We often hear about cholesterol – particularly when it comes to diet – but we rarely stop to think about what it actually is and the function it performs. Although frequently mentioned in a negative context, it also carries out vital roles in the body as well.
Dr Leah Austin is a General Practitioner and Nutritional Therapist at St John & St Elizabeth Hospital and has a keen interest in nutrigenomics (nutrition and genetics). Here she explains precisely what cholesterol is, what it does and what measures we can take to ensure we are keeping it in a healthy range.
What is cholesterol?
Cholesterol is a fat-like chemical (lipid) that is made in the cells of the body, with a quarter of total cholesterol being made in the liver. Cholesterol helps maintain the integrity of cell membranes and is important in the body’s production of hormones, vitamin D and bile acid. The liver adjusts the amount of cholesterol it produces in response to the amount of cholesterol circulating in the body.
We all know that water and fat don’t mix, so cholesterol is coated in proteins by the liver in order that it can be carried in the blood. These are known as lipoproteins.
There are two different types of lipoprotein
These are known as low-density lipoprotein (LDL) and high-density lipoprotein (HDL).
The main function of LDL is to carry the cholesterol to parts of the body where it is needed. If there is more than is needed, LDL can build up in the artery walls – a process called atherosclerosis – which can then go onto to cause heart disease. So in basic terms, this is the ‘bad’ cholesterol.
HDL serves to mop up any excess LDL cholesterol and take it away from the cells and artery wall to the liver where it is either broken down or excreted. In essence, HDL is the ‘good’ cholesterol.
Ideally, you want to have an equal amount of both.
We can test whether you have high cholesterol
We can check for high cholesterol with a simple blood test. We have a marker indicating the average levels of cholesterol in the population, and if your blood test shows a level of cholesterol above the average of what’s considered healthy, you are considered to have high cholesterol.
High cholesterol can cause problems
If there’s a build-up of LDL (the ‘bad’ cholesterol), you may get extra deposits of a fatty, waxy substance in your arteries, which can lead to problems in the blood supply to your bodily organs.
High levels of LDL cholesterol also usually go hand-in-hand with general inflammation in the body. If you’re inflamed or have a chronic health problem, this seems to correlate with higher LDL cholesterol, and the body’s inflammatory response makes it more likely to cause plaque formation in the arteries.
Your diet can raise or lower your cholesterol
In terms of foods that are likely to have a negative impact on your cholesterol level, refined sugar and trans-fats (i.e. fried food, margarine and crisps) have no health benefits and may directly increase cholesterol levels in the blood. Processed foods and meats should also be avoided.
On the other hand, a mediterranean-style diet that balances protein, fibre, carbohydrates and fat can go a long way to helping reduce your cholesterol levels. This might include things like:
- Soluble fibre, i.e. whole fresh fruit and vegetables. Eating the skin of fruits and vegetables can also be a good way to maximise your fibre intake, as can sprinkling some mixed seeds over a salad.
- Healthy oils, such as extra virgin olive oil. Don’t heat it because it will lose its benefits, but try adding it to salads, cooked vegetables or soup. Alternatively, just have a 25ml dose on its own every day.
- Omega-3. The SMASH fish are a great source of Omega-3; Sardines, Mackerel, Anchovies, Salmon and Herring. You should aim for two or three portions per week.
- Nuts. 30g of raw, unsalted nuts daily is a good amount to have.
- Oats, specifically 90g of organic whole rolled oats per day, perhaps mixed with seeds or nut butter. Try mixing with water, almond milk or hemp milk (the unsweetened and organic kind, to avoid emulsifiers)
- Smart foods. A one-shot drink like Benecol contains plant stanols or sterols that can help lower your cholesterol.
Exercise can help lower cholesterol too
The better your general health, the better your cholesterol levels – so apart from lowering your alcohol consumption and giving up smoking, one of the best things you can do to maintain a healthy level of cholesterol is to take up exercise.
If you’re not used to exercising at all, I would start gradually with walking 15-20 minutes a day to start off with. If you do too much at once and you’ve been sedentary for a lot of your life, there’s actually a risk that you could cause more inflammation in the body by pushing too hard – particularly if you’re overweight. You want to build up your exercise routine gradually.
There is medication for high cholesterol but it’s a long-term commitment – with side effects
The medication we use to treat high levels of cholesterol is called statins, which lower the density of LDL cholesterol. However, it can have a side effect known as myositis which causes muscular aches and pains and reduces your energy levels. It can also have an impact on the liver, so we always need to check liver function after starting someone on statins.
The other thing to say about statins is that they have to be taken for ten years before they begin to reduce your risk factor, so it’s not the most immediate solution to high cholesterol. I’ve had some really good – and considerably faster – results with patients simply through changing nutrition and lifestyle, and working with them to understand why their cholesterol is elevated in the first place.
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