Saturated Fats & Heart Health - A myth?
Saturated fats. Unsaturated fats. Seed oils. Cardiovascular disease risk. Cholesterol. Heart health.
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We all know that high consumption of saturated fats leads to heart disease, right? Well, let me present you with a paradox, the French paradox to be precise.1
This epidemiological paradox was first observed in the 1980s by Serge Renaud, and observed that even though the French have a diet very high in saturated fats (butter, meat, cream) they also have relatively low incidence of coronary heart disease (CHD). This contradicts the worldwide belief that high consumption of saturated fats being a risk factor of developing CHD.
But let’s take a few steps back first before we dive straight into this.
Type of Fats
There are three main types, (i) unsaturated, (ii) saturated, and (iii) trans fats.
Unsaturated can be further broken down into monounsaturated and polyunsaturated, their difference lies in their chemical structure, polyunsaturated have more than one double bond in their fatty acid chain. Also, polyunsaturated fats can only be obtained via food, as our body cannot produce it on its own. For example, salmon and walnuts.
Typically, food sources tend to contain one of the three - or if more than one, then one is always in majority. (that is raw produce / food not a cooked meal or a baked treat) But there are cases where two types are present, like with milk or pork which contain both saturated and trans fat, with the latter being at a much smaller proportion.
It was actually quite hard to find a graphic that showed the breakdown of each with no misinformation around the examples and the health impact. Which also brings me to my next point, which is the type of fat sources. For example, canola (rapeseed) oil is an unsaturated fat, but it also happens to be a seed oil, that’s used for industrial applications too (sounds delicious, right?). A lot of infographics would mark it as green and state it reduces heart disease risk, while in reality as it’s a seed oil it causes high inflammation and is prone to high oxidation. The reward of consuming for such a seed oil for “heart disease risk reduction” is evident, and clearly, it’s not there!
The graph above shows the trend of heart disease related death against the total PUFAs (polyunsaturated fatty acids) consumption, aka seed oils, over the years in the US. I know it’s not the most up to date but considering how then UPF (ultra processed food) was not the majority of food consumed, the relationship / trend is clear. I know I’ll probably be challenged as to correlation does not equate to causation, and yes, I do agree in general, but not in this case. As there have been multiple studies and clinical trials actually not succeeding in lowering the risk of cardiovascular disease (CVD) when increasing the seed oil intake of participants.2
Other RCTs, did show that when saturated fats were replaced with polyunsaturated fats, cholesterol was indeed lowered but that did not translate to a lower risk of death from CHD or lower all-cause mortality.3 En contraine, they observed that there was an increased mortality rate of 22% for each 30 mg/dL (0.78 mmol/L) reduction in serum cholesterol for those participants which their saturated fat source (animal fat etc) was changed to linoleic acid (aka polyunsaturated fats), like that of corn oil and corn oil polyunsaturated margarine.
If you’re wondering where the idea of polyunsaturated fats being branded as “heart-healthy” originated from, well, the American Heart Association (AHA) signed off on polyunsaturated fats, in the form of seed oils, as good for heart health in the 1960s. Side note, they also happened to be paid $1.7MM by P&G to promote it who sold and sells Crisco, their famous vegetable oil product. To put it into perspective, $1.7MM is equivalent to around $20MM in today’s money. Definitely not suspicious at all…
So, where did this notion begin of fats → cholesterol → heart disease?
Back in the 1950s, there was some studies which were published suggesting that saturated fats raise LDL cholesterol (the bad type), and LDL causes heart disease. The former part does indeed hold, but the catch is that the cholesterol within the plaques first has to be oxidised to be taken up into the arteries - which was clearly overlooked when they came out saying that saturated fat is the devil and cause of heart disease.4 In reality, the linoleic acid which comes from seed oils, causes those LDL particles to oxidise and hence plaque is formed in the arteries. See the snipped from the study by Dinicolantonio et al. below for further explanation on the mechanism.5
Just to clarify, fat consumption, especially that of saturated fats, does indeed raise cholesterol, both HDL and LDL - the good and bad cholesterol, respectively. But in order for that to directly translate to plaque and increased risk of CHD the LDL cholesterol needs to be oxidised first.
The graphic below shows the effect of the various types of dietary fats on HDL, LDL, and triglycerides with respect to whether they increase or decrease them. Triglycerides are the most common type of fat in our body, they’re stored in fat cells and are released when your body needs energy. They also lead to CHD, as high levels contribute to atherosclerosis (the thickening and hardening of the arteries) and are also associated with increased inflammation, which is the root cause of most disease. They’re quite easily avoided, by decreasing trans fat intake (which you should be doing either way), limiting alcohol consumption, regular exercise, and by maintaining a healthy weight.
So, is steak & butter the solution?
Well Yes, But Also No. As much as I love a good steak, and bread with butter, going to the extreme of a high saturated diet, like that of carnivore is not a solution either. You’re shifting from one extreme to another. Also, high consumption of meat, means high phosphorus intake, which can impact kidneys, bone health (as the calcium is leached from the bones), and CVD like that of arterial stiffness. The phosphorus can be relatively easily off balanced by increased calcium intake, as they work together, but that’s also not a solution. Don’t forget that a healthy diet is a balanced diet.
In the same manner as above, where the type of fat source is important, the same holds with respect to the quality of the produce. For example, grass-fed butter is superior to normal butter, as those cows have a better nutrient profile. This means higher levels of omega-3 fatty acids, fat soluble vitamins, and conjugated linoleic acid (CLA). CLA has various benefits, this includes anti-cancer properties and also fat reduction. While if we were to compare, with the well-advertised “healthy alternative” of margarine, which happens to be an UPF of hydrogenated vegetable oils (which creates trans fat), and tends to be mixed with emulsifiers, colouring agents, and fortified vitamins, to me it is clear which is the healthier option. It truly begs the question of how margarine is healthier than butter, a natural product which we have been consuming since ancient times?
A 2021 study by Gaeini et al. when looking at 2.8k adults over a 10-year follow-up period, and the association of dietary fat intake and incidence risk of cardiovascular outcomes, concluded that saturated fat intake was not associated with higher risk of heart disease.6 Another 2021 study by Gribbin et al. only looking at Australian women and the association of carbs and saturated fat intake on CVD and mortality, concluded that saturated fat consumption didn’t increase the risk of heart disease or death. They also concluded that it may even be associated with lower risk of conditions like type 2 diabetes, obesity, and high blood pressure. 7
To start summing up, as with any nutritional and epidemiological study, a lot of the times there are ulterior motive (*cough* money *cough*) to promote or support something specific like a product or ingredient (see skincare too). All I’m saying is take some things with a pinch of salt, especially when it comes to nutrition. Think of how people used to it in the olden days and evidently, they were far healthier than we are now. To this day the British Heart Foundation (BHF) states that saturated fats are indeed associated with increased levels of non-HDL, meaning LDL - which is indeed a true fact. But they forget to mention that this LDL needs to be oxidised first, prior to being linked to CVD.
Having grown up in Greece, I am an olive oil type of person (that’s a monounsaturated fat), but still do love butter and can see its benefits. And if I have it, I only have the grass-fed version, just like my steak and collagen. :) So instead of buying your typical seed oil the next time you’re doing your weekly shop, opt for olive oil, or butter instead. A good way to think about it is did this exist 100+ years ago, if the answer is no, then you should probably put it back on the shelf. And let’s not forget about exercising, it’s able to raise HDL (the good kind) and reduce LDL (the bad kind) and also triglycerides (which are also bad).
I think I will close this off in the most unorthodox way possible, considering I preach healthy living, but it is a fun fact - well kinda. Turns out that McDonald’s used to fry everything in tallow (beef fat) from 1940-1985, and then in 1990 it switched over to a vegetable and seed oil mix; the so advertised “heart-healthy” oils. This was done as McDonald’s was pressured by Sokoloff to do so - I suspect money was also involved. Sokoloff was the founder of the American Heart Savers Association - quite ironic, right?
Would love to hear your feedback about the voiceovers, I know they’re far from perfect but thought I would try it out! :)
I hope you enjoyed, thank you for taking some time out of your day to read / listen to my post! See you next week! :)
Other posts you may like / mentioned:
Ferrières, J. (2004). The french paradox: lessons for other countries. Heart, 90(1), 107-111. https://doi.org/10.1136/heart.90.1.107
Kummerow, F. A. (2014). Two lipids in the diet, rather than cholesterol, are responsible for heart failure and stroke. Clinical Lipidology, 9(2), 189–204. doi: 10.2217/clp.14.4
Ramsden, C. E. et al. "Re-evaluation of the traditional diet-heart hypothesis: analysis of recovered data from minnesota coronary experiment (1968-73)". BMJ, 2016, p. i1246. https://doi.org/10.1136/bmj.i1246
Holvoet, P., Vanhaecke, J., Janssens, S., Werf, F. V. d., & Collen, D. (1998). Oxidized ldl and malondialdehyde-modified ldl in patients with acute coronary syndromes and stable coronary artery disease. Circulation, 98(15), 1487-1494. doi: 10.1161/01.cir.98.15.1487
Dinicolantonio JJ, O’Keefe JH. Omega-6 vegetable oils as a driver of coronary heart disease: The oxidized linoleic acid hypothesis. Open Hear. 2018;5(2):1-6. doi:10.1136/openhrt-2018-000898
Gaeini, Z., Mirmiran, P., Bahadoran, Z., Aghayan, M., & Azizi, F. (2021). The association between dietary fats and the incidence risk of cardiovascular outcomes: Tehran Lipid and Glucose Study. Nutrition & metabolism, 18(1), 96. doi: 10.1186/s12986-021-00624-6
Gribbin, S., Enticott, J., Hodge, A., Moran, L. J., Thong, E. P., Joham, A. E., … & Zaman, S. (2021). Association of carbohydrate and saturated fat intake with cardiovascular disease and mortality in australian women. Heart, 108(12), 932-939. doi: 10.1136/heartjnl-2021-319654
Thanks for the insights! It's indeed still such a controversial topic, but one's you start to look deeper you see that there's a lot of shady business going on. Like your article suggests, I avoid any seed oil and go for butter, olive oil, coconut oil, and even lard (more common in Brazil and also Italy I think).
I'm going to remember: did this exist a 100 years ago? It's very helpful.
Coconut oil is a good shout too! Not something very native to me, but definitely a great option too. I guess lard is the tallow equivalent, thinking of it I believe some UK dishes do require lard, like the pastry of pies.
It’s pretty crazy if you see the power of companies that run the food industry, and of course the capital that has been gained from it. They’re definitely partially responsible for the obesity epidemic. Baby formula and baby milk is another controversial one. If you read the ingredients you’d be very surprised at what is in them…