May 2018 Issue

CPE Monthly: Health Benefits of Hemp Seeds
By Ginger Hultin, MS, RDN, CSO
Today's Dietitian
Vol. 20, No. 5, P. 44

Suggested CDR Learning Codes: 2020, 2070, 3100, 4040
Suggested CDR Performance Indicators: 8.1.3, 8.1.4, 8.3.1
CPE Level 2

Take this course and earn 2 CEUs on our Continuing Education Learning Library

The Cannabis sativa L. plant is an annual herbaceous plant that has been grown agriculturally for centuries. An ancient crop native to central Asia, there's evidence that it grew during preagricultural stages of human development.1,2 Cannabis sativa L. is a crop used for food, fibers, and oil for human consumption and industrial use.3 Hemp is the variety used in industry and food, while marijuana is the variety used as a drug recreationally and medicinally. Both hemp and marijuana are strains of Cannabis sativa L.

There are different varieties of Cannabis sativa L. based on their usage. One is industrial hemp, or hemp used for food or material, which is low in the psychoactive cannabinoid delta-9-tetrahydrocannabinol (THC). THC is found in higher levels in marijuana plants, another variety of Cannabis sativa L. The higher THC levels in marijuana contribute to the recreational or medicinal effects sought from its use. Comparatively, hemp is so low in THC, at 0.2%, the standard established by the European Union, that it can't be used as an inebriant.1,4 Due to much confusion from the public in differentiating between hemp and marijuana, both species have faced legal bans in Canada and the United States. The noninebriating hemp plant is now making a comeback as a sustainable crop that has many benefits in the food supply for health and industry. Except where otherwise noted, hemp, in this article, refers to industrial hemp.

This continuing education course reviews the health benefits of hemp seeds and shares strategies clients can use to incorporate the seeds into their diets.

History and Regulation
Used widely for modern fabric, paper, building materials, medicine, and food for both humans and livestock,5,6 the hemp plant has a complicated history. There's evidence that hemp seed oil has been used in the diet as medicine and in textiles for at least 3,000 years in China, where it originated.7 Cannabis was considered sacred in ancient Tibet and used to facilitate meditation in tantric Buddhism.7 Hemp likely was first brought to Europe before the Christian era by Scythian invaders in 450 BC.7 It's been known to Africans since the 15th century and used medicinally there as well. Before cannabis came to North America for use in early settlements, the plant's seeds first came to Brazil, brought by African slaves and used both ritually and medicinally.7 In early US history, cannabis was cultivated and used widely for fiber and industrial material.1,7

The cultivation of hemp was prohibited in Canada in 1938, when the Canadian Opium and Narcotics Act made farming of all cannabis illegal.1,4 The same year, the United States issued the Marihuana Tax, placing cultivation under control of the US Treasury Department, which made it possible to grow hemp in the United States only with permission from the US Drug Enforcement Agency.1 Since this time, linseed has replaced hemp seed for oil in paints and varnishes.8 In 1970, the US Marihuana Tax was repealed and replaced with the Comprehensive Drug Abuse Prevention and Control Act, which treated marijuana and hemp as the same, not taking into account industrial vs recreational varieties.1 In 1998, regulations in Canada began allowing commercial cultivation of hemp, and changes to the US Agricultural Act of 2014 allowed industrial hemp to be cultivated under strict control.1 China is the largest producer of hemp in the world, and Europe is experiencing an economic resurgence of hemp fiber in its marketplace.1

Hemp and marijuana differ in their psychoactive cannabinoid content due to breeding and the part of the Cannabis sativa L. plant used.1,9 Psychoactive compounds are found primarily in resins secreted by gland cells on leaves, so this part of the marijuana plant is used medicinally and recreationally.9 Drug varieties contain 2% to 5% THC per dry weight, though much higher levels have been reported. In contrast, industrial hemp used for textiles and food is bred to contain no more than 0.3% THC.9 The part of the plant used for textiles and fibers is the stem, and the part used for food is the seeds.1 If hemp products used for food, cosmetics, or industry are processed and cleaned properly, they contain low to no residual THC.9

Hemp seeds are a type of seed rich in nutritive properties with links to human health when incorporated into the diet.8 However, some studies have found the presence of THC in seed and oil products, particularly when they aren't cleaned or have been exposed to external contacts with seed hull resins.9

An additional compound found in Cannabis sativa L. is cannabidiolic acid, which can enhance the intoxicant effects of THC. Cannabidiol is considered a psychoactive drug with antianxiety, antipsychotic, and antidepressant effects.1,2 Cannabinoids don't possess psychoactive effects until they're decarboxylated by adding heat.10 Ultraviolet radiation accelerates the ripening of cannabis plants; therefore, cannabidiol conversion to THC is enhanced in tropical latitudes.10 Industrial hemp is grown in northern latitudes in Canada and the United States, where conversion would be low.10 These unripe varieties also are low in THC and decrease the risk of psychoactive effects, especially when they're consumed in the diet as hemp seeds or oil.10

Nutrients and Dietary Uses of Hemp
Hemp seed is used in the diet in many forms, from edible oil and milk to flour and protein powder. There's evidence that hemp seed has been consumed in the diet throughout recorded history by humans and animals.5,7 The nutritional benefit comes from the fiber content, the protein, and the oil, which contains healthful unsaturated fatty acids, phytosterols, and nutrients.3 Hemp seed is composed of 20% to 25% protein, 20% to 30% carbohydrate, 25% to 35% oil, and 10% to 15% insoluble fiber.2,4,5,10,11

Hemp seed is rich in a variety of nutrients including magnesium, phosphorus, iron, and manganese.3 Hemp also contains antioxidant properties that combat oxidative stress—an imbalance between reactive oxygen species, also called free radicals, to help quench their potentially damaging effects.11,12 Researchers have found that hemp hydrolysate is an excellent reducing agent, tested by the amount of Fe3+ reduced to Fe2+, which indicates its potential as an antioxidant that could benefit human health.11 It's also been shown to reduce H2O2 toxicity, again proving to have a strong antioxidant effect.12 Hemp products contain terpenes, antioxidants that have been cited in the research as anti-inflammatory, antiallergenic, and cryoprotective.10

Hemp seed oil is rich in antioxidant carotenoids, sterols, and tocopherols.1,4,6,13 In fact, more than 540 phytochemicals have been identified in hemp.2 Tocopherol antioxidant content is rich at 80 to 110 mg/100 g, gamma-tocopherol being the main source at 85%.10,13 Hemp seed contains a variety of terpenophenolic compounds including phytocannabinoids.1,2 Cannabinoids in the cannabis plant interact with the human endocannabinoid system, which includes receptors that play a role in appetite, pain sensation, mood, memory, inflammation, insulin sensitivity, and fat and energy metabolism. These effects, however, don't come from consuming food sources since they're only present there in very small amounts compared with the much higher levels in marijuana used recreationally.2

Health Benefits of Hemp
Hemp seeds in the human diet have been studied for their possible health benefits including antihypertensive properties, plasma fatty acid improvements, cardiovascular support, protein content, and relief of atopic dermatitis.6,14-17

Plasma Fatty Acid Improvements
Both omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) are essential for human growth and development and likely play a positive role in the prevention and treatment of chronic diseases, including coronary heart disease and inflammatory conditions such as osteoarthritis and atopic dermatitis.6,18 When changes in plasma fatty acid profiles are observed posthemp seed oil treatment, linoleic acid, alpha-linolenic acid (ALA), and gamma-linolenic acid (GLA) change significantly.8 Cardiovascular and inflammatory processes may be improved by the fatty acid profile in hemp seeds through reduction in blood clots, arterial plaques, and LDL cholesterol levels.16,17

Hemp seeds contain a combination of healthful dietary fats including the omega-3 PUFA ALA and stearidonic acid (SDA) and the omega-6 PUFA GLA.1,3,6,10,18 More than 80% of the fatty acids in hemp seed oil are PUFAs.5,6,8 Uniquely, hemp seeds contain up to 7% GLA and 2.5% SDA.13 A common source of dietary omega-3 fatty acids are cold water fish such as salmon and halibut, but for those looking to diversify their omega-3 intake and those who prefer plant sources of these dietary fats, seeds including hemp seeds offer a rich alternative.16

Essential fatty acids (EFAs) are critical for human health and must be consumed through diet, as humans can't make them internally.8 EFAs compete for access to delta-6 desaturase, the same rate-limiting enzyme in mammalian cells that transforms both omega-3 and omega-6 fatty acids into a variety of essential metabolites.6,8,16 The conversion enzyme delta-6 desaturase has a higher affinity for ALA than for linoleic acid, hence having a proper dietary balance of both ALA and linoleic acids of about a 2.5:1 ratio is critical to health.6,8 Studies show that Western diet ratios are often between 15:1 and 17:1, deficient in omega-3 and excessive in omega-6.16 When this imbalance occurs, signaling molecules, including proinflammatory hormonelike fatty acid compounds such as prostaglandins, thromboxanes, and leukotrienes, contribute to negative health outcomes including formation of blood clots, arterial plaques, and other inflammatory disorders.10,16 Studies show that GLA and SDA, the metabolic products of EFAs linoleic acid and ALA, in hemp seed oil bypass the delta-6 desaturase step of lipid metabolism, aiding in human health through better access to these fatty acids.6

Phytosterols and Cholesterol-Lowering Ability
In a study analyzing the fatty acid content of 30 species of plant seeds, hemp seed showed the lowest amount of monounsaturated fatty acids (MUFAs) at 12.9% but the highest amount of PUFAs at 76.2%, the majority of which (57%) were linoleic acid.18 The balance of omega-6 to omega-3 fatty acids in hemp oil has been linked in studies to positive cardiovascular health benefits including reduction of fibrinogen, which plays a protective role against atherosclerosis or hardening of the arteries.3,6

In addition to having a healthful fatty acid profile, virgin hemp seed oil contains 3,922 to 6,719 mg/kg of phytosterols, including beta-sitosterol, which has been linked to decreased cholesterol levels.10,12,19 Phytosterols are plant-derived compounds similar in structure and function to cholesterol that have been linked to decreased incidence of CVD because of their ability to lower both total cholesterol and LDL.10,19,20 Similar to the imbalance of omega-3 to omega-6 fatty acids, modern Western diets are low in phytosterols. It's thought that early human diets were rich in these compounds, perhaps providing as much as 1 g per day.20 Clinical trials demonstrate that 0.8 g of plant sterols or stanols lower LDL cholesterol by inhibiting cholesterol absorption and helping clear circulating levels.20 Humans can't synthesize phytosterols as they can cholesterol, so dietary intake is critical for health.20 Hemp seed oil and hemp seed meal can be used to exert inhibitory effects on cholesterol intake and increase cholesterol excretion in humans.10,12

Intake of hemp seeds has been linked to significantly decreased mean fasting LDL and increased HDL levels in animal studies.17 In a 20-day study on hemp seed feed on rats, HDL increased significantly (p=0.01) and LDL reduced significantly (p=0.00).17 Note, in this study, triglyceride and cholesterol levels were reduced, but not significantly (p=0.165 and p=0.387).17 Because elevated LDL cholesterol and low HDL cholesterol are significant factors for coronary artery disease, more studies such as this are needed to determine possible therapeutic effects on humans.6,17 These researchers hypothesize that the presence of soluble fibers and PUFAs could explain the positive effects of hemp seeds on their subjects.17

Blood Pressure
In vitro and in vivo animal studies have shown that peptides from hemp seed powder inhibited angiotensin-converting enzyme (ACE), a substance that narrows blood vessels, and renin, which can increase blood pressure through sensors in the kidneys.14 Hemp seed protein hydrolysates, or partially broken down proteins that have been exposed to heat, acid, or enzymes that break the bonds linking the amino acids, were tested on two enzymes that regulate human blood pressure: renin and ACE. Researchers observed that in vitro or in a petri dish the hemp seed protein hydrolysates inhibited both renin and ACE. The hydrolysates were then given orally to hypertensive rats. The researchers observed that systolic blood pressure in the rats decreased a statistically significant amount (p<0.05).15

Dermatitis
Hemp seed oil has been used to treat atopic dermatitis in humans because of its balanced omega-6 and omega-3 profile.6 According to Callaway and colleagues, a 20-week randomized, single-blind crossover study of 20 patients comparing the effects of 30 mL (2 T) of olive oil or hemp seed oil daily found statistically significant improvements in plasma GLA levels (p<0.05).6 Subjective decreases in dermatitis symptoms including skin dryness and itching proved statistically significant in the hemp seed oil group (p=0.027 and p=0.023).6 Furthermore, the hemp seed intervention group reported a decrease in the need for dermal medication to treat dermatitis symptoms (p=0.024).6 No improvements in symptoms were reported in the olive oil intervention group. Olive oil and hemp seed oil differ considerably in fatty acid profile; hemp seed oil contains more than 80% PUFAs including GLA and SDA, while olive oil contains mainly MUFAs and completely lacks GLA and SDA.6 This study had several limitations, including a small size of only 16 patients finishing the study, the vast majority of whom were female. Though the sample size wasn't representative, the findings were significant and could suggest the potential for future studies on this simple dietary intervention for atopic dermatitis.

Protein
Hemp seeds are well recognized as a rich protein source, second only to soybeans in plant-based protein content.3,5,8,17,19,21 Hemp protein may be superior to soybean protein because it doesn't contain the trypsin inhibitors that reduce protein absorption.17 Furthermore, because hemp seeds don't contain oligosaccharides, they may increase digestibility when compared with soy products.17 Studies including research on hemp seeds, hemp protein powder, and hemp protein isolate have found that hemp seed protein is rich in proteins albumin and edestin, both rich in essential amino acids.8

When compared with soy protein isolate and casein, a dairy-derived protein, hemp protein isolate had similar or higher levels of aspartic acid, glutamic acid, serine, arginine, leucine, phenylalanine, and lysine.5 Except for sulfur-containing amino acids and lysine, hemp protein isolate is similar or superior in all other amino acids.5 Hemp seeds are particularly rich in amino acids methionine and cysteine.5,8 The amino acid profile of hemp seeds is comparable to both soybeans and egg whites.19 For all of these reasons, hemp protein powder is commonly used as a dietary supplement and is easily accessible in the protein powder market.

Industrial and Environmental Considerations
Hemp has many industrial uses. It can be used as an ingredient in printer's ink, wood preservative, varnish, detergents, and soaps.1,4 Because of its PUFA ratio, hemp often is used in cosmetics and lotions.4 Hemp seed is used in animal feed, with studies noting it as a valuable food source for farm animals.19 Hemp seed feed has been shown to improve the omega-3 profile of eggs when fed to laying hens.8 It's also proven to be a good source of protein in feed for cows and sheep.8 Hemp seed meal shows promise for farmed fish feed.8 Some researchers refer to hemp as an "emblematic example of a multipurpose crop" because of its many uses.2

Hemp fiber from the stalk of the plant is used in clothing, netting, and paper.1,4 The plant dry matter of hemp is composed of the carbohydrate polymers cellulose and hemicellulose combined with polymer lignin, making it a renewable resource and biomass source that can be used for building materials, fuel, and insulation.1,2 Because hemp grows much more quickly than do trees, it can provide much higher quantities of material in a shorter amount of time.2 It can be used as a lightweight, high strength-to-weight ratio building material and insulator because of its cellulosic and woody fibers.2 Industrial hemp products include hemp-lime concrete and stucco.1 Because of their insulating as well as antibacterial properties, hemp fibers are used for animal bedding.2

Cannabis plants can survive in any province or state in North America, though domesticated varieties prefer a moderate climate with more water than wild varieties.1 Hemp production prefers soil similar to that in which corn is grown—well-aerated loam soil. Fertility requirements for hemp are similar to high-yielding wheat crops. Hemp scores high in biodiversity, second only to crops such as alfalfa. It doesn't require as many pesticides as other crops and produces environmentally friendly manufactured final products.1 Furthermore, it's a crop with good resistance to drought and pests.2 Currently, Kentucky and Ontario are major growing regions for hemp.1

Moreover, hemp plants are included in plants used for phytoremediation of soil contaminated with heavy metals such as cadmium, zinc, and iron.3,11,22 Phytoremediation is the use of living green plants for environmental benefit in removing contamination. It's considered a low-cost, low-energy cleanup technique. Studies show that the leaves of plants store large quantities of metal while seeds contain a lower amount, making hemp seeds likely safer to eat when considering environmental contamination.3

It's also possible to use hemp seed oil as biodiesel fuel by converting it through transesterification with methanol or ethanol.1,23 Hemp seeds have a high seed yield and contain a high oil content.23 These properties paired with a low cultivation cost and low environmental impact for growing make hemp a viable option for biodiesel creation.23 Hemp biodiesel meets industry standards for quality fuel and contains desirable properties such as low cloud point and low kinematic viscosity.23 It also has a lower freezing point, making it potentially advantageous for biodiesel engines in cold climates.

Challenges
Omega-3 fatty acid content among plant seeds, including hemp seeds, varies, so understanding how much of these compounds a serving contains is difficult to determine. One study by Kuhnt and colleagues found that yielded oil content of seeds is dependent on variables such as oil extraction procedures and growing conditions including climate, soil cultivations, and degree of ripeness.18

As with any other type of food, it's possible to be allergic to hemp seeds. However, since hemp seeds and fiber aren't in the ragweed family, anyone with this common allergy will be safe. In a very small study done on laboratory personnel, IgE-mediated hypersensitivity reactions to hemp, including symptoms such as allergic rhinitis, asthma, and cutaneous symptoms, were observed.24,25 There have been sporadic reports of allergic reactions to hemp products consumed in restaurants, but it's more commonly associated with recreational drug use.24 Industrial hemp dust exposure may be a concern for occupational small airway lung disease, which is associated with textile dust exposure in work environments.25

Hemp seeds and oil have relatively short shelf lives and are subject to rancidity and oxidative deterioration.1,13 Hemp seeds contain high levels of chlorophyll, thereby requiring light protection upon harvest.8,13 Hemp seeds and oil have a propensity to go rancid more quickly than do similar products. Virgin hemp oil is dark in color due to the chlorophyll in the seeds that it's extracted from. In Russia, hemp seed oil is referred to as "black oil" because of the color and can have a slightly bitter aftertaste.8 A participant in one study dropped out due to the unpleasant taste of the product when taken orally.6 Hemp products in the diet require special treatment and care for these reasons. Because of the delicate nature of hemp seed oil, being prone to auto-oxidation when exposed to heat or light, it isn't appropriate to heat it or cook with it at high temperatures.8

Regarding hemp as an environmentally friendly resource, there are many potential benefits but also some challenges. This crop is susceptible, as other crops are, to environmental issues such as soil erosion and depletion. Growing hemp does involve a relatively high water requirement, though studies state that it's lower than crops such as cotton.1 Given current prices and environmental incentives, hemp seed oil isn't competitive as an alternative fuel, though there's hope for this possibility in the future.1

Trace amounts of THC can be detected in foods made from hemp products, in a manner similar to the way trace amounts of morphine can be found in poppy seeds.8 Oil pressed from uncleaned seeds may have a higher THC content because cleaning the seeds removes any remaining resin.8 Seed kernels contain very low levels of THC because the majority of this compound is located on the outside of the seed hulls.9

Studies have found that there's no significant intoxication effect from consuming dietary hemp products.8 Older studies from the 1990s have raised concern about drug testing for employment and consumption of commercial hemp foods causing confirmed positive test results.9 In a small 2001 study by Leson and colleagues, 15 volunteers consumed four different THC doses from 0.09 to 0.6 mg for 10 days in an effort to mimic the possible consumption through hemp food products on the market at that time.9 After daily ingestion of up to 0.45 mg THC in oil, these participants' urine samples didn't test positive for the substance. Daily THC intake of 0.6 mg resulted in urine concentration of one-third the cutoff used by most private employers (15 ng/mL) and is the suggested limit according to these researchers to be safe from risk.9 As a reference, 0.6 mg/day of THC from food sources equals 125 mL hemp oil containing 5 μg/g or 300 g of hulled seeds at 2 μg/g.9

Putting It Into Practice
It's important to help consumers differentiate hemp and marijuana products. Hemp is used as a food source and in industry, while marijuana is used medically and recreationally.1 Hemp seeds are washed and cleaned as part of processing. THC isn't found in hemp seeds that have been properly cleaned.17 Dietary hemp products have many potential health benefits including providing a variety of minerals and antioxidants, PUFAs and plant sterols, fiber, and protein; they can be included safely in the diet in a variety of ways.

Hemp seeds can be eaten raw, cooked, or roasted; there's evidence that prehistoric humans consumed hemp seeds in these ways.8 Hemp is consumed in many forms, including ground into protein powder, flour, or meal. Because hemp products don't contain gluten, these flours are a good alternative to wheat products. It can be used as a plant-based milk or oil, providing a nutty taste.13 Raw hemp seeds can be consumed as a topping or garnish and in cereals. Try advising your clients to add hemp seeds to granola or other recipes for a boost of nutrition and complexity in texture. They also can include them in homemade energy and protein balls or bars and incorporate them in muffins, breads, and cookies. Raw or roasted hemp seeds can be sprinkled on salads or used in dressing for added texture and nutrients. Because of their relatively soft texture, raw hemp seeds also can be added to smoothies.

Hemp products likely will be showing up on grocery store shelves more in the future, and consumers can be encouraged to experiment with these products. Unless a client has an allergy to hemp products, hemp seeds and oil are healthful and safe additions to the diet. According to Leizer and colleagues, "The value of hemp seed oil is only beginning to be recognized in the marketplace" and will be of increased interest to the mainstream consumer in future functional food trends.10

— Ginger Hultin, MS, RDN, CSO, is a nutrition and health writer and certified specialist in oncology nutrition in Seattle. She's immediate past-chair of the Vegetarian Nutrition Dietetic Practice Group, past president of the Chicago Academy of Nutrition and Dietetics, and author of the blog Champagne Nutrition.


Learning Objectives

After completing this continuing education course, nutrition professionals should be better able to:
1. Discuss the nutritional composition of hemp seeds.
2. Describe three potential health benefits of hemp seeds.
3. Assess the environmental and sustainability benefits of adding hemp seeds to the diet.


CPE Monthly Examination

1. Hemp seeds are higher than other seeds in which type of fatty acid?
a. Alpha-linolenic acid
b. Stearidonic acid
c. Gamma-linolenic acid
d. All omega-3 fatty acids

2. In which fatty acid is hemp oil richest?
a. Monounsaturated
b. Polyunsaturated
c. DHA
d. EPA

3. Which is true for regulations concerning growing hemp?
a. It remains illegal in both the United States and Canada.
b. The United States must import all industrial hemp from the European Union.
c. Growing hemp is now legal in the United States, but not in Canada.
d. Growing hemp is legal but heavily regulated in the United States and Canada.

4. Which of the following describes hemp protein isolate as compared with soy protein isolate?
a. It's significantly lower in essential amino acids.
b. It's not comparable because the species differ too much.
c. It's similar in essential amino acids.
d. It's significantly higher in essential amino acids.

5. Hemp seeds are uniquely rich in which antioxidant?
a. Gamma-tocopherol
b. Beta-carotene
c. Allyl sulfides
d. Stearidonic acid

6. How did the study by Callaway and colleagues characterize hemp seed oil as compared with olive oil?
a. As producing no significant improvement in atopic dermatitis symptoms
b. As performing equally well in reducing both skin dryness and itchiness
c. As decreasing atopic dermatitis symptoms but unreliably so due to small sample size or participants
d. As causing statistically significant improvements in atopic dermatitis symptoms

7. Phytosterols can cause which of the following health outcomes?
a. Decreased HDL cholesterol
b. Decreased LDL cholesterol
c. Increased blood methionine
d. Increased triglycerides

8. Which is not a common culinary use of hemp products?
a. Hemp milk as a plant-based milk alternative
b. Hemp protein powder
c. Hemp leaves as a salad green
d. Hemp seeds in granola

9. Which is true about possible intoxicating effects of dietary hemp?
a. All forms of dietary hemp pose a risk of psychoactive effects of THC.
b. Properly cleaned seeds contain no intoxicating effects.
c. The stems of hemp fibers contain the majority of this plant's psychoactive compounds.
d. Because hemp doesn't contain THC, it isn't intoxicating.

10. What is phytoremediation?
a. A farming technique unique to hemp plants
b. An extraction process to separate blood pressure-lowering amino acids from hemp seeds
c. An oil-free hemp-based cosmetic product
d. The use of living green plants for environmental benefit in removing contamination


References

1. Cherney JH, Small E. Industrial hemp in North America: production, politics and potential. Agronomy. 2016;6(4):58.

2. Andre CM, Hausman JF, Guerriero G. Cannabis sativa: the plant of the thousand and one molecules. Front Plant Sci. 2016;7:1-17.

3. Mihoc M, Pop G, Alexa E, Radulov I. Nutritive quality of Romanian hemp varieties (Cannabis sativa L.) with special focus on oil and metal contents of seeds. Chem Cent J. 2012;6(1):122.

4. Oomah BD, Busson M, Godfrey DV, Drover JCG. Characteristics of hemp (Cannabis sativa L.) seed oil. Food Chem. 2002;76(1):33-43.

5. Tang CH, Ten Z, Wang XS, Yang XQ. Physicochemical and functional properties of hemp (Cannabis sativa L.) protein isolate. J Agric Food Chem. 2006;54(23):8945-8950.

6. Callaway J, Schwab U, Harvima I, et al. Efficacy of dietary hempseed oil in patients with atopic dermatitis. J Dermatolog Treat. 2005;16(2):87-94.

7. Zuardi AW. History of cannabis as a medicine: a review. Rev Bras Psiquiatr. 2006;28(2):153-157.

8. Callaway JC. Hemp seed as a nutritional resource: an overview. Euphytica. 2004;140(1-2):65-72.

9. Leson G, Pless P, Grotenhermen F, Kalant H, ElSohly MA. Evaluating the impact of hemp food consumption on workplace drug tests. J Anal Toxicol. 2001;25(8):691-698.

10. Leizer C, Ribnicky D, Poulev A, Dushenkov S, Raskin I. The composition of hemp seed oil and its potential as an important source of nutrition. J Nutraceuticals Funct Med Foods. 2000;2(4):35-53.

11. Wang XS, Tang CH, Chen L, Yang XQ. Characterization and antioxidant properties of hemp protein hydrolysates obtained with Neutrase. Food Tech Biotech. 2009;47(4):428-434.

12. Lee MJ, Park SH, Han JH, et al. The effects of hempseed meal intake and linoleic acid on Drosophila models of neurodegenerative diseases and hypercholesterolemia. Mol Cells. 2011;31(4):337-342.

13. Matthäus B, Brühl L. Virgin hemp seed oil: an interesting niche product. Eur J Lipid Sci Tech. 2008;110(7):655-661.

14. Girgih AT, He R, Malomoa S, Offengenden M, Wu J, Aluko RE. Structural and functional characterization of hemp seed (Cannabis sativa L.) protein-derived antioxidant and antihypertensive peptides. J Funct Foods. 2014;6:384-394.

15. Malomo SA, Onuh JO, Girgih AT, Aluko RE. Structural and antihypertensive properties of enzymatic hemp seed protein hydrolysates. Nutrients. 2015;7(9):7616-7632.

16. Simopoulos AP. The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomed Pharmacother. 2002;56(8):365-379.

17. Karimi I, Hayatghaibi H. Effect of Cannabis sativa L. seed (hemp seed) on serum lipid and protein profiles of rat. Pakistan J Nutr. 2006;5(6):585-588.

18. Kuhnt K, Degen C, Jaudszus A, Jahreis G. Searching for health beneficial n-3 and n-6 fatty acids in plant seeds. Eur J Lipid Sci Technol. 2012;114(2):153-160.

19. Lee MJ, Park MS, Hwang S, et al. Dietary hemp seed meal intake increases body growth and shortens the larval stage via the upregulation of cell growth and sterol levels in Drosophila melanogaster. Mol Cells. 2010;30(1):29-36.

20. Phytosterols. Oregon State University Linus Pauling Institute website. http://lpi.oregonstate.edu/mic/dietary-factors/phytochemicals/phytosterols. Updated March 2017.

21. Malomo SA, He R, Aluko RE. Structural and functional properties of hemp seed protein products. J Food Sci. 2014;79(8):C1512-C1521.

22. Phytoremediation: an environmentally sound technology for pollution prevention, control and remediation. United National Environment Programme website. http://www.unep.or.jp/Ietc/Publications/Freshwater/FMS2/1.asp. Accessed November 27, 2016.

23. Li SY, Stuart JD, Li Y, Parnas RS. The feasibility of converting Cannabis sativa L. oil into biodiesel. Bioresour Technol. 2010;101(21):8457-8460.

24. Herzinger T, Schöpf P, Przybilla B, Ruëff F. IgE-mediated hypersensitivity reactions to cannabis in laboratory personnel. Int Arch Allergy Immunol. 2011;156(4):423-426.

25. Ocampo TL, Rans TS. Cannabis sativa: the unconventional "weed" allergen. Ann Allergy Asthma Immunol. 2015;114(3):187-192.

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