There has been a lot of interest in the products of the hemp plant lately. CBD or cannabidiol is extracted from the flower heads for medicine. The stem fibres have been used for millennia, and have experienced a resurgence in the last few decades for making sustainable clothing. The mature seeds are enlivening bread and other products, while hemp seed oil is being pressed and sold as a nutritious addition to the kitchen cabinet.
Hemp has been hanging around us humans for a long time. It diverged from its nearest relative, hops (yes, the plant that flavours and preserves beer) at least 27 million years ago. This is thought to have occurred on the central Asian plateau. Since then, it thrived in soils that were enriched with nitrogen, relatively sunny and near to water. At first, wandering herds of wild horses often produced a habitat like this. The horses would churn and ‘enrich’ the soil as they spent time near rivers and lakes. Hemp is pollinated by the wind, and the seeds are dispersed by animals, and by rivers and streams. Sometimes the seeds can be carried along in the hooves of the grazing animals, and so follow the herds from one ideal habitat to another!
This is where humans come in. As we evolved and migrated out of Africa and our range crossed over into that of hemp, we developed a taste for the seed and oil very early on. People were a boon to hemp, providing ample habitat for it: nitrogen-enriched soil from human and food waste, clear ground from settlements, and proximity to water – we like to drink too! As people gathered their favourite types of hemp seed – those that tasted best or contained more oil, they would have dropped some around the campsite unintentionally. In this ideal nutrient-rich environment, we began growing hemp and breeding it for oil and seed – before we even knew we were farming.
Hemp seeds can contain up to 40% oil by weight. This is a relatively high number and makes hemp seed oil easier to extract than a lot of other edible oils. Like olives, the seeds have a simple method of oil extraction. They are crushed to release the nutrients, then are pressed to squeeze out the liquids. They may then be spun, settled, and filtered to obtain a delicious and healthy oil. The oil is a little unstable – like extra virgin olive oil – so is best stored in a dark green bottle and used fresh.
Hemp seed oil has been used since at least 6000 years ago in China. It’s been known for centuries to be a nutritious food, containing many of the components of a healthy diet. The best-known nutrients in hemp seed oil are linoleic and linolenic acids – which are omega-6 and omega-3 fatty acids. Omega fatty acids are essential amino acids for building proteins, and cannot be produced in the body. They occur in hemp seed oil in the ‘perfect’ ratio of 3:1. Very few foods contain them and even less contain them in the proper ratio. Hemp seed oil has this and is a reliable source of omega-9 amino acids.
Hemp seed oil is a versatile and nutritious alternative to some of the other food oils available. Due to the delicate nature of hemp seed oil, it should not be heated to very high temperatures. Using it in smoothies, salads or other cold dishes is ideal, although it is said that a light sautee will not damage its nutritional qualities either.