Looking at our diet is an important part of tackling sleep problems. Can eating certain foods help us fall asleep?
There is a perception that eating Turkey makes you sleepy. Think about how you or your relatives fall asleep on the couch after a big Thanksgiving or Christmas dinner! The idea that Turkey makes us sleepy has some solid science behind it.
Turkey contains tyrptophan which the body uses to make serotonin, well known for affecting our mood but which also plays an important role in triggering sleep. The body uses serotonin to make melatonin, a substance which as it builds up makes us feels sleepy and is critical in our daily cycle between sleep and being awake.
In fact turkey does not contain any more tryptophan that a range of other foods. Turkey contains tryptophan because turkey is a source of protein and tryptophan is an amino acid, the building blocks of protein.
Sources of Tyrptophan
Other meats, dairy and nuts that contain protein are sources of tryptophan, some in higher amounts that turkey.
- Chicken is similar to turkey in its content and much more frequently available.
- The best meat is rabbit although hard to get hold of. Nearly as good are beef, pork or even goat.
- Cheddar is the common cheese with the highest amount of tryptophan. Cottage cheese is the best healthier alternative.
- Tuna and salmon are good sources
- For vegans or vegetarians, Tofu is a great source of tryptophan.
- Sunflower seeds, almonds and cashew nuts are also high in tryptophan.
- Porridge oats are not just for breakfast and make an ideal pre bed snack loaded with tryptophan. Make with milk and bananas to maximise the load.
- Dark chocolate also contains tryptophan. Reason enough to have a second piece!
Including these items in your meals is enough to get the amount of tryptophan you need to help with sleep. Research shows reductions in the time it takes to fall asleep can be achieved from around 1g of tryptophan and improved deep sleep from as little as 250mg (one quarter of a gram)1.
This amount can be easily achieved by eating the foods described above. For example, 4 oz of turkey breast (114 grams) will in itself provide enough. So, combining a few of the foods above in your daily cooking will ensure you get enough tryptophan.
There is some debate about how much of the tryptophan consumed from food is able cross the blood brain barrier for it to be converted in the brain for serotonin. This is because the proteins we consume in food consists of other amino acid as well as tryptophan which hinder its uptake into the brain.
This brings us back to the big Thanksgiving or Christmas dinner, both meals rich in carbohydrates – think potatoes, stuffing, cranberry sauce, desserts and all the rest. Eating carbohydrates causes the body to produce insulin which leads to the absorption of certain amino acids, but not tryptophan, into muscle. The tryptophan which remains in the blood stream can then more readily cross into the brain and lead to sleepiness.
The other reason why a meal rich in carbohydrates and especially sugar can lead to sleepiness is its impact on the Orexin receptors in the brain.
Orexin is another molecule that helps regulate the cycle between sleeping and awake. Lower levels of orexin lead to sleepiness2. Sugar inhibits orexin production. This is also why some people feel sleepy after consuming large amounts of sugar, the sugar crash.
In evolutionally terms this makes sense. If someone has eaten they can rest whereas if they are hungry they need to stay awake to find food to survive.
1. ^ Hartmann E, Spinweber CL. 1979. Sleep induced by L-tryptophan. Effect of dosages within the normal dietary intake. J Nerv Ment Dis. 167(8):497-9.
2. ^ SAKURAI Takeshi. 2007. The neural circuit of orexin (hypocretin): Maintaining sleep and wakefulness. Nature reviews Neuroscience. 8(3):171-81.