Shelled Hemp Seed

Common names: Hemp seed, hemp fruit, huo ma ren

Botanical names: Cannabis sativa, Cannabis indica

Parts used and where grown

Hemp is a form of the same plant as marijuana that generally has much lower levels of the psychoactive cannabinoid compounds. The seed and seed oil have probably been used for food, cooking, and lamp oil in Asia and North Africa for millennia. Hemp is believed to come from China. The nutty seeds normally have a hard shell which has to be removed to make it edible. Today, in order to be legal in most countries, the seeds must be treated so that they cannot be planted and grown.

Shelled hemp seed has been used in connection with the following conditions (refer to the individual health concern for complete information):

Science Ratings

Health Concerns

Atherosclerosis

Attention deficient–hyperactivity disorder (ADD/ADHD)

Eczema

Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars

Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star

For a herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Historical or traditional use (may or may not be supported by scientific studies)

Hemp is known from archeological and historical records to have been used for a very long time for making fibre for clothing and ropes. The edible seeds and oil expressed from the seeds are noted in ancient Chinese medicine for their medicinal effects as well. Known as huo ma ren (literally “fire hemp seed”), hemp seed is used primarily for alleviating constipation as a bulk-forming laxative.¹ Hemp is also mentioned in ancient Egyptian medical texts such as the Ebers papyrus as well as other places for use in making rope.²

Active constituents

Hemp seeds contain oil that is relatively rich in essential fatty acids. In particular, hemp oil is a source of both the omega-3 fatty acid alpha-linolenic acid (ALA) and the omega-6 fatty acid gamma-linolenic acid (GLA). A tablespoon of seeds generally contains 3 to 4 grams of total fat, of which 70% are polyunsaturated fats and as much as 15 to 20% are ALA.³ GLA content is generally much lower at roughly 2 to 5%. ALA and GLA and other plants that contain one or both of these substances, such as linseed, borage, evening primrose, and black currant, are known or strongly believed to have benefits for a variety of inflammatory conditions, atherosclerosis, and some neurological problems. However, the benefits of hemp seed for any of these issues has not been studied. Hemp also contains natural vitamin E and a significant amount of protein.⁴

An unidentified compound or compounds from an extract of hemp seeds has been shown to promote memory, learning, and immune function in mice.⁵ ⁶ It is believed to act by stimulating a brain enzyme known as calcineurin.

Hemp seeds contain cannabinols such as delta-9-tetrahydrocannabinol (THC), the psychoactive compounds found in marijuana leaves, flowers, and seeds. The levels are generally significantly lower than those found in marijuana products, and most tests have found that volunteers fed even large amounts of shelled hemp seed or oil do not have psychological effects and do not have positive urine tests for marijuana.⁷ ⁸ However, some reports have found that some people can develop sufficient levels of THC metabolites in their urine that they would be considered to have smoked marijuana.⁹

How much is usually taken?

Typically 1 tablespoon (15 grams) of shelled hemp seed is taken twice per day.

Are there any side effects or interactions?

For most people there are no side effects, except sometimes loosening of the stool. However, some people may experience hallucinations or euphoria if they are particularly sensitive to THC or if they happen to use a brand that has somewhat higher THC levels. As the oils in hemp seed are known to inhibit platelets, anyone taking hemp seed oil with anticoagulant drugs should be aware that there is a theoretical possibility that bleeding could occur.

At the time of writing, there were no well-known drug interactions with shelled hemp seed.

References
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1. Chen JK, Chen TT. Chinese Medical Herbology and Pharmacology. City of Industry, CA: Art of Medicine Press, Inc., 2003.

2. Nunn JF. Ancient Egyptian Medicine. Norman: University of Oklahoma Press, 1996:156.

3. Fitzsimmons S. Hemp seed oil: Fountain of youth? Br J Phytother 1998;5:90–6.

4. Odani S, Odani S. Isolation and primary structure of a methionine- and cystine-rich seed protein of Cannabis sativa. Biosci Biotechnol Biochem 1998;62:650–4.

5. Luo J, Yin JH, Wei Q. The effect of calcineurin activator, extracted from Chinese herbal medicine, on memory and immunity in mice. Pharmacol Biochem Behav 2003;75:749–54.

6. Luo J, Yin JH, Wu HZ, Wei Q. Extract from fructus cannabis activating calcineurin improved learning and memory in mice with chemical drug-induced dysmnesia. Acta Pharmacol Sin 2003;24:1137–42.

7. Leson G, Pless P, Grotenhermen F, et al. Evaluating the impact of hemp food consumption on workplace drug tests. J Anal Toxicol 2001;25:691–8.

8. Steinagle GC, Upfal M. Concentration of marijuana metabolites in the urine after ingestion of hemp seed tea. J Occup Environ Med 1999;41:510–3.

9. Fortner N, Fogerson R, Lindman D, et al. Marijuana-positive urine test results from consumption of hemp seeds in food products. J Anal Toxicol 1997;21:476–81.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or chemist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires March 2007.

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