Your guide to the uses and health benefits of hemp

by Dr Karen Bridgman June 27, 2013

Hemp (Cannabis sativa) is arguably one of the oldest crops known to humankind. While hemp originated in northern India, the oldest known records we have of hemp farming go back 8000 years in Persia. Records tell us hemp industrialisation began about 5000 years ago in central Asia and north Africa, in ancient Persia, China and Egypt.

Hemp is a fast-growing, high-biomass-producing plant that has traditionally been grown as a multi-use crop — until the World War II, when farmers in the USA were subsidised to grow hemp for fibre and oil. After the war, competition from synthetic fibres and increasing anti-drug sentiment resulted in less and less being grown, until 1958 when there was virtually none being grown in Western countries.

This is changing. Currently, there are worldwide moves to grow and regulate the use of this ancient and incredibly useful plant. Governments (including the Australian government) are increasingly licensing farmers to grow crops of hemp for its many industrial uses. For several years now, hemp has been cultivated in Canada, China, Thailand and such European countries as France, Germany, Romania, Italy and the UK.

As the economic conditions are similar in Canada and Australia, the former is considered the benchmark when it comes to developing local industries. Canadian hemp generates around $480 million annually and the products are used mainly for fibre, animal and bird feed and oil for cosmetics, although the use of hemp seed as a human food and for its essential fatty acids is fast becoming an economic proposition.

Agricultural and environmental benefits

One of the agricultural and environmental advantages of hemp is it requires very little water and very little in the way of pesticides. Hemp can easily be grown organically and, long term, it benefits the environment as it improves the fertility of the soils in which it is grown — unlike cotton, for example, which is hemp fibre’s major competitor. Cotton uses huge resources in water and chemicals and contributes to large-scale environmental degradation. From the same area of land, hemp can also produce 250 per cent more fibre than cotton and 600 per cent more fibre than flax.

Hemp has an ideal profile to fit into sustainable farming systems: it offers alternative land use and is a key rotation crop that will increase the yields of crops following it by revitalising and improving soil structure. For farmers it does not require a long-term commitment in land use (four months to achieve sufficient maturity for harvest) and has a similar management structure to that of other crops — without the necessity of chemical use. Hemp can also play a major role in the remediation of soils that have been contaminated by heavy metals.

Hemp has also been shown to be a major contributor to carbon sequestration. In other words, it is an excellent “carbon sink” and is believed to be one of the most powerful tools for removing carbon from the environment.

Hemp cultivation and production do not harm the environment. Hemp produces four times as much pulp as wood with at least four to seven times less pollution. In terms of paper production, one acre of hemp will substitute for approximately four acres of trees.

Even better, the returns on hemp seeds are potentially higher than for hemp fibre and, in contrast to the fibre, seeds can be processed and marketed for consumption on a small scale by small farmers with low costs (100ha for seed compared to 10,000ha needed for fibre production). Farmers with smaller farms will potentially be able to enter the industry.

The ABC’s Landline program recently featured hemp as a major agricultural product that is being grown in Australia. Most states now have licensed hemp growers as the strong, versatile fibre can be used for such diverse industries as building and masonry, textiles (including furnishings and clothing) and fibreglass manufacture. It can also be manufactured into an effective biodegradable plastic.

From an agricultural perspective, hemp provides the raw material for many applications. Between 30 and 40 per cent of the bark (stem) can be used for high-fibre applications; 60–70 per cent of the stem core (the hurd) can be used for paper, textiles, composites, plastics and in the Automotive industry; the seeds are an important food source and there is an already existing market for various pharmaceutical applications.

THC versus CBD

The hemp plant is a complex plant, the main components (cannabinoids) of interest medicinally being THC (delta-9-tetrahydro-cannabinol) and CBD (cannabidiol). While medicinally, the foliage and leaves of high-THC plants have been used as a sedative and narcotic drug, when growing hemp for food, industrial use or textiles, varieties are chosen and agricultural conditions are provided that significantly reduce the THC levels in the plant.

Hemp can be grown to increase THC levels for the drug (and medicinal) market or to increase the CBD levels for the food and industrial market. While these may be similar compounds, the former has the hallucinogenic properties while the latter inhibits any hallucinogenic activity. It’s impossible to get “high” on industrial hemp or hemp food seeds.

THC and CBD compete for activity in the body and hemp grown for food has little to no hallucinogenic properties.

Industrial uses for hemp fibre

Hemp has been used for thousands of years as an ideal fibre for the sails and ropes of ships, including those of the Royal Navy. The word canvas is derived through Latin from the Greek cannabis. Hemp “canvas” is also what many of Europe’s most famous artworks were painted on. Rembrandt, Van Gogh and Gainsborough made use of this versatile material.

Building materials

Hemp fibre (the “hurd” or woody pith or core in the middle of the stalk) can be processed into many building materials that are strong, cheap, easy to use, with high thermal qualities (fire-retardant) and incredibly energy-efficient. The hurd is used in construction materials as well as hemp plastics. When the local Aboriginal elders from northern NSW were asked their opinion, their spokesperson stated that hemp was environmentally sound and culturally appropriate for Aboriginal building programs, unlike many other building materials that have been used in the past.

Papermaking

Hemp is used in detergents and soap manufacture and has many similar uses to linseed oil such as a fuel for lighters, in printer’s inks and as a wood preservative, among others. Paper making is another of the major uses for its fibre.

Textiles

Hemp was one of the world’s commonest and most versatile textile fibres before the invention of the cotton “gin”, which made for more efficient processing of cotton. Fabrics are made from the fibres around the stem and these can be processed into a strong, durable yet soft cloth similar to linen (from flaxseed). As a fabric, hemp is soft, can be grown easily and processed chemical-free and is non-allergenic, so it makes strong, long-lasting clothing and bedding as well as furnishings and fabrics. It can also be used for coarser fabrics such as hessian.

Biodiesel

Hemp oil is currently being investigated for use as an effective biodiesel.

Hemp facts

Until the 1900s, 90 per cent of all ship’s sails and ropes worldwide were made of hemp.
Until the 1880s all school books were made from either hemp or flax. Large books like the Holy Bible were commonly printed on strong hemp paper.
Henry Ford’s first Model T ford used hemp based gasoline, and was largely constructed of hemp as it made a ‘plastic’ that was 10 times stronger than steel (according to a 1941 edition of Popular Mechanic)

Hemp seed as a food

Internationally, you can purchase a wide range of hemp foods: hemp pasta, hemp salad dressing, hemp breads and biscuits, hemp icecream and even hemp soap made from hemp oils. The Canadian Hemp Trade Alliance cites at least 20 studies of clinical trials for the good nutritional effects of hemp on diabetes, cardiovascular diseases and weight reduction.

Industrial uses of hemp have been clarified and the plant is being grown successfully for these purposes, yet the use of hemp for food is still the subject of much debate. To date, Australia is the only country in the world not to recognise hemp as a food. Yet research has shown it is a high source of nutrients such as highly digestible proteins and essential fatty acids, particularly the important omega-3 and omega-6 fatty acids. If hemp foods are legalised in Australia it would give great incentive to farmers to grow this versatile plant.

Food Standards Australia currently has applications before it to grow low-THC hemp as a food (Application 1039). The main problem envisaged for hemp as a food source is the potential for difficulties and complications imposed by law enforcement agencies if these crops are approved, though these issues have all been resolved by Canada, Europe and the rest of the world.

Nutritionally, hemp seed is rich in vitamins A, C, D and E and beta-carotene. It is high in minerals, including phosphorus, potassium, magnesium, sulphur and calcium, with smaller but adequate amounts of iron and zinc. Zinc is an important co-factor for the metabolism of the fatty acids the seed also contains.

In terms of the “macronutrients”, hemp seeds contain 20–25 per cent protein, 20–30 per cent carbohydrates, 25–35 per cent oil and 10–15 per cent insoluble fibre. The protein is similar to soy protein and is an adequate source of this major nutrient for vegetarians. The hemp seed meal and oil have long been used as food sources for humans and have a tasty, nutty flavour.

Hemp seed is also used frequently as a food source for birds and fish and as stock food. Chickens, particularly, love hemp seed as a food and the high proteins and fats help to keep them healthy.

CBD: Cannabidiol

CBD (the non-hallucinogenic component of hemp seed) is a very interesting substance in itself and has been shown to have a variety of therapeutic properties. Research shows it to be an effective anti-inflammatory (working through nitric oxide and several cytokines) and an antioxidant for colitis. It appears to reduce inflammation and both the degree of lipid peroxidation and production of damaging free radicals in intestinal epithelial cells. In several mouse studies it was found to prevent inflammatory bowel disease.

CBD has also been shown to be an effective anti-inflammatory for the central nervous system and has been investigated for its role in reducing the neuropathic pain and spasticity from the debilitating disease multiple sclerosis. CBD inhibits cholesterol ester formation in human fibroblasts as well as in aortic medial cells by up to 80 per cent, by modifying a gene that regulates the metabolism and removal of cholesterol, potentially reducing symptoms of cataracts, premature atherosclerosis and osteoporosis.

Hempseed oil

Hemp seed oil is tasty and has shown advantages over many commercial vegetable oils, being reputed to have an excellent ratio of the two important essential fatty acids — linoleic (omega-3) and linolenic (omega-6) — that regulate the inflammatory process. Cold-pressed hemp seed oil is an excellent antioxidant with high free-radical-scavenging activity.

Hemp oil is one of the richest plant sources of omega-3 fatty acids, important in these days when marine sources of omega-3 are increasingly limited due to overfishing.

Hemp seed and its oils have demonstrated Health benefits such as regulating abnormal cholesterol levels and lowering high blood pressure. Used both internally and topically, it is an important oil to relieve dry, scaly skin diseases such as atopic dermatitis, and this anti-inflammatory activity can be employed to relieve other inflammatory conditions such as arthritis.

As with flaxseed oil, the high level of polyunsaturates in hemp oil indicates it should not be used for cooking at high temperatures and should be stored in a cool, dark place. It is excellent, however, for foods such as salad dressings.

Cosmetic use

In cosmetics, hemp oil is used for light body oils and lipid-enriched creams that penetrate the skin, providing the whole body with an effective source of omega-3 and omega-6 fatty acids. It is also used in lotions, moisturisers, shampoos, soaps, lipsticks and lip balms.

Hemp has been — and still is — of major economic and pharmaceutical importance throughout the world, virtually since the dawn of humankind. With its multitude of industrial uses, its sustainability as an agricultural crop and its potential as a major food source, there is no end to the potential of this fascinating plant.

With worldwide food shortages and climate change exacerbated by current agricultural and industrial practices, the use of hemp fibre for industry, and hemp seed and its oils for food, may make this ancient plant the plant of the future.