Just to follow up here is an article from Sally Fallon from the Weston Price Foundation on Hemp.

Hemp: Not for Human Consumption
By Sally Fallon

A number of companies are now selling hemp oil, toasted and shelled hemp seeds and granola bars containing hemp seeds. This is not a good use for hemp. Hemp may be appropriate for domestic animals and birds, but it should not be used for human food. In China, where cultivation of hemp originated, hemp oil was used occasionally, but there are no references in the Chinese literature to the use of hemp seeds as food for human beings. (Simoons, Food in China, 1991)

Hemp oil has been promoted in recent years as a “heart healthy” oil that is rich in essential fatty acids and low in saturated fat. Hemp oil is indeed highly unsaturated, and this is exactly why it should be avoided. Hemp oil is over 75 percent polyunsaturated, containing about 55 percent omega-6 fatty acids and about 20% omega-3 fatty acids. It contains only about 10 percent saturated fatty acids and 10 percent monounsaturated fatty acids. It is, therefore, highly unstable and prone to oxidation; and the high content of linoleic acid makes it particularly unsuitable for human consumption. Diets containing an excess of polyunsaturated fatty acids, particularly omega-6 fatty acids, have been linked not only to heart disease but also to cancer and autoimmune disease.

An additional problem derives from the fact that hemp oil may contain traces of cannabinoids and these substances can then turn up in the urine of those who consume it. In one research project, seven adult volunteers purchased hemp oil from a health food store and ingested 15 milliliters each. Urine samples taken at 8, 24 and 48 hours after ingestion were positive for THC. (Journal of Analytical Toxicology October 1997 21(6):482-485.) If these volunteers had been obliged to give a urine sample to their employers, they would have failed their drug test.

Because hemp oil is highly unsaturated, it makes an excellent base for paints and varnishes. In fact, there is no need to consider hemp for human consumption except in small quantities for medicinal purposes. There are many good fats and oils that humans can use and there are many good industrial uses for all the by-products of the hemp plant. Let’s not make the same mistake with hemp that we have made with soy, by promoting its inappropriate use as a human food.