Cholesterol - It's not the enemy!31 October 2018
Cholesterol…we’ve all heard of it, most of us had ours tested, but what if I was to say cholesterol isn’t necessarily the enemy?
The message that “cholesterol is bad and if you have high cholesterol you should take a statin to lower it” is out of date and not in sync with the most recent scientific evidence (1,2,3,4). The story of cholesterol is not black and white and rather a more confusing story that I am hoping to clear up in conjunction with National Cholesterol month.
The Diet-Heart Hypothesis
Let’s start with the diet-heart hypothesis that suggests that eating cholesterol and saturated fat raises cholesterol in the blood. The hypothesis originated with studies in both animals and humans more than half a century ago and has become deeply ingrained that consuming foods such as red meat, eggs and bacon will raise our cholesterol levels. It has since come out that this research was flawed, and more recent and higher quality evidence does not support this theory (5,6).
Our body likes to have a certain level of cholesterol in our blood at any one time (approximately between 1,100 and 1,700 milligrams) with 25% coming from our diet and the other 75% produced by the liver. Much of the cholesterol found in food cannot be absorbed by our bodies. The body tightly regulates the amount of cholesterol in the blood and when cholesterol intake in the diet goes down, the body makes more. When cholesterol intake in the diet goes up, the body makes less (5).
Studies have shown that 75% of the population’s blood cholesterol levels are not affected by dietary consumption of cholesterol. The other 25% are known as ‘hyper-responders’ and dietary cholesterol does modestly increase both LDL and HDL cholesterol; BUT it does not affect the ratio of LDL to HDL or increase the risk of heart disease (7,8,9,10). In other words, eating cholesterol isn’t going to give you a heart attack.
Cholesterol is a fatty like substance and in order to be carried in the blood, needs to be bound to a carrier called lipoproteins. There are two main lipoproteins that are classified by their density; low-density lipoprotein (LDL) and high-density lipoprotein (HDL). This is the sciencey bit so think of the blood as a road, the lipoproteins as cars and the cholesterol as the passengers. Scientists used to believe that the number of passengers in the car was the driving factor in the development of heart disease, however more recent studies suggests that it’s the number of cars on the road (i.e. LDL particles) that matters most. Atherosclerosis and heart disease can occur when there are a lot of cars on the road at the same time, which increases the likelihood that some cars will crash into the side of the road. The side of the road in this analogy are the arteries, so a ‘car crash’ will cause a build up of plaque in the arteries.
The significance of this in terms of determining your risk of heart disease is profound. When you’ve had your cholesterol levels checked, you will have likely been told your total, LDL and HDL cholesterol. This tells you the concentration of cholesterol (passengers) inside of the lipoproteins (cars) which is not the driving factor behind plaque formation and heart disease. The number of LDL particles (cars) in the blood should be measured instead.
So you might ask what causes an elevated number of LDL particles (cars) in the blood. LDL particles carry cholesterol as well as triglycerides, fat soluble vitamins and antioxidants; so they are like the bodies’ taxi service that delivers important nutrients to the cells and tissues. There is a limit to how many passengers each car can take and each car (LDL particle) has a certain number of cholesterol molecules and a certain number of triglycerides. As the number of triglycerides increases, the amount of cholesterol it can carry decreases which causes the liver to manufacture more LDL particles…which can then increase the likelihood a ‘car crash’ will take place.
Consuming a high amount of sugar, insulin resistances, type 2 diabetes, abdominal obesity and high blood pressure have all been shown to increase triglyceride levels. So actually sugar could be cause of heart disease! But unfortunately these isn’t new news. Dr Krauss, one of the world’s leading cholesterol experts ran a study in the 1980s when low-fat was all the rage. Healthy individuals with normal cholesterol were fed a low-fat, high-carb diet and the results were quite shocking. He discovered that the participants cholesterol profiles changed from healthy into heart attack-prone profiles showing high triglycerides.
So what can we do to reduce the risk of atherosclerosis and heart disease?
1. Sugar is not only a factor in the development of heart disease but over consumption can also lead to the development of insulin resistance, type 2 diabetes and obesity. Try to reduce your consumption of refined sugars and incorporate in complex carbohydrates instead (e.g. starchy carbohydrates, wholegrain carbs, quinoa etc)
2. Trans-fat (fast food, cakes and biscuits) has been shown to have negative impact of heart disease development so this is one type of fat to remove from your diet.
3. Fibre, specifically soluble fibre can help to reduce heart disease risk by binding and eliminating cholesterol and increasing the clearance of LDL particles. Soluble fibre is found in oats, nuts, seeds, legumes, fruits and vegetable.
4. Antioxidant rich food can help protect against heart disease by reducing oxidative damage (which is a major risk factor for heart disease). Fruits and vegetables are major antioxidant sources but also foods such as green tea, dark chocolate and nuts and seeds are all potent sources.
5. Exercise has been shown to reduce LDL particle concentration even independently of diet. Regular exercise (30 minutes everyday) prevents the development and progression of atherosclerosis. Exercise also aids maintenance of body weight, blood pressure control and insulin sensitivity.
6. Stress – the release of adrenalin when we are stressed has been shown to increase LDL particles. Try to incorporate stress management techniques into your daily life and where possible reduce external stressors.
7. Consume fatty fish (mackerel, salmon, trout) as these have been shown to have several cardiovascular benefits. Consuming monounsaturated fat (olive oil, nuts, avocados) can also reduce LDL particles and triglycerides and reduce overall inflammation.
This is still only part of the very complex and confusing story that is cholesterol. If you are concerned about your cholesterol (or someone you know!) and feel that you could benefit from diet and lifestyle stages, please get in touch to book your free 30-minute call with me.