The Truth About Good and Bad Cholesterol

Woman in yellow jumper holds heart

You’re probably aware that cholesterol is something you should be monitoring, but what exactly is it, and what steps can you take to keep your cholesterol profile healthy? We spoke to Sarah Noone, a registered Dietitian with the Irish Heart Foundation, to find out more. 

What Is Cholesterol?

We hear a lot about cholesterol, but what exactly is it? “Everyone has cholesterol,” Sarah explains. “It’s a type of fat in our blood which is produced by the liver.” Some of the cholesterol in our bodies comes from the food we eat and while it gets a bad rap, not all cholesterol is bad. “Our bodies need a certain amount of cholesterol for normal cell function, to help digestion and produce certain hormones,” she notes. There are two types of cholesterol; one is called HDL (the good kind) and the other is called LDL (the bad kind). 

Why is Some Cholesterol Considered Bad? 

A high LDL (the bad kind of cholesterol) can cause health problems if left untreated. “It sticks to your artery walls and this causes narrowing of the arteries,” Sarah explains. “This narrowing reduces the blood supply to your heart and brain.” Unfortunately, this comes with potential risks. “If the arteries that carry blood to your heart get damaged and blocked,” Sarah notes, “it can lead to a heart attack. If this happens in the arteries that carry blood to your brain it can lead to a stroke.” 

High cholesterol can be caused by many factors and some of these factors are out of your control. These include things like age, gender, ethnic background, family history, kidney or liver disease or an underactive thyroid. “Things that we can change that may cause high cholesterol include; our diet, being physically active and achieving and maintaining a healthy weight,” Sarah explains.  Smoking can also lead to high cholesterol levels, and the build-up of tar it causes in your arteries makes it easier for cholesterol to stick to your artery walls.

“Triglyceride is another type of fat in our blood,” Sarah explains, “and it is also affected by what we eat and drink.” For instance, eating a lot of sugary processed foods can make you more likely to have a high triglyceride level. “Triglycerides can be raised in diabetes, obesity, kidney disease, with an underactive thyroid and too much alcohol. Triglycerides can also contribute to the narrowing of the artery walls, increasing your risk of heart disease.”

What About Good Cholesterol?

Our bodies also contain a good kind of cholesterol (HDL). “HDL can help keep bad cholesterol in check by transporting it away from the arteries to the liver, where it is broken down and removed from the body,” Sarah explains. Some more good news about good cholesterol is that it’s been associated with a reduced risk of coronary heart disease. 

If you’re interested in increasing your good cholesterol, the evidence supports the following advice: 

Increase your physical activity: Aim for 150 minutes a week of moderate intensity activity (brisk walking, slow cycling) or 75 minutes a week of vigorous intensity activity (jogging, running).

Reduce trans fats – This type of fat is found in processed foods such as cakes, biscuits, pastries and deep-fried foods. Trans fats not only decrease your good cholesterol but they increase your bad cholesterol. Avoid foods with ‘hydrogenated fat’ or ‘partially hydrogenated oils’ listed in their ingredients (for example, pies, biscuits, cakes or fried foods).

Achieve and maintain a healthy body weight through a combination of exercise and a balanced nutritious diet. “Things like including regular meals, portion control, limiting treat foods and physical activity can be helpful,” notes Sarah.

What Steps Can We Take to Protect Our Heart? 

Table full of food, Mediterranean diet

So now that you know the difference between the two types of cholesterol, you might be wondering how you should eat to protect your heart. Sarah’s advice? Head to the Med! Not on your holidays, but with your diet. “A cardio-protective Mediterranean diet is the first line dietary approach for the prevention of heart disease and stroke,” she advises. 

“At its core,” Sarah explains, “the Mediterranean diet is an entire dietary pattern rich in fruits and vegetables, whole grains, olive oils, beans, nuts, seeds, and legumes in addition to oily fish,” so far so delicious. “It also contains moderate amounts of dairy, while consumption of red and processed meats along with sweets and treats, is low.”

Other Steps We Should Take

Couple out for walk in forest

Following a Mediterranean diet is a great start to keeping your cholesterol profile healthy, but it should also be accompanied by some general healthy lifestyle changes too. “The evidence recommends regular physical activity, alcohol intake limited to moderation, achieving and maintaining a healthy weight,” Sarah advises. 

Research shows that many people in Ireland drink more than the recommended maximum safe level of alcohol. “We should always remember that alcohol guidelines should act as a limit, not a target, and try to drink well below this threshold,” Sarah notes. 

“Alcohol has an effect on heart health and it can increase heart rate and blood pressure. It also contains a lot of calories which can contribute to unwanted weight gain, risk factors for heart disease and stroke,” Sarah explains. This is in addition to all the other potential effects alcohol has on our health including an increased risk of cancer.

If you’re a smoker, look at supports to help you quit – it will have a huge impact on your overall health. 

What should you do if you're concerned about cholesterol levels?

“People with high cholesterol often have no noticeable symptoms,” Sarah explains. “The only way to know if you have high cholesterol is to go to your doctor and have a blood test.” How often you get checked varies depending on individual factors like your family history or pre-existing illness. But even if you have no family history of heart disease or stroke, in general, if you’re over 40 then it’s recommended you book in to have a cholesterol check.


At Irish Life Health some of our plans offer  health screening to help you take greater control of your own health. Learn more about our Health Screening benefit.