Fast facts about edible hemp
Industrial hemp naturally has low levels of THC, which is made by the plant (probably as a sunscreen or to deter insects from eating it). But levels will have to be monitored regularly. This may necessitate setting up a dedicated screening capability in some Australian states, as the crop becomes established.
Hemp seeds are actually like a little nut, with a crisp shell and a soft heart. Mostly you will find them for sale in health food shops. Typically, it will be the hemp-seed hearts you can buy; already released from the shells, they have a mild, nutty flavour.
Hemp seeds contain around 25% protein, up there with soybean and even better than quinoa. Most of the essential amino acids are present, plus valuable minerals and amounts of vitamin E.
A rich source of ‘good’ oils
Hemp seed hearts are also rich in oils, with a ratio of omega 6 to omega 3 polyunsaturated fats of around 3:1.
Now we can add hemp seeds and oil to the relatively limited list of good plant sources of these fats. Nutritionists increasingly highlight the importance of balancing the amounts of omega-6 and omega-3 polyunsaturated fats in our diets.
Hemp oil can be cold-pressed out of the seeds. It is likely that the oil itself will also become more readily available as a product in Australia now the law has changed. However, this oil often contains chlorophyll, the group of pigments in plants that gives them their green colour. The oil is quite unstable and oxidises quite quickly. To slow this rancidity process down, the oil should be stored in a brown bottle away from direct sunlight.
Still some questions
It is less clear what types of polysaccharides or dietary fibre hemp seeds contain, and what our microbiome will make of hemp seeds when they get to the lower reaches of our digestive system. Will the microbes there be able to ferment this seed material?
Fermentation of foods in the lower intestine can produce protective anti-inflammatory byproducts. Hemp may be able to contribute to this.
Or maybe the seeds will just provide dietary bulk that helps move food through our digestive systems and prevents constipation (also useful from a health perspective).
Australia is late to the party
Hemp has been around for centuries and the seed has been freely available to eat in countries such as the US, Canada and the UK for many years. But its food value has only recently started to be appreciated.
It’s now finding its way into breads, breakfast cereals and other baked goods with increasing regularity.
The food use of industrial hemp is by no means the whole story though, and this crop is incredibly versatile. Plants can be grown for organic animal feed, for fibre to go into paper, fabric or soundproofing for cars and the the residues can be used as a biofuel feedstock to power our vehicles. Hemp could even be 'torrefied' (roasted like coffee beans) to make a brown coal equivalent, or converted to provide essential high value chemicals.
Author disclosure statement
Rachel Burton receives funding from the Australian Research Council and has recently undertaken work on hempseed funded by the South Australian Department of State Development in collaboration with the South Australian Research and Development Institute (SARDI).
This article was initially published in The Conversation AU on 13 November 2017 and is republished here under The Conversation's Creative Commons licence.