Most People Have the Wrong Cholesterol.
Do you know which foods contain good cholesterol and which ones contain bad? If you think so, ha! A trick question! Cholesterol in our food is not “good” or “bad”, unlike cholesterol readings in blood tests, which are not as closely related as we are used to thinking.
What is cholesterol really?
We produce cholesterol in our body. It is a key part of cell membranes and we use it as a building block for the production of important chemicals like hormones, vitamin D and bile.
Other animals also produce cholesterol, which is why you’ll find it in animal products such as meat, dairy products, and eggs. Because cholesterol is a lipid (it mixes well with oil, but not water), you’ll usually find it in the fatty parts of your food. But this is not a type of fat!
Plants do not produce cholesterol, so all vegetarian oils (such as vegetable oil) are automatically cholesterol free.
More importantly, since we ourselves produce cholesterol, the amount we eat doesn’t really matter. Cholesterol, while important for our body, is not important in our diet. If you never eat another cholesterol again in your life (hello vegans!), Your body will still produce a lot and live normally.
In fact, we make a lot more cholesterol than we eat (even if you’re an avid predator). The liver regulates cholesterol production based on what we eat and gets rid of any cholesterol it doesn’t need, so even if you eat a ton of cholesterol, it has little to no effect on what’s in your blood.
Dietary cholesterol is different from blood cholesterol
Some people confuse fat with cholesterol. There are good and bad fats , but the cholesterol you eat doesn’t make that much difference. When it’s on your plate, it’s just cholesterol. It only becomes “good” or “bad” when it is packed into particles in your bloodstream.
These good and bad packages are lipoproteins : small particles that carry fat and cholesterol to specific places in your body. Low-density lipoproteins, or LDL , are considered bad because people who have a lot of them are more likely to develop heart disease. LDL can get stuck in the walls of arteries, leading to atherosclerosis , hardening of the arteries, which can lead to heart attacks and stroke.
High-density lipoproteins, or HDL , help remove LDL particles to avoid plaque formation. So it’s good to have a lot of HDL (think H for happy) and it’s bad to have a lot of LDL.
What do these blood tests mean?
This is where blood tests come into play. Decades ago, all we could measure was the total cholesterol in a blood sample. This number turned out to be useless. What’s really important is the number of HDL and LDL particles (and maybe some other details like the size of those particles), but we have to stick with whichever is easiest to measure.
So, when you do a blood lipid test, the numbers include total cholesterol, HDL cholesterol (that is, the amount of cholesterol that is carried in HDL particles), and triglycerides. From these numbers, the lab can calculate how much cholesterol your LDL particles were likely to have. These HDL cholesterol and LDL cholesterol numbers give you an idea of how likely you are to develop atherosclerosis, which can lead to a heart attack.
According to the latest guidelines for doctors , you can determine your risk of a future heart attack using a few facts: your cholesterol levels, your blood pressure, and whether you smoke or have diabetes (which increases your risk). That, along with your age, race, and gender, will make an ominous prediction about your percentage of chances of having a heart attack in the next ten years.
If the risk is greater than 7.5%, as recommended, your doctor should talk with you about taking statins, which lower LDL cholesterol and have been shown to prevent recurrent heart attacks in people who have had one before .
Cholesterol-modifying drugs are controversial. While statins prevent recurrent heart attacks, they are of little or no benefit to people who have never had them before. And other types of cholesterol-altering drugs, such as niacin (which raises HDL levels), do not reduce heart attacks in the real world . This suggests that statins may not work by lowering LDL in the blood, but by some other mechanism that simply lowers LDL as a side effect.
Meanwhile, statins have some unpleasant side effects, including muscle pain, which can make exercise unpleasant or impossible, and exercise is important for lowering the risk of heart disease. Therefore, if your cholesterol levels are not very good, schedule a detailed conversation with your doctor about the risks and benefits of medications.
What You Eat Affects Cholesterol – But Blood Doesn’t What You Think
The cholesterol we eat has little or no effect on the cholesterol or lipoproteins in our bodies – at least for most of us. (Some experts recommend that people with diabetes continue to abstain from eggs .)
Otherwise, a heart-healthy diet will improve your LDL and HDL levels regardless of the amount of cholesterol that goes through your lips. Opinions differ – it’s nutrition, after all – but you’ll always do the right thing by sticking to three principles that everyone agrees on : Don’t eat trans fats, eat less sugar, and eat lots of vegetables.
After that, you can follow the standard advice : Eat less saturated fat and more soluble fiber to lower your LDL cholesterol. Exercise and eat plenty of omega-3 fatty acids (found in fish and nuts) to raise your HDL levels. Triglycerides are not a cholesterol, but they seem to increase your risk of heart disease, and you can lower them by avoiding sugar and refined carbohydrates.
The DASH diet is a classic meal plan that achieves these goals (and also maintains low blood pressure for salt-sensitive people). The Mediterranean diet is another good option. And you can always apply the advice above by changing your regular diet to include more fruits, vegetables, and whole grains.
Illustration by Sam Woolley.
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