How marijuana can help treat anorexia

In Top Stories by Dr. Tim Sandle, Ph.D.

Adding cannabinoids to anorexia-stricken mice helped the animals recover from the eating disorder and return to a normal weight, according to a new research report from Katholieke Universiteit Leuven in Brussels.

Cindy Casteels, a post-doctoral researcher, has also published a PhD thesis in molecular imaging of the type 1 cannabinoid receptor in movement disorders. Cannabinoids are chemical compounds found in the brain, and the most well-known cannabinoid is THC, the psychoactive compound in marijuana.

The Medical Marijuana Review spoke with Casteels about her research and its implications for anorexia sufferers.

Anorexia nervosa is an eating disorder characterized by food restriction and irrational fear of gaining weight, as well as a distorted body self-perception. Around 1 percent of American women suffer from anorexia nervosa.

Some physicians believe there could be a connection between a dysfunctional endocannabinoid system (ECS) and eating disorders. The ECS is a term given to a group of lipids and receptors that are involved in a variety of physiological processes. Casteels explains the significance of the ECS: “The endocannabinoid system (ECS), a major neurotransmission system, is involved in numerous physiological processes often related to homeostatic balance but also in neuro-protection, motor behavior, memory regulation, addiction and cognition. It consists of a family of naturally occurring lipids, the endocannabinoids, of degradation proteins and of cannabinoid receptors.”

These receptors are found in the brain, organs, connective tissues, glands and immune cells, and are produced naturally by the body. One function of the ECS, Cindy explains, helps to control the way the body reacts to certain foods and the feeling that people get from eating food (these are termed the “hedonic aspects” of eating). One type of receptor, found as part of the ECS, is called CB1, and is part of the brain region that controls food intake, reward and energy balance.

As well as being triggered by the 85 known cannabinoids found in the body, the ECS also interacts with the phytocannabinoids found in marijuana, such as the Delta-9-tetrahydrocannabinol (THC). This reaction is in a similar way to the cannabinoids present in the human body. The main ECS receptor stimulated is by THC is CB1. This is the same receptor that is linked to food intake and food enjoyment.

Casteels says that defects in the endocannabinoid system and eating disorders are interlinked. From this starting point, different areas of research – including Casteels’ new study mentioned earlier – are in progress to see if the ECS can be controlled by using stimulants to help someone overcome an eating disorder. Casteels adds: “Regarding food intake, animal studies showed that CB1 knockout mice are leaner than control mice due to reduced food intake, and the same mice are resistant to diet-induced obesity when subjected to a highly caloric diet without their energy uptake being reduced.”


To explore this further, Casteels’ research team at KU Leuven undertook studies on rats (rodents are good candidates for studying eating disorders). In the study, one group of rats were bred to be anorexic and were placed in cages with running wheels; another group were also bred to be anorexic but they were not given wheels; a third group were fed a normal diet and were given running wheels; and a final “control group” were fed normally but did not have a wheel for exercise. These various groups were designed to mimic behaviors in people.

For the simulation of anorexia, the animals were food restricted (only allowed access to limited amounts of food for short periods) and were given unrestricted access to a running wheel. This served to reproduce both the behavioral and neurophysiological conditions of anorexia nervosa. The presence of the exercise wheel was considered important because many people with anorexia tend to exercise regularly. To model anorexia, Casteels explains that “the target weight was ~85% of initial weight.”

Once the rats were returned to normal conditions, those who developed “anorexia” had reduced appetites and didn’t regain normal weight when their routine feeding and exercise patterns were returned. However, the control group, which was given cannabinoids in its feed, did recover.

The outcome of the study demonstrated the effectiveness of cannabinoids in rescuing animals from the body-weight loss associated with anorexia nervosa. The study’s results have been published in the European Journal of Nuclear Medicine and Molecular Imaging.

Further research into the effect of cannabinoids on the ECS within animals (and whether this can help to reduce the likelihood of long-term anorexia) will be required before human trials are attempted. According to Casteels: “Of special interest, we have observed a similar finding of a widespread increase in female anorectic patients, suggesting validity of our animal model to mimic human CB1 receptor alterations in anorexia nervosa.”

It’s possible that THC from medical marijuana could provide a source of cannabinoids to help with anorexia treatment, once again proving how marijuana can be an effective medicine for a harmful disease plaguing millions.

Flickr photo via user daniellehelm


Dr. Tim Sandle, PhD, is a microbiologist, specializing in healthcare and pharmaceuticals. He is also a writer and journalist who is interested in science, history, politics and current affairs. Follow him on Twitter @TimSandle