By Kris Kresser.
Unfortunately, cardiovascular disease is one of the most misdiagnosed and mistreated conditions in medicine. We’ve learned a tremendous amount about what causes heart disease over the past decade, but the medical establishment is still operating on outdated science from 40-50 years ago
Eating cholesterol isn’t going to give you a heart attack. You can ditch the egg-white omelettes and start eating yolks again. That’s a good thing, since all of the 13 essential nutrients eggs contain are found in the yolk. Egg yolks are an especially good source of choline, a B-vitamin that plays important roles in everything from neurotransmitter production to detoxification to maintenance of healthy cells. Studies show that up to 90% of Americans don’t get enough choline, which can lead to fatigue, insomnia, poor kidney function, memory problems and nerve-muscle imbalances.
What about saturated fat? It’s true that some studies show that saturated fat intake raises blood cholesterol levels. But these studies are almost always short-term, lasting only a few weeks. Longer-term studies have not shown an association between saturated fat intake and blood cholesterol levels. In fact, of all of the long-term studies examining this issue, only one of them showed a clear association between saturated fat intake and cholesterol levels, and even that association was weak.
If you’re wondering whether saturated fat may contribute to heart disease in some way that isn’t related to cholesterol, a large meta-analysis of prospective studies involving close to 350,000 participants found no association between saturated fat and heart disease. A Japanese prospective study that followed 58,000 men for an average of 14 years found no association between saturated fat intake and heart disease, and an inverse association between saturated fat and stroke (i.e. those who ate more saturated fat had a lower risk of stroke).
Another strike against the diet-heart hypothesis is that many of its original proponents haven’t believed it for at least two decades. In a letter to the New England Journal of Medicine in 1991, Ancel Keys, the founder of the diet-heart hypothesis said:
Dietary cholesterol has an important effect on the cholesterol level in the blood of chickens and rabbits, but many controlled experiments have shown that dietary cholesterol has a limited effect in humans. Adding cholesterol to a cholesterol-free diet raises the blood level in humans, but when added to an unrestricted diet, it has a minimal effect.
In a 2004 editorial in the Journal of American College of Cardiology, Sylvan Lee Weinberg, former president of the American College of Cardiology and outspoken proponent of the diet-heart hypothesis, said:
The low-fat, high-carbohydrate diet… may well have played an unintended role in the current epidemics of obesity, lipid abnormalities, type 2 diabetes, and metabolic syndromes. This diet can no longer be defended by appeal to the authority of prestigious medical organizations.
We’ve now established that eating cholesterol and saturated fat does not increase cholesterol levels in the blood for most people. In the next article, I’ll debunk the myth that high cholesterol in the blood is the cause of heart disease.