As the name suggests, palmitic acid is an organic compound found in generous amounts in all varieties of palm oil. It is however a fatty acid of the saturated type that exists in many other plant and animal species. It is actually the most widespread of all fatty acids in nature and can be produced from numerous plant sources. It is very common in nature because it has numerous biological roles and can be used in both food and industry. Palmitic acid is part of the composition of common products like milk, butter or cheese.
Pure palmitic acid looks like white crystals that are not soluble in water and have a melting point of 145.5°F. It has some alternative scientific names like hexadecanoic acid or cetylic acid. Palmitic acid is the first product of lipogenesis, the transformation of glucose into various fatty acids. It is the first of these compounds, which later become triacylglycerols after reacting with glycerol.
The name of the compound comes from the French word palmitique, which means the inner core of the palm trees. All plants have such a core, also known as the pith, which consists of a network of spongy cells. These are located in the center of the trunk or the stem and transport nutrients to all parts of the plant.
Palmitic acid was isolated for the first time in 1840. It was a French chemist, Edmond Frémy, who discovered it in saponified palm oil. Even today, this is the main industrial way to produce the acid, by hydrolyzing the fat components on palm oil using very hot water at over 200 degrees Celsius. The output can then be distilled further until pure acid is isolated. Frémy was involved in the production of candles and his research focused on this goal. However, he is also famous for discovering a very strong oxidizing mixture named Frémy’s salt in 1845, still renowned among chemists.
Many plants and organisms synthetize palmitic acid but the amounts are usually low. It can be found naturally in a number of very common food animal products like meat, cheese, milk and butter. Rich vegetable sources are sunflower oil, soybean oil and cocoa butter. Spermaceti is rich in cetyl palmitate, which is a cetyl ester of the acid.
This compound became important during the Second World War because it was an ingredient in the production of napalm. Napalm was made by mixing aluminum palmitate with aluminum naphthenate and was added to volatile liquids like gasoline. It thickened the mix and allowed it to burn for a longer period of time.
Palmitic acid might be a health hazard for humans. According to the World Health Organization (WHO), it might increase the risk of heart disease. The findings date from a 2003 study on the link between a healthy diet and the onset of chronic diseases. However, other tests have not confirmed the results yet and they continue to be disputed by some scientists.
It must be said that the World Health Organization insists it has solid evidence that palmitic acid consumption raises the LDL blood levels. According to the WHO, the results have been confirmed by several studies and point to a greater risk of heart disease. Palmitic acid is now common in human diet, mainly as retinyl palmitate. This compound is added in low fat milk to replace the lost vitamins and is a powerful antioxidant and vitamin A source. It is produced by combining the alcohol form of vitamin A (retinol) with palmitate, in order to create a stable compound.
Further studies were conducted on rats and found disturbing evidence. In one test, rats were fed for a long period with a mixture of 80% carbohydrates and 20% palmitic acid. They showed significant changes of their nervous system. In particular, insulin production was altered and the most important hormones with a role in weight control (leptin and insulin) had their signals blocked.
The palmitic acid was also found to have a nasty effect on cancer cells. Metastasis progressed very quickly in lab mice who suffer from a form of human oral cancer cells. All fatty acids are especially known to increase the lethality of CD36+ cells, which initiate metastasis.
It must be noted that palmitic acid found in plants is different from the one in animals, the structure is not the same and neither is the effect after consumption.
It is an excellent choice for numerous industrial uses, since it is very cheap and can be produced fast. One of the most important applications is as an emulsifier in the cosmetics industry, especially in soap and cleaning products. It is a texturing ingredient in various foods and can be used as a protective cover on fruits and vegetables. It is also a source for other compounds like esters and both nonionic and anionic surfactants. Further refining or mixing results in chemical additives like cetyl alcohol or isopropyl palmitate.
Palmitic acid can preserve the smoothness of human skin, which makes it a great low-cost ingredient in soaps. Beeswax also includes palmitic acid and it is an ingredient in many other care and cleaning products. Palmitic acid can cover blemishes when used in the production of makeup and it serves as a cleaning ingredient in some surfactants.
Because of its cheapness, the palmitic acid is widely included in all kinds of cosmetics, as well as soaps and even mold release agents for industrial purposes. The particular compound used is sodium palmitate, which can be produced very easy by turning palm oil into soap. Palm oil is made from palm trees of the Elaeis guineensis variety, then combined with lye or caustic soda in order to hydrolyze the ester compounds in the oil. The results are sodium palmitate and glycerol.
When added in food, both palmitic acid and its sodium salt improve at the same time the texture and the natural feel inside the mouth. This is very important in cheap processed foods. Even organic products allow sodium palmitate as an ingredient, since it acts like a natural additive. When reacted with aluminum, palmitic acid is an ingredient in napalm, a flammable mixture used as a weapon. Cetyl alcohol, a common component in cosmetics and cleaning products, is synthetized by hydrogenating palmitic acid.
As for the medical uses of the palmitic acid, it is prescribed as a treatment for mental diseases, especially schizophrenia. INVEGA Sustenna® is the commercial name of an anti-psychotic drug consisting of paliperidone palmitate. Paliperidone palmitate actually acts like a carrier for the active compound, administered by intra-muscular injection. Since palmitate is oily, the effect lasts longer as a lot of time is needed until it is eliminated by the human body.