The “Lipid Hypothesis,” or “Cholesterol Theory,” suggests that saturated fats—which are loaded with cholesterol—are the cause of heart disease.

Today, sixty years later, we are learning that this theory was based on flawed science and that saturated fats, like those in butter, meat, cheese, eggs, and coconut oil, do not actually contribute to any increased danger for cardiovascular risk. (1,2)

Now, before you hit the “delete” button, let me explain. There are many studies that have linked the ingestion of saturated fats to higher cholesterol levels, but few, if any, have linked saturated fats directly to heart disease. Surprisingly, the “Cholesterol Theory” was so widely accepted by the scientific community that, if a substance was found to increase cholesterol levels, it was simply assumed that the substance would also increase cardiovascular risk.

The New Science

In the last few years, researchers have reviewed old studies and designed new studies to determine the effect of saturated fats (cholesterol) on the heart and cardiovascular system. In one meta-analysis by Harvard researcher Dr. Frank Hu, he reviewed 21 studies that included more than 347,747 subjects which measured the association between saturated fats and cardiovascular issues.

The results were astounding! The folks who consumed the highest amount of saturated fat had the exact same incidence of any cardiovascular issue as those who consumed the least amount of saturated fat. (1)

The result: saturated fat was not a cardiovascular risk factor.

Another study, published in the Netherlands Journal of Medicine in 2011, suggests that while a diet high in saturated fat will slightly increase cholesterol levels, there is no evidence to show that it will increase the risk of any cardiovascular issues. (2)

There’s more!

In another meta-analysis review, more than 150,000 people were evaluated for over five years. They found that the risk of dying from any cause was significantly greater in the group with the lowest levels of cholesterol (below 160mg/dL).

The group with borderline high levels of cholesterol (200-239mg/dL) had a significant decreased risk of dying from any cause, but it was the group with the highest cholesterol (above 240mg/dL) that had the most decreased risk of dying from any cause. (3)

Bottom line: according to this study, the lower your cholesterol, the greater your risk of dying!

Why Are Saturated Fats Important?

Saturated fats are those fats that are basically solid at room temperature. They are solid because they are more stable—no weak double-bonds that you find in mono-saturated (one double-bond) and poly-unsaturated fats (many double-bonds).

As a result, these fats can stand up to cooking at high heat much better than unsaturated fats, because there are no weak double-bonds to break. Once the bonds break, the oil has a greater risk of going rancid and becoming the toxic substance known as free radicals.

Saturated fats are loaded with cholesterol, and we desperately need cholesterol for hormones, cell membranes, fat soluble vitamins and much, much more. The fact is, the liver manufactures way more cholesterol on a daily basis than we could ingest—even on a high cholesterol diet.

 

 

References: 

1. B. Hu et al. Meta-analysis of Prospective Cohort Studies Evaluating The Association of Saturated Fat and Cardiovascular Disease. American Journal of Clinical Nutrition 91, no 3, 2010: 502-9
2. S. Kuipers et al. Saturated Fat, Carbohydrates and Cardiovascular Disease. Netherlands Journal of Medicine. 69, no 9. 2011: 373-78
3. Hamazaki et al. Blood Cholesterol: A Good Marker for Health in Japan. World Review of Nutrition and Dietetics 100. 2009: 63-70

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Editor: Renée Picard

Photo: Taryn at Flickr