Fat is confusing. Does it make you fat? Does it raise cholesterol, block your blood vessels and cause heart attacks? What’s the whole thing with good cholesterol and bad cholesterol anyway? In this blog we take a short tour around the latest research and look at where it leaves us when it comes to putting food on the plate.
Fats and oils (also called fatty acids) tend to be categorised according to their molecular structure, or to put it another way, according to how “saturated” they are. This is just a reference to the type of chemical bond between some atoms in the fat molecule, which thankfully we won’t go into, but the classification is useful when it comes to explaining which ones are healthy and which are not.
Monounsaturated Fatty Acids (MUFAs)
MUFAs are good for us, the most well-known being olive oil, one of the main pillars of the much-touted Mediterranean diet. MUFAs are found in nuts and avocados, as well as olives, and also in animal fat, including butter, lard and poultry fat, something that is rarely acknowledged. In fact, it might be worth pointing out here that nearly all fats contain a mixture of fatty acids of varying saturation, even though we tend to talk about them as “saturated” or “unsaturated”, for example, and animal fat is a case-in-point.
MUFAs are sometimes subject to heavy processing, high heat and refinement which turns them rancid and inflammatory. Canola oil is a perfect example of this: refined and bleached to within an inch of its life with strong chemicals so that it has a long shelf life, it then has to be deodorised to make it palatable! As long as you stick to extra virgin, cold-pressed or expeller-pressed versions, you’re ok: they’re good for you. They promote a healthy heart, protecting it from disease, and they increase insulin sensitivity. Incidentally, they don’t hold up terribly well to high heat, so use in salad dressings but avoid cooking with them.
Polyunsaturated Fatty Acids (PUFAs)
PUFAs are where the waters start to muddy because here we get the good, the bad and the ugly. Broadly speaking, they can be divided into omega 3 PUFAs and omega 6 PUFAs, the yin and yang of the PUFA world, if you like. Omega 3 PUFAs, typically found in oily fish, wild game, and grass-fed meat and dairy, are anti-inflammatory; in other words, they suppress inflammation and inflammatory conditions which is why people take omega 3 fish oil supplements for a healthy heart (cardiovascular disease is essentially a chronic inflammatory disease) or for arthritis, for example. Omega 6 PUFAs, on the other hand, are inflammatory, and they are found in vegetable oils as well as nuts, seeds, grains and beans, and of course, any oils that are made from them. If you are already aware that most of the diseases of the Western world are a direct result of long-term chronic inflammation, you may think that these omega 6 PUFAs are to be avoided at all costs, but the fact is that we do need to have some in our diet. We need to be able to mount an inflammatory response when we cut ourselves so that we heal, for example.
A problem arises when the relative amounts of omega 3 and omega 6 that we should have in our bodies become unbalanced as a direct result of our diet. Ideally, the omega 3: omega 6 ratio should be about 1:1 for optimal health. However many people have a ratio of about 1:7, and people who live on processed and junk food will have a ratio closer to 1:20. This is because the oils used in processed food, typically vegetable oil, corn oil or soybean oil, are high in omega 6 PUFAs. And once the ratio of fats leans heavily in favour of omega 6, you’ve effectively got a scenario predisposing to a chronically inflamed body, primed for obesity, diabetes, cancer, dementia and more besides.
It also has to be said that the medical and government guidelines published since the war on saturated fat started in the 1970s, to replace butter and lard with vegetable oils and margarine, have had a significant part to play in the downturn of our health due to the ramping up our intake of inflammatory omega 6 fats. Even now, potato crisps are touted as healthy if they have been cooked in something like sunflower oil, whereas in fact they are inflammatory! Doubly so, in fact, because these oils are unstable when heated, turning them rancid and making them even more damaging to our health.
Most people don’t eat enough omega 3 PUFAs, certainly not enough to counterbalance their omega 6 intake. If you don’t eat very much oily fish, grass-fed meat or wild game, then you may want to consider a supplement. The bottom line on omega 6 PUFAs is to get them in moderation from the whole food, such as nuts, seeds and beans, not the oils and margarines made from them, and to avoid junk food and processed food as much as possible.
Incidentally, the omega 3: omega 6 ratio has an importance when it comes to the meat and dairy that you eat. Although we think of beef and dairy as being in the “saturated fat” camp, as we said before, animal fat contains unsaturated fat as well. A cow raised on grain will produce milk and fat (including fat within the flesh) that is much higher in omega 6 fats than a cow raised exclusively on grass, which will have a favourable ratio of omega 3: omega 6 of about 1:1.
So, you can see that omega 3 is the “good” and that omega 6 is the “bad” of PUFAs, so what is the “ugly” that we referred to earlier? This is a reference to what happens to vegetable oils when they are processed by bombarding hydrogen atoms at them to prolong their shelf life and solidify them, producing hydrogenated or trans fats. This fake fat is so far removed from nature that even flies know better than to land on it! It is now known that the body just can’t deal with this fake fat properly, and consuming it regularly is linked to obesity and diabetes, cardiovascular disease and cancer.
Saturated Fatty Acids (SFAs)
This is where things get really interesting. And controversial. Saturated fat kills, right? We’ve been told that for decades. But actually, it’s much more complicated than that. For a start, there are over thirty different types of saturated fat, and the types found in plants, such as coconut oil, are very different, and behave differently in the body, to those found in animal flesh, which again is different to those found in dairy products.
The reason that saturated fat is thought of as unhealthy is due to its association with heart disease and cholesterol, so let’s look at this in more detail.
Saturated fat, cholesterol and cardiovascular disease
This is how the story goes: saturated fat increases LDL cholesterol, the so-called “bad cholesterol”, and an increase in LDL increases the risk of cardiovascular disease (CVD). Therefore saturated fat raises the risk of CVD and so to reduce that risk, you need to lower your LDL by replacing butter and lard with vegetable oils and margarine. Let’s see if this holds up to scrutiny.
A conclusive (and rather unethical) study came to light recently, although it was actually carried out many years ago. It was a gold-standard study (a randomised controlled trial, or RCT) where 9000 inmates of mental institutions were divided into two groups without their knowledge or consent, and fed with butter and animal fat or with margarine and vegetable oil. The latter group reduced their LDL score significantly. So it would seem that part of the story is correct: replacing animal fat with vegetable oil lowers your LDL, But here’s the other part of the study that is much more interesting: the group with the lowered LDL also suffered significantly more heart attacks and death from CVD.
Other studies have shown that of all the heart attack patients admitted to hospital and monitored, 75% have LDL that your doctor would describe as “normal” and 50% have a reading that would be regarded as “optimal”! And a lower LDL reading in the over-sixties has been known to be associated with a higher risk of stroke for some time now.
So it would seem that the second part of the story doesn’t hold up. Lowered LDL doesn’t seem to lower your risk of stroke or heart attack. In fact, it seems to do the opposite. Why is this?
What is LDL and why all the hype around it?
LDL is actually made up of particles of different sizes and densities. Large, fluffy, beachball-style particles are perfectly harmless. Small, dense, golfball-style particles, on the other hand, are the ones to watch out for. They embed into the artery wall more readily and are more easily oxidised, both of which are part of the process of arterial plaque build-up, which is the precursor to CVD.
If LDL goes up because of an increase in the beachball particles, there is nothing to worry about because they are harmless and there is no sinister implication to your health. But if the number of golfball particles increase, then you are increasing your risk of CVD.
And here’s the rub: you can lower your overall LDL reading by increasing the golfball particles and decreasing the beachball particles. So your doctor’s happy with your LDL reading, but you’ve increased your CVD risk! If you ever have a cholesterol test, make sure you get an LDL-P test included, which is a test of particle size. Any other LDL reading is pretty meaningless.
So what increases the number of LDL golfballs? A diet high in carbohydrates and sugar! Even so-called healthy wholegrains will increase your LDL profile in this way, whereas a high fat (including saturated fat), low carbohydrate diet increases the LDL particle size favourably, from golfball to beachball. Incidentally, MUFAs have been shown to decrease the number of golfball particles, hence the association of olive oil with a healthy heart. And trans fat, you won’t be surprised to learn, increases them!
All of this leaves a burning question, though. Why the completely misguided obsession with the LDL reading in the first place? One word: statins. Or, more specifically, the multi-million pound industry behind them. Statins reduce LDL very effectively, and for the companies who produce them to make a big profit, we have to buy in to the link between a lowered LDL and a lowered risk of heart disease. Pharmaceutical companies wield a huge amount of power in this respect by financially sponsoring various health organisations and the government. It means that they have a huge say in the messages that go out to the general public.
If you are advised to take statins, you might want to weigh up very carefully the benefits with the side effects, the most notable of which are muscle damage, memory loss and diabetes. Be aware that they don’t actually work by their LDL-lowering capability. After all, LDL-lowering drugs have been around for decades without any benefit to mortality rate from CVD. Statins actually have a mild antioxidant effect, which more likely accounts for their pitifully small success rate. But there are better antioxidants out there with no side effects, and real food would be a good start at getting them.
Coconut oil and MCTs
Every now and again an article appears in the media to scare the living daylights out of anyone who is using coconut oil in their diet: a recent report went as far as claiming that it is poisonous! Is it? No, in a word. It is a hugely beneficial oil. Again, it is a saturated fat, but it differs from animal SFAs by containing a large proportion of medium chain triglycerides or MCTs. These are smaller molecules of fats than those associated with animal fat, and as such, require less (or no) processing, meaning that the body can use them for energy immediately. Coconut oil also has numerous other properties and books abound on this topic; it is anti-bacterial and anti-fungal for a start. From a culinary standpoint, it is stable at high heat, so an ideal cooking oil.
We’ve tried to keep this brief! As you can imagine, just the topic of cholesterol is massive in its own right, as is the topic of all the different type of SFAs. And as for grass-fed dairy and cattle, we hardly touched the surface!
Practically, though, where does everything we’ve discussed leave us in terms of how to eat?
We’ve broken it down to 5 key points:
1) Olive oil is an extremely beneficial addition to a diet for its healthy heart benefits alone. Use it liberally but reserve it for salad and vegetable dressings because it is easily damaged when heated.
2) Try to include oily fish regularly, as well as grass-fed meat and wild game. If you don’t eat much of these, consider an omega 3 supplement. Incidentally, if you eat conventionally-raised meat, trim the fat as much as possible, whereas you will benefit from eating the fat if it is grass-fed; it is likely to contain more omega 3 than farmed salmon.
3) There’s no need to avoid omega 6 oil completely; eat nuts, seeds and beans in moderation.
4) Use a saturated fat to cook with, since they are the most stable when heated. Butter, ghee and coconut oil (flavourless varieties are available) are ideal, as well as the artisan fats that have fallen out of favour, such as lard and tallow.
5) Butter your bread! In fact, it’s the bread that will do more damage to your health, but that’s a whole other topic! Go the extra mile and make it grass-fed butter for a better PUFA profile.
It’s going to take time to reverse the message about fat, but it is imperative that we do so; the fat we eat is actually the key to sustained and vibrant health.