Heart-Gut Link: The Role of Plant-Based Nutrition

An old saying suggests that "you are what you eat." New research each year provides further evidence to support this idea. Ongoing studies are uncovering strong evidence for the importance of the gut-brain axis in overall health outcomes. Scientists have recently explored the connection between gut and heart extensively. An analysis of over 50,000 individuals who carry the single-cell organism Blastocystis, present in our gut, revealed that its presence is linked to improved cardiovascular health outcomes and a decreased body fat percentage. The study found that Blastocystis carriers had lower diastolic blood pressure, reduced C-peptide, a marker of insulin production, and a lower risk of obesity and disorders linked to altered gut ecology. However, the study also found that Blastocystis carriers had no clear trend in total cholesterol levels or fasting glucose levels.

Researchers of this study aimed to establish a relationship between the quality of diet, Blastocystis, and audiometric indicators in about 57,000 individuals from 32 countries. The results reported that the organism's composition varied by region and dietary pattern.

A higher level of Blastocystis was linked to a healthy, wholesome, plant-based, minimally processed diet.

The research noticed improved cardiometric parameters in people with higher levels of Blastocystis. The study also reported the presence of increased Blastocystis with a 6-month personalized dietary intervention. The same group of researchers revealed in a 2021 single-cohort study that guts bacteria harbouring Blastocystis impact postprandial glucose levels, body mass index, and other biomarkers.

Blastocytosis - A brief note

The role of Blastocystis in host health is still unclear. Blastocystis is a widespread unicellular eukaryote with remarkable genetic diversity. It is currently categorized into at least 28 distinct species, referred to as subtypes (ST). In humans, eight of these STs have been identified, with ST1, ST2, and ST3 being the most common. Generally transmitted via the fecal-oral route, they are among the most common intestinal protozoa in stool samples. Due to Blastocystis' high prevalence and unknown pathogenicity, two possible hypotheses may explain Blastocystis' correlation with gut microbiota. First (theory of positive role): Blastocystis might contribute to microbiota diversity in healthy individuals, so it would be considered an indicator of good gut health. The second theory (theory of negative role): Blastocystis may affect some gastrointestinal disorders such as IBS by altering the gut microbiota. In Blastocystis-positive individuals, there was a decreased abundance of Bifidobacteria and Faecalibacterium prausnitzii, two bacteria essential for maintaining the gut's homeostasis, suggesting Blastocystis may negatively affect gastrointestinal health.

However, the gut-cardiovascular connection goes beyond Blastocystis.

Cardiovascular outcome and gut health - the link

In the past twenty years, researchers have explored how gut bacteria affect the intestines and how the outcomes are related to cardiovascular diseases (CVDs). Recent studies show that gut bacteria can influence the body's functions. CVDs are a significant cause of illness and death, often considered more severe than chronic kidney disease. For gut bacteria to work in the body, their molecules must enter the intestinal lining or surface cells. These bacteria use pathways involving trimethylamine, N-oxide, short-chain fatty acids, and bile acids.

By affecting these pathways, gut bacteria can lead to heart failure, atherosclerosis, high blood pressure, heart muscle damage, heart attacks, and coronary artery disease.

Inflammation is thought to be a major contributor to many health issues, particularly those related to the heart. The microbiome is believed to play a significant role in fighting inflammation. Recent research suggests a link between the composition of one's gut flora and risk factors for heart disease, including high blood pressure, high cholesterol, and obesity. Previous studies have also associated an imbalanced gut microbiome with increased risk for various cardiovascular diseases such as coronary heart disease, heart failure, stroke, heart attack, hypertension, and atherosclerosis.

The gut microbiome can potentially harm the heart by producing trimethylamine-N-oxide (TMAO). When gut microbes feed on choline found in red meat, poultry, eggs, and certain fish, they produce trimethylamine (TMA), which is then converted into TMAO in the liver.

High TMAO levels are associated with cholesterol, artery-narrowing plaque, inflammation, blood vessel dysfunction, and cardiovascular risk factors such as high blood pressure.

Studies have linked TMAO to different types of heart disease, including atherosclerosis and increased risk of heart attacks or stroke. Additionally, a study from October 2019 found a link between TMAO and disease severity and mortality rate in people with peripheral artery disease. A study published in March 2023 found that high levels of TMAO in blood plasma were independent predictors of major adverse cardiac and cerebrovascular events after acute myocardial infarction (heart attack).

Healthy gut, healthy heart - dietary guidelines

We need more fibre, more plant-based, prebiotics & probiotics along with a heart-healthy diet.

Besides maintaining a heart-healthy diet, ensuring you get enough dietary fibre to support the gut-heart connection is critical. High-fibre foods benefit the heart as they are low in saturated fats and sodium. Additionally, fibre feeds gut bacteria, promoting their health. They break down fibre into beneficial substances like short-chain fatty acids, which are linked to improved blood pressure, blood sugar, reduced inflammation, and weight loss, all of which support cardiovascular health.

Scientific studies have associated higher dietary fibre intake with reduced long-term cardiovascular disease risk and lower incidence and mortality from heart disease. Plant-based diets generally are richer in fibre, polyunsaturated fatty acids (PUFAs), folate, vitamin C, vitamin E, and magnesium than meat-based diets. This is incredibly beneficial because the fibre and PUFAs act as prebiotics, nourishing beneficial gut microbes.

In simple terms, probiotics are beneficial bacteria for the gut microbiome, while prebiotics are their food. Some natural prebiotic foods include oats, bananas, onions, artichokes, spinach, and chia seeds. Probiotics are available as food supplements, and their effectiveness depends on the specific strains they contain. Certain probiotic strains can indeed support gut health and reduce cardiovascular disease risk. However, the wide variety and lack of regulation of probiotics make it challenging to recommend specific products. It's advisable to consult your physician before starting any probiotic or prebiotic regimen.

More plant-based doesn't mean going vegan, eat right!

A healthy diet promotes good health. You can reduce inflammation and heart disease risk by eating fruits, vegetables, and cold water fatty fish like salmon, pacific herring, and sardines. Research suggests that plant-based diets can benefit gut health. It's unnecessary to be vegan, but consuming plenty of whole fruits and vegetables can help reduce gut inflammation, boost beneficial bacteria, and support digestion and cardiovascular health. Both food quality and the environment in which it's consumed are essential—taking the time to sit at a table in an inviting atmosphere, being mindful when eating by slowly chewing food and savouring the experience. Enjoying a meal together away from technology and convenience is beneficial not only for our bodies and guts but also for our hearts, minds, and overall well-being, even if these benefits can't be easily measured in a study.