Melatonin and Seasonal Affective Disorder

Melatonin is a hormone released by the pineal gland, which is located at the base of the brain. Melatonin is naturally found, in small amounts, in grains, fruits, vegetables, and some meats. In the brain, it is manufactured by the amino acid tryptophan (which also makes serotonin-the antidepressant neurotransmitter). Melatonin plays a central role in the natural sleeping/waking cycle. The production of melatonin is directly influenced by exposure to light. Normally, its level rises in the mid to late evening (as the light fades), causing lethargy, and declines in the morning (with the appearance of light), giving a natural wake-up call.

Irregularity in melatonin production can lead to Seasonal Affective Disorder (SAD), more popularly known as winter depression. It happens usually during the shorter winter days when the earlier arrival of evening triggers an earlier (or sometimes later) production of melatonin in the body. Symptoms associated with SAD include:

Depression
Fatigue
Lethargy
Anxiety
Craving for Carbohydrates

To cope with the SAD symptoms, patients are advised to have one to two hours of exposure to bright, ultraviolet light, available at various stores. During the winter months, SAD patients should use these lights daily in the early evening. On the other hand, patients suffering from insomnia should avoid bright lights, about 2 to 3 hours before bedtime. In addition, they may choose to supplement their melatonin level by nutritional means. Following foods naturally contain melatonin:

Oat
Sweet Corn
Barley
Rice
Tomatoes
Bananas

Foods that decrease melatonin level include: alcohol, caffeine (coffee, chocolate, and tea), tobacco, extra vitamin B12 sources.