Your gut bacteria have more to do with cholesterol than you might think! Although the digestive and cardiovascular systems are two very different systems with very different jobs, they are connected by what is called a "gut-centric axis". Taking care of your gut microbiome can not only help maintain healthy cholesterol in healthy individuals, but also support healthy functioning of the cardiovascular system.
The word "cholesterol" conjures images of high-fat diets and clogged arteries. Still, while cholesterol has long been a villain, it remains an important part of health. So much so that we can't live without it!
Our understanding of the factors that influence cholesterol in the body has changed dramatically as new research has come to light. All of our cholesterol problems are no longer the humble fried egg, but the complex interplay between genetics, diet, lifestyle and...you guessed it, the microbiome.
If you've been chasing healthy cholesterol readings, turning your attention to your gut may help. But before we learn how to manage cholesterol, we need to understand it.
Let's go into detail.
Understanding cholesterol: The good and the bad
Cholesterol is a waxy, fat-like substance that is present in every human cell and has many important functions, including:
Form cell membranes
Modulator of cell signalling and nerve conduction
Precursor to hormones, bile acids (BA) and Vitamin D
When it comes to cardiovascular system function, cholesterol itself is not the problem, but the transporter (AKA lipoprotein) and where it transports cholesterol. These lipoproteins can be divided into different types, the most relevant of which include:
The good (High Density Lipoprotein Cholesterol) – These deliver free cholesterol from our tissues to the liver for elimination via the bowels
The Bad (LDL cholesterol) - These carry cholesterol from the liver to the tissues. Small amounts are necessary, but too much can build up in blood vessels and cause atherosclerotic plaques.
How does the gut microbiome affect cholesterol?
Our gut microbiome can help control our cholesterol levels in a number of ways. Some recently discovered processes include:
Coprostanol Conversion – Certain bacterial strains have been shown to convert cholesterol into a substance called coprostanol. Due to its structure, enteroprostenol is rarely absorbed by the intestinal wall and is easily excreted through the intestine, making it an efficient cholesterol elimination route. High amounts of coprostanol found in faeces is associated with healthy cholesterol, leading researchers to believe that cholesterol-coprostanol converting bacteria play an important role the maintenance of healthy cholesterol in healthy people.
Bile Acid Deconjugation – Bile acids are synthesized from cholesterol and are an important part of fat digestion. While most bile acids are reabsorbed and recycled back to the liver, about 5% are metabolized by gut microbes, making them another important excretion pathway for cholesterol
Cholesterol entrapment – Certain bacterial strains can act like vacuums, sucking up cholesterol in the gut to form part of their own membranes. This process is thought to offer a protective benefit to the bacteria.
Although the above processes are strain-specific, they have been found in many probiotic strains, including those belonging to the genera Lactobacillus and Bifidobacterium. 
Did you know?
About 80% of the cholesterol in the body is produced by the liver. The remaining 20% comes from dietary sources.
Diet matters: The diet-microbiome-cholesterol link
One of the most effective ways to support a healthy microbiome and healthy cholesterol is through a healthy diet.
So how can we achieve this balance? The latest research shows:
Fats – Eat less total fat and increase the ratio of unsaturated fats (such as salmon and olive oil) to saturated fats (such as animal products), which have been shown to increase the number of beneficial gut bacteria and help support healthy cholesterol
Fibre –Fiber foods are not only a wonderful food for us, but also for our microbes. Not only do they help slow the absorption of sugars, fats, and cholesterol in the gut lining, but they also promote the growth and activity of beneficial microbes. Microbe-loving, fiber-rich, cholesterol-lowering foods include whole grains (like oats) and a variety of fruits and vegetables.
Plant polyphenols – Known for their antioxidant properties, these plant molecules can aid in cholesterol metabolism and excretion. Think green tea, brightly colored fruits, vegetables, and red wine (a little bit!).
Probiotics– Beneficial bacteria can be found in fermented foods, such as yogurt, and can also be supplemented with products such as probiotics. Both have been shown to support gut microbial balance and healthy cholesterol. Beneficial species include Bifidobacterium longum, Bifidobacterium infantis, Bifidobacterium breve, and Lactobacillus plantarum.,,
The growing evidence supporting the link between the gut microbiome and cholesterol is yet another reason why taking care of your microbiome, matters!
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