By Sophie Medlin, Consultant Dietitian (formerly at King’s College London)

Sleep has become widely recognised as playing a really important role in our overall health and wellness – alongside diet, stress management and exercise.

Recently, researchers have been learning more about how poor sleep influences our dietary choices, as well as how diet influences sleep quality. Not sleeping for long enough or poor quality sleep are associated with increased food intake, a less healthy diet and weight gain. Lack of sleep also leads to increased snacking and overeating. And it causes us to want to eat foods high in fat and carbohydrates – with increased chemical rewards to the brain when we do eat these foods.

Essentially, poor sleep drives your body to find high energy foods to keep you awake which makes fighting the cravings for unhealthy foods very difficult to resist. But, on the other hand, when we have slept well our appetite hormones are at a normal level. We don’t crave unhealthy food so much – and we can make better choices about what to eat.

The science of sleep

All cultures around the world have traditions about which foods promote sleep. Foods such as milk, chamomile, kiwi fruit and tart cherries, have all been said to work wonders for a good night’s sleep. Given how much the food we eat affects us on a day-to-day basis, it is not surprising that our diet plays such a big role in our quality of sleep. What we eat also has a big impact on our organ function, immune system, hormone production and brain function.

A really important hormone that controls our sleep patterns is melatonin. Melatonin is produced in the brain and the amount of melatonin you produce and how efficiently our brain uses it is affected by our diet. One of the biggest influence on our melatonin levels appears to be our intake of a type of protein called tryptophan. Tryptophan is an essential amino acid – the building blocks of proteins. Essential amino acids are a group which our bodies cannot make, it can only be sourced through diet.

Other nutrients that appear to be helpful for sleep include B vitamins and magnesium. This is because they help tryptophan to be more available in the body. If your diet is lacking tryptophan, B vitamins or magnesium. It is very likely that your melatonin production and secretion will be affected and your sleep quality will be poorer.

Eat to sleep

It stands to reason then that following overly restrictive diets or diets that put you at risk of nutrient deficiencies can really affect your sleep. But by increasing your intakes of foods rich in specific nutrients, it may well help to promote better sleep quality and duration.

Dairy foods, for example, can be great at helping you sleep. Not only is dairy an excellent source of tryptophan, but it also contains magnesium and B vitamins which help to promote the activity and availability of tryptophan. Nuts, like dairy, also contain all the nutrients known to promote increase melatonin production and support its release.

Fish is a great source of tryptophan and B vitamins. Fish with bones, such as sardines, will also provide magnesium. Including fish in your diet regularly may help to promote healthy melatonin production when you need it. Pulses, beans and lentils also contain high amounts of tryptophan and B vitamins. Adding some tofu or paneer to a vegetable stew or curry can also help to increase your likelihood of having a great night’s sleep. You could also add in some soya – which is another good source of tryptophan – to optimise your sleep potential.

And if you’re still struggling to sleep, it might be that you’d benefit from some meat. Meat of all kinds contains all the essential ingredients for a good night’s sleep. So if you can’t nod off at night, maybe think about adding some lean meat to your diet.

If you find yourself hungry before bed, for the ideal bed time snack, try a glass of semi-skimmed or skimmed milk, a small banana or a few nuts – all of which can really help to improve your sleep and your willpower the next day. It’s also worth pointing out that it takes around an hour for the tryptophan in foods to reach the brain, so don’t wait until just before bedtime to have your snack. And it’s also advisable to have a balanced diet that includes plenty of foods that are high in tryptophan throughout the day to optimise your chances of a good night’s sleep.

Sophie Medlin is ‎a Consultant Dietitian. She was formerly a lecturer and researcher in Nutrition and Dietetics at King’s College London and Plymouth University