Stearic acid is a common 18-carbon saturated fatty acid found in various dietary fats. It occurs naturally in both animal and vegetable fats and oils.
Sources of Stearic Acid
Stearic acid is found in a variety of foods, with varying concentrations. Animal-based sources are generally higher in stearic acid compared to plant-based sources, though there are notable exceptions.
Meats like beef, pork, and lamb contain stearic acid, with beef tallow and lard being particularly rich sources. Lard has around 11.1 g per 100 g, and beef tallow even higher at about 16.7 g per 100 g. Lean ground beef (95% lean, 5% fat) can have stearic acid making up approximately 16% of its total fat, while a skinless, roasted chicken breast contains about 8% of its total fat as stearic acid. Dairy products, such as butter and hard cheeses like Parmesan, also contribute to stearic acid intake, with butter containing around 9.4 g per 100 g. Chicken eggs, especially the yolk, provide a notable amount, approximately 3.7 g per 100 g.
Cocoa butter is a particularly rich source of stearic acid, often containing between 33% and 35% of its fatty acid content. This makes chocolate products a significant dietary contributor of this fatty acid. Other vegetable oils and fats that contain stearic acid include shea butter, palm oil, and cottonseed oil. Shea butter is particularly high, with concentrations ranging from 28% to 45%. Some nuts like macadamia nuts and roasted peanuts also contain stearic acid. Coconut oil and palm oil are also known to contain stearic acid.
Impact on Health
Stearic acid exhibits unique metabolic properties compared to other saturated fatty acids, particularly concerning its influence on cardiovascular health. Unlike many saturated fats that tend to raise LDL (“bad”) cholesterol levels, stearic acid often has a more neutral effect. This is largely due to its conversion in the body.
In the human body, stearic acid can be converted into oleic acid, which is a monounsaturated fatty acid. Studies indicate that a notable portion of dietary stearic acid, around 9-14%, undergoes this desaturation process to become oleic acid.
While some research on stearic acid’s effects on HDL (“good”) cholesterol has shown inconsistent results, it is generally considered to have a neutral or potentially slightly beneficial effect. Some studies suggest it may slightly decrease the ratio of total cholesterol to HDL cholesterol when compared with palmitic or myristic acid, which are other saturated fatty acids. Stearic acid does not increase the risk of heart disease and may even be beneficial for heart health.