Is cholesterol really all bad? Here are 4 things to know about cholesterol as you age
Cholesterol has earned a reputation as a “bad guy” when it comes to your health. Indeed, too much cholesterol in the bloodstream can make its way into the walls of your arteries, the process known as atherosclerosis (clogging of the arteries). Too much cholesterol accumulation in the arterial walls can impede blood flow to important locations like your heart and brain.
Unfortunately, this simplified version of the cholesterol story tells only one side, the bad side. On the good side, cholesterol is an important component of the cell structure, plus it’s necessary for the creation of several hormones, such as vitamin D, and enzymes needed to help you digest food. This means the cholesterol story is quite complex.
Because cholesterol is important for several bodily functions, the body does not rely on getting a minimal daily amount of cholesterol in your diet. Instead, your liver can produce all the cholesterol you need from carbohydrates, fats, and proteins, and without consuming any dietary cholesterol. Cholesterol is found in animal products, but vegans aren't cholesterol-deficient. That's because the body produces what it needs.
Let’s assume you do consume a large amount of dietary cholesterol. This doesn’t necessarily mean your blood cholesterol concentration will increase. This is because the liver strives to maintain what it believes is an optimal level of cholesterol in the blood, and when there is too much it will act to pull some out of circulation.
Understanding this relationship between consumption of dietary cholesterol versus production has been helpful in our efforts to regulate cholesterol concentration in the blood. When cholesterol stepped into the spotlight as something bad that clogs your arteries, there was a knee-jerk response to quit eating foods high in cholesterol like egg yolks, shellfish, organ meats, etc. Unfortunately, this accomplished very little to reduce the concentration of blood cholesterol.
Here's what to know.
What is saturated fat and how is it connected to cholesterol?
Eventually, research revealed that although dietary cholesterol is not the problem, other dietary factors are indeed a problem. The first to be identified was saturated fat.
Because the liver is a production factory for cholesterol, there needs to be a feedback mechanism telling the liver when blood cholesterol gets too high. The feedback comes from receptors in the liver that monitor blood cholesterol concentration, and when the concentration gets too high, cholesterol is removed from circulation and used to produce bile, which is stored in the gall bladder. This generally works well unless saturated fat blocks liver receptors from accurately reporting blood cholesterol concentration. When this happens, the liver is essentially “blind,” too much cholesterol is produced, and the excess ends up in the bloodstream.
What is trans fat and how is it connected to cholesterol?
To combat the above, food producers gave us trans fats that were supposed to replace saturated fat and be healthier. An example is trans fats in margarine replacing saturated fat in butter. Unfortunately, trans fats turned out to be worse than saturated fats and contribute to higher blood cholesterol. Thus, the prevailing wisdom for quite some time focused on reducing dietary saturated fat and trans fats, and other dietary influences on cholesterol were ignored.
Now we know better and too much “added” sugar in the diet is a major problem. Added sugar refers to sugar added during food processing to enhance taste, and the sugar contained in soft drinks, sweets, etc. Natural sugar found in fruits and vegetables is not a problem.
What impact do lipoproteins have in cholesterol?
To understand this connection, you must understand that the total cholesterol in the blood is made up of several different types of lipoproteins (a mixture of cholesterol, fat, and protein). LDL (low-density lipoprotein) is considered “bad” cholesterol that is highly involved with clogging the arteries. It has a bad reputation even though it is simply doing its job of transporting cholesterol produced in the liver to parts of the body where it can be used to create hormones, enzymes, etc. However, in transit, the cholesterol contained in LDL can be prematurely deposited in the arterial wall, promoting clogging.
Other lipoproteins include VLDL (very low-density lipoprotein) which primarily transport fat from the liver throughout the body. VLDL also contains a modest amount of cholesterol. There is also HDL (high-density lipoprotein), the so-called “good” cholesterol that scavenges throughout the blood vessels and can transport cholesterol that has been erroneously deposited in the arterial wall by LDL back to the liver.
How does sugar consumption impact cholesterol?
When you consume excess sugar, it goes to the liver where it can be converted to fat. When fat is produced, it can either be transported away from the liver via VLDL or stay in the liver. Both options are problematic. If fat stays in the liver, it increases the risk of fatty liver disease. Or the fat-laden VLDL is transported throughout the system and ends up in capillaries where enzymes detach fat from VLDL leaving behind the cholesterol. Essentially, the result is a transformation as VLDL sheds its fat load and is converted to “bad” LDL, and the source is too much sugar in the diet.
A typical cholesterol profile for adult Americans is pretty bleak with an unhealthy total cholesterol of 205 mg/dl and LDL well above 100. A desirable healthy profile is less than 150 total cholesterol, and LDL less than 70 (the lower the better).
In summary, if you want to improve your blood cholesterol profile, a good place to start is to reduce your intake of saturated fat, trans fats, and “added” sugar.
Reach Bryant Stamford, a professor of kinesiology and integrative physiology at Hanover College, at [email protected].
This article originally appeared on Louisville Courier Journal: What to know about good versus bad cholesterol as you age
