Hemp and Nutrition

"The quality of an oil or fat is most importantly determined by its fatty acid composition. Hemp is of high nutritional quality because it contains high amounts of unsaturated fatty acids, mostly oleic acid (C18:1, 10%–16%), linoleic acid (C18:2, 50%–60%), alpha-linolenic acid (C18:3, 20%–25%), and gamma-linolenic acid (C18:3, 2%–5%) (Fig. 37). Linoleic acid and alpha-linolenic acid are the only two fatty acids that must be ingested and are considered essential to human health (Callaway 1998). In contrast to shorter-chain and more saturated fatty acids, these essential fatty acids do not serve as energy sources, but as raw materials for cell structure and as precursors for biosynthesis for many of the body’s regulatory biochemicals. The essential fatty acids are available in other oils, particularly fish and flaxseed, but these tend to have unpleasant flavors compared to the mellow, slightly nutty flavor of hempseed oil. While the value of unsaturated fats is generally appreciated, it is much less well known that the North American diet is serious nutritionally unbalanced by an excess of linoleic over alpha-linonenic acid. In hempseed, linoleic and alpha-linolenic occur in a ratio of about 3:1, considered optimal in healthy human adipose tissue, and apparently unique among common plant oils (Deferne and Pate 1996). Gamma-linolenic acid or GLA is another significant component of hemp oil (1%–6%, depending on cultivar). GLA is a widely consumed supplement known to affect vital metabolic roles in humans, ranging from control of inflammation and vascular tone to initiation of contractions during childbirth. GLA has been found to alleviate psoriasis, atopic eczema, and mastalgia, and may also benefit cardiovascular, psychiatric, and immunological disorders. Ageing and pathology (diabetes, hypertension, etc.) may impair GLA metabolism, making supplementation desirable. As much as 15% of the human population may benefit from addition of GLA to their diet. At present, GLA is available in health food shops and pharmacies primarily as soft gelatin capsules of borage or evening primrose oil, but hemp is almost certainly a much more economic source. Although the content of GLA in the seeds is lower, hemp is far easier to cultivate and higher-yielding. It is important to note that hemp is the only current natural food source of GLA, i.e. not requiring the consumption of extracted dietary supplements. There are other fatty acids in small concentrations in hemp seed that have some dietary significance, including stearidonic acid (Callaway et al. 1996) and eicosenoic acid (Mölleken and Theimer 1997). Because of the extremely desirable fatty acid constitution of hemp oil, it is now being marketed as a dietary supplement in capsule form (Fig. 38)."