Serotonin is a neurotransmitter that carries messages in the brain regarding satiety, sleep patterns and general feelings of well being. Antidepressant drugs known as selective serotonin reuptake inhibitors, or SSRIs, are designed to alleviate the symptoms of depression by increasing serotonin levels in the brain. An amino acid called tryptophan provides a link between serotonin levels and diet. By increasing your consumption of certain tryptophan rich foods, you may be able to influence your serotonin levels.
Low Protein
Serotonin itself is not capable of crossing through the blood brain barrier, but its precursor, an amino acid called tryptophan, is. Because of this, consumption of serotonin itself can not increase levels of serotonin in the brain, but consumption of tryptophan can. You may know that tryptophan is present in turkey. The sleep inducing aftereffects of a big Thanksgiving meal are often attributed to the presence of tryptophan. However, in order for tryptophan to be converted into serotonin in the brain, it must first cross the blood-brain barrier. High protein foods such as turkey contain a lot of other amino acids besides tryptophan, and as the "Encyclopedia of Neuroscience" explains, these amino acids compete with tryptophan for transport through the blood-brain barrier and thus inhibit its ability to enter the brain and be converted to serotonin. A diet designed to increase brain levels of serotonin should include low protein sources of tryptophan.
High Carbohydrate
As Columbia University's Health Q&A Internet Service explains, carbohydrates may hold the key to increasing serotonin through dietary sources. Carbohydrate consumption has been shown to increase serotonin levels, but some of the carbohydrates that achieve this are rather unhealthy food choices, such as candies and sweets. So, that that pint of Ben and Jerry's Chunky Monkey ice cream really has improved your mood by increasing your serotonin levels. However, you also must consider what it does to your waistline and your blood glucose levels.
The mechanism by which carbohydrates affect serotonin levels is believed to involve insulin. Insulin levels spike after a high sugar meal, and insulin causes a decrease in most amino acids in the blood. Tryptophan levels, however, don't decrease. They remain in the blood, and the lack of competition from other amino acids allows them more ready access to the blood-brain barrier. The U.S. Army Research Institute of Environmental Medicine has investigated the affects of carbohydrates on serotonin levels and found that they are increased in resting subjects who consume high tryptophan levels. The Research Institute suggests that tryptophan is helpful in elevating brain serotonin levels in exercising subjects as well, and may help to improve athletic performance and decrease pain sensitivity.
Eating to Increase Brain Serotonin
Carol Kelly, coordinator of Nutrition Education at Emory University, suggests choosing complex carbohydrates, rather than simple carbohydrates, as a healthy source of tryptophan. Simple carbohydrates, such as sugary desserts and juices, deliver a mixed bag of health consequences: a quick jolt of energy, followed by a precipitous decline in alertness. Complex carbohydrates such as whole grains and sweet potatoes deliver sugar to the blood stream more slowly and offer a host of other healthy nutrients in addition to tryptophan.
References
- American Journal of Clinical Nutrition: Carbohydrate Administration During a Day of Sustained Aerobic Activity Improves Vigilance, as Assessed By a Novel Ambulatory Monitoring Device, and Mood
- Emory University Student Health and Counseling Services: Smart Food!!
- Go Ask Alice!: Serotonin and Foods?
- Encyclopedia of Neuroscience: Tryptophan
- The Franklin Institute: Nourish - Proteins
