What does your gut have to have to do with your heart health and other chronic disease?
In the past few years, scientists have dedicated millions of research dollars to the investigation of the microbiome, the complex ecosystem of microorganisms that inhabit our intestinal tracks and colon. The Human Microbiome Project, which the NIH launched in 2008, is exclusively dedicated to studying how changes in the human microbiome influence health and disease. As a result, there is growing recognition and evidence demonstrating that our diet and lifestyle impacts our health by the influence it has on the balance and vitality of our microbiomes.
Microbes exist throughout the digestive system, starting in the mouth; however, most microbes or bacteria live in our large intestine. The large intestine can hold as much as four pounds of approximately 100 trillion bacteria cells at a time, with up to 500 different types of microbe species. That's 1 to 3 percent of our body mass or 2 to 6 pounds of bacteria in a 200-pound adult. Together, they form the intestinal flora known as gut flora or microbiota. Our relationship with our intestinal microbes is symbiotic; they depend on us to thrive as much as we rely on them for optimal health.
A Balanced Microbiome
We start producing gut bacteria the moment we are born, and there is new evidence suggesting that this process may even begin in utero. Our friendly gut microbes support digestion and the synthesis of several important nutrients such as biotin, vitamin B12, folic acid, thiamine and Vitamin K. They also protect us from harmful bacteria and pathogens while impacting our immune system and overall health. "Our gut bacteria serves as a filter for our largest environmental exposure -- the food we eat," explains Dr. Stanley Hazen, the Chair of Cellular and Molecular Medicine and Section Head of Preventive Cardiology and Rehab at Cleveland Clinic.
Disruptions in the fine balance of our gut flora can impact our immune system and contribute to immune disorders, obesity, heart disease, and even brain health. Research suggests that a plant-based approach works to balance the composition of our gut flora which in turn can promote your health and prevent diseases including heart disease, diabetes, and kidney disease. Foods that are rich in high-fiber and are fermentable, which means non-digestible or undigested carbohydrates, will help to balance gut flora and reduce risk factors such as elevated cholesterol and obesity. On the other hand, additional research indicates that a diet high in animal fats and protein, along with high stress, can affect the gut flora and limit the diversity and balance impacting health.
Everyone's Gut is Different
Gut microbes are categorized as good, bad or neutral depending on how they affect our body. Every person, similar to their own fingerprint, has a variety of different types and proportions of gut bacteria. According to Brenda Watson's The Hope Formula, a healthy person has a ratio of approximately 80-85 percent good and neutral bacteria and 15-20 percent of bad bacteria. These ratios, however, can reverse due to a variety of reasons including unhealthy eating, aging and poor digestion. Researchers are only beginning to understand how the differences in gut bacteria can affect everything from the way we metabolize certain foods to impact on the body's immune system.
The Problem with Meat
It turns out that certain compounds in animal foods such as meat and eggs may have a detrimental effect on heart health when metabolized by gut bacteria. When certain animal foods that contain carnitine (found in meat) and choline (found in egg yolks and high fat dairy) are digested, gut flora breaks these substances down into a compound called trimethylalamine (TMA), which is absorbed in the bloodstream and metabolized to trimethylamine-N-oxide (TMAO) in the liver. TMAO then circulates in the blood where it can impact cholesterol metabolism and the transportation of cholesterol into the arteries. This process can contribute to the formation of atherosclerotic plaque, which, according to research from the Cleveland Clinic, increases the risk of heart disease and stroke.
Carnitine itself does not cause damage, but when metabolized by gut bacteria in the intestines into TMAO, this new substance can lead to the damaging effects of atherosclerosis. There have been various studies over the last several years indicating the connection between high TMAO and heart disease (as well as strokes and kidney disease), including research conducted at Cleveland Clinic which clearly shows the link between atherosclerosis and high levels of TMAO. The research shows that within a couple hours after meat-eaters ate a steak their TMAO levels soared. The outcome, however, was different when vegans consumed a steak. The study showed that vegans produced virtually no TMAO after eating meat. The researchers hypothesized that the gut flora of vegans may impact the metabolism of carnitine in a way that does not lead to the production of TMAO.
How a Plant-Based Diet Affects Gut Bacteria
It turns out that a plant-based diet helps to contribute to more protective good bacteria. Another research review published in Nutrients 2014 looked at the impact of a vegan diet on gut bacteria and showed that the gut profile of vegans has a reduced reduced number of pathobionts, which are disease causing organisms, compared to omnivores and even vegetarians. The research is revealing new insights for the prevention and treatment of heart disease. While more research is required to clarify the potential link between gut microbiota and CHD risk reduction, it's becoming clear that consuming a diet rich in plant foods, dietary fiber, and fermentable substrate, is a useful strategy for improving systemic health and possibly by altering gut microbiota.
Prebiotics and A Healthy Gut
A large number of human intervention studies have shown that the consumption of certain foods that contain prebiotics, which are chemicals that induce the growth or activity of microorganisms (e.g., bacteria and fungi) that contribute to the well-being of their host, can result in changes in the gut microbiota (flora) by producing a prebiotic effect. This refers to the stimulation of growth and activity of good microbiota in our inner ecosystem. The promising effects on health are especially recognized by the increase in bifidobacteria. Recent data shows an association of increased bifidobacteria on cancer growth, weight management, metabolic syndrome X, and enhanced calcium absorption.
Prebiotic foods (see info graphic) that create healthy gut flora include:
Tempeh, Miso, Natto: aids in digestion, boosts nutrient absorption, trumps out unhealthy bacteria.
Recipe: Tempeh and Tomatillo Sauce
Plain Yogurt (choose nonfat for Ornish Reversal)
Cruciferous Vegetables such as Broccoli: packed with glucosinolates that can fight against inflammation and cancer.
Recipe: Chopped Broccoli and Cauliflower
Kimchi and Sauerkraut: improves the health of intestinal walls, boost immune system Beans- releases short-chain fatty acids and boost vitamin absorption, improves satiety.
Recipe: Pot of Beans
Jerusalem Artichokes: rich in inulin fiber.
The Microbiome is an emerging field of research and we are only at the beginning of discovering the impact the gut flora has on our health. Continued research will reveal more about the vastness of our microbiota. In the meantime, following a plant based approach continues to show promise for our heart and gut health.
How have you noticed the connection between your heart and your gut?
Have a questions regarding transforming your way of eating and living, Ask Dr. Ornish!