Tuesday, June 23, 2015

Melatonin and Food

As a nation, we’re tired. About 35% of American adults get less than 7 hours of sleep each day, according to results from the Behavior Risk Factor Surveillance System survey reported by the Center for Disease Control in a Morbidity and Mortality Weekly Report. Our national lack of sleep may be related to our plugged-in way of life, irregular work schedules, and conditions like obstructive sleep apnea and insomnia. Inadequate sleep is associated with increased risk of car accidents, problems at work, and chronic health issues like obesity, type 2 diabetes, heart disease and depression.(CDC-Sleep)

As a nation, we like quick fixes and food. It is not surprising that a June 22, 2015 search of  “melatonin and food” yielded 795,000 hits. Here are but a few examples of what I found:

Can you eat your way to better sleep? Is there melatonin lurking in your food? Is the key to a good night of sleep just a matter of eating certain foods before bed? 

Overview of melatonin


Melatonin is a hormone produced by the pineal gland. When light hits the eyes signals are sent from the retina to the hypothalamus in the brain. 

"Circadian rhythm labeled" by National Institute of General Medical Sciences - Circadian Rhythms Fact Sheet. Licensed under Public Domain via Wikimedia Commons - https://commons.wikimedia.org/wiki/File:Circadian_rhythm_labeled.jpg#/media/File:Circadian_rhythm_labeled.jpg

In the hypothalamus, there is a region called the suprachiasmatic nucleus (SCN). The SCN acts as our biological clock. 

  • The SCN responds to signals from the retina by transmitting messages throughout the body, including the pineal gland. 
  • The SCN tells the pineal gland to stop producing and sending out melatonin in response to environmental cues such as light. Cues like light tell the brain it is time to be awake.
The body's production of melatonin is impacted by the environment. Melatonin production can be inhibited by natural sources of light like the sun as well as artificial sources of light like indoor lighting, televisions, computer monitors, and phone screens. 
  • As daytime fades and the body's exposure to light diminishes, the SCN proportionately reduces how much inhibitory signals it sends to the pineal gland. This allows the pineal gland to start producing and releasing melatonin. 
  • As melatonin levels gradually rise in the blood, the body begins to prepare for sleep. You start to feel drowsy. 
    • This is when the body is ready to prepare for sleep but we often don't (can't) listen to those signals.
  • Melatonin levels remain high through the night and start to fall away in the early morning. 
The body works very hard to maintain its 24-hour body clock – its circadian rhythm – and the pineal gland and melatonin are one part of a greater system. For more information about the pineal gland, melatonin, and SCN, check out the Howard Hughes Medical Institute.org: Biointeractive - Human SCN . Here is information about circadian rhythms and non-24 hour clocks in people who are totally blind National Sleep Foundation: Non-24, facts and prevalence.


Are there foods I can eat to increase my melatonin levels?

Many foods contain melatonin. The amount of melatonin in foods is small and varies from crop to crop and animal to animal (Peuhkuri K. et al.) According to a web-post by Garcia Ray at the Cleveland Clinic Wellness, cherries, corn, red grapes and bananas are examples of foods with melatonin. The melatonin produced by the pineal gland drives the melatonin levels in the blood. The melatonin the body makes has the greatest influence on your melatonin status. It remains unclear what (if any) impact melatonin from food has on the human body.

When I searched foods and melatonin, I found articles that emphasized bananas, oats, oranges, tomatoes, almonds, walnuts, fish, milk, and cherries. For most people, these are good foods to include as part of healthy lifestyle. At this time, there isn’t research to support eating these foods for their melatonin content or melatonin boosting potential. 

Some writers suggested eating or drinking these foods as dessert or before bed. That is an individual decision based on your dietary preferences and health. Regardless of whatever and whenever you eat, remember that what you eat and drink contributes to your overall daily nutrient and calorie intake. It doesn’t matter if it is part of a bedtime snack, dessert, dinner, etcetera. It can be easy to forget to make room in your eating plan for something new. Tart cherries get more attention in research and public media than some other foods regarding their melatonin content. One cup of tart cherry juice may contain just as many calories as a can of regular soda (around 100 to 120 calories). If you changed nothing else in your life but added one cup of tart cherry juice every day, then that could easily lead to 5 to 12 pounds of gradual weight gain over one year.  

Final thoughts


Going to bed and waking up at consistent times, controlling the light sources in your environment, getting regular exercise, and engaging in meditation and relaxation are techniques that promote better sleep. Currently, there isn't evidence to support eating certain foods to increase human melatonin levels. 



Please discuss any concerns you have about the quantity or quality of your sleep with your primary healthcare provider. 

An example of sleep from an expert.


Citations

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