Saturated Fats Explained
Let’s take a few minutes to explain saturated fats and what I think you should know about them. They are one of the 3 major types of dietary fat that you should understand, so I’m going to take a few minutes to explain what they are and how they can affect your health.
The first thing I want to talk about is structure, since that is important to understand how it’s different from trans fatty acids and mono and polyunsaturated fatty acids. In this picture you are looking at a complete saturated fatty acid. Fatty acids contain a long tail which is composed of only carbon and hydrogen atoms. At the head of any fatty acid is what’s called a carboxyl group. They are the same on all fatty acids so I won’t spend any more time talking about them, because they don’t define the distinction between the different fatty acids or types of fat.
The reason this is a saturated fatty acid is the absence of any carbon-carbon double bonds. If you take away 1 hydrogen atom on two adjacent carbon atoms, you can get a carbon-carbon double bond. The absence of this double bond is what makes it saturated. All of the carbons in the fatty acid chain or tail are fully “saturated” with hydrogen atoms. The number of carbon atoms in the chain can vary, which can also affect how your body metabolizes the fatty acid.
Of the three different types of fatty acids, saturated fat is the most controversial. There is mixed evidence over the influence of saturated fat on your health. Some studies show a negative effect and others show no effect.
History of Saturated Fat
Beginning around the 1950s, it was widely held that saturated fat were bad for your health. Namely, they were believed to increase your risk heart attack, stroke, high cholesterol, atherosclerosis (or clogged artery), and perhaps certain types of cancer. In retrospect, it appears this was not based on science, but rather a more political agenda promoting the shift from dietary fat to more carbs.
The low fat concept stems from the concept that dietary fat directly correlates with the fat levels in your blood. After all, if you increase your dietary fat intake then your body’s going to respond with increased serum levels of fat, right?. This was a very widely held belief in the scientific community until the last couple of decades where this has been begun to be debunked.
As an aside, one of the biggest mistakes in nutrition and dietary history was naming two totally different things cholesterol. Dietary cholesterol and serum cholesterol are entirely different yet because of their names, can be extraordinarily confusing for anyone, even for healthcare professionals.
Now as the decades progressed, some very smart people looked at some of the studies out there that already suggested that saturated fat was not the enemy. After all, it’s found in plants and animals, which we have been consuming for thousands of years, so how bad could it really be? Well they started doing more, and more and more research.
In the last 15 years or so there have been numerous studies published examining the relationship between saturated fat intake and cardiovascular disease. More recently, a handful of meta-analysis have been published. In case you don’t know, a meta-analysis summarizes ALL the research on a given subject and is the gold standard for answering questions like this one. One specific meta-analysis that I like found no association between cardiovascular disease and saturated fat intake, the link is available in the discussion. Most of the more recent studies have drawn similar conclusions.
So why does saturated fat still get a bad rap?
The first is nutritional dogma. The idea that saturated fat is bad for your health is a cornerstone of nutritional education and has been for nearly 75 years. The second, which is linked to the first, is medical and nutritional inertia. It takes a long time for professionals to ‘buy in’ to such a monumental change. Sort of like doing a U-turn with an aircraft carrier, the dietary fat landscape is going to change but it doesn’t happen overnight.
A few more points before you label saturated fat ‘not guilty’.
The first is that while a significant amount of publications find no negative effect of saturated fat consumption, there are some that do. More research is going to be required in good, randomized, prospective trials to fully put this controversy to rest.
The second is that most, if not all, major governing medical bodies still advocate for a diet low in saturated fat. This includes the American Heart Association, American & British Dietetic Association's, Center for Disease Control and many more. This is most likely a reflection of the nutritional dogma and inertia that exists and will probably change in the coming years.
Saturated fats occur naturally in many animal products, especially red meat and dairy, including milks, creams, cheese, etc. They are also found in fried foods and some plant oils.