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Cholesterol

You’ve heard the term ‘cholesterol’. We have all seen foods and medications advertised on television boasting they will help to reduce your cholesterol levels. But what exactly is cholesterol and why does it need to be low?

Most of the cholesterol in our blood is produced by the body itself. It has an essential role in all cell membranes and how every cell in the body functions. However, people with high cholesterol concentrations in their blood have a higher risk of coronary heart disease than people who have lower levels. The risk is particularly high if you have a high concentration of LDL cholesterol and a low level of HDL cholesterol.

What are LDL and HDL cholesterol?

LDL (low-density lipoprotein) cholesterol and HDL (high-density lipoprotein) cholesterol transport fats, including cholesterol, around the body.

  • LDL is considered the ‘bad’ carrier as it takes cholesterol from the liver via the arteries (the blood vessels carrying blood away from the heart) to be stored in other parts of the body. If there is too much in our arteries it can accumulate in the blood vessel walls, restrict blood flow and even cause a complete blockage. A blockage in the heart causes a heart attack; in the brain, a stroke.
  • HDL is considered the ‘good’ carrier as it carries cholesterol away from the blood to the liver, where the cholesterol is metabolised. 

How cholesterol levels are measured

Blood cholesterol concentrations can be measured through a simple blood test. It will usually measure total cholesterol, LDL cholesterol and HDL cholesterol, and a ratio of total cholesterol to HDL cholesterol. 

What causes high cholesterol?

The main factors likely to increase total blood cholesterol levels (in particular LDL) include

  • family history of high cholesterol
  • eating too many foods high in saturated fat
  • being overweight (especially when stored around your belly)
  • physical inactivity
  • smoking
  • high levels of stress

How to reduce high cholesterol?

Unfortunately, we can’t change our family history, but we can increase HDL and reduce LDL cholesterol concentrations by being more active, maintaining a healthy weight, eating a heart-healthy diet, reducing stress and not smoking. Some people may also require medication to help lower their cholesterol levels. Contact your doctor for advice on whether medication is necessary for you.

Nutrition tips to reduce cholesterol

Making small changes to everyday eating is a good way to lower blood cholesterol levels. Base your diet around whole plant foods i.e., fruit, vegetables, whole grains such as oats, and legumes. They are high in soluble fibre, which may help lower blood cholesterol. Also, focus on reducing foods high in saturated fats and swapping them with healthier fats (monounsaturated and polyunsaturated fat).

Go plant powered

  • Opt for whole-grain options. Oats and barley are extra special because they are high in a type of soluble fibre called ‘beta glucan’. Beta-glucan helps to lower ‘bad’ LDL cholesterol in your blood. Porridge and baked beans on toast have good amounts of soluble fibre.
  • Try to fill half your lunch and dinner plate with vegetables.
  • Try chopped fruit on breakfast cereal, an extra piece of fruit with lunch.
  • Eat legumes and beans frequently (e.g., lentils, red kidney beans, chickpeas, baked beans). Ideas include substituting half the mince in a recipe with lentils, adding beans and lentils to your soups and having a few plant-based meals a week.
  • Foods rich in soy protein (tofu, soya beans, soy milk) may also contribute to a small cholesterol-lowering effect.

Reducing saturated fat

  • Choose low-fat dairy products such as trim (green top) or reduced-fat (light blue top) milk, low or reduced-fat cheeses (including edam and cottage cheese), and low-fat yoghurts.
  • Choose lean cuts of meat, removing any visible fat from meat and skin from chicken.
  • Reduce fat required for cooking by grilling, baking, stir-frying in a non-stick pan, or microwaving.
  • Some foods are higher in saturated fat than we realise because the fat is hidden in the food. Some examples of these foods are coconut cream, deep-fried foods, potato chips, cakes, biscuits, pies, and pastries. So it is best to only eat these foods occasionally. Palm oil (often found in a lot of packaged baked goods) and coconut oil are both high in saturated fat as well.

Choose healthier fats (in place of saturated fat)

  • Choose oils such as olive, canola, and sunflower oils. Extra virgin olive oil has the added benefit of being heat stable and antioxidant-rich.
  • The Heart Foundation recommends that “Eating 3-4 small handfuls of nuts and seeds each week is helpful to reduce the risk of heart disease”.
    • Try a few unsalted nuts (such as almonds or walnuts) as a healthy snack.
    • Sprinkle seeds over your breakfast or salads.
  • Swap butter for avocado or nut butter e.g., peanut butter.
  • Oily fish such as salmon, tuna, and mackerel are high in heart-healthy omega-3 polyunsaturated fat. It’s recommended men have 610mg of long-chain omega-3 daily and women have 430mg daily to reduce the risk of heart disease (Nutrient Reference Value, 2017). This is around 2 servings of oily fish a week.

Eggs and cholesterol

There is a lot of confusion around eggs and cholesterol but it’s important to note the difference between dietary cholesterol and blood/serum cholesterol.

  • Dietary cholesterol is the cholesterol found in food such as eggs, prawns and other animal foods.
  • Blood/serum cholesterol is the cholesterol found in your blood and is the cholesterol we have been talking about in this article. LDL and HDL cholesterol are types of blood/serum cholesterol.

Eggs are high in dietary cholesterol but relatively low in saturated fat. We know now that dietary cholesterol only slightly increases our blood cholesterol levels (and responses vary from person to person). If you are trying to reduce your cholesterol levels, eating less saturated fat and upping your intake of whole plant foods is more important than your egg intake. In saying that, those with type 2 diabetes or at an increased risk of heart disease are encouraged to eat no more than six eggs a week. To learn more about eggs, visit our ‘Eggs’ webpage.

What about Plant Sterols? Will they reduce high cholesterol?

Plant sterols (or phytosterols) are found naturally in very small quantities in a variety of plant foods such as grains, vegetables, fruit, legumes, nuts, and seeds. They actively lower cholesterol by partially blocking the absorption of LDL or “bad” cholesterol in the digestive system. The Australian New Zealand Food Code permits the addition of plant sterols to edible oil spreads, breakfast cereals, milk, and yoghurt.

In a systematic review by Food Standards Australia New Zealand (FSANZ) (2014) it was concluded that there is a ‘High’ degree of certainty that increased plant sterol intake reduces blood total and LDL cholesterol concentrations.  Because of the strong evidence plant sterols are effective in lowering LDL cholesterol, FSANZ approved a health claim.

The Health Claim states that  2g of plant sterols daily lowers cholesterol within 4 weeks as part of a healthy diet low in saturated fat. This has been proven in over 40 clinical trials that cholesterol is lowered by up to 9% within 4 weeks. The New Zealand Nutrition Foundation endorses this claim. Note that foods with added plant sterols only ‘work’ if eaten frequently in the recommended amounts. These foods are can be expensive and your overall diet is more important.

More info

References

FSANZ (2014) Systematic review of the evidence for a relationship between phytosterols and blood cholesterol. Report prepared by Food Standards Australia New Zealand, Canberra.

National Health and Medical Research Council (Australia) and Ministry of Health (New Zealand) (2017) Nutrient Reference Values for Australia and New Zealand: Summary.

Last updated: July 12, 2022

Last modified: July 13, 2022