Coconut oil: it’s a controversial cooking ingredient with a debated reputation for heightening your cholesterol.
Once upon a time in the Western world, the popular oil used in Asian dishes was touted as a superfood. Back then many thought it was good for your heart, so it was celebrated as a healthier alternative to other plant-based and animal cooking oils.
That was until ‘coconut-gate’ exploded in mid-2017, after the American Heart Association released advice saying that coconut oil was full of cholesterol’s sworn enemy: saturated fat.
Since then, health experts have remained divided on whether the saturated fat-heavy product, coconut oil, can help or hinder your cholesterol-lowering plans.
In an attempt to determine an evidence-based outcome, Dr Michael Mosley and the BBC team involved in Trust Me I’m a Doctor put coconut oil to the cholesterol test, in an episode airing on SBS on Monday 26 February at 8.30pm.
“Even the academics were surprised… It’s one of those things where you expect to find one result and you get something different."
Recruiting the help of academics from University of Cambridge, the team conducted a scientific trial involving 94 volunteers aged 50 to 75 years old with no history of diabetes or heart disease. The study aimed to test the effect that different fats would have on individual’s cholesterol levels.
Volunteers were randomly allocated into one of three groups, each of which tested a different fat: extra-virgin olive oil, extra-virgin coconut oil and unsalted butter. Every day for four weeks, the study’s participants ate 50 grams (or about three tablespoons) of their designated fat.
Baseline measurements were taken before and after the four weeks testing period to ascertain LDL levels (low-density lipoprotein, or “bad” cholesterol) and HDL (high-density lipoprotein, or “good” cholesterol) as well as other health markers.
As Dr Mosley explains, the results weren't as he expected.
“The assumption was that coconut oil is saturated fat and can make your cholesterol worse,” Dr Mosley tells SBS. “But what surprised everyone was that coconut oil was the fat that came out the best.
“Even the academics were surprised… It’s one of those things where you expect to find one result and you get something different. That’s why I love doing science journalism because people have assumptions and you go and test them.”
How did coconut oil redeem itself?
Dr Mosley says that, as predicted, the LDL levels of butter eaters increased by about 10 per cent on average while their good cholesterol, HDL, rose by around five per cent.
The volunteers who downed olive oil saw a non-significant reduction in LDL cholesterol and a five per cent rise in good cholesterol. Meanwhile, the people in the controversial coconut oil group experienced – on average – no increase in LDL levels. Instead, there was a 15 per cent rise in their good cholesterol.
Having high levels of HDL has been shown to provide anti-inflammatory benefits. It's also been linked to a decreased risk of heart disease.
“The evidence for that comes mainly from animals, so it was fascinating to see this effect in free living humans.”
It remains unclear as to why coconut oil came out as the best fat for heart-health. However, one University of Cambridge academic involved in the study floated a theory in an article written by Dr Mosley about the research results for The Times (UK).
“Perhaps it is because the main saturated fat in coconut oil is lauric acid and lauric acid may have different biological impacts on blood lipids to other fatty acids,” Cambridge Professor Kay-Tee Khaw told Dr Mosley in an interview. “The evidence for that comes mainly from animals, so it was fascinating to see this effect in free living humans.”
Cooking with coconut oil
However, Dr Mosley explains to SBS, no hard-and-fast claims can be made off the back of one study, regardless of how sound it is. More research is needed to prove that coconut oil has no negative impact on LDL cholesterol levels and a positive affect on HDL cholesterol in all populations, and to firmly establish other health claims.
Even still, the doctor says he will be using coconut oil to cook at home when the flavour matches the meal he’s making.
“I’m a fan, he says. “I’m not going to encourage you to guzzle gallons of the stuff but if you like cooking with it and you like the taste of it, then go for it. My wife is a GP and she likes it so we eat it.”
“But then there’s my roast potatoes. I prefer to have them with olive oil than coconut oil because it has a strong flavour [that doesn’t match the potatoes].”
“I’m not going to encourage you to guzzle gallons of the stuff but if you like cooking with it and you like the taste of it, then go for it."
Coconut oil, extracted from the flesh of the coconut, has a slightly nutty flavour and a reasonably long shelf life of about 18 months.
“Also the other good thing is that that coconut oil is very stable at heat, unlike vegetable oil, which produces nasties when you cook it,” says Dr Mosley.
“Olive oil, lard and coconut oil don’t break at heat.”
The smoking temperature – when a product begins to smoke and the fat content starts to break down – of extra virgin coconut oil is 177 degrees Celsius and refined coconut oil is 222 degrees Celsius.
Butter has a smoking point of around 120-150 degrees Celsius. Extra virgin olive oil’s smoking point is 191 degrees Celsius although the extra light variety is considerably higher at 242 degrees Celsius.
The final episode of Trust Me I’m A Doctor (season 7) airs on Monday 26 February at 8.30pm on SBS ONE. Catch-up online after broadcast via SBS On Demand.
Watch Trust Me I'm A Doctor, season 7 episode 3 below.
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