety and tolerance of microencapsulated Lactobacillus reuteri NCIMB 30242 in a yogurt formulation: a randomized, placebo-controlled, double-blind study.” Food Chem Toxicol. 2012 Jun;50(6):2216-23.

Leonard Smith, MD
Dr. Leonard Smith is a prominent Board-Certified, general, gastrointestinal and vascular surgeon who had a successful private practice for 25 years. In addition to his active surgery practice, he also incorporated lifestyle, diet, supplementation, exercise, detoxification, and stress management into many of the therapies he would prescribe. Many of his patients with cancer, cardiovascular disease, and other serious illnesses did so well under his treatment regimes that he began to devote most of his career to foundational health care and preventive medicine.