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Cholesterol: What You Need to Know

October has been ‘National Cholesterol Month’ in the U.K. In recognition of this, I would like to take the opportunity to discuss this essential and often misunderstood element of human nutrition and health in order to dispel some of the misunderstanding that surrounds it. It is important for your health that you do not get stuck in the ‘low cholesterol good, high cholesterol bad' fallacy and that you understand the important role cholesterol plays in your body.

First things first

Cholesterol is an organic molecule made up of 27 carbon atoms, 45 hydrogen atoms and an oxygen/hydrogen pair. It is important to know this to better understand what is meant by ‘good’ cholesterol and ‘bad’ cholesterol. It is not the cholesterol molecule that is good or bad. There is only one type of cholesterol molecule.

Cholesterol gets transported around the bloodstream and deposited to tissue cells around the body where it is needed. However, since it is a fat, it cannot travel alone as it would end up as a useless glob (think of bacon fat floating in a pot of water). It therefore gets transported around the bloodstream (along with other fats such as triglycerides) in tiny protein covered particles that mix easily with blood, called lipoproteins (lipo (fat) + protein). Lipoproteins come in a range of different shapes and sizes. However, I am going to focus this article on the lipoproteins that get the most attention and that most people are more familiar with, i.e. low-density lipoproteins (LDL) and high-density lipoproteins (HDL). It is these lipoproteins that are ‘good’ or ‘bad’.

Understanding ‘good’ and ‘bad’ cholesterol

Let’s start by looking at LDL. It is these particles that get labelled as ‘bad’ cholesterol. LDLs deliver cholesterol to the tissues. LDL is a low-density molecule. The analogy I like to give is comparing golf balls (LDLs) to a big, light beach ball (HDL). If you keep throwing a golf ball against a wall it will eventually damage the wall. Whereas if you keep throwing a big beach ball against the wall it won’t damage it. If the bloodstream has a high number of LDLs hitting against the arterial walls, they will eventually start damaging the arteries, setting the scene for inflammation. Due to the small size of the LDLs, some may even become lodged in the arterial wall, oxidising and again resulting in an inflammatory response. LDLs are thus strongly associated with the build - up of artery - clogging plaque. HDLs on the other hand, are not only less likely to damage the arterial wall due to the fact that they are ‘large buoyant ‘molecules but they take cholesterol from the cells back to the liver, mopping up any cholesterol left behind in the arteries. Once in the liver, excess cholesterol is either cleared away or recycled. About 50% of cholesterol is reabsorbed by the small bowel, making its way back into the bloodstream.

Some important facts about cholesterol

Cholesterol is so important that our liver and intestines make about 80% while only about 20% comes from the food we eat. Our bodies make cholesterol according to demand. Cholesterol is converted to pregnenolone which is the immediate precursor for the synthesis of all of our steroid hormones, including testosterone, oestrogens and cortisol. So it makes sense that if you are highly stressed, more cholesterol is required to make stress hormones. Infertility is a classic symptom of stress, often due to the fact that there is insufficient cholesterol and pregnenolone to make the hormones oestrogen, progesterone and testosterone. If blood levels of cholesterol are high, this can be in response to the need for more cholesterol and the liver’s response to that need.

Cholesterol has numerous other important functions in the body:

  • It builds the structure of all cell membranes

  • It is essential for the body to produce the active form of vitamin D. We need cholesterol in our skin cells to make vitamin D from sunlight

  • It produces the bile acids which help the body digest fat and absorb important nutrients

  • 25% of cholesterol in the body is found in the brain. Cholesterol is an integral component of the myelin sheaths that allow our brain cells to communicate with each other.

Over 50% of heart attacks occur in people with normal to low cholesterol levels

Here are some other surprising facts about cholesterol and cardiovascular disease (CVD):

  • Over 50% of heart attacks occur in people with normal to low cholesterol levels.

  • Insulin resistance is responsible for about 50% of high blood pressure and there is a strong correlation between cardiovascular disease and diabetes.

  • There is a higher risk of death as we get older if cholesterol levels are too low.

LDLs come in different shapes and sizes. Are they all ‘bad?’

For decades, the oversimplified view of cholesterol – that all LDL is the same and that all LDL is bad, has impacted the way we view cholesterol and heart disease and has affected the food we eat. This has resulted in the oversimplified and erroneous belief that all saturated fat consumption raises our risk of heart disease. This belief has also led to many people swallowing the most prescribed class of drugs of our time – statins. However, the view that all LDLs are the same has evolved in recent years, calling the entire LDL cholesterol premise into question with the ability to now analyse LDL sub particles down to their smallest subcomponents. We now understand that LDL comes in 4 basic forms:

  • A large form (big and fluffy)

  • A denser form (intermediate-density lipoprotein)

  • A small LDL

  • A very small LDL.

Like HDLs, the large, big and fluffy LDLs are largely benign and harmless while the smaller and denser particles cause more damage. Today there is also a greater understanding that a diet high in saturated fat mainly boosts the HDL and large LDL particles, whilst a diet high in carbohydrates and low in fat propagates the harmful smaller forms.

The problem

The main problem today is that testing LDL levels without testing the size of the particles, is not a reliable marker for heart disease risk and can result in unnecessary fear and cholesterol lowering drug prescriptions. There are many labs today that test LDL particle size and it is important, when testing CVD risk, to test not only LDL particle size but also LDL/HDL ratio.

To summarise

Cholesterol is a natural substance that our bodies produce for a variety of important functions. It is carried through the body to the cells (along with other fats such as triglycerides) in one of three containers – LDL, HDL, VLDL (Very Low Density Lipoproteins). The belief that the cholesterol in your eggs ends up in your arteries is not entirely accurate. Although there is a link between the cholesterol you eat and the cholesterol in your arteries, it does not automatically follow that if you eat more you store more. Your body’s uptake of cholesterol from the food you eat is highly regulated. If you are eating a lot of eggs every week, your liver will simply produce less of its own cholesterol due to the surplus of cholesterol from your food. Triglycerides are fats. Triglycerides are converted from sugar, carbs and trans fats and are carried around the body in the more harmful VLDLs. LDL mainly carries cholesterol. Thus, if your LDL levels are high but made up in the main of light, fluffy, bigger molecules, you are less at a risk of arterial damage than if the bulk of the LDL levels are made up of VLDLs.

Now you understand cholesterol better, here are some diet and lifestyle tips to keep you healthy:

  1. Increase omega-3 fatty acids -  The fat free, low fat diet has been so ingrained in the minds of so many for so long that they still find it difficult to incorporate fat into their diet. However, understanding which are the essential healthy fats is an important place to start. A diet rich in these fats not only helps reduce inflammation, but also decreases the triglycerides that contribute to high levels of the smaller, more dangerous lipoprotein particles, converting them into the lighter, fluffier, bigger, more protective particles. Including anti-inflammatory foods in your diet, such as salmon, herring, sardines, flaxseed and even seaweed, benefits your heart by improving your overall cholesterol profile.

  2. Avoid long periods of stress.

  3. Avoid fried food that produces AGEs , particularly when very browned. These are known to contribute to inflammation and oxidative stress and are linked to diseases such as CVD and diabetes.

  4. Eat plenty of fresh fruit and vegetables - These are full of antioxidants which disarm free radicals, preventing them from causing damage. When small LDL particles get stuck in the walls of the arteries, they become oxidised, creating free radical damage to the arterial wall. Antioxidants are thus an important component of a diet aimed at preventing CVD.

  5. Try the Mediterranean Diet - One of the best studied diets in terms of cardiovascular health is the 'Mediterranean diet'. This diet includes fish, a variety of fresh salads, vegetables, olive oil, nuts, legumes, whole grains and moderate alcohol consumption.

  6. Exercise. Staying fit is important for health generally and for preventing heart disease. This does not have to be running at high speed on a treadmill every day as this also causes oxidative stress for some. Think about moving more – getting off public transport a few blocks away from work and walking the rest of the way, taking the stairs instead of a lift more often, pacing when on your mobile phone instead of sitting, taking an evening stroll after dinner etc

  7. Give up smoking.

  8. Maintain a healthy weight.

  9. Be familiar with your blood pressure and have your lipid profile checked every few years. If you have high blood pressure, consider taking up to 500mgs of magnesium a day which helps relax muscles. An overlooked cause of heat attack is calcification of the arteries caused by a build up of calcium levels in the blood.

  10. Check your homocysteine levels. This is an easy, inexpensive blood test. High homocysteine is associated with an increased risk of CVD

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