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Questions About Natural Products

Hemp Oil

Hemp oil ingestion causes positive urine tests for delta 9-tetrahydrocannabinol

J Anal Toxicol 1997 Oct;21(6):482-5

Costantino A, Schwartz RH, Kaplan P.

A hemp oil product (Hemp Liquid Gold) was purchased from a specialty food store. Fifteen milliliters was consumed by seven adult volunteers. Urine samples were taken from the subjects before ingestion and at 8, 24, and 48 h after the dose was taken. All specimens were screened by enzyme immunoassay with SYVA EMIT II THC 20, THC 50, and THC 100 kits. The tetrahydrocannabinol carboxylic acid (THCA) concentration was determined on all samples by gas chromatography-mass spectrometry (GC-MS) (5). A total of 18 postingestion samples were submitted. Fourteen of the samples screened above the 20-ng cutoff, seven were above the 50-ng cutoff, and two screened greater than the 100-ng cutoff. All of the postingestion samples showed the presence of THCA by GC-MS.

I receive a few questions per month on the benefits of hemp oil. Although promoted by Dr. andrew Weil as non-narcotic, evidence suggests that levels of THC, the psychoactive component in marijuana, in in hemp oil is significantly high enough to trip convnetional drug screening tests. Another study described 4 patients who suffered gastrointestinal disorders and psychological effects after eating salad prepared with hemp seed oil.(1)

Hemp oil contains 57% linoleic and 19% linolenic acids, in the three-to-one ratio that matches our nutritional needs. These are the essential fatty acids -so called because the body cannot make them and must get them from external sources. The best sources are oils from freshly ground grains and whole seeds, but EFAs are fragile and quickly lost in processing. EFAs are the building blocks of longer chain fats, such as eicosapentaenoic and docosahexaenoic acid that occur naturally in the fat of cold-water fish like sardines, mackerel, salmon, bluefish, herring, and, to a lesser extent, tuna.

The is a lectin in marijuana (2) which, although not blood type specific, does bond to glucose, perhaps the most abundant sugar in the body. Another species of hemp have been shown to contain lectins capable of binding to galactose and fucose, raising questions about suitability in blood group O and B. (3)

Safety? Hemp oil is undoubtably safe and for some people may well be a fine source of essential fatty acids. However, if you are in the type of employment that requires periodic drug testing you may well want to avoid using it.

  1. Meier H, Vonesch HJ. [Cannabis poisoning after eating salad]. Schweiz Med Wochenschr. 1997 Feb 8;127(6):214-8. German.
  2. Tumosa CS. A lectin in the pollen of marihuana, Cannabis sativa L. Experientia 1984 Jul 15;40(7):718-9
  3. Ersson B. A phytohemagglutinin from Sunn hemp seeds (Crotalaria juncea). II. Purification by a high capacity biospecific affinity adsorbent and its physicochemical properties. Biochim Biophys Acta. 1977 Sep 27;494(1):51-60

The Ask Dr. D'Adamo internet advice column ran from 1996 to 2009, at which time Dr. D'Adamo's teaching and programming responsibilities no longer allowed him to devote time and resources to directly answering visitor questions. However we've recently reorganized this treasure-trove of material and made it again available to his readership. He occasionally posts new entries. These are marked with a NEW tag.

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