Type 2 diabetes is a chronic disorder characterized by the body's insensitivity to, and/or a lack, of insulin, a hormone produced in the pancreas that is responsible for blood glucose, or blood sugar, metabolism. If the body doesn't respond to insulin, known as insulin resistance, or it is not present, known as insulin dependence, blood glucose levels elevate. In conjunction with a poor diet and exercise habits, researchers have identified a possible link between reduced melatonin levels and an increased risk for type 2 diabetes.
Melatonin Production
The pineal gland, located in the brain, uses the amino acid tryptophan to produce melatonin, which peaks during the night when there is little light and lowers during the day. According to MayoClinic.com, melatonin levels are highest just before bedtime. Seasonal affective disorder, or SAD, occurs during the winter months when dark nights last longer. Patients with SAD experience an overproduction of melatonin, which leads to oversleeping, depression, fatigue and weight gain. Weight gain contributes to the development of type 2 diabetes.
Biological Clock
The brain controls the body's biological clock, which regulates the circadian rhythm. The circadian rhythm is a 24-hour cycle that the body identifies as periods of light and dark. When the eyes experience low light levels, melatonin receptor proteins in the eyes and brain trigger melatonin production in the pineal gland, inducing a sleepy feeling.
Melatonin and Diabetes
Researchers have possibly identified a relationship between altered genes that encipher the melatonin receptor 1 protein and reduced insulin secretion. Insulin-secreting cells contain this protein, which is why its alterations could lower insulin secretion. When insulin is not produced in quantities the body needs, blood glucose levels elevate. Uncontrolled blood glucose levels lead to the development of type 2 diabetes. A study published in "The Journal of Pineal Research" in March 2006 found that type 2 diabetics have reduced melatonin levels.
Heart Disease and Diabetes
Heart disease is the number one complication of diabetes. According to Dr. Mehmet Oz, host of The Dr. Oz Show and a professor of surgery at Columbia University, free-floating sugars in the blood stream are like "shards of glass" flowing through the blood vessels. The sugar nicks the inner lining of blood vessels, and a clot forms. If the clot dislodges, it may travel via the blood stream to an area where plaque has accumulated and lodge, causing a full occlusion, or blockage, of the blood vessel. This blockage disrupts blood flow and starves muscles and tissues of oxygen, causing necrosis, which is the premature death of living tissues and bodily cells. The location of the blockage and whether or not it dissipates dictates the severity of the damage it causes to the body.
Melatonin and Oxidative Stress
Type 2 diabetics tend to experience an increased amount of oxidative stress, which occurs when free radicals chemically react with other molecules in the body. Insulin-secreting cells are sensitive to oxidative stress. "The Journal of Pineal Research" published a study in 2009 that suggested that a daily dose of 5 mg of melatonin may reduce the damage caused by oxidative stress in elderly, type 2 diabetic patients. Additional research is needed to make a definitive connection between melatonin's antioxidant actions and the regulation of insulin secretion.
Melatonin Supplements
Melatonin supplements help restore the circadian rhythm for people who have "confused their nights and days." According to MedlinePlus, travelers suffering from jet-lag or workers with a changing work schedule and an altered sleep-wake cycle may use melatonin supplements to restore their normal sleeping patterns. People with blindness use melatonin to create a day-and-night cycle. Consult your doctor to determine if adding a melatonin supplement is right for you.
References
- The Dr. Oz Show; Put Down That Cupcake; Mehmet Oz, M.D; December 2009
- MedlinePlus: Melatonin; December 2010
- Baptist Health Systems; Melatonin; June 2011
- "Journal of Pineal Research"; Function and Expression of Melatonin Receptors on Human Pancreatic Islets; R.D. Ramracheya et al.; April 2008
- "PLOS One"; Polymorphisms Within the Novel Type 2 Diabetes Risk Locus MTNR1B Determine β-Cell Function; Harald Staiger et al.; December 2008
