Coconut oil “as unhealthy as beef fat and butter” was splashed across the headlines this month after the American Heart Association (AHA) released a review of the data on the effects of dietary saturated fat intake and its replacement of other types of fat and carbohydrates on cardiovascular disease* (CVD).
In summary, they concluded that replacing saturated fats with polyunsaturated fats reduced the risk of CVD. Just to make clear, this is not new evidence, but a review of all the scientific evidence that we have on dietary fats so far.
Shall we take a step back and de-code some of the science?
We can largely group dietary fat into two categories; saturated fats and unsaturated fats (monounsaturated, and polyunsaturated). There is also a third group, trans fats, which are formed by artificially hardening unsaturated fats through a process called ‘Hydrogentation’ – i.e. liquid oils turned into solids fats by processing.
Without boring you too much with the science, what makes a saturated fat different to an unsaturated fat is basically it’s structure; The simplest unit of fat is the fatty acid. A fatty acid with a single bond is a saturated fat, and a fatty acid with a double bond is an unsaturated fat. The structure of these fats is what makes them behave differently in the body, and ultimately determines how they impact our health.
Unsaturated fats tend to be liquid at room temperature – think olive oils, nut oils, fish oils, but also nuts and seeds! There are two types of unsaturated fats; monounsaturated (single double bond) and polyunsaturated fatty acids (two or more double bonds).
Monounsaturated fats are found in olive oil and other plant oils, avocados, nuts and seeds. Polyunsaturated fats (PUFAs) are rich in foods such as oily fish, walnuts, flaxseeds, and vegetable oils. The two main PUFA’s in our diet are omega 3 and omega 6. These are essential to our diet which means we need to get them from our food as our body can make them itself.
The evidence shows that replacing saturated fat with unsaturated fat, especially polyunsaturated fats, can reduce the risk of CVD. How would this diet look? exactly like the Mediterranean diet! So a diet full of good quality oils such as olive oil and avocado oil, nuts and seeds, whole grains, fresh fruits and vegetables, seafood and dairy.
Saturated fats tend to be solid at room temperature – think butter, coconut oil and steak! I’m sure you’ve heard of saturated fat, and for all the wrong reasons too! When I was at school we were taught that fats were either; good fats (monosaturated), very good fats (polyunsaturated), or bad fats (saturated and trans fats).
Science is never that black and white. We can’t simply lump foods into a ‘good’ category and a ‘bad’ category, although as humans we naturally do. We don’t like uncertainty, and we want answers. Yes there are some foods which are more nutritionally beneficial than others (i.e. contain more vitamins, minerals, and fibre) but it completely depends on how much of that food you’re eating, and what your diet looks like on the whole. For example, that gelato that I had last night was full of refined sugar and saturated fat but I only had 2 scoops, I’m not eating it for every meal of the day, and the rest of my diet is pretty nutrient dense and balanced.
So, what makes saturated fats ‘bad’ in the first place?
Saturated fat increases the the levels of LDL cholesterol (a.k.a. bad cholesterol) which we know is an associated risk for CVD. However, it also raises the good HDL cholesterol which reduced our risk of CVD. So this means that our total cholesterol (i.e. HDL + LDL), another risk marker for CVD, is high but the ratio is improved.
Confusing I know right? However the AHA also write “changes in HDL cholesterol caused by diet or drug treatments can no longer be directly linked to changes in CVD, and therefore, the LDL cholesterol–raising effects should be considered on its own”
Although the AHA report only looks at a few studies dealing with coconut oil in particular, it is 82% saturated fat, and those studies have shown that coconut oil does indeed raise blood cholesterol – again, both the LDL and the HDL kind. So from that we can’t exactly say coconut oil directly increases our risk of CVD, but the indirect link between ‘bad’ cholesterol and CVD is still there and so the AHA advise avoiding it.
To conclude, our understanding of coconut oil has not changed overnight, it just sounds like that in the press.
The AHA have done a pretty good review of the current evidence and have reiterated that replacing saturated fats with unsaturated fats can reduce your risk of CVD.
So with that said coconut oil is certainly not a superfood (it never has been) but it probably is not a supervillain either. Use it sparingly in cooking, as you would with butter or any other fat, but make use of other oils also. I will still be using coconut oil in certain dishes, particularly in my desserts and asian recipes, but I also use a variety of other oils in my cooking such a olive oil, sesame seed oil, avocado oil and butter.
*Cardiovascular disease (CVD) is an umbrella term for all diseases of the heart and blood vessels, including coronary heart disease, stroke, and high blood pressure.
- Dietary Fats and Cardiovascular Disease: A Presidential Advisory From the American Heart Association
- Saturated Fatty Acids and Risk of Coronary Heart Disease: Modulation by Replacement Nutrients
- Saturated fat, carbohydrate, and cardiovascular disease
- Accruing evidence on benefits of adherence to the Mediterranean diet on health: an updated systematic review and meta-analysis