C15 fatty acid, or pentadecanoic acid, is an odd-chain saturated fatty acid. While dietary advice has historically grouped all saturated fats together, emerging science is beginning to differentiate between them. This research highlights C15 as a unique fat with distinct properties, prompting a re-evaluation of how different saturated fats function within the body.
C15 Fatty Acid in the Diet
The primary dietary source of pentadecanoic acid is full-fat dairy products like butter, whole milk, and certain cheeses. The butterfat in cow’s milk contains about 1.2% of this fatty acid. Ruminant meats, such as beef and lamb, also contain C15, though in smaller quantities than dairy.
The concentration of C15 in these foods can vary, as milk from grass-fed cows has higher levels than milk from corn-fed animals. While some fish and plants contain trace amounts, they are not primary sources. The body can also produce small amounts of C15, but diet remains the main source for most people.
Biological Role and Cellular Impact
As an odd-chain saturated fat, C15’s structure allows it to integrate into cell membranes, contributing to their stability and strength. This helps armor cells against age-related breakdown. Studies have shown that pure C15 can improve cellular strength.
This fortification helps protect cells from lipid peroxidation, a form of cellular damage. By making the membrane more robust, C15 shields the cell from stress. This structural support extends to the membranes of mitochondria, the energy-producing centers of the cell.
Improved mitochondrial function is another aspect of C15’s biological role. By helping to maintain the integrity of mitochondrial membranes, this fatty acid supports efficient energy production.
Health Research and Associated Outcomes
Observational studies have linked higher levels of circulating C15 to positive health outcomes. Individuals with more C15 in their bloodstream have a lower risk of developing certain chronic conditions, including type 2 diabetes and various forms of cardiovascular disease.
These large-scale studies have also associated higher C15 concentrations with indicators of healthy aging and longevity. Experimental research has uncovered that C15 has anti-inflammatory and antifibrotic properties across various human cell systems.
One clinical study involving obese participants found that C15 supplementation increased circulating levels of the fatty acid and was well-tolerated. Some participants also saw improvements in certain liver enzymes.
Supplementation and Considerations
For individuals whose diets are naturally low in C15, such as those following a vegan diet or avoiding full-fat dairy, supplementation is an emerging option. Because the primary sources of C15 are animal-based, a supplement can provide a direct and concentrated form of this fatty acid. This allows for intake without the additional calories, sugars, or other types of saturated fats found in whole foods.
When C15 is consumed through food, it is attached to triglyceride molecules and must be broken down by digestive enzymes before it can be absorbed. A pure C15 supplement, however, provides the fatty acid in a free form that is readily available for the body to absorb and use. This can lead to more efficient uptake compared to dietary sources.
Current research and supplement manufacturers suggest daily dosages in the range of 100 to 200 mg. As a naturally occurring fatty acid that is a component of common foods, C15 is considered safe. Clinical trials have reported good tolerance with no adverse events at supplemental doses.