What’s Cholesterol and Why is it Important?
By Justine Szafran
What is cholesterol, and when is it “good” or “bad?” What are the cholesterol recommendations for people with diabetes, and how can you keep up healthy cholesterol levels?
You may have had your cholesterol levels measured by a healthcare professional at some point in your life. Or at any moment while watching TV, an ad for a cereal that can “lower your cholesterol” pops up on your screen. But what is cholesterol? Is all cholesterol bad for you, and how do you keep your cholesterol levels in a healthy range? We want to answer your questions about cholesterol: what it is, the difference between good and bad cholesterol, and how to maintain healthy cholesterol levels if you have diabetes.
What is Cholesterol?
Cholesterol is a waxy, fat-like substance found in all of your body’s cells. It is produced naturally by your liver, and it can also be found in some of the food you eat. Not all cholesterol is harmful; in fact, it’s essential for the body to function. Cholesterol is a necessary component of the membrane structure of every cell in your body. It is also needed for making some hormones, vitamin D, and for various other essential functions.
Cholesterol travels through your body in your bloodstream, attached to molecules made of both fat and proteins that are called lipoproteins. Cholesterol levels are an important measure of risk for heart and vascular disease. So, while your body needs cholesterol to survive, too much cholesterol can lead to potentially serious heart conditions.
Because cholesterol is produced in your body, high levels of cholesterol can be genetic and outside of your control – if anyone in your family has a history of high cholesterol, talk with your healthcare professional about how to lower your risk.
What is the Cholesterol in Your Food? Unpacking Dietary Cholesterol
Many of the fat substances in your body, including cholesterol, are produced naturally – this production is determined by your genes and your metabolism, and is likely not something you can change. However, you have more choice in the fats that enter your body through your food. Saturated and trans fats are the main culprits when it comes to increased cholesterol in the bloodstream – these fats prevent liver cells from effectively removing cholesterol from your blood. It’s important to monitor your intake of foods that contain these types of fat. To keep your cholesterol in check, a basic rule of thumb is to avoid saturated and trans fats. Saturated fats mainly come from animal sources of food and trans fats mostly originate from oils through a food processing method called partial hydrogenation. Both trans fats and saturated fats harm the body’s ability to combat heart disease. Learn more about saturated fat, trans fat, and ways to make healthy food choices here.
While foods containing saturated and trans fats can raise your body’s cholesterol levels, natural dietary cholesterol does not have the same effect. According to the Mayo Clinic, the cholesterol found in foods such as eggs has not been shown to affect overall cholesterol levels. Here’s how this works: when your dietary intake of cholesterol goes down, your body makes more of the cholesterol it needs to function; when dietary cholesterol goes up, your body makes less of the molecule. Because of this balancing effect, consuming a bit more dietary cholesterol doesn’t noticeably impact blood cholesterol levels in most people.
It is more important to focus on eating less unhealthy fats than to stress about dietary cholesterol – although moderation with dietary cholesterol is still recommended as your body doesn’t need too much cholesterol overall to function.
What Are the Different Types of Cholesterol?
Cholesterol can be attached to two different types of lipoproteins: high-density lipoprotein (HDL) or low-density lipoprotein (LDL). The two differ in how much of the molecule is made up of cholesterol and how much is made up of protein.
HDL cholesterol is considered to be beneficial, or “good cholesterol.” This is because it removes harmful LDL cholesterol from your bloodstream. To do this, HDL brings excess LDL cholesterol to the liver (where it’s broken down), delivering it away from your heart and other organs. Because of this powerful ability, higher levels of HDL are associated with a lower risk of heart disease.
LDL cholesterol, however, carries cholesterol to cells and can accumulate on the walls of your blood vessels, narrowing the passageways your blood uses to travel throughout the body. This can become dangerous: narrow vessels make it hard – or impossible – for blood, oxygen, and nutrients to travel to the heart and brain and can lead to a heart attack or stroke. LDL is thus considered “bad cholesterol,” and higher levels of LDL can increase your risk of these severe health issues. Eating too much saturated fat can reduce how much LDL cholesterol your liver cells can remove from your blood.
You may have also heard of triglycerides – another type of fat in the body that is not considered a type of cholesterol. Triglycerides and cholesterol both show up in the common blood lipid level lab test. Triglycerides store excess energy from your diet; high triglycerides can contribute to thickening of the walls of arteries. Learn more about how triglycerides and cholesterol both relate to heart disease here.
What Does Cholesterol Have to Do with Diabetes?
If you are someone with type 1 or type 2 diabetes, it is important to be proactive about your cholesterol, especially if you don’t have stable glucose levels. People living with diabetes are more likely to be at risk for heart disease and stroke, especially at a young age, so it’s important to be as proactive as possible to keep your heart healthy.
Compared to people without diabetes, people with diabetes are more likely to experience lower levels of HDL and higher levels of LDL cholesterol. This means that there is not enough good cholesterol – which normally helps to reduce your bad cholesterol – to effectively do its job. That’s why it’s especially important for people with diabetes to monitor HDL and LDL levels and adopt healthy habits – including diet and exercise – to avoid health complications that could arise. The dangerous combination of low HDL and high LDL can lead to a greater risk of coronary heart disease over time. You’ll find tips for managing cholesterol levels below, and you can learn more about heart disease and how to keep your heart healthy here. Exercise can actually help you increase your HDL (good) cholesterol levels – click to read the Cleveland Clinic’s “Cholesterol Guide: Exercise Tips.”
What Cholesterol Level Should You Aim For?
Whether or not you have diabetes, try to keep your cholesterol levels within these recommended ranges:
LDL cholesterol levels lower than 100mg/dL
HDL levels greater than 40mg/dL. Women tend to have higher HDL levels on average than men, so women can aim for HDL greater than 50mg/dL.
Maintaining healthy cholesterol levels will help lower your risk for heart disease, which is especially important for people with type 1 or type 2 diabetes. To monitor your cholesterol levels, regular lab tests are recommended. Speak with your healthcare professional about how to make sure your cholesterol levels remain in a healthy range. To learn more about your lab tests, read our article on standard diabetes lab tests and how to understand their results.
Tips for Managing Your Cholesterol
Switch out processed and refined grains for whole grains. Dietary fiber is critical for promoting healthy cholesterol in the body, but refined grains are stripped of fiber when processed. Consuming whole grains (which include the entire grain) has been shown to improve blood cholesterol levels and lower your risk of heart disease, stroke, and obesity.
Foods like pasta and bread are available in whole wheat or whole grain versions which have high levels of dietary fiber. These kinds of swaps are tasty and helpful for lowering cholesterol levels.
Chips, crackers, and sugary cereal should be limited – though you can try whole grain options made with oats, seeds, quinoa, flax, or lentils.
When reading a food’s nutrition label, look for a list of simple whole grain ingredients other than white flour.
The American Heart Association suggests that adults aim for about 25 grams of fiber per day, though your healthcare professional may suggest more or less.
Make sure you’re eating vegetables and fruits with every meal. Vegetables and fruits contain vitamins and nutrients that your body needs, in addition to more fiber.
Having tomatoes, arugula, and berries with breakfast is a good way to start your day.
For lunch, make sure to get some greens like spinach, kale, and lettuce into your meal, or try some sliced carrots and bell peppers with hummus for a delicious snack.
For dinners, it’s easy to make vegetable soups, chilis, or roasted vegetables for a warm meal that incorporates heart-healthy choices.
Avoid saturated and trans fats. Saturated fats differ from healthier unsaturated fats because they are usually solid at room temperature (and trans fats are a type of saturated fat).
Saturated fats include foods like butter, animal fats, and processed food (most premade breakfast sandwiches or freezer meals can hide dangerous saturated fats). Red meat and the skin and fat from chicken and turkey have high saturated fat levels.
Saturated fats raise both HDL (good) and LDL (bad) cholesterol levels.
Trans fats can lower HDL (good) while raising LDL (bad) cholesterol.
Remember that dietary cholesterol is different than saturated fat (and, in moderation, generally will not affect your cholesterol levels).
Read our article on dietary fat here.
Use healthy oils. Healthy oils are low in saturated fat and instead contain unsaturated fat.
Oils such as canola, extra virgin olive oil, avocado oil, vegetable oil, safflower oil, peanut oil, flaxseed oil, walnut oil, and sesame oil are good options because of their relatively low saturated and trans-fat content.
At the end of the day, we’re not perfect – some days you might eat some saturated fat or forget to eat enough fiber. It’s important to do your best to make choices that keep your cholesterol levels in a healthy range. Remember to look over your lab results; talk with your healthcare professional about your cholesterol lab tests and additional strategies to help manage your cholesterol.
This article is an update to our 2009 article on cholesterol.