Cholesterol explained

Why you need it – and where things go wrong

Understanding cholesterol

Cholesterol plays a key role in your body. It is:
• essential for building and maintaining cell membranes
• converted to bile which is needed for digestion
• involved in the manufacture of vitamin D
• a building block for many essential hormones

Acting as a ‘starter’ hormone, cholesterol enables the manufacture of steroid hormones, including:
• the sex hormones progesterone, oestrogen and testosterone – so low cholesterol levels can lead to a low sex drive
• the adrenal hormones – cortisol, which helps control blood sugar levels, and aldosterone, which helps control blood pressure.

Cholesterol is made in the liver and its production is usually cleverly based on the amount your body needs.

Cholesterol can also be taken in through food, but is only found in large amounts in animal products.

In the past, the advice was to avoid cholesterol-rich foods, such as eggs and prawns, but it is now recognised that for most people dietary cholesterol doesn’t actually impact cholesterol levels in the body.

If you eat too much of it, your body simply manufactures less and excretes the cholesterol it doesn’t need.

Cholesterol and heart disease

Cholesterol becomes a problem when the levels in the blood get too high.

This can indicate that there is some damage to the arteries and that cell-building cholesterol is helping to repair it. It is this ‘patching up’ process that causes ‘atheromas’, or plaques, in the arteries. When plaques become unstable they can burst and block the arteries, causing a heart attack.

High total cholesterol levels are a still deemed a risk factor for cardiovascular disease, although some research questions the importance of this reading. A more significant risk factor may be the types of cholesterol that make up your total levels.

There are also many other factors associated with an increased risk of heart disease.
■ diet ■ obesity ■ stress ■ lack of exercise ■ high blood pressure ■ smoking ■ diabetes ■metabolic syndrome ■ triglyceride levels ■ how easily your blood clots ■ homocysteine levels ■ high blood sugar levels ■ the level of inflammation in your body.

Different types of cholesterol

Total cholesterol levels comprise many more readings than you will normally be told about. These include:

  • HDL (High Density Lipoproteins)
generally seen as ‘protective’ cholesterol because it transports cholesterolfrom the arteries back to the liver where it can be processed for excretion
  • LDL (Low Density Lipoproteins)
generally viewed as ‘bad’ cholesterol because it takes cholesterol from the liver to the arteries where it can cling to the walls of the blood vessels.

New research indicates that HDL and LDL can also be further broken down into ‘good’ and ‘bad’ fractions. Small, dense LDL particles are ‘bad’ because they are associated with more artery plaques than large size LDL particles.

It may therefore be the type of LDL you have which influences the risk of atherosclerosis, commonly known as hardening of the arteries.

Lipoprotein(a) – Lp(a) – levels are also important. These are proteins which can attach to LDLcholesterol, making it stick more easily on to the artery wall. They also inhibit the healing ‘clotting’ mechanism in the plaque. Some research suggests that elevated Lp(a) levels indicate a greater heart disease risk than high LDL levels alone.

Cholesterol that is attacked by free radicals is known as oxidised cholesterol. Oxidised LDLcholesterol is frequently found in arterial plaques, which is why antioxidants are so important for artery health.

Keeping cholesterol at the right level

Nutritional advice no longer recommends limiting cholesterol-containing foods such as eggs but some dietary changes may help reduce cholesterol levels. These include eating:

  • Low GI/GL foods

There is evidence to suggest that eating highly processed carbs and a high GI/GL diet has a negative effect on cholesterol and heart disease rates.

  • Foods with Omega 3 fatsMore Omega 3 fats

Substantial research on Omega 3 fat intake indicates reduced death from heart disease in people who have higher Omega 3 intakes.

  • Oily fish
  • Walnuts
  • Pumpkin seeds
  • Flaxseeds
  • Less saturated fat

And more ‘healthy’ fats – put simply, the famous Mediterranean diet.

  • Olive oil
  • Nuts
  • Seeds
  • Fish
  • No trans fats

Trans fats negatively impact many heart disease markers, including cholesterol, Lp(a) and inflammation so minimise your intake of processed and deep fried foods.

  • More vitamin C-rich foods

Low vitamin C levels may be associated with high Lp(a) levels, so focus on boosting vitamin C intake.

  • Antioxidant-rich plant foods

It is oxidised cholesterol that is packed away in the artery walls and which in turn attracts more debris around the plaques, so keep your antioxidant level high as a preventative measure. This means plenty of phytonutrient-filled fruits, vegetables, whole grains and pulses.

 

 

 

 

 

 

 

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