If you haven't already read last week’s blog post on seed oils (rapeseed oil, sunflower seed oil and more) and how they’re wreaking havoc with our health, then do go back and have a read as it really sets the scene for this post. Today’s blog is on cholesterol, but it might not be exactly what you were expecting...if this post piques your interest and you have further questions, then don’t hesitate to get in touch with our contributing author, Nutritional Therapist Grace Kingswell (@gracekingswell).
So, let’s get into it - cholesterol!
In 1952 Ancel Keys, an American physiologist, put forward a hypothesis (that was purely observational and not yet based on any medical evidence) that suggested that cholesterol was the cause of cardiovascular disease. This was because he had found cholesterol in arterial plaques and because animal fats contain cholesterol he claimed that cholesterol from animal fat causes heart disease.
In 1953 he carried out a study that was supposed to prove his ‘heart-diet’ hypothesis. He looked at 6 countries and the correlation (n.b. in science this does not mean causation), between heart disease and total fat in the diet. He cherry picked which countries he studied and basically put together stats to prove his theory. This study, and others, were later pulled apart by well established statisticians. It helped his case, however, that the US president at the time had a heart attack in 1955, just as Ancel was making his case. Fear rippled through America.
Despite Ancel Keys’ flawed studies, he somehow managed to elbow his way onto the American Heart Association Committee in 1961, and persuaded them to put out guidelines that replaced saturated animal fats (butter, lard, ghee) for polyunsaturated seed oils (like vegetable oil, rapeseed oil and corn oil).
In 1973 Ancel, and others, did put together a proper study called The Minnesota Coronary Experiment. It looked at over 10,000 subjects and took place over 52 months. The control group continued to eat a diet high in saturated animal fats and the intervention group ate a serum cholesterol lowering diet and replaced animal fats with polyunsaturated fats (PUFAS) from corn oil and margarine. So, the results: The intervention group had a 14% reduction in cholesterol, but there was a 22% higher risk of death, mainly from cancer but also heart disease, for each 30 milligram/dL reduction in cholesterol. So essentially, a huge failure of a study. This was the study in which Ancel really wanted to prove his hypothesis and the results categorically did not confirm it. Yes it reduced cholesterol but it increased a whole host of other, life-threatening diseases.
And now for the really shocking piece of the puzzle: this was unpublished data until 2016. For 43 years this information about cholesterol and seed oils has been buried and even now, we’re still all confused about it. You can see why! Ancel Keys truly changed the world (and not for the better), and he wasn’t even a medical doctor or a nutritionist, he was a physiologist with a hypothesis and some dodgy science.
So why, then, are we all still so confused about cholesterol? How many eggs can we eat a day? Do we need to limit our intake of butter and other animal fats?? Why does the NHS still recommend a low fat diet? Why are we all on statins??I think the answer is simply because this information just hasn’t been circulated widely enough. As Nina Techolz, author of The Big Fat Surprise said on a podcast recently, “the demonisation of cholesterol was the biggest mistake in medical history.”
Why do we need fat?
Breast milk is made up of 30-50% saturated fat. This gives you some idea as to how important saturated fat is in the maintenance and development of health. We need cholesterol to stay healthy, our brains are made of cholesterol and our brain actually makes cholesterol itself to be used all around the body for a multitude of reasons, including hormone production and structural cell membranes.
We also use cholesterol to convert sunlight into Vitamin D. Not enough cholesterol? You simply won't be able to convert and make any of the active form of vitamin D and the knock on affects the immune system and how much calcium we can take up and store in our bones. Saturated fat in animal foods, a.k.a where the cholesterol is, also contains all of the fat soluble vitamins A, D, E and K that we need to stay healthy. So without enough fat in our body we can suffer nutrient deficiencies.
I think one of the main issues with how we still see cholesterol these days is the way it’s being measured. On a standard cholesterol blood test you have your HDL cholesterol (your ‘good’ cholesterol), your LDL cholesterol (‘bad’ cholesterol), and then your total triglycerides. The thing to point out is that HDL and LDL aren’t cholesterol in themselves, they’re just the carrier molecules that carry the cargo that is cholesterol. There also aren’t just two subfractions (LDL and HDL), there are thirteen. It’s the SDLDL (Small Density Low Density Lipoprotein) that’s actually an issue and more of a biomarker for cardiovascular disease - but it’s not routinely tested.
So when we see LDL cholesterol coming back on a blood test, it could be cause for concern regarding heart disease, but it also could not be. That’s when it’s important to look at your diet, your genetic history and your lifestyle. Are you eating real food, real fats? Or ‘frankenfats’ like margarine, seed oils, processed food and lots of sugar? Are you moving your body daily?
Sugar and Insulin Production
Saturated fat is tasty and it also triggers our satiety hormone (a.k.a makes us feel full and satisfied). Go on a low fat diet and remove saturated fat and food firstly tastes boring, and secondly you’re nowhere near full - so your hunger increases. Low fat foods that remove the fat content typically replace it with something to make it taste good, sugar. So we have fat free yoghurt, for example, that’s actually full of sugar - or these days, sweeteners.
Unlike Ancel Keys’ flawed medical studies, there really is concrete evidence that shows how increased sugar in the diet, which leads to insulin resistance, increases cholesterol. And actually, the combination of high fat and high sugar together is far more a cause for concern. A high fat, low carb diet is actually healthy - despite what we’ve been led to believe.
So as you can see, it’s really not as simple as saying ‘dietary cholesterol equates to serum cholesterol,’ because it just doesn't work like that. There’s a lot of learning and unlearning that needs to be done when it comes to cholesterol and saturated fat. For more information and for an in-depth look at this topic, have a listen to this podcast episode where myself and Nutritional Therapist Jade Leighton explore the topic further.