Cholesterol is mainstream news these days. Take a walk through any supermarket isle and you will be bombarded with signs for low-cholesterol and cholesterol-free products. Advertisements abound for dairy spreads that claim to lower your cholesterol. Pharmaceutical companies advertise cholesterol-lowering medication and its benefits. In some countries, such as the UK, this medication (statins) can now be purchased straight over the counter in pharmacies without a doctor’s prescription.
You probably already know that cholesterol has something to do with heart disease. Heart disease is the biggest cause of death in Ireland for men, and one of the best ways to prevent heart disease is to keep your cholesterol at a healthy level. But, like many people, you may be confused about cholesterol, all the different fats you eat, what happens to them in your body and how they affect your heart. So what is the story with cholesterol? Why is it important? And what should you do about it?
What Is Cholesterol?
Cholesterol is a soft fatty-like substance that, in healthy amounts, is used by the body for normal cell function. You need a certain amount of cholesterol for all the cells in your body to work properly and to produce important hormones. Some of the cholesterol in our systems is made in the liver and we get the rest from our diets. Food rich in cholesterol and saturated fat will increase the amount of cholesterol in our systems.
The problem is that, over time, excess cholesterol in the blood vessels can cause the cholesterol to stick to the walls of the blood vessels, leading to the development of fatty plaques (see diagram on page 94). These plaques can then cause narrowing of the blood vessels and eventually lead to heart disease or stroke.
In this context, it is worth knowing what the normal values of these types of cholesterol are. These are shown in the table below. There are two main types of cholesterol: LDL and HDL.
LDL Cholesterol
Firstly, the bad guy: LDL cholesterol. This is the bad cholesterol, which I call ‘lousy’ cholesterol. The less LDL or lousy cholesterol you have the better. This figure should be less than 3 millimoles/litre (less than 2.5 mmol/litre if you are diabetic or already have heart disease).
LDL cholesterol comes from two separate sources. Firstly, as most of us know, we get LDL cholesterol in our diets. Particular sources of LDL cholesterol include fried foods and stodgy carbohydrates. Secondly, LDL cholesterol is made in the liver and some people simply make too much LDL cholesterol. Therefore, even if you eat a very healthy diet, it is still possible to have high total and high LDL cholesterol levels.
What Do Raised LDL Cholesterol Levels Do To Me?
LDL cholesterol travels from the liver through the arteries to other parts of the body. Over time, raised LDL cholesterol levels can allow it to stick to the inner lining of your arteries or blood vessels, causing narrowing, hardening and ultimately blockage of the fine blood vessels that bring blood around the body to vital organs like the heart and the brain. Imagine sticky goo like sticky toffee pudding: this is just what LDL cholesterol is like, sticking to the walls of the blood vessels. This process of narrowing and hardening, known as atherosclerosis, occurs over many years. Raised cholesterol can be a silent condition, with no symptoms whatsoever, until one of the tubes blocks over and results in a heart attack or a stroke. High levels of LDL cholesterol increase your risk of heart disease.
Dietary Sources of LDL Cholesterol
Saturated fats can raise your LDL cholesterol levels and you find saturated fats in foods like butter, hard margarine, lard, cream, cheese, fatty meat, cakes, biscuits and chocolates. Processed foods are usually high in saturated fats.
Hydrogenated fats or trans-fats also raise the level of LDL cholesterol as well as accelerating the rate of artery blockage. Recently it has been shown that starchy carbohydrates can also increase your LDL cholesterol level. Examples of starchy carbohydrates include white bread, biscuits, cakes and many cereals (excluding oat-based cereals).
How Can I Lower My LDL Cholesterol Level?
There are a number of things you can do to help reduce your LDL cholesterol levels. Start off by having a good look at your diet. Keeping a diary of everything you eat over a seven-day period, or at least over a weekend and one or two weekdays, can give you an ideal opportunity to look at not only what you eat but also when and why. This might throw up a few surprises for you. Cutting down significantly on starchy carbohydrates like white bread, biscuits and cakes and also on fries is a good place to start. It is useful to focus on positive changes that you are likely to stick to rather than being negative and saying ‘I can’t have this’ and ‘I can’t have that.’ Therefore, I would encourage you to think about heart-healthy options where possible:
Benefits of Fish Oil
International studies have found less heart disease in people who eat fish regularly. It has been shown that Eskimos in Greenland who eat nearly a pound of fish a day have low rates of death from heart disease. This may well be due to the health benefits of fish oils containing omega-3 fatty acids, which help to make the blood thinner and less likely to clot, help protect the delicate linings of arteries, and may also lower blood pressure.
Rich dietary sources of omega-3 include cold water fish such as salmon, trout, mackerel, sardines and herring. Specifically there are three groups of men who may benefit from fish oil, either in dietary form or supplements. Firstly, men who already have coronary heart disease are recommended to eat one portion of oily fish a day. Secondly, for men who suffer from arrhythmias – irregular heart beats – the omega-3 fatty acids in fish oil can stabilise electrical activity in the heart and calm arrhythmias. Thirdly, men with high levels of triglycerides (blood fat), can benefit because fish oil supplements have been shown to help lower triglycerides.
Fibre
Fibre comes in two forms: water soluble and insoluble. It is the soluble fibre that helps reduce cholesterol levels. It does this in two ways. Firstly, high-bulk food fills us up and leaves less room for fat in the diet. Secondly, it helps the body to clear LDL cholesterol from the system, which lowers the level of LDL in the blood. Good sources of soluble fibre include oat bran, beans, peas, lentils and corn. Pectin, a soluble fibre found in such fruits as apples, citrus fruits, cranberries and sour plums, can also reduce high cholesterol levels. Wheat bran, which is an insoluble fibre, has no direct effect on cholesterol.
HDL Cholesterol
Secondly, the good guy: HDL cholesterol, which I call ‘happy’ cholesterol. High levels of HDL cholesterol can help protect you from heart disease. HDL cholesterol is called good cholesterol because it mops up excess LDL cholesterol left behind in your arteries and carries it to the liver, where it is broken down and passed out of the body. It also helps to impede hardening of the blood vessel walls by preventing LDL from causing damage. There is increasing evidence now that low HDL cholesterol (i.e. a HDL value of less than 1 mmol/litre) is an independent risk factor for heart disease. So, keeping your HDL or happy cholesterol high, in other words keeping it over 1, helps to protect against heart disease. It appears that the higher the HDL the more protection you get.
So Not All Cholesterol Is Bad For Me Then?
Absolutely not. HDL cholesterol is good for your health. Unfortunately many men suffer from low HDL cholesterol. Research has shown that smoking, raised blood pressure, diabetes and being overweight are associated with low HDL cholesterol.
So What Can I Do to Raise My HDL Cholesterol Levels?
There are a number of things you can do to raise your HDL cholesterol levels:
Triglycerides
Triglycerides are a type of fat found in the blood. Too much triglyceride in your blood can increase your chances of heart disease. There are many reasons why your blood fat may be raised, including:
What Can I Do if My Triglyceride Levels Are Too High?
Make sure your diet is heart-healthy (as for low cholesterol) and eat plenty of oily fish, which is rich in omega-3. Keep your weight down, take plenty of exercise and moderate your alcohol intake.
Sometimes several of the above factors may be involved. So if your blood fat level is raised it is time to look at your diet, maybe, as we suggested earlier, by keeping a food diary over a week or so, not only of what you eat but also of your exercise habits and alcohol intake. Maybe some positive changes can be a key step towards improving, not only your blood cholesterol and blood fat levels, but your overall health as well.
How Can I Check My Cholesterol Level?
A blood test provided by your family doctor can analyse your cholesterol numbers for you. Remember to fast for at least 12 hours prior to this test being taken. Raised LDL and low HDL levels are both independent risk factors for heart disease. Therefore, it is important to know your LDL and HDL values as well as your total cholesterol value and blood fat (triglycerides) level. A ‘lipid profile’ is the name of the blood test to check total cholesterol as well as HDL cholesterol, LDL cholesterol and blood fat (triglyceride) levels.
How Often Should I Have It Tested?
This depends on your family history and your individual circumstances. There are still a lot of men out there who don’t know their cholesterol level, so getting it checked is a good start. If it is raised, your doctor will probably recommend regular monitoring of it and assessing its response to a heart-healthy, low-cholesterol diet. If you are on treatment for high cholesterol then it is recommended that you have it checked every six months or so.
Cholesterol-Lowering Foods and Spreads
There are now a range of foods that can help lower your cholesterol. These foods have ingredients called ‘plant stanol esters’, which reduce the amount of cholesterol in food absorbed from your stomach into your blood after eating. By doing this they can lower the level of cholesterol in your blood. However, these products don’t affect the production of LDL cholesterol in the liver, so if you are programmed to make too much cholesterol then you will continue to make too much regardless of what you eat or when.
There are a variety of these food products for sale in supermarkets and they include spreads, yogurts and milk. They may help if your cholesterol level is high but they are no substitute for a heart-healthy diet. Examples on the Irish market include Benecol and Flora Pro.Activ. These products can also be expensive. Talk to your doctor to see if they may be suitable for you.
Cholesterol in Your Genes
Sometimes dietary and lifestyle changes don’t result in cholesterol levels returning to normal. This may be because you have a genetic predisposition to make too much cholesterol, in which case, no matter how healthy your diet is, your liver is still going to make too much LDL cholesterol at night. This can cause confusion because it is often wrongly assumed that if your cholesterol is up then it must be your diet that’s causing it. Some Irish men are simply genetically programmed to make too much cholesterol – for them it is all in the genes. In my experience, for most men it’s a bit of both: a sub-optimal diet and lifestyle, often with a family history of heart disease and a genetic predisposition. A good start is getting your cholesterol checked and then having a discussion with your family doctor about the significance of the results.
Medical Treatments to Lower Your Cholesterol
A family of drugs known as statins, of which there are several types, can be used to lower your cholesterol levels. They work by blocking the production of LDL cholesterol in the liver. This means that the amount of cholesterol that can be dumped into the blood is decreased and, at the same time, the amount of LDL the liver can remove from the blood is increased. The result of this process is lowered total and LDL cholesterol values. Statins are also believed to have an anti-inflammatory benefit on the coronary arteries, so that they tend to stabilise blockages and reduce the risk of potentially life-threatening clots being created.
Many studies have shown the benefits of statins in terms of reducing the risk of heart attack and stroke, which are two common long-term complications of raised LDL cholesterol levels. The bottom line is that the effectiveness of statins is beyond question.
Clinical studies show that these drugs can lower LDL cholesterol by up to 60 per cent and raise HDL cholesterol by up to 10 per cent. Large studies of statins show that the use of these drugs is associated with a 20 to 30 per cent reduction in death and in the incidence of major cardiovascular events, such as heart attacks, strokes and angina.
For most people, statins seem to be fairly well tolerated, with the most commonly described side effects including abdominal wind and sometimes muscle aches. Less common effects include nausea and drowsiness. Hair loss has also been described. These side effects are relatively uncommon. However, serious side effects can occasionally occur and regular monitoring is essential.
Statins are known to cause muscle problems. On rare occasions severe muscle aches and pains can occur, which usually reverse on stopping the drug. A rare but potentially serious side effect is where the muscles break down. This is called rhabdomyolysis and can lead to kidney failure and even death. This is thought to affect about one in every fifty thousand people who take statins. Therefore it is important to be vigilant about side effects and discuss them with your doctor. Statins are broken down through the liver so it is advised that a liver blood test be done at six monthly intervals to check liver function.
At least five statins are currently on the market in Ireland: atorvastatin (Lipitor), fluvastatin (Lescol), pravastatin (Lipostat), rosuvastatin (Crestor) and simvastatin (Zocor).
Studies on the long-term safety of statins are reassuring so far. This is important, as most people prescribed statins will probably need to take these drugs for many years. There does not appear to be any evidence of an increased risk of death from non-cardiac causes.
Ultimately, the decision as to whether you need a statin to treat your cholesterol is best taken in consultation with your family doctor. He or she will be able to advise you of the pros and cons in your particular case.
As doctors, we try to look at your overall risk of heart disease, which takes into account several risk factors including your age, whether or not you smoke, your blood pressure, your blood sugar levels, your weight and your family history. It is almost always better to try out a cholesterol-lowering, heart-healthy diet for several months before embarking on medication. Having said that, there is no doubt that many lives have been saved since statins arrived on the scene.
Key Points
