Cholesterol is generally a word that brings lots of negative thoughts like 'heart disease' and 'diets', but what does the latest research actually tell us?
Cholesterol is a lipid (fat) molecule important in our bodies for cell structure, hormone synthesis and bile production. Different types of cholesterol in the blood can be measured with pathology tests, you may have seen letters like HDL (high density lipoproteins) or LDL (low density lipoprotein). High LDL levels have been shown to increase risk of coronary artery disease and stroke in large observational studies and randomized controlled trials. HDL cholesterol helps to unblock arteries.
So how do we keep LDL levels low, and HDL levels high? The latest research suggests most of the cholesterol in the blood is made by the liver and the rest from the fats we eat. So rather than avoiding cholesterol in food we need to look at the types of fat we eat. It was previously thought that a low fat diet was the answer however studies now show that replacing saturated fats with unsaturated fats is the key to optimal blood cholesterol levels.
Which is which, you ask? Read on!
Saturated fats (increase LDL and decrease HDL)
Animal fats- fat on meat, skin on chicken, full fat dairy
Palm oil, coconut oil
Processed foods like cakes, biscuits, chips, pastries etc.
Monounsaturated fats (decrease LDL)
Nuts- cashews, hazelnuts, almonds, peanuts, macadamia nuts
Oils- canola, olive, rice bran
Polyunsaturated fats (decrease LDL and increase HDL)
Fish- tuna, salmon, mackerel
Nuts- pecans, walnuts, pistachio nuts
Linseed and sesame seeds
Oils- sunflower, safflower, cottonseed, grape seed
So swap cooking butter for canola oil, swap steak for fish, swap chips for nuts, swap mayo for avocado and enjoy a healthy heart!
Healthy body weight and smoking cessation have also been proven to lower LDL and increase HDL levels respectively.
Soluble fiber, found in fruits and vegetables, can lower LDL levels in the blood. This can also be achieved with fibre supplements like psyllium husks and B-glucan from oats and barley.
Clinical trials demonstrate a 20% reduction in triglycerides as well as an increase in HDL levels with fish oils. Check your dosage though, up to 6g of DHA and EPA (omega 3 fatty acids) could be needed. One 1000mg fish oil capsule may only have 0.3g of these necessary fatty acids. Eat fish 3 times a week instead!
Watch this space! More research is needed but there is potential!
Niacin (vitamin B3) has been shown to increase HDL levels and reduce triglycerides, however it has not been shown to impact risk of cardiovascular events.
Studies show red yeast rice products can be as effective as station medication for lowering cholesterol levels however they are unregulated in Australia and can cause liver and kidney problems. They are not currently recommended.
20g per day of soy protein can modestly lower LDL levels, and this impact is amplified if soy foods replace high saturated fat foods such as animal meats.
If you have abnormal cholesterol levels talk to your doctor. If you would like to change your cholesterol levels make an appointment with an Eat Smart Accredited Practicing Dietitian for a customised plan.
Written by our Eat Smart Dietitian & Accredited Practicing Dietitian, Casey James