You're lying in bed, and you can't sleep. If you think a little midnight snack might help to "soothe" your nerves, perhaps you should think again. While an occasional midnight raid on the refrigerator poses no threat to health for most of us, as a habitual pattern to combat sleeplessness, Night Eating Syndrome (NES) can play a powerful and destructive cyclical role in individuals battling obesity, affecting as many as one quarter of severely obese individuals.
In a recent report of a collaborative effort involving behavioral and endocrine studies conducted in the United States and Norway, researchers shed new light on NES. The article, published in JAMA, suggests that NES - characterized by nightly binging to combat stress and insomnia, followed by morning-after bouts of anorexia - may be deeply rooted in stress-related hormonal imbalances.
Researchers from the Weight and Eating Disorders Program at the Department of Psychiatry of the University of Pennsylvania School of Medicine evaluated 10 individuals with NES. These individuals consumed over 50% of their food calories after 6 p.m. In addition, their sleeping and mood patterns differed greatly from controls, with mood falling steadily after 4 p.m., and nightly awakenings averaging 3.6 times per night.
Looking for possible biochemical triggers underlying this pattern, scientists from the Clinical Research Department and the Laboratory of Gastroenterology of the University Hospital in Tromso, Norway examined the hormone activity of NES patients (12 night eaters and 21 controls) over the complete light-dark cycle. They found that the night eaters - both normal and overweight - had significantly lower melatonin levels during the night than did the controls. Since melatonin levels normally rise at night to induce and sustain sleep, this may explain why NES patients wake up more frequently at night.
NES has been linked to hormone imbalances; high cortisol, low melatonin and leptin may make things worse. Leptin, the "hunger hormone" which rises at night to suppress appetite, was also lower in the NES patients, partly explaining their nocturnal food cravings. This "distinctive neuroendocrine pattern" in individuals with NES may provide the key to more successful treatment, said the researchers.
Therapy to increase the natural nocturnal rise in melatonin, reduce the body's adrenal stress response and raise leptin levels or improve leptin sensitivity are options that may help these patients overcome the disorder. Another key may involve the availability of tryptophan, an important amino acid, in the body. More than 70% of the nighttime eating to combat anxiety involved binging on carbohydrates. These foods are believed to increase the amount of tryptophan available for conversion to serotonin, the calming neurotransmitter in the brain that promotes an overall sense of well-being and, in turn, converts to melatonin.
NOTE: Addressing hormonal and biochemical imbalances in patients with chronic eating and mood disorders can be crucial for uncovering fundamental causes and contributing factors that underlie cyclical, habitual patterns of insomnia, overeating, and depression.