The old saying may be true, maybe the way to a man's heart really is through his stomach. Studies show that gut health and heart health are intricately linked and the key to a healthy heart might lay within your gut.
Heart disease is the leading cause of death in the United States. So, it's no surprise that nearly everyone knows someone who's been affected. The effects of heart disease are devastating and can take families by surprise.
To fight this, we've been taught since a young age to eat healthy and exercise for a strong and healthy heart. Cereal boxes are plastered with "heart healthy" seals of approval and promises of decreasing your cholesterol. Schools even waged campaigns to teach children just how important it is to take care of their heart.
Even with country-wide education and significant advances in modern medicine, the last decade has shown an increase in the number of people affected by heart disease with rates continue to climb.
It makes you wonder: Is eating 'healthy' and exercising really enough to prevent heart disease?
The evidence seems to indicate that there's a piece missing from this puzzle, and growing research is pointing to the gut microbiome. The gut-heart connection is so substantial that soon cardiologists will likely be sending their patients to see a gastroenterologist and vice versa. 
Could there be a day where a stool sample, oral swab, or a breath test for certain bacteria or metabolite could reliability predict your risk for heart disease? Some researchers believe this is a reality that is closer than we think.
This also suggests you might not want to dismiss gastrointestinal issues too quickly. A little gas and bloating here and there might not seem like a big deal, but if it goes unaddressed for too long (or worse, covered up with over-the-counter medications), it could lead to more significant issues down the road.
So, how does the gut potentially contribute to heart disease?
First, bacteria that should be found only in the colon can migrate to the small intestine and cause problems. Second, when specific bacteria are exposed to a high protein diet, it can lead to the production of harmful byproducts, some of which are associated with heart conditions. And third, when particularly troublesome bacteria leak through the intestinal lining and into the bloodstream, it can lead to widespread systemic inflammation.
Let’s take a closer look.
When Bacteria Migrate: The SIBO & Heart Disease Link
Almost half (47 percent) of all Americans have at least one of the primary risk factors for heart disease – high blood pressure, high cholesterol, or smoking.  Almost a quarter of the American population is estimated to have small intestinal bacterial overgrowth (SIBO), but for those with irritable bowel syndrome (IBS), this can be as high as 78 percent.1 What researchers are finding is that the risk for developing heart disease is increased in individuals that already have a gastrointestinal condition. The reverse is also true, with chances being higher for having GI issues if you are suffering from a heart condition.
In a 2018 study published in the journal Digestive Disease and Sciences, patients with SIBO had an 80 percent higher chance of having heart disease.  They also had an increased number of coronary arteries that were affected.
SIBO has also been associated with deep vein thrombosis, which is when a blood clot forms in one of the deeper veins in the body.  Researchers believe these results may be due to a pro-inflammatory state caused by lipopolysaccharide (LPS). LPS is an endotoxin (a toxin that is present inside a bacterial cell) that is found in the outer membrane of gram-negative bacteria which can cause inflammatory responses throughout the body if given a chance to leave the gut.
These results taken together may suggest a connection between the gut and the heart. The composition and function of the microbiome and produce metabolites that have been associated with an increased risk for developing and having heart disease.
Too Much TMAO? When Protein Causes Problems
Another harmful bacterial metabolites researchers are investigating is trimethylamine N-oxide or TMAO. When certain gut microbes use choline, found in high quantities in eggs, red meat, poultry, and fish, they can produce trimethylamine (TMA). TMA can than be converted into TMAO, which has been linked to plaque formation in arteries (atherosclerosis).
In a review published in the Journal of the American Heart Association, 19 studies confirmed a link between elevated TMAO levels and increased risk of heart disease. People who had higher levels of blood serum TMAO were 62 percent more likely to have heart conditions. 
High TMAO levels have also been associated with higher mortality rates, independent of other commonly linked risks such as kidney disease, diabetes, and obesity. These findings suggest that evaluating serum levels of TMAO may be an additional factor to consider when gauging someone's risk of developing cardiovascular disease.
Leaky Gut & LPS – The Likely Reason Microbes End Up in Your Artery Walls
A disrupted gut lining is a third potential mechanism by which the gut could be the underlying cause of cardiovascular disease. When the gut lining weakens, it becomes permeable or 'leaky.' A leaky gut allows particles such as food and bacteria to move into the bloodstream and cause inflammation and allergies. This is especially problematic when there are lipopolysaccharides (LPS) present. When large amounts of LPS enter into circulation, it can lead to systemic inflammation, causing a cluster of symptoms called metabolic endotoxemia. 
Metabolic endotoxemia can occur when blood serum levels of LPS increase two to three times that of the normal amount. These elevated LPS levels have been associated with a higher risk of cardiovascular disease and mortality.  A leaky gut lining can increase the risk of LPS entering into circulation which can lead to metabolic issues and contribute to the likelihood of cardiovascular disease.
Another interesting fact is that certain microbes have been found in artery plaques of patients with heart disease. For years, scientists couldn't figure out how they got there. One hypothesis said if you have an impaired gut lining, certain microbes translocate into the bloodstream and relocate in artery walls, causing inflammation and contributing to heart disease. However, more research is needed to strengthen this connection, and it's one scientists are keeping their eyes on.
The Good News? Short-Chain Fatty Acids for the Win!
It's not all bad news when it comes to the gut-heart connection. The good news is there are healthy compounds your gut microbiota produce called short-chain fatty acids that protect the heart.
These beneficial short-chain fatty acids, such as butyrate, are almost exclusively made via the gut microbiome.  Studies have found that these microbial byproducts are involved in blood pressure regulation along with other physiological functions.8
A 2017 review on the gut microbiome and blood pressure concluded that future treatments for cardiovascular disease should aim to treat high blood pressure through modulation of the gut microbiome. 
Fighting Heart Disease with Gut Health
Gut microbiome research takes the idea of eating for a healthy heart to a whole new level. This is excellent news because fighting the number one killer in our country needs to be a top priority. You don't have to wait for research to tell you exactly how to have your microbes work in your favor, you can leverage it right now and take steps to improve the health of your gut microbiome today.
Here are 5 ways you can begin improving the health of your gut microbiome immediately:
1. Avoid sugar – Sugar isn't great for your gut microbiome because harmful bacteria and fungus like Candida albicans love to feast on it. High sugar diets have been shown to alter gut microbiome composition and function.
2. Use antibiotics only when absolutely necessary – Antibiotics cause widespread alterations of the gut microbiome because they don't discriminate between good and opportunistic bacteria.
3. Reduce your NSAID use – Nonsteroidal anti-inflammatory drugs (NSAIDs), like Advil and aspirin, alter the composition of the gut microbiome and can decrease the integrity of your gut lining, potentially contributing to leaky gut.
4. Exercise – Exercise isn't just good for your heart, it's for your gut too! Exercise has been shown to enrich microbial diversity and increase beneficial bacteria.
5. Quit smoking – Smoking is one of the top three biggest risks factors for heart disease, and it wreaks havoc on your gut microbiome. You already know smoking is bad for you, now it's time to really quit.
Want to learn more? Check out 19 Science-backed Ways to Improve Your Gut Health