For thousands of years, various cultures have used hemp for clothing, food and medicine -- even George Washington and Thomas Jefferson grew the plant on their farms. Today, hemp seed is used in food products and supplements, with sales of hemp protein powder increasing 21 percent from 2007 to 2008, according to the market research firm SPINS. Hemp supplement makers often target bodybuilders, but though hemp seed is rich in proteins needed for building strong, healthy muscles, it does not have any magic muscle-building properties.
It's easy to confuse hemp with marijuana because they're from the same plant family, Cannabis sativa L. However, hemp is created for industrial use from the stalks and seeds of any of the 1,000 plant varieties, whereas marijuana refers to the flowers and leaves of certain varieties that are smoked. Further, hemp seed is low in tetrahydrocannabinol, or THC, the psychoactive component in marijuana. Findings published in the "Journal of Analytical Toxicology" in 2008 showed that hemp foods in the marketplace do not contain detectable levels of THC. Despite its name, hemp seed isn't really a seed; it's a nut covered with a hard shell that can be eaten raw, roasted or ground into meal or oil. Hemp seed muscle-building supplements are typically in the form of powders or protein bars.
Whole hemp seed is high in oil and fiber, and it also contains B vitamins, vitamin E, trace minerals, and phytosterols, which are compounds that work in the intestine to lower cholesterol absorption. But it is the protein in hemp seed that is important for muscle. Whole hemp seed contains up to 25 percent protein, with more essential fatty acids than any other plant source. Hemp protein is composed of the proteins albumin and edestine, both of which are easily digested. Hemp seed oil is rich in omega-3 fatty acids, especially alpha-linolenic acid and linoleic acid. Hemp seed protein was first used as a muscle booster in the 1950s in Eastern Europe to treat the muscle wasting caused by tuberculosis.
Strength-training athletes need more protein, which a 2006 article in the "Journal of the International Society of Sports Nutrition" reported was due to increased oxidation of amino acids during exercise, the repair of damaged muscles and the need for elevated protein synthesis to build muscle tissue. AFAA Certified Personal Trainer Billy Locke says that hemp protein is the best protein for building muscle and promoting overall health because its nutrient density is greater than other protein powders. Plus, it's filled with bioavailable enzymes and good bacteria to facilitate the conversion of amino acids to muscle.
The United States is the only industrialized nation that doesn't allow industrial hemp production, although hemp byproducts are not themselves illegal. It is possible that in some cases, hemp seed could become contaminated with THC through contact with the stems and leaves during processing in amounts high enough to be detectable in urinalysis samples. Hemp seed products are prohibited by the U.S. Air Force for this reason.
Some studies have suggested a link between high protein consumption among athletes and an increased risk of kidney damage and calcium loss, but a study reported in the "Journal of the International Society of Sports Nutrition" in 2009 found the evidence to be inconclusive. Another study reported in the same journal in 2011 found that metabolic acidosis in bodybuilders, which leads to increased urinary excretion of nitrogen and calcium, could be offset by taking dietary and supplemental potassium and calcium.