Nutritional Profile and Benefits of Hempseed, Nut and Oil By Gero Leson & Petra Pless
Hemp foods are expanding onto the shelves of grocery and natural food stores across North America. By definition, these are foods containing hempseed oil, whole seeds, hulled seeds or ‘hemp nuts’, and hemp flour the ground seed cake. Available hemp food products currently include salad dressings, nutrition bars, bread, cookies, granola, nut butter, corn chips, pasta, ice cream and cold pressed oil supplements. These products are not sold for the “hemp cachet” alone; manufacturers promote hemp foods for their exceptional nutritional benefits. Examining the composition of hempseed will help explain these benefits.
Like other oil seeds, the hemp nut, i.e. hulled seed, consists mainly of oil (typically 45%), protein (35%), and dietary fiber and other carbohydrates (10%, predominantly stemming from residues of the hull).
Composition of hemp nut
In addition, the nut contains vitamins particularly the tocopherols and tocotrienols of the Vitamin E complex, phytosterols and trace minerals. Overall, hemp’s main nutritional advantage over other seeds lies in the composition of its oil, i.e. its fatty acid profile, and in its protein that contains all of the essential amino acids in nutritionally significant amounts and in a desirable ratio.
Most oil seeds contain plenty of linoleic acid (LA), an essential fatty acid (EFA) from the “omega-6” family, yet they offer little alpha-linolenic acid (ALA), the other EFA from the “omega-3” family. Health agencies around the world agree that humans should ingest these EFAs in an omega-6/3 ratio of about 4. Since seed oil and fats in meat, both low in omega-3, account for most of our fat intake, Western diets typically have omega-6/3 ratios of 10 and more, which is far too rich in omega-6. Recent clinical research continues to identify this imbalance as a cofactor in a wide range of common illnesses: cardiovascular diseases, arthritis, diabetes, skin and mood disorders. A 1999 workshop by the U.S. National Institute of Health (Web Site) demonstrated the impressive benefits of a balanced omega-6/3 ratio in our diet: reduced risk of atherosclerosis, sudden cardiac death and certain types of cancers, decrease in the symptoms of rheumatoid arthritis, mood improvement in bipolar disorders, and optimized development in infants.
In clinical studies, these benefits are often achieved using omega-3 rich fish and flaxseed oil supplements. A more “holistic” approach is to shift our general dietary fat intake towards nuts and oil with a better omega-6/3 ratio. Hemp nut and oil offer, varying somewhat with plant variety, omega-6/3 ratios of 3 and less. This exceeds the target ratio of 4 and compensates in part for omega-3 deficiencies in the rest of our diet. No other vegetable oil that can be used for so much of our cooking (up to 300° F) offers EFAs at such high levels in a desirable omega-6/3 ratio.
Typical fatty acid composition of vegetable oils;
Hemp oil also provides significant amounts of the ‘super’ polyunsaturated fatty acids, notably gamma-linolenic acid (GLA) and stearidonic acid (SDA). These are not essential themselves, but our body only naturally produces them from the LA and ALA essential fatty acids, respectively. Supplementation with GLA and SDA appears to alleviate the symptoms of atopic dermatitis and other skin diseases in some patients treated with black currant seed oil, which has a similar fatty acid profile to hempseed oil, but is much more expensive and difficult to find.
Clinical trials of the putative benefits from ingested hempseed oil are currently under way at the University of Kuopio in Finland to assess the extent of these potential benefits. GLA and SDA content in hempseed vary considerably with variety and this needs to be considered when using hempseed oil to alleviate such symptoms. Hempseed oil typically contains less than 10% of saturated fatty acids. Unlike other more sensitive oils like flaxseed, hemp oil can be heated up to 150° C (300° F) for prolonged periods of time for cooking or baking purposes, without forming hydrogenated (hardened) or refined trans-fatty acids, known to be particularly detrimental to the blood cholesterol balance.
The hemp nut protein is also of exceptional high quality relative to amino acid (AA) composition and the protein structure, the latter affecting digestibility and utilization of protein by our body. Hemp protein contains all of the essential amino acids in nutritionally significant amounts at a ratio closer to “complete” sources of protein (like meat, milk, eggs) than all other oil seeds except soy beans. Hemp nut protein consists of two globular proteins, albumin (1/3) and edestine (2/3), with a structure very similar to proteins manufactured in our blood, and are thus readily digestible. Hemp nut protein appears to be free of antinutrients, which are found in soy to interfere with protein uptake. Thus, eating hempseed or nuts delivers protein with an AA composition as we need it and in a structure readily utilized.
Hemp’s nutritional advantage over other sources of fats and protein thus lies in its highly desirable balance of basic nutrients. Simply put, when eating hempseed, nut and/or oil, our body obtains much of what it needs without the caloric ballast of non-essential nutrients. Yet, unlike fish and flax oil supplements and protein powders, properly processed hemp seed offers these benefits “in taste,” i.e. with a nice flavor profile. Fresh cold pressed hemp seed oil and hemp nuts, particularly when toasted, add a nice nutty flavour to many dishes and off the shelf food products.
Thus, hemp nut and oil are attractive both nutritionally and culinary, rendering them truly modern food sources.
Gero Leson, D.Env. is an environmental scientist and consultant with extensive experience in food and fibre uses of hemp and other renewable resources.