Palmitoleic acid (C16:1) is a monounsaturated fatty acid composed of 16 carbon atoms and 1 double bond. It is a typical ω-7 fatty acid. Other ω-7 fatty acids in the same category include vaccenic acid (11-C18:1) and C20:1, C22:1 ω-7 isomers.

Palmitoleic acid and other ω-7 fatty acids are distributed in most animals and plants, but species with high content are rare.

Seed oils of major oil crops such as soybeans, rapeseed, and peanuts contain only trace amounts of palmitoleic acid (<1%), and animal oils contain slightly higher levels, such as lard and sheep oil, which are only 2-4%, which is difficult to meet dietary nutritional needs.

At present, wild plants are the main source of palmitoleic acid. Seabuckthorn seeds contain 4.4% palmitoleic acid, but seabuckthorn fruit oil can accumulate 25% palmitoleic acid. In addition, the seed oil of Doxantha unguiscati, a woody vine native to the Amazon rainforest, South America, and tropical regions of Central America, contains 64% palmitoleic acid. The palmitoleic acid content of macadamia nut oil, another tropical plant, is 30%, while that of macadamia nut oil is 17%. Other plant oils with high palmitoleic acid content include tung oil (6-11%), nutmeg oil (5%), salsa salsa seed oil (2%), and prickly ash seed oil (2-8%).

Interestingly, ω-7 fatty acids such as palmitoleic and vaccenic acid usually exist simultaneously in plants. For example, elm oil contains both palmitoleic acid (8%) and vaccenic acid (11%); radish (Raphanus sativus L.) seed oil contains ω-7 isomers of C18:1, C20:1, and C22:1, with amounts of 0.7-1.3%, 0.1-0.3%, and 0.4-1.1%, respectively.

However, wild plants that accumulate ω-7 fatty acids at high levels have low yields and narrow geographical distribution, and cannot be planted and commercially produced on a large scale like major oil crops. In my country, only sea buckthorn is widely distributed and has good development value.

In recent years, it has been found that the proportion of palmitoleic acid in some microalgae cells can reach 20% to 30%, and some can even exceed 50%. For example, Oscillatoria sp. cells in cyanobacteria can accumulate up to 54.5% palmitoleic acid, and the palmitoleic acid content in Eustigmatos Magnus and Eustigmatos polyphem of the Eustigmatoidae can account for 39.6% to 57.8% of the total fatty acids. Tribonema sp. of the Xanthophyta has the characteristics of high oil content (>50% dry weight) and high palmitoleic acid content (>50%). Therefore, using microalgae may be a new way to solve the source of palmitoleic acid.

Fish is currently another major source of dietary palmitoleic acid. The content of palmitic acid in fish oil is about 10%, such as 6.9% in anchovies, 10% in tuna, 8-15% in anchovy oil, 7% in herring oil and cod liver oil, 8.4% in whale oil, and 12% in hairtail oil. However, the palmitic acid in most fish oils comes from food blue algae.

Health Benefits

The immunometabolism effects of palmitoleic acid observed in cell culture, animal models and humans mainly include:

The effect of palmitoleic acid on fat-binding protein (FABP): Palmitoleic acid can be used as a lipid hormone (information hormone) to communicate with tissues and organs to regulate systemic metabolism, thereby affecting the formation of fat, etc., and affects obesity.

Palmitoleic acid can reduce the level of C-reactive protein (CRP), which is a key indicator of inflammation. Reducing inflammation can reduce the risk of heart disease and stroke; in terms of anti-inflammatory effects, the human body is more sensitive to ω-7 than ω-3. Palmitoleic acid can increase the fluidity of cell membranes, reduce the content of low-density lipoprotein cholesterol (LDL) in the blood, and reduce the obstruction of blood vessels caused by the formation of atherosclerotic plaques in blood vessels, thereby preventing arrhythmias and reducing hypertension.

Palmitoleic acid can increase the body’s sensitivity to insulin, stimulate cells to secrete insulin, and is effective for diabetes and metabolic syndrome without obvious side effects.

Palmitoleic acid can affect PPAR-alpha-related enzymes, and increase the lipolysis and lipase mechanism of adipocytes, thereby enhancing systemic glucose metabolism, inhibiting hepatic steatosis, and regulating triglyceride formation in adipocytes. Oral administration of palmitoleic acid to male mice can promote the secretion of satiety hormones. Palmitoleic acid can regulate the accumulation of plasma lipids in hamsters and intervene in diseases such as fatty liver and atherosclerosis. By examining several basic physiological indicators of thousands of Chinese volunteers, it was found that palmitoleic acid can regulate fatty acid factors and system metabolic balance, thereby affecting blood sugar, inflammatory markers, and metabolic balance indicators. Some people have studied the effects of palmitoleic acid on neurons in the central nervous system and found that the level of brain-derived neurotrophic factor is related to the content of palmitoleic acid in cells, indicating that palmitoleic acid can regulate brain nerves to affect cellular lipid metabolism.

Applications

Palmitoleic acid has important application value in nutrition, medicine, and even industry.

In the field of health, it can be used in six aspects, including heart health, anti-inflammation, improving insulin sensitivity, replenishing mucous membrane moisture, and resisting aging of skin, hair, and nails.

my country’s population is rapidly aging, and the number of people suffering from metabolic syndromes such as diabetes and hyperlipidemia is growing rapidly, which will generate a huge demand for health products and pharmaceutical preparations of ω-7 fatty acids mainly based on palmitoleic acid.