Fats are no longer the enemy

Debunking the myth that saturated fats are the cause of heart disease

Fats have gotten a bad rap in the past. You know the storyline that we all have been told over the years: fats make you fat and they are the cause of high cholesterol and coronary heart disease.

It all started back in 1961 when the Framingham Heart Study came out showing a correlation between high serum cholesterol and an increase risk for coronary heart disease health and strokes. Since then we all, doctors included, have been convinced that fats, particularly saturated fats should be avoided. This led to a major push by medical, governmental and public health messages to encourage people to switch from eating diets of saturated fats (butter, meats and eggs) to using vegetable oils and low fats foods.

However research in the last decade have challenged that thought process. One such study was published in The American Journal of Clinical Nutrition. This review looked at prior studies that had been preformed on diet of saturated fat and the risk of coronary heart disease and stroke.   It actually showed that there was no evidence that dietary saturated fat was associated with an increase risk of coronary heart disease or stroke.

Next, more evidence that saturated fats are not the problem was shown when the data from a couple of randomized studies; the Sydney Diet Heart Study and Minnesota Coronary Experiment (MCE), were reanalyzed. These studies were designed to test whether replacement of a diet of saturated fats with one using a vegetable oil (linoleic acid) would reduce the risk of coronary heart disease and death by lowering cholesterol. Both studies showed that despite the fact that switching from saturated fats to this vegetable oil resulted in a decreased the cholesterol levels, there was not a decrease the risk heart disease or deaths. Instead the opposite was shown. There was actually an increased risk of death and heart attacks in the vegetable oil group.   Further more in the MCE study, the participants who had the greatest reductions in serum cholesterol had the highest risk of death. Additionally, the MCE study showed that despite lowering the cholesterol levels, there not any improvement in the atherosclerosis at autopsy.

So if eating saturated fats leads to an increase in cholesterol but not an increased risk of heart diseases then what is the cause of atherosclerosis coronary heart disease? To better understand this, let’s take a look of what we mean when talk about cholesterol.

When you get your cholesterol check it will have it broken down into total cholesterol, HDL, LDL and triglycerides. HDL is typically been considered the good or Healthy type cholesterol, and LDL is the bad or Lousy type of cholesterol. However it is not the LDL itself that is the problem, or cause of atherosclerosis.  It is when the LDL becomes oxidized that it causes atherosclerosis. Oxidation occurs which sugars attach to the LDL molecule making it nonfunctional. When it is dysfunctional it attaches to the lining of the arteries, which then results in an inflammatory response and eventually atherosclerosis plaques formation. So what is the cause of oxidation of the LDL molecules? The very things that we were told to eat to prevent heart disease; carbohydrates i.e. sugar and vegetable oils such as Linoleic acid or corn oil.

So I know it is a hard habit to break but one that is essential to your health. Stop eating those “low fat” foods, ditch the vegetable oils and margarines.   Go ahead use real butter and don’t feel guilty about eating those eggs and bacon.  Your brain and your heart will thank you for it.

Bibliography

Lawrence, G. D. (2013). Dietary Fats and Health: Dietary Recommendations in the Context of Scientific Evidence. Advances in Nutrition, 4, 294-302.
Ramsden, C. E. (2016). Re-evaluation of the traditional diet-heart hypothesis: analysis of recovered data from the Minnesota Coronary Experiment (1968-73). British Medical Journal, 353, 1-17.
Ramsden, C. E. (2013). Use of dietary linoleic acid for secondary prevention of coronary heart disease and death: evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis. British Medical Journal, 346, 1-18.
Siri-Tarino, P. E. (2010). Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease. The American Journal of Clinical Nutrition, 91, 535-546.