If you’ve ever had your cholesterol tested or read up on the fat-like waxy substance, then you’ll know that there are different types of cholesterol. For some time, we were led to believe that LDL cholesterol was the really bad variety, causing heart attacks, angina, heart disease and stroke. Whereas HDL cholesterol was thought to protect us from these health complaints. Although, there is some truth in this idea, it isn’t as clear-cut as we all think and there is new evidence that shows that HDL cholesterol is not always good. Yes, high LDL levels are bad news as a build up in LDL cholesterol can cause atherosclerosis (narrowing of the arteries) and other health complaints, but does a high level of HDL or good cholesterol always mean a healthy heart? Is high HDL cholesterol always good? Can HDL be too high?
- What is the role of HDL cholesterol?
- How do you get high levels of HDL?
- Why have opinions on high HDL changed?
- Is high HDL cholesterol bad for you?
- How will this new study affect cholesterol tests?
- How do I know if I have SCARB1?
- Other medical conditions that cause high levels of HDL
- How can I protect against cardiovascular diseases?
- Final thoughts
What is the role of HDL cholesterol?
Cholesterol is formed in our livers and also occurs naturally in a number of foods. Cholesterol plays an important role in the formation of some hormones, bile and Vitamin D. However, LDL cholesterol is atherogenic, which means that high LDL levels can cause plaques (or fatty deposits) to build up in your arteries, when the arteries narrow in this way it is difficult for the blood to get through to your organs. This restriction in blood flow can cause a number of health complaints, such as angina. If a blockage forms then the blood supply can be cut off completely, when the blood supply to the heart is interrupted then heart attacks occur. A stroke is what happens when the blood flow to the brain is blocked. Knowing that cholesterol problems can cause such a negative impact on your health is a good incentive to learn all about cholesterol.
It is HDL’s job to remove the LDL cholesterol from the blood stream, by collecting it up and transporting it to the liver to be reprocessed. As HDL collects up LDL cholesterol, it stops it from building up in the arteries and causing potential problems.
How do you get high levels of HDL?
There are a few steps that you can take to boost your HDL cholesterol level. These include aerobic exercise, reaching a healthy weight and abstaining from smoking. As cholesterol occurs naturally in some foods, you can use your dietary choices to increase HDL levels too. High HDL cholesterol foods include nuts, fish and olive oil. These lifestyle changes are all natural and healthy ways to raise your HDL level, however a sudden rise in cholesterol levels can be a sign of something that may not be as good for your health.
Why have opinions on high HDL changed?
When carrying out a cholesterol check (otherwise known as lipid panel or lipid profile) your doctor will always check for HDL levels too. Doctors used to associate HDL levels with a reduced risk of heart attack, leading to the conclusion that high HDL levels could protect against heart attacks and various cardiovascular conditions. Scientists developed this notion further and came up drugs that could synthetically raise HDL levels in the hope of reducing the risk of heart attacks in patients. The trials using these drugs indicated something quite different. High HDL levels did not help, which led to the question is high HDL cholesterol always good? Can HDL be too high?
Is high HDL cholesterol bad for you?
The studies have established that elevated HDL cholesterol levels are not always good for you, but are they actually connected to heart problems? A study from Cambridge University showed that it might be. In fact, it has been uncovered that certain rare genetic mutations can leave people with high HDL levels. The trials identified a specific gene called SCARB1, which only affects 1 in 1,700 people. Every individual who had this mutated gene also had a very high level of HDL cholesterol as well as an 80% increased risk for heart attack. That risk is exactly the same risk percentage as the one given to smokers. By delving deeper, scientists discovered that the mutation was affecting the way in which the HDL performed. The mutation was preventing the HDL cholesterol from transporting the LDL cholesterol to the liver for reprocessing. This means that our previous belief that a high HDL level means a healthy heart, is not strictly true, especially when the HDL in question is not functioning properly. Vast amounts of time and money have been pumped into the manufacture of HDL cholesterol over the years, in the hope that they would work in a similar manner to statins and dramatically reduce the amount of bad cholesterol in our blood. This new research indicates that raising HDL levels is not enough, as well as showing us that if someone’s HDL count is high it does not necessarily mean that their risk of heart attack is low.
Rather than looking at HDL levels there could be better ways to assess how effective someone’s HDL is. For instance, analysing the size of various HDL particles or establishing how well they are able to transport LDL cholesterol would be far more useful than establishing the level of HDL.
How will this new study affect cholesterol tests?
When analysing your lipid profile it is standard practice for the lab to establish the following data; your whole cholesterol count, your LDL level, your HDL level and your triglyceride level. High total cholesterol will always cause alarm bells to ring. Triglycerides are fats that occur in the blood and are linked to coronary artery disease and heart disease. A high level of triglycerides can indicate a serious heart problem and so it is important information to collect. The normal range is HDL cholesterol is 40-50 mg/dL for men and between 50-59 mg/dL for women. Even though HDL over 40 mg/dl or above is desirable, HDL over 90 means that there is an increased risk of arteriosclerosis (thickening of the artery walls). At such a high level, the HDL cholesterol can start to reverse its role and even take fat from the liver to the body tissue. If your HDL level is over 100 then this risk is even more significant.
Although, the new research shows that a high level of HDL cholesterol doesn’t always mean an increased risk of heart attack, in the average person, a high level of HDL cholesterol is a sign of good heart health. If a patient exhibited constantly high levels of both HDL and LDL cholesterol, then it is likely that a doctor would investigate further. High total cholesterol can be a sign of numerous cardiovascular problems. Knowing that a high level of HDL cholesterol is not always good for you means that changes will need to be made in the way that we test a patient for risk of heart attack. In the future, doctors are hoping to introduce the practice of genetic testing on anyone who exhibits unusually high levels of HDL cholesterol. Being able to establish if someone has SCARB1 could be highly valuable information and could help to protect them from heart disease.
How do I know if I have SCARB1?
Genetic mutations are simply permanent alterations in the DNA sequence of a person, making their DNA different to that of others. These mutations are hereditary or somatic (acquired) and often go unnoticed. In the case of SCARB1, unless your genetic profile was thoroughly examined, you might never know about your mutation.
The sensible way to approach this new information about HDL levels, is to think about how it affects your health. Knowing that a high level of HDL cholesterol may not mean what we once thought makes it even more important that we pay attention to our LDL cholesterol and triglyceride levels. If your LDL levels are low, and your HDL levels are high it is likely that your HDL is working effectively. If your HDL levels are high, as well as your LDL levels then it is important to consider ways in which to keep your heart healthy. HDL over 90 could be caused by a variety of different factors. A genetic mutation is unlikely to cause a sudden rise in cholesterol levels, it will be more of a gradual process. If you do experience a sudden rise in cholesterol levels then it is more likely to be related to your lifestyle or even an illness. If you find yourself asking why did my cholesterol go up suddenly? Then you need to talk to your doctor all about cholesterol and high HDL causes so that they can give you the best advice possible.
Other medical conditions that cause high levels of HDL
Medically, abnormally high levels of HDL are known as Hyperalphalipoproteinemia. This is not a disease, it is simply a term used to describe “the presence of abnormally high levels of high-density lipoproteins in the serum.” As hyperalphalipoproteinemia is not a disease, it has no symptoms but it is linked to a history of alcohol abuse and associated diseases, such as multiple symmetric lipomatosis or Madelung’s disease which causes fatty tumours to grow around the neck and shoulders. Other high HDL causes include sustained aerobic exercise such as regular long distance running, as well as certain medications (including statins, fibrates, niacin and oral oestrogens). If you are taking any sort of medication then it is essential that you always read the list of side effects carefully. If you happen to be taking a medication that could potentially cause a change in your cholesterol levels then it is more important than ever that you take the steps to protect yourself against heart disease. If your HDL level is over 100 mg/dL then you will need to seriously reassess your lifestyle choices for the sake of your health.
How can I protect against cardiovascular diseases?
- Limit the amount of saturated fat, trans fat and sodium in your diet
- Eat a wide variety of fruit and vegetables on a daily basis
- Include plenty of fibre in your diet, including whole grains
- Aim to eat oily fish at least twice a week (or take omega 3 supplements if you are vegan or vegetarian)
- Cut back on meat (especially red meat) and dairy products
- Opt for low fat dairy products where possible and eat plenty of nuts, seeds and legumes to ensure that you have enough protein in your diet
- Cut back on sugary drinks
- Engage in 2 and a half hours of moderate physical exercise each week (or 1 hour and a quarter of intense cardiovascular exercise)
- Ensure that you engage in muscle-strengthening exercise at least twice a week
- Cut back or abstain from cigarettes and alcohol
- Maintain a healthy weight and don’t exceed the daily calorie requirements for your weight and gender
For a long time we have believed that a high level of HDL cholesterol in the blood is a clear indication that someone has a healthy heart and a lower risk of cardiovascular diseases. The knowledge that this is not strictly true, means that we need to take more responsibility for our own well being. If you happen to have high levels of HDL it could be due to a genetic mutation or because of your healthy diet and lifestyle choices. To ensure that the HDL that you have in your body is working effectively, it is important that you make sensible lifestyle choices and do all you can to ensure the best possible heart health, regardless of your HDL levels and if you have cholesterol problems. As high HDL cholesterol foods are great for your health, you can include them as part of a balanced diet without any concern or worries. Sensible lifestyle choices are the key to enjoying all round better health and will have a positive impact on many aspects of your well being, not just your cholesterol.