Depressing. A consensus based on nothing much, still lasted three generations
For years, people with the kind of high cholesterol linked to their genes, were told they could lower their cholesterol if they stopped eating things like butter, cream, eggs, cheese, chocolate, and even coconut oil.
A new study looked for evidence to justify that advice and couldn’t find any. They are, of course, not the first — even in the 1950s John Yudkin was already warning people about the dangers of sugar. But the vested interests and fat-police leapt into gear, and thus and verily a million low-fat products filled the shelves, most of them with added sugar.
How many people did this consensus kill?
“For the past 80 years, people with familial hypercholesterolemia have been told to lower their cholesterol with a low saturated fat diet,” said lead author David Diamond, professor and heart disease researcher at the University of South Florida. “Our study showed that a more ‘heart healthy’ diet is one low in sugar, not saturated fat.”
Familial hypercholesterolemia is a genetic disorder that causes people to have cholesterol levels 2-4 times higher than the average person. Organizations, including the American Heart Association, have suggested they avoid eating food from animal sources, such as meat, eggs and cheese, and to avoid coconut oil. An international team of experts on heart disease and diet, including five cardiologists, reviewed dietary guidelines for people with familial hypercholesterolemia. They say they couldn’t find any justification for health experts to recommend a low saturated fat diet.
Diamond and his co-authors say following a low-carb diet is most effective for people at increased risk of heart disease, such as those who are overweight, hypertensive and diabetic. Their findings are consistent with another paper recently published in the “Journal of the American College of Cardiology,” which provided strong evidence that food that raises blood sugar, such as bread, potatoes and sweets, should be minimized, rather than tropical oils and animal-based food.
Sugar (and most carbohydrates) push up blood levels of insulin. It’s an ancient hormone that goes right back through the evolutionary tree all the way to yeast, and in yeast it’s tightly involved with lifespan (for us too). It’s a key signaling molecule, but without combine-harvesters, yeast and all the animals in between, didn’t manage to overdose on carbs.
One day someone will write a book on how that consensus was busted. That would be interesting. Meanwhile hopefully, the cult of the expert will be viewed with even more suspicion.
80 years. Where were all the science communicators?
The paper is freely available in full.
We have evaluated dietary recommendations for people diagnosed with familial hypercholesterolaemia (FH), a genetic condition in which increased low-density lipoprotein cholesterol (LDL-C) is associated with an increased risk for coronary heart disease (CHD). Recommendations for FH individuals have emphasised a low saturated fat, low cholesterol diet to reduce their LDL-C levels. The basis of this recommendation is the ‘diet-heart hypothesis’, which postulates that consumption of food rich in saturated fat increases serum cholesterol levels, which increases risk of CHD. We have challenged the rationale for FH dietary recommendations based on the absence of support for the diet-heart hypothesis, and the lack of evidence that a low saturated fat, low cholesterol diet reduces coronary events in FH individuals. As an alternative approach, we have summarised research which has shown that the subset of FH individuals that develop CHD exhibit risk factors associated with an insulin-resistant phenotype (elevated triglycerides, blood glucose, haemoglobin A1c (HbA1c), obesity, hyperinsulinaemia, high‐sensitivity C reactive protein, hypertension) or increased susceptibility to develop coagulopathy. The insulin-resistant phenotype, also referred to as the metabolic syndrome, manifests as carbohydrate intolerance, which is most effectively managed by a low carbohydrate diet (LCD). Therefore, we propose that FH individuals with signs of insulin resistance should be made aware of the benefits of an LCD. Our assessment of the literature provides the rationale for clinical trials to be conducted to determine if an LCD would prove to be effective in reducing the incidence of coronary events in FH individuals which exhibit an insulin-resistant phenotype or hypercoagulation risk.
Diamond, D et al (2020)Dietary Recommendations for Familial Hypercholesterolaemia: an Evidence-Free Zone, BMJ Evidence-Based Medicine, 2020; bmjebm-2020-111412 DOI: 10.1136/bmjebm-2020-111412