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.7 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 flax, 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.8
An unidentified compound or compounds from an extract of hemp seeds has been shown to promote memory, learning, and immune function in mice.9, 10 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.11, 12 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.13