Food For Sleep: nutrition, circadian rhythms and understanding melatonin
Updated: Sep 12, 2020
Can nutrition or certain foods benefit our sleep? Absolutely. We just need to understand our sleep processes - our circadian rhythm and the hormones involved in order to know what our bodies need for these to function well.
Sleep and Stress Hormones
Melatonin is our main sleep inducing hormone, produced in larger amounts in the evening and overnight, reducing towards the morning and low during the day.
Melatonin has an inverse relationship to cortisol (one of our main stress/alert/awake hormones). Cortisol lowers overnight and peaks in the morning to keep us alert and awake.
When we are stressed and overthinking, our cortisol can remain too high, not allowing melatonin to do it's job at night by encouraging a deep and restful slumber.
One of the reasons that stress reduction and relaxation apps are so effective for insomnia, is that they help our bodies to lower cortisol naturally, and in doing this we allow melatonin to do it's job.
This takes us out of sympathetic nervous system dominance (fight or flight) and in to parasympathetic nervous system dominance (rest and digest).
The cycles of these hormones are central to the concept of circadian rhythm. One of the baseline requirements and central pillars for human health.
We are not naturally nocturnal creature - our biology is wired for wakefulness during the day, restorative sleep at night. And when these cycles are in a healthy rhythm, so too are our other cycles - menstruation, fertility and rhythms of mood. We are going with the flow, not against it.
So in lining all of those things up, indirectly melatonin is vital for healthy cycles. It is also an important anti inflammatory and immune regulator, and is often prescribed as a supplement by integrative doctors for inflammatory conditions such as endometriosis, as well as for onset insomnia.
How is melatonin produced?
We create the majority of melatonin in the pineal gland, located close to the centre of our brains.
A tiny, pine cone shaped structure, the pineal gland was the last of the endocrine (hormone producing) glands to be discovered, and so for a long time the job of this little gland was not fully understood.
It was once dubbed “the third eye” and in the 1600’s believed by some such as French philosopher, scientist and mathematician René Descartes to be the “principal seat of the soul, and the place in which all our thoughts are formed” , a theory later dismissed by scientists.
We understand it’s main job to be the secretion of melatonin, detection of light (by signals sent from the eye to the pineal gland) and the subsequent regulation of circadian rhythm.
All hormones in the body need to be made from other molecules. Melatonin is made from an amino acid called tryptophan, which is then converted into 5htp, then into serotonin and onto melatonin.
There are some very important nutrients required for all of these conversions to occur including iron, folic acid, magnesium, B6, zinc and vitamin C.
This is how we look at which foods might help with melatonin production and sleep.
To convert serotonin to melatonin the body needs darkness. This is one of the reasons that strong light exposure in the evenings can be detrimental, and blocking blue light can be beneficial.
In fact, for very simple enhancement of melatonin and support for the pineal gland - make sure you are exposed to natural light in the mornings, dim light in the evenings, and darkness while sleeping.
Melatonin Containing Foods
Up until the 1970’s it was thought that melatonin was only produced by animals (for their own sleep, we do not ingest melatonin when ingesting animal products), however melatonin has since been found in varying degrees in all plants which have so far been studied. Most plants only contain small amounts, with the highest levels found in -
Sour/tart cherries (different to our summer cherries)
Tryptophan Containing Foods
The amount of melatonin in foods is quite small (tart cherries take the cake), however looking at how our bodies can make their own melatonin and providing the ingredients will greatly increase this hormone (and help with the mood regulating neurotransmitter serotonin - win, win).
Trytophan is an amino acid, a component of protein so these high protein foods are all high in tryptophan -
Nuts and seeds
Magnesium containing foods
Magnesium helps with the conversion of tryptophan to 5htp, and 5htp to serotonin.
It is also incredibly important for the production of GABA - or prominent “calming’ neurotransmitter which can tell cortisol to chill the hell out.
Magnesium has a tendency to be quite depleted in Australian soils due to the age of our continent, and modern farming practices so this is often a nutrient I might consider supplementing in times of greater demand - ie prolonged or acute stress, anxiety, the postnatal years and with increased muscle demand (ie sports people).
Magnesium can be found in -
Spinach and silverbeet (and other dark green veg but particularly high in these two)
Seeds - pumpkin, hemp, sunflower, sesame, chia
Legumes - white beans, lima beans, kidney beans, chickpeas, lentils
Grains - rice, quinoa, buckwheat
Nuts - Brazil nuts, cashews, almonds, pine nuts, walnuts
Dark chocolate (yes!) - go for 70% cocoa solids or higher
Smaller amounts in avos, bananas, greek yogurt
Iron, folic acid, B6, zinc and vitamin C are the other cofactors we discussed. Here's a quick snapshot of where to find these guys -
Iron - red meat, poultry, fish and seafood, dark green veggies, parsley
Folic acid - dark green veg, asparagus, citrus fruit
B6 - red meat, poultry, fish and seafood, dark green veggies, bananas
Zinc - oysters, red meat, poultry, fish and seafood, nuts and seeds, dark green veggies
Vitamin C - citrus fruit, kiwi fruit, berries, red capsicum, green veggies, herbs
Best to eat before bed?
Recommendations are often made to get these sleep assisting foods in before bed, however as long as you are providing the ingredients - your very clever body will decide what to do with them and when, and eating too close to bedtime can disturb sleep so I am not too worried about making sure these are evening snacks.
In short, a variety of foods throughout the day should ensure you are getting enough ingredients, coupled with a healthy sleep routine and supporting your body in creating natural circadian rhythms will polish of the job.
Just another example of how a broad, varied and sensible wholefoods based diet that is not too restrictive is a great place to start if confused about eating for health and hormones (notice how sugar, additives and other foods chemicals never make these lists? Funny that :) )