Maintaining a Healthy Microbiome
Probiotics For Cardiovascular Health
While the cardiovascular system does not appear to have a microbial community of its own, much attention has recently been drawn to the role of the gut microbiome on cardiovascular health and disease. Research has linked gut dysbiosis to atherosclerosis and hypertension (Lau 2017), and some evidence points to a role of gut microbiota in heart failure (Nagatomo 2015). Clinical trials have shown that probiotic and prebiotic supplements can support weight management and improve other metabolic and inflammatory markers correlated with cardiovascular health (He 2017; Upadrasta 2016).
Probiotics and Blood Pressure
Findings from numerous laboratory and animal studies suggest probiotic bacteria and their fermentation byproducts may have beneficial effects in people with high blood pressure. Possible mechanisms for this effect include reducing oxidative stress and systemic inflammation, improving cholesterol metabolism and dietary calcium absorption, and inhibiting the action of a vasoconstrictive enzyme called angiotensin-converting enzyme (ACE) (Daliri 2017; Upadrasta 2016). In a five-year observational study, intake of dairy products fermented with Lactobacillus casei strain Shirota three or more times per week was associated with a reduced risk of developing hypertension (Aoyagi 2017). In a three-week pilot trial in 40 subjects with obesity and hypertension, blood pressures and body mass indices were reduced in those who received a cheese fermented with the probiotic L. plantarum TENSIA compared to cheese without the probiotic bacteria (Sharafedtinov 2013).
Probiotics and Cholesterol Metabolism
A meta-analysis of 13 trials with a combined total of 485 participants found that probiotic therapy in general can effectively reduce total and LDL-cholesterol levels. In this analysis, L. acidophilus strains were found to have strong lipid-reducing effects (Shimizu 2015). Other Lactobacillus bacteria, such as L. reuteri and L. plantarum, have also been shown to reduce total cholesterol and LDL-cholesterol levels in clinical trials (Lau 2017; Shimizu 2015).
In a randomized trial in 127 subjects with high cholesterol levels, taking capsules with 2.9 billion CFUs of the probiotic L. reuteri NCIMB 30242 twice daily led to a 9.1% decrease in total cholesterol levels, an 11.6% decrease in LDL-cholesterol levels, and a 13.4% improvement in LDL- to HDL-cholesterol ratio compared with placebo after nine weeks. The participants receiving L. reuteri NCIMB 30242 also had lower levels of the inflammatory markers C-reactive protein and fibrinogen at the end of the trial (Jones, Martoni, Prakash 2012). In addition, a second analysis of the results from this trial showed that vitamin D levels increased in those receiving probiotic therapy (Jones 2013). Eating yogurt containing L. reuteri NCIMB 30242 for six weeks was also found to lower elevated total and LDL-cholesterol levels in a placebo-controlled trial with 114 participants (Jones, Martoni, Parent 2012).
In another controlled trial in 49 adults with normal to mildly elevated cholesterol levels, a supplement providing 2 billion CFUs of L. plantarum ECGC 13110402 taken twice daily for 12 weeks lowered LDL-cholesterol levels. A subset of participants who were over age 60 years also had improvements in triglyceride and HDL-cholesterol levels after using the probiotic. Reduced blood pressures were also noted in those receiving the probiotic (Costabile 2017).