Photo credit: https://www.superfoodevolution.com/hemp-seed.html
Why so much hype about hemp? It seems that in recent years we can’t go anywhere without hearing about hemp. Hemp use extends from industrial purposes such as textiles, insulation, ‘hemp-crete’ and biofuel; to food products and of course, medicine. Depending on the intended purpose, producers may use different cultivars, growing conditions, and harvesting techniques.
In this article, we hope to shed light on the differences between hemp resin (the source of all those cannabinoids and terpenes used in hemp-derived medicines) and hemp seeds that are processed for their nutritional value. While the information provided applies to both human and veterinary use, we are of course, most interested in how this applies to products available for use in animals.
Without standardized terminology, consumers are often easily misled about a product's content, and its role in treatment. Most people are now aware that hemp is a term used to describe Cannabis plants that have a low THC content. In Canada, as well as many other countries, hemp is legally defined as a cannabis plant - or any part of that plant - in which the concentration of THC is 0.3% w/w or less in the flowering heads and leaves. The concentration of THC must take into account the potential to convert delta-9-tetrahydrocannabinolic acid (THCA) into THC.
The cannabis plant produces tiny glandular structures known as trichomes that cover the flowers and small leaves - called sugar leaves - that grow within the cannabis flower. It is within these trichomes where all the resin is produced. The resin contains a number of different cannabinoids and terpenes, with the amounts and profile varying between cultivars and growing environment. This resin is then extracted from the plant to be used in medicine, as well as recreational use for cannabis plants with higher THC levels. Female flowers that are protected from fertilization (hence produce no seeds), have been found to produce the greatest yield of resin, with fertilized plants suffering from up to a 56% reduction in these essential oils.1 Therefore, when grown for the purpose of resin collection, the aim is always to avoid fertilization from male plants and the subsequent seed production.
When the female plant is fertilized by a male plant, seeds develop among the flowers and small sugar leaves of the plant. These seeds consist of an outer shell with a fatty, soft white-green inner component that is edible. These seeds are produced at the end of the plants growing cycle, just prior to being harvested.
Photo credit: http://redextract.com/2019/10/17/cannabis-anatomy/
Much of the nutritional interest in hemp seed comes from the fact that it is rich in 3 different polyunsaturated fatty acids (FA): linoleic acid (LA), alpha-linolenic acid (ALA), and gamma-linolenic acid (GLA); with an advantageous ratio of 3:1 of Omega 6 to 3 FA. In people, LA can undergo conversion to the other essential Omega-3 fatty acids, docosahexaenoic acid (DHA) and acid (EPA). However, it is worth noting that while LA remains an essential fatty acid for both dogs and cats, dogs have poor conversion of ALA to EPA and production of both AA and EPA from LA and ALA, respectively, is almost completely absent in cats due to the low activity of the enzyme delta-6 desaturase.2
Hemp seeds also are an excellent source of high-quality protein and fibre (10-15%), Vitamin E and other minerals like zinc, calcium, potassium, phosphorus. The oil content in hemp seeds is about 30% and the protein content about 25%; both of high nutritional value. Protein from hemp seeds is easily digestible and contains arginine, which is documented to support cardiovascular health and boost immune system function.3 With this popularity comes some confusion surrounding how much if any, cannabinoid content is in the hemp seed itself.
As previously noted, both cannabinoids and terpenes are produced in trichomes found only on the flowers and small leaves of the cannabis plant. Hemp seeds produce no cannabinoids. It is no surprise then that hemp seed products have negligible cannabinoid or terpene content.
Hemp seeds may, however, acquire a small amount of resin from contact during the hemp harvesting process. Unfortunately, the majority of these contact cannabinoids are removed from the hemp seeds during the washing and shelling process after harvest.
Hemp seed oil is produced when hemp seeds are cold-pressed. This oil contains a number of fatty acids, all of the essential amino acids, including high levels of the amino acid arginine. Once the oil has been extracted, the remaining ‘hemp cake’ can be processed into hemp flour - a nutritious, high-protein, gluten-free flour rich in fatty acids and amino acids, that is often used in baking (usually mixed with grain flour).
Hemp seed oil is commonly sold as an oil for use in cooking, a base for salad dressings, as well as being used as a carrier oil in the production of cannabis oils. Like other carrier oils such as MCT oil (medium-chain triglycerides), sunflower oil, olive oil, pumpkin seed and avocado oil, these oils are plant or nut-based oils that do not contain any significant cannabinoids but are combined with cannabinoid molecules to ‘carry’ them into your system.
On its own, however, there has been much speculation about what, if any, cannabinoids and terpenes exist in hemp seed oil. Various studies have examined the chemical composition of this oil to determine if cannabinoids and terpenes are present. While some studies have shown trace amounts of cannabinoids and terpenes, it is generally considered that the amounts found in hemp seeds are far below the level that has been shown to produce a biological effect.4 Generally, hemp seed was found to contain approximately 0.1mg of CBD per kilogram of seed, although there were some exceptions, with products found having much higher levels. In a study examining hemp seed products available for purchase in Italy5, they found that although a range of different cannabinoids could be identified, they all fell below a level of 5ppm. Another study, however, found that hemp seed oil could contain a CBD level of up to 1000ppm.6
It is still unknown what, if any, effect these low levels of cannabinoids may have on human and/or animal physiology. If one is to presume that there is a potential effect, it would then become important to know the complete composition of the oil, including its cannabinoid and terpene profile, as any therapeutic effect is dependent on the chemical constituents of the particular hemp seed oil.
With the exploding popularity of cannabis as a medical therapy, and the high nutritional value of hemp seeds, it is important that consumers understand the basic science of cannabis in order to understand exactly what they are purchasing. While hemp seed products may contain trace levels of cannabinoids and terpenes acquired through contamination during processing, these products should be considered only as nutritional supplements. For those looking to supplement their pets with cannabinoids for therapeutic effect, they are better to discuss their needs with their veterinarian and obtain guidance for choosing a regulated product that has cannabinoid levels that have been scientifically proven to produce a biological effect.
To help demonstrate the ambiguity of some of the commonly used terminology, we have included some examples below:
Hemp Oil: Technically, can refer to any oil derived from the hemp plant, but most commonly used to describe hemp seed oil - devoid of any significant cannabinoids.
Hemp Seed Oil: Oil derived from hemp seeds, which contain a large percentage of fatty acids, as well as other nutrients. Hemp seeds do not contain any cannabinoids or terpenes but may become ‘contaminated’ with resin from the plant flower during processing, and if not adequately removed during washing, can result in trace amounts of cannabinoids in the final oil product.
Hemp-derived CBD Oil: This refers to an oil high in cannabidiol (CBD) that was extracted from hemp plants. The CBD may be dissolved into hemp seed oil, or any other carrier oil, for ease of administration. This term does not differentiate if the product contains only CBD (otherwise known as a CBD isolate), or a range of cannabinoids and terpenes naturally found in the hemp plant.
CBD Oil: A very broad term to describe an oil-based product containing CBD. This could be hemp-derived CBD, or it could contain CBD extracted from other cannabis plants. The term does not clarify the source of the CBD or concentration nor does it provide information on the presence, absence, or concentration of other compounds from the cannabis plant, including other cannabinoids such as THC, terpenes, or flavonoids.
Full-Spectrum CBD Oil: A cannabis extract that contains all of the cannabinoids, terpenes, and flavonoids found in the parent plant, ideally in a similar ratio to that found in the raw material.
Broad-Spectrum CBD Oil: Similar to Full-Spectrum products, Broad-Spectrum products contain many of the cannabinoids, terpenes, and flavonoids found in the original plant material, however, there may be some missing compounds. Generally, these missing compounds are lost during the extraction technique or are due to the intentional removal of THC to extremely low levels to reduce the intoxicating effects that it may cause.
In summary, we hope this article demonstrated the differences between hemp resin and hemp seeds, revealed some of the nutritional advantages of hemp seed oil, and was able to define common cannabis vocabulary. Without standardized terminology, we appreciate the confusion surrounding a product's content, and we hope this article provides information that allows a consumer to make informed decisions on where to look for therapeutic levels of cannabinoids, terpenes and flavonoids.
Citti, C., Linciano, P., Panseri, S., Vezzalini, F., Forni, F., Vandelli, M. A., & Cannazza, G. (2019). Cannabinoid Profiling of Hemp Seed Oil by Liquid Chromatography Coupled to High-Resolution Mass Spectrometry. Frontiers in plant science, 10, 120. https://doi.org/10.3389/fpls.2019.00120
Citti, C., Pacchetti, B., Vandelli, M. A., Forni, F., & Cannazza, G. (2018). Analysis of cannabinoids in commercial hemp seed oil and decarboxylation kinetics studies of cannabidiolic acid (CBDA). Journal of pharmaceutical and biomedical analysis, 149, 532–540. https://doi.org/10.1016/j.jpba.2017.11.044