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The nutritional benefits of hemp seeds

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Hemp seeds won’t get you high, but they are a good protein source – and legal.

Hemp has long been grown under permit in New Zealand for the production of hemp oil and fibre. But recent law changes allow hemp seed to be legally sold as a foodstuff.

In April 2017, transtasman ministers approved a change to the Australia New Zealand Food Standards Code to allow hemp seed to be sold for human consumption. Amendments were made to the Misuse of Drugs (Industrial Hemp) Regulations 2006 and the Food Regulations 2015 so that this could happen.

Once those law changes were finalised, hemp seed – but no other part of the plant – was allowed to be sold as food from November 12, 2018. However, the growing, possession and trade of whole seeds requires a Ministry of Health licence.

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Hemp and marijuana are technically different names for the same genus and species of plant, Cannabis sativa, but there is one important difference: the levels of psychoactive components, notably tetrahydrocannabinol (THC).

THC is the main psychoactive compound in cannabis, but the plant contains hundreds of other compounds, including other cannabinoids.

When cannabis is smoked, vaporised or consumed as a food or extract, the psychoactive components have mental and physical effects, such as changed perception, heightened mood and increased appetite. Because of these short-term effects, as well as the long-term ones, such as impaired motor skills, paranoia and anxiety, the plant is banned in many countries, including New Zealand.

However, hemp (low-THC Cannabis sativa) has extremely low levels of these psychoactive components. To meet production regulations, hemp seeds must come from a plant with leaves and flowering heads that contain no more than 1% delta 9-tetrahydrocannabinol. And the seeds must contain no more than 5mg/kg total THC (total amount of delta 9-tetrahydrocannabinol and delta 9-tetrahydrocannabinolic acid). The seeds must also be hulled before sale, which makes them infertile.

Like most seeds and nuts, hemp seeds are a rich source of nutrients. But information about the New Zealand-grown seeds’ nutritional content is not yet available, says Carolyn Lister, principal scientist and team leader for food and health information at Plant & Food Research.

Her team has put these seeds on its “priority food list” to collect data to add to the New Zealand Food Composition Database.

However, Lister says the US Department of Agriculture’s database shows that hemp is relatively high in protein (31.6g/100g) compared with some other seeds, such as chia (16.5g/100g), sunflower (20.89g/100g) and flax (18.3g/100g).

But because hemp seeds are hulled, they are lower in dietary fibre (4g/100g) than seeds such as chia (34.4 g/100 g), says Lister.

“The fat [lipid] content of most seeds is high. But the different seeds have different profiles of fatty acids. In terms of minerals, the seeds also vary. For example, hemp is higher in magnesium than chia, but chia is higher in calcium.”

Lister says hemp seeds, like other seeds and nuts, should not be compared weight for weight with other foods. “Some of the circulating information about hemp’s composition can be misleading. One of the annoying things people do is compare hemp products with other foods on an equal-weight basis. However, you wouldn’t eat the same weight of hemp seeds as you would a piece of fruit or a vegetable.

“Hemp isn’t a miracle cure-all, but it does contain valuable components, for some of which we are still learning the full health benefits,” says Lister.

She recommends eating a balance of different nuts and seeds, because of their differing nutrient levels. And because no one food can provide everything you need.

This article was first published in the April 20, 2019 issue of the New Zealand Listener.