Hemp Seeds - History, Uses, and Benefits
These are some of the most common nicknames for marijuana, a plant that when smoked or orally ingested, has mind and body-altering properties. In fact, it's the most commonly used illegal drug in the United States. 
Unfortunately, the plant that produces the drug, Cannabis sativa L, gets a bad rap. The non-drug portion, hemp, has been used for food, fiber, and medicinal purposes since 1,700 B.C. in Egypt. 
Related: The 6 Best Plant-Based Protein Sources
This article will discuss the uses and benefits of hemp seeds, a component of the cannabis plant that won't get you high but rather offers fiber, protein, healthy fats, and health-promoting properties.
Once it reaches maturity the cannabis plant is harvested and divided into two parts, the drug and non-drug portions. The drug portion contains a concentration of delta-9-tetrahydrocannabinol (THC) between 1% and 20%.  When smoked or orally consumed this concentration of THC will alter your mental state.
The non-drug portion, also known as hemp seeds, has a THC concentration of less than 0.3%.  In moderate quantities hemp seed consumption will not cause psychoactive effects nor will it cause you to fail a drug test.
Three tablespoons (30 grams) of hemp seeds provide 166 calories, 9.5 grams of protein, 14.5 grams of fat, 2.5 grams of carbohydrates, 1.2 grams of fiber, and zero cholesterol.  Hemp seeds contain all essential amino acids and are particularly high in L-arginine, an amino acid critical for nitric oxide production.  Unfortunately hemp seeds are not considered a complete protein source because of the insufficient L-lysine and relatively low L-leucine content. 
The protein digestibility-corrected amino acid score (PDCAAS) for whole hemp seeds, hemp seed meal, and dehulled hemp seeds are 51%, 49%, and 65%, respectively.  For comparison, whey and casein proteins have a PDCAAS value of 100% and rice has a value of 50%. Removing the hemp seed hull improves both protein digestibility and PDCAAS value.
Hemp seeds are also a great source of polyunsaturated fats, essential fatty acids, vitamins, and minerals. Their fat content is comprised of 56% linoleic acid (LA), 22% alpha-linoleic acid (ALA), 9% oleic acid, 5% palmitic acid, 4% gamma-linoleic acid, 2% stearic acid, and 2% Stearidonic acid. 
Linoleic acid is an Omega-6 essential fatty acid and ALA is an Omega-3 EFA. Hemp seeds contain 360mg potassium, 485mg phosphorus, 210mg magnesium, 2.38mg iron, and 2.97mg zinc per 30-gram serving.  Hemp seeds also contain an appreciable amount of the antioxidant vitamin E. By conventional convention hemp seeds are a nutrient-dense superfood.
Hemp Seed UsesHemp seeds are sold in raw, oil, and protein powder forms. Raw hemp seeds offer a nice balance of healthy fats, protein, fiber, vitamins, and minerals. Raw dehulled hemp seeds offer a more bioavailable source of protein compared to whole hemp seed or ground up hemp seeds, also known as hemp seed meal. Those who use raw hemp seeds prefer to throw one to three tablespoons in their meal replacement shake, yogurt, or oatmeal daily.
Hemp seed oil offers a concentrated source of the beneficial Omega-3 and Omega-6 fatty acids without the added fiber, vitamins, minerals, or protein. Manufacturers produce hemp seed oil by grinding down and placing the raw hemp seeds under tremendous pressure achieved only by a machine. Consume one to three tablespoons of hemp seed oil depending on your caloric needs and activity level.
Those looking to increase their fiber and protein intake may want to try hemp protein powder. Manufacturers dry, grind down, and defat hemp seeds to create a product with 15 grams of protein, 9 grams of carbohydrates, 7 grams of fiber, and 3 grams of fat per 1 scoop (30-gram serving). 
While this product is only 50% protein by weight it offers 28% of the recommended daily fiber intake as well as good amounts of calcium of iron. Since hemp seeds are low in the amino acid L-lysine, hemp protein powder is often combined with other vegan protein sources like pea, quinoa, rice, potato, or chia protein to create a blend with a complete amino acid profile.
Hemp Seed Benefits
Unfortunately, there are not many studies examining the beneficial effects of hemp seed because of legal dispute related to cannabis production. Most states in the United States prohibit the growth and harvesting of hemp seeds. Canada, Australia, Austria, China, Great Britain, France, and Spain are the largest producers of hemp seeds. 
Chances are your raw hemp seeds, oil, or protein powder is sourced from one of those countries. Thankfully there have been a handful of studies examining the benefits of hemp seeds, specifically hemp seed oil, in both animal and human models.
Hempseed will not increase the blood levels of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) seen with fish oil supplementation or alpha-linolenic acid (ALA) concentrations as seen with flaxseed oil supplementation.  However, 30 milliliters or 2 tablespoons of hemp seed oil can significantly increase blood levels of linoleic acid (LA) and Gamma-linolenic acid (GLA) as well as lower the total cholesterol to high-density lipoprotein (HDL) cholesterol ratio. 
LA and GLA are Omega-6 essential fatty acids that are not naturally produced by the human body and must be consumed through food or supplementation. A meta-analysis of fifteen studies found that linoleic acid does not negativity impact common inflammatory markers such as C-reactive protein, fibrinogen, or cytokines.  Contrary to what the fitness industry is telling you, not all Omega-6 fatty acids cause inflammation in the body.
Multiple studies on linoleic acid also support its ability to decrease blood pressure, total cholesterol, and bad cholesterol (LDL) without negatively impacting and in some cases improves good (HDL) cholesterol.  The GLA and L-arginine content found in hemp seeds offers anti-inflammatory benefits through inhibiting the increase of or decreasing C-reactive protein values. 
The anti-inflammatory benefits of oral hempseed oil consumption also carry over to the skin. A 20-week study found that daily hempseed oil consumption significantly decreases the skin's transepidermal water loss, dryness, and itchiness.  These patients used smaller and less frequent amounts of topical skin medication which saved them both time and money while improving their quality of life.
Animal studies support the use of hempseed oil for increasing polyunsaturated fatty acid content in the blood as well as normalizing blood clotting in those with high cholesterol. A 12-week rodent study found that a diet with 5 to 10% of the calories coming from hempseed oil significantly increases both Omega-3 and Omega-6 essential fatty acid levels in the blood. 
For a person eating a 2000 calorie diet, this equates to 100 to 200 calories per day coming from hemp seed oil. This averages to one or two tablespoons of hemp seed oil.
A second study fed a diet with 10% of the calories coming from hemp seed oil to animals with high cholesterol and found it helped to normal platelet aggregation, or blood clotting levels.  High cholesterol levels in the blood negatively impacts the body?s natural ability to clot blood and stop bleeding, but hemp seed oil may help to counteract those effects.
There are two small studies examining the benefits of hemp seed meal protein hydrolysate (HMH) in rodents. Young rats and adult rats with high blood pressure (hypertension) were fed a diet with between 0.5% and 1.0% of the calories coming from HMH for four and eight weeks, respectively.
Young and adult rats consuming HMH had normal systolic blood pressure at the end of the study whereas those consuming placebo (casein), did not.  Unfortunately there has not been a human study to determine if these effects carry over.
Rats consuming HMH also had significantly lower angiotensin-1-converting enzyme (ACE) and renin levels in the blood.  High ACE levels are correlated with sarcoidosis, a condition characterized by swollen lymph nodes and collections of inflamed cells throughout the body.  Chronically high renin levels may indicator improper adrenal function. 
A second study of young rats with high blood pressure examined the antioxidant effects of HMH when comprising 0%, 0.5%, or 1.0% of daily caloric intake for eight weeks. Those consuming a diet with HMH significantly increased superoxide dismutase (SOD) and catalase (CAT) levels while also decreasing total peroxides (TPx) levels. 
SOD and CAT are potent antioxidants that fight free radicals in the body. High TPx levels are correlated with oxidative stress. Hemp seed meal protein hydrolysate offers promising benefits for those with hypertension and those looking to combat oxidative stress. Additional studies are needed to determine if these effects also apply to humans.
References1) DrugFacts: Marijuana. National Institute on Drug Abuse (NIDA), National Institutes of Health, Mar. 2016, Accessed Oct. 2016.
2) Rodriguez-Leyva, Delfin, and Grant N Pierce. ?The Cardiac and Haemostatic Effects of Dietary Hempseed.? Nutrition & Metabolism 7 (2010): 32. PMC. Web. Oct. 2016.
3) Basic Report: 12012, Seeds, hemp seed, hulled. National Nutrient Database for Standard Reference Release 28, United States Department of Agriculture, May 2016, Accessed Oct. 2016.
4) Frank, Kurtis. "Hemp Protein - Scientific Review on Usage, Dosage, Side Effects." Examine.com, 2016, Accessed Oct. 2016.
5) House, J. D., et al. "Evaluating the Quality of Protein from Hemp Seed (Cannabis Sativa L.) Products Through the Use of the Protein Digestibility-corrected Amino Acid Sc..." National Center for Biotechnology Information, J Agric Food Chem, Nov. 2010, Accessed Oct. 2016.
6) Hemp Protein Powder 1lb - Organic Omega Fatty Acids. True Nutrition, 2016, Accessed Oct. 2016.
7) Kaul, N., et al. "A Comparison of Fish Oil, Flaxseed Oil and Hempseed Oil Supplementation on Selected Parameters of Cardiovascular Health in Healthy Volunteers. - PubMed - NCBI." National Center for Biotechnology Information, J Am Coll Nutr, Feb. 2008, Accessed Oct. 2016.
8) Johnson, G. H., and K. Fritsche. "Effect of Dietary Linoleic Acid on Markers of Inflammation in Healthy Persons: a Systematic Review of Randomized Controlled Trials." National Center for Biotechnology Information, J Acad Nutr Diet, July 2012, Accessed Oct. 2016.
9) Callaway, J., et al. "Efficacy of Dietary Hempseed Oil in Patients with Atopic Dermatitis." National Center for Biotechnology Information, J Dermatolog Treat., Apr. 2005, Accessed Oct. 2016.
10) Girgih, A. T., et al. "Preventive and Treatment Effects of a Hemp Seed (Cannabis Sativa L.) Meal Protein Hydrolysate Against High Blood Pressure in Spontaneously Hyperten..." National Center for Biotechnology Information, Eur J Nutr., Aug. 2014, Accessed Oct. 2016.
11) Angiotensin-Converting Enzyme (ACE): The Test. Lab Tests Online, American Association for Clinical Chemistry, 30 Oct. 2015, Accessed Oct. 2016.
12) Aldosterone and Renin: The Test. Lab Tests Online, American Association for Clinical Chemistry, 26 Feb. 2016, Accessed Oct. 2016.
13) Girgih, Abraham T. et al. ?A Novel Hemp Seed Meal Protein Hydrolysate Reduces Oxidative Stress Factors in Spontaneously Hypertensive Rats.?Nutrients 6.12 (2014): 5652?5666. PMC. Web. Oct. 2016.