- Mental Health
Depression, Lactose Intolerance, Tryptophan and Serotonin
Science and depression
Depression is more than a state of sadness. It is a condition characterized by chronic sadness and most often associated with a chemical imbalance. The most common chemical associated with depression is serotonin. This is the chemical that is adjusted within the brain by most anti-depressant medications. The mechanism of this process is not important for this article. This short article addresses the role of digestion in serotonin levels.
Serotonin production begins within the gastrointestinal tract. Serotonin is ultimately the result of the breakdown of tryptophan. I found out a few years ago as a lactose intolerant person I could not eat turkey. The consumption of turkey caused the same gastrointestinal distress as the ingestion of lactose (for me this is mostly milk and not all milk products). I began to wonder why this happened and if this could have had an effect on my mental health. I began to wonder if my inability to eat turkey and digest lactose would result in the decrease of serotonin that caused my depression (or at least contributed to it). My curiosity led me to some interesting articles with some interesting findings.
In an article by Ledochowski, Spernerunte Rweger, and Fuchs (1998), preliminary studies conducted on 30 women suggested that lactose intolerance had an effect on depression. Women with lactose intolerance scored higher on the Becks Depression Inventory than the women without the digestion problem. This article does not claim that lactose intolerance causes depression but that it can be related to higher depression scores. Not only did these women have higher depression scores but they reported irritable bowel syndrome and problems with premenstrual syndrome. This article also explores the idea that lactose malabsorption can interfere with the metabolism of tryptophan (not necessarily the kind in turkey) into serotonin, causing lower levels of serotonin in the intestines and lower level available for absorption into the blood and brain.
Depression of course has other contributing factors and the influences on brain chemistry are complex. Simply feeling sad and upset for long periods of time can affect brain chemistry. Does lactose intolerance play a role in understanding how it is that some people can be crippled by depression and overcome by more easily by feelings of sadness than others? I do not know but it would be interesting to see more studies and find out if people with lactose intolerance are more susceptible to clinical depression that those without the digestive problem.
My depression started as a child. I do not know why I was depressed as a child (could it have been due to my inability to absorb lactose). Later in life i experienced severe depression (I was hospitalized multiple times). The reason I was experiencing depression in my mid 20's was because i was dealing with the death of my father and was living in chronic pain from a car accident. I was also drinking too much and suffered from anorexia and bulimia. I often wonder if my depression was severe because of this pre-dispositon to low serotonin levels or would I have experienced the same levels of depression if my levels were normal at the time of these big life changes. I will never know and I did not start taking medications until after I tried to commit suicide. Would I have fared better had I been taking anti-depressants as a preventative medication before I experienced the death of my father. I am sure someday there will be more answers. There are so many questions when it comes to matters of physical and mental health. There are so many ways in which one influences the other.
I just thought I might bring to light one interesting study conducted linking physical sickness as a cause for mental illness. I find this link to be important in these economic times where mental health is increasingly taking a back seat to physical health. Many insurance companies do not cover mental health issues and many people do not think mental illness is a true medical problem. The increased knowledge of the link between mental and physical health (and not just physical well-being) may bring about more understanding and hope for those that need mental health care (they may just get some insurance) and make those with mental health problems feel less like they are simply a burden with no real medical problem.
Ledochowski, M., Spernerunte Rweger, B., and Fuchs, D. (1998). Lactose malabsorption is associated with early signs of mental depression in females: A preliminary report. Diseases and Science, 43, 11, p. 2513-2517.