Why Stearic Acid is One of the Most Important Fats For Metabolic Health
Stearic acid may be a fat loss star
Fat is flavor. It’s such an important component of our diet because it carries many of the aroma compounds that make food flavorful and delicious. Fat is also important nutritionally. We need fat to make cell membranes and important signaling molecules like steroid hormones and prostaglandins.
Most of us are familiar with how dietary fat is divided into saturated, monounsaturated, and polyunsaturated fats. But in each of these classes exist several individual species of fatty acids. For example, palmitic acid is a saturated fatty acid with 16 carbon atoms and stearic acid is a saturated fatty acid with 18 carbon atoms. Stearic acid may be particularly important for maintaining healthy body composition. It has been shown to be beneficial in regulating energy metabolism in fat tissue in both human and rodent studies. Read more below.
Stearic acid
Stearic acid (C18:0) is a saturated fatty acid found at high concentrations in animal fats and cocoa. This particular saturated fatty acid has been studied a lot over the last decade because it seems to have biochemical properties unique from similar types of fatty acids.
Studying how different nutrients in food interact with our bodies is fascinating, but at the end of the day, we eat food..not nutrients. Here are some of the best food sources of stearic acid. Note that the table below lists exclusively fat sources but ribeye steak could be considered a good source of the same fats in beef tallow and chocolate contains cocoa butter (at least real chocolate does).
Stearic acid content of selected fats and oils. Data from USDA Nutrient Database for Standard Reference (2007); Adapted from https://www.beefresearch.org/resources/human-nutrition/white-papers/stearic-acid#:~:text=Major%20food%20sources%20of%20stearic,tallow%2C%20lard%2C%20and%20butter.
Effects on blood lipids and body fat
Stearic acid does not raise blood low-density lipoproteins (LDL) to nearly the extent as its two-carbon-shorter relative, palmitic acid(1). However, I don’t think LDL alone means very much since cholesterol and lipoproteins do not seem to be pulling the trigger on cardiovascular disease.
Where stearic acid gets really interesting is when we look at research showing how it interacts with our fat tissue. Feeding mice stearic acid shrunk their visceral fat in comparison to other types of high-fat diets or a low-fat diet (2). Wow! It was the saturated fat that made these mice lean…not the “healthy fats” or the low-fat diet!
There is actually good data in humans that support that original mouse study. Stearic acid supplementation in humans was shown to boost a process called mitochondrial fusion (3). This process is very important for the repair of damaged mitochondria and is being studied as a potential mechanism that could be used to slow aging. The human study at hand also demonstrated that stearic acid supplementation seemed to make the mitochondria more efficient at burning fat for energy.
Another study showed that stearic acid concentrations were lower in women with large fat cells compared to women that had small fat cells in their adipose tissue. This observation further supports the mechanism that stearic acid causes fat cells to shrink and shows this association holds true in humans (4).
Finally, stearic acid might cause fat tissue to secrete a hormone called adiponectin. Adiponectin is usually seen as a marker of health because it promotes insulin sensitivity and reduces inflammation. A mouse study showed that supplementation with saturated fat high in stearic acid reduced the toxic effects of ethanol consumption on the liver by increasing adiponectin secretion (5). Polyunsaturated fat supplementation was not protective; in fact, it made the disease state worse. The important thing to understand about this study is that saturated fat only increased adiponectin secretion in the liver damage model, not under normal conditions. Future human studies will hopefully clarify exactly how saturated fat intake regulates the secretion of adiponectin and other hormones from fat tissue.
How to consume more stearic acid
As shown in the table above, animal fats and chocolate are the best sources of stearic acid. High-quality beef tallow is an excellent source of stearic acid and will make virtually anything you cook with it delicious. Fatty cuts of meat like short ribs would be another good source.
Dark chocolate with low sugar content is another food that could be used to boost stearic acid intake. Cocoa butter is actually the richest source of stearic acid by concentration. Making hot cocoa from scratch using 100% cacao chocolate is one of my favorite ways to get stearic acid in my diet.
I hope this essay has been informative. I would like to end with a fun fact. Jeanne Calment was a French woman and supercentenarian who lived to the impressive age of 122. While we cannot pinpoint exactly what blessed her with this extraordinary longevity, it was said she enjoyed up to a whopping 2.2 pounds of chocolate every week. If that’s true, then she certainly consumed a lot of stearic acid.
Cheers.
Take-home messages:
- Stearic acid has been shown to promote visceral fat loss in mice
- Stearic acid activates mitochondrial function in humans
- It’s plausible that stearic acid could be a useful tool for weight loss in humans
- Chocolate and animal fats are the best sources of dietary stearic acid