With an ideal ratio of omega-6 and -3 fatty acids and some plant chemicals thought to lower high blood pressure, hempseed oil has potential as part of a heart-healthy diet, according to Spanish researchers.
They analyzed the makeup of oil extracted from Cannabis sativa, often called industrial hemp, which is a cousin of marijuana but with very low levels of the chemical in pot that provides a high.
"This is an interesting study that gives new information on the bioactive compounds found in hempseed that may potentially lower blood cholesterol levels and have an anti-atherogenic action," Grant Pierce told Reuters Health in an email.
Pierce is executive director of research at St. Boniface Hospital in Winnipeg, Manitoba, Canada. He was not involved in the new study.
"C. sativa L., an annual herbaceous plant, is known by its long, thin flowers and spiky leaves. The plant is considered to be native of western and central Asia and has also been cultivated commercially in Europe and in parts of China, Japan, Canada, and the United States," write Maria Angeles Fernández-Arche, a pharmacology researcher at the University of Seville, and her colleagues.
In addition to a 3,000-year track record in the manufacture of cloth and paper, hemp has long history as a food and folk medicine, they point out in the Journal of Agricultural and Food Chemistry.
Hempseed is known to have high levels of vitamins A, C and E, minerals and fiber, the researchers say. But they wanted to analyze hempseed oil to better understand its potential for modern food and medicine.
Hempseed oil has a very interesting polyunsaturated fatty acid composition, Fernández-Arche told Reuters Health in an email, because it has an optimal omega-6 to omega-3 ratio of about 3 to 1.
Her main area of research is natural products and the bioactive compounds they contain.
The researchers examined the fatty acid profile of hempseed oil and found that polyunsaturated fatty acids (PUFAs) made up about 75 percent of the oil. PUFAs include omega-6 and omega-3, the fatty acids found in some meats as well as flax and fish oils.
The high amounts of one omega-3 fatty acid, alpha linolenic acid, "may have favorable nutritional implications and beneficial physiological effects on the prevention of coronary heart disease and cancer," the authors write.
Saturated fats and monounsaturated fatty acids each amounted to about 12 percent of the oil.
A high ratio of polyunsaturated to saturated fats has been linked to reductions in cholesterol levels and atherosclerosis, so the proportions seen in hemp oil have the potential to help prevent heart disease, the researchers write.
They also detected plant chemicals, such as beta-sitosterol and campesterol, which have been linked to lower heart attack risk, and reduced LDL cholesterol (the bad kind). Sterols may also lower inflammation and slow the progression of atherosclerosis, the team notes.
This study doesn't prove that hempseed oil has any clinical benefits yet - that will take additional research with human subjects, they point out.
Fernández-Arche said, however, that her team is studying "the effect of the intake of this oil and this effect on the stress induced in animals, and the preliminary results are very promising."
Pierce, who has studied the health effects of both flax and hemp seeds, says of hemp, "It has several potentially important bioactive compounds that could have beneficial cardiovascular effects. It is a very heart healthy seed and oil."
He noted that hempseed oil contains less oleic acid than other heart-healthy oils, such as olive or canola oil, but added that studies on animals indicate hempseed might reduce the clotting of blood platelets that lead to heart attacks.
Pierce thinks flaxseed oil has more health benefits than hempseed oil. "In our animal experiments, flaxseed has shown more potent cardiovascular effects than hempseed," he said.
"We have also shown significant blood pressure lowering effects of flaxseed in human trials," he noted. (See Reuters Health article of November 1, 2013).
But to be fair, he added, hempseed has not had similar trials conducted in humans.