Melatonin
Melatonin is a hormone that is made in the part of the brain called the pineal gland, as well as in the gastrointestinal tract (the gut). It helps to regulate circadian rhythms and enhances sleep. Melatonin is an anti-oxidant and seems to have immune-stimulating activity in the body.
Natural light activates "light receptors", also known as photoreceptors, in the retina, which are located at the back of the eye. These receptors initiate the production of melatonin in the pineal gland, which may partially explain melatonin’s relationship with circadian rhythm. Melatonin is secreted in the evening time and levels remain high throughout most of the night. Melatonin is decreased in elderly patients. Some medications, such as some blood pressure medicines (eg, beta-blockers), may also decrease natural melatonin levels.
Since melatonin is also made in the gut, a healthy gut may be an important factor in maintaining healthy melatonin levels.
Usage
Many studies have found that melatonin has anti-cancer activity and may promote the shrinking of solid tumors. In fact, melatonin is one of the most well-researched dietary supplements in integrative oncology. This effect seems to be in part related to the immune-stimulating effects of melatonin. Melatonin also appears to support cell repair and apoptosis (death) of cancer cells. Clinical studies have found that melatonin supplementation in people with various solid tumor types leads to better tolerance of chemotherapy and radiation along with improved response to these treatments. For these reasons, melatonin is often recommended by integrative providers for people with cancer.
Outside of cancer care, the most common use of melatonin supplementation is to support better sleep and to minimize jet lag, etc.
Food Sources
There are many plant-based foods that contain melatonin. These include:
- Flax seeds
- Orange bell peppers
- Tart cherry juice
- Walnuts
- Tomatoes
- Mustard seeds
- Goji berries
- Almonds
- Raspberries
Dose
For trouble falling asleep, doses as low as 0.5 mg can be used, though melatonin can safely be used up to 20 mg nightly. Be aware that higher doses don’t necessarily help you sleep better. If you are struggling with waking in the middle of the night, you may want to try a sustained release (or extended release) formulation. Keep in mind that supplemented melatonin will not suppress your own production of melatonin nor is it addictive - therefore stopping it will not cause any withdrawal symptoms.
Side Effects
The main side effect of melatonin is fatigue, so if you are feeling groggy the next morning, try a lower dose. Melatonin can also increase dreaming in some people.
Drug Interaction
If you are taking the blood pressure medication nifedipine, some studies have found that taking melatonin at the same time may increase blood pressure and heart rate.
