One of the biggest points of confusion concerning health and nutrition has been over cholesterol. Is it good or bad? What foods effect it? Does high cholesterol really impact my health? The reasons it’s changed so much is because early researchers started noticing a trend (people with high cholesterol tended to die from heart disease), they ran an experiment (maybe not eating cholesterol will lower risk), and eventually agreed on the results (avoiding dietary cholesterol did little to reduce blood cholesterol levels or cardiovascular risks).
However, the correlation still remains: high levels of LDL cholesterol (the bad kind) and low levels of HDL cholesterol (the good kind) seem to be associated with a much higher risk of death from cardiovascular disease. The difference now is we have a better understanding of why, as well as how to positively influence cholesterol levels though diet, exercise, and medications like statins. Our more recent understandings about the importance of the microbiome has shed even greater light on the mysteries of how cholesterol effects your health. I’ll explain a little bit about how your gut interacts with LDL cholesterol to harm your cardiovascular health and some things you can do to greatly reduce your risk factors.
LDL and HDL are not cholesterol
Let’s start with the biggest point of confusion, LDL and HDL are not actually cholesterol, they are molecules called lipoproteins and their job is to carry cholesterol and triglycerides to and from the liver. LDL carries fatty molecules from the liver to the cells so it can be used to repair cell walls, make hormones, etc and HDL grabs cholesterol and triglycerides from your system and shuttles it back to the liver so it can be disposed of. We think of HDL as good because it cleans up your blood vessels, but the story of why LDL is bad is a bit more complicated. We need cholesterol delivered to our cells in order to live so LDL serves a vital role, but one of its little known benefits can also cause dangerous problems.
LDL also soaks up endotoxins
If you ever hear someone talk about cleanses and getting rid of toxins, feel free to stop listening. Endotoxins, however, are something different. Another name is lipopolysaccharides (LPS). These molecules are found in the outer membranes of many types of bacteria, even the “good” bacteria that populate our microbiomes. As long as these bacteria are isolated in your gut, these endotoxins can’t harm you, but a poor diet that’s high in added sugars and low in fiber starts the chain reaction that turns LDL into an endotoxin-soaked sponge that triggers chronic inflammation and accelerates aging and disease risk.
As I mentioned in the article about the microbiome, if you give the good bacteria in your gut fiber, they create short chain fatty acids that feed the cells in your intestines. Your intestinal cells then do two things that drastically strengthen your immune system and overall health. The first thing they do is secrete a slimy substance called mucin that strengthens the barrier between all the bacteria in your digestive tract (good and bad) and your blood stream. It also signals for your intestines to reduce the amount of oxygen in the colon. The good bacteria in your system are anaerobic so they actually die off in the presence of too much oxygen. Harmful pathogens like E coli and Salmonella can live in an oxygen rich or poor environment, but they will really thrive and do you harm if the good bacteria die off and leave room for them to grow. Fiber keeps your beneficial bacteria and gut barrier strong so that you’re protected from the invading bacteria and viruses that you consume with every meal.
If you don’t give your microbiome fiber, then your good bacteria starve and actually start devouring the mucin barrier that protects your body from invasion. Once the barrier is down, your immune system starts killing bacteria (good and bad) as they cross into the blood stream. This prevents bacteria from colonizing places they shouldn’t be, but their deaths release a ton of endotoxins into your system.
We’re very sensitive to LPS and a build up of endotoxins can lead to sepsis and death. To prevent this, the LDL that has already delivered it’s payload of cholesterol uses it’s newly available receptors to soak up and somewhat neutralize the LPS in your system. This is why infections cause your LDL levels to climb rapidly.
I say that LDL somewhat deals with endotoxins because while it does grab LPS and prevent it from harming your tissues, it then gets stuck there and prevents the LDL from getting reabsorbed and disposed of by the liver. Worse yet, your immune system then sees this endotoxin-bound-LDL molecule and assumes it’s an invading bacteria. Your body then increases localized inflammation as it tries to kill this “bacteria.” Since it’s not actually a bacterial cell, it just gets coated in attacking immune cells and becomes a foam cell, which is a precursor for dangerous arterial plaques. This is why one study found that chronic inflammatory autoimmune diseases like rheumatoid arthritis, lupus, and inflammatory bowel disease (which are all caused by microbiome dysfunction) drastically increase the risk of death from cardiovascular disease.
What you can do
LDL isn’t inherently good or bad, but it becomes problematic when it triggers chronic inflammation. In order to reduce your cardiovascular risks, you need to prevent this dangerous chain of events from happening. A lot of the common advice you’ll find out there for reducing cholesterol applies, but that’s not the focus of my advice. We’re not trying to reduce LDL, we’re trying to prevent it from being weaponized. A side effect of preventing endotoxins from flooding your system is that your body will naturally reduce your LDL levels anyway.
1. All kinds of fiber. We’re learning more and more about the microbiome each day, but our understanding is still in it’s infancy. The one thing all researchers agree on is that you want as diverse a range of bacteria species as possible. A low variety of species leads to dysbiosis and disease. Since different types of bacteria prefer different kinds of fiber, you should eat a wide variety of fruits and vegetables. Some good options include barley, whole oats, mushrooms, onions, garlic, leeks, berries, asparagus, bananas, beans, nuts, and on and on.
2. Probiotics as needed. As I mentioned above, populations of good bacteria can be starved off completely with a poor diet. You may need to increase your diversity before you really double down on prebiotics (fiber). Fiber can also feed harmful species so if you’re the type that has bad reactions to dietary fiber, you probably want to add probiotics to the mix. I’m a big fan of fermented cabbage foods like kimchi and sauerkraut because they also are a great fiber source. Eating both at the same time helps the good colonies flourish quickly. I also suggest miso, kefir, kombucha, and yogurt to add a little extra variety to the mix.
3. Anti-inflammatory foods. Fish, walnuts, flaxseeds, and other sources of omega-3 fatty acids will reduce runaway inflammation as well as provide a ton of benefits for your brain. Saturated fats don’t cause dangerous levels of cholesterol but monounsaturated fats like olive oil and avocados improve inflammation and make weight loss easier (another thing that reduces chronic inflammation).
4. Skip the sugar and processed foods. Neither your intestinal cells or beneficial bacteria can feed off simple sugars, but plenty of harmful species can. While they starve and bring down your gut barrier, pathogenic species proliferate and take over. In addition, many ingredients in processed foods were approved by the FDA as safe before we understood what the microbiome really did for us. We’re now learning that common additives and preservatives degrade the mucosal layer in the intestines and cause widespread inflammation. Simple rule, if you can’t pronounce the ingredient, don’t eat it.