Can what I eat disrupt my sleep?

Can what I eat disrupt my sleep?

Sleep isn’t just useful for keeping us alert throughout the day - good sleep is absolutely crucial for both our physical and mental health. Lack of good quality sleep can have a real impact on our memory, mood, pain perception, immune system and more - virtually every system in our body is impacted by sleep (or lack of). Inadequate sleep can increase levels of inflammation in the body, which as you’ll know from my previous articles, is a huge player in illness, disease and recovery. So if you struggle with rheumatoid arthritis, painful periods, type 1 diabetes, gastrointestinal issues and other health problems associated with inflammation, taking a closer look at your sleep quantity and quality can be extremely valuable. Or if you're an active person who exercises regularly, you will know that paying attention to what you eat during the day has a huge impact on how you sleep, recover and therefore feel the following day. So let’s get started....

Our circadian rhythm is the body’s internal ‘clock’ and determines our sleep/wake cycle, deciding when we should be sleepy, and when we should be alert. Among others, the most crucial hormones in maintaining our circadian rhythm are melatonin, GABA (Gamma-Aminobutyric acid) and serotonin. In fact, you may have heard of melatonin being referred to as the sleep hormone, because it is the primary hormone that influences our circadian rhythm and helps us drift off into restful sleep. As well as influencing sleep, these hormones also play a role in mood regulation and calming the nervous system, which dampens the stress response (i.e. inflammation) and helps us to feel relaxed (1).

So what should you be including in your diet for good sleep?

Including high quality fats and proteins in your diet is really important. Fats (especially cholesterol) make up the structural components of hormones, so by not eating enough you can adversely affect melatonin production (2). Try to include a source of fat with each meal and snack; avocados, olive oil and olives, oily fish, nuts and seeds are all good choices as they contain unsaturated fatty acids, including the important omega-3 fatty acids (you can read more about the types of fats here) butter, ghee and coconut oil are higher in saturated fats and cholesterol and can be included, too. Amino acids (the components that make up protein) are also essential for hormone production. Tryptophan is one such amino acid that is of particular importance for sleep, as it is needed for the production of melatonin and serotonin (3), hormones crucial for both mood and sleep.

Carbohydrates are another important diet component for melatonin production - but be selective about the ones you choose. Highly refined, processed carbohydrates (such as white bread, pasta and biscuits) are broken down to sugar and released into the bloodstream very quickly, wreaking havoc on your blood sugar balance, which in turn will have a knock-on effect on your sleep quality (4). Ever wake in the middle of the night feeling anxious, and perhaps even hungry? That’s likely due to a drop in blood sugar during your sleep. To prevent this, choose starchy carbohydrates from roots, shoots and fruits to keep blood sugar balanced throughout the day and night - think sweet potatoes, white potatoes, brown rice, parsnips, pumpkins, oats and lots of colourful vegetables.

Although many vitamins and minerals are involved in circadian rhythm and sleep regulation, magnesium is one of the most crucial. Magnesium is required for over 300 cellular reactions in the body (and probably many more we don’t yet know about) - and many of us are low or deficient. As well as being required to control the body's stress response (by regulating cortisol, which can keep you awake), but magnesium also increases levels of GABA, a neurotransmitter which promotes deep, restorative sleep by calming the nervous system (5). Foods high in magnesium include nuts and seeds, such as pumpkin, chia and almonds, darky leafy greens, fish and legumes. Although it is available in a wide variety of foods, for help with sleep I often recommend supplementation to my clients as magnesium from food is not easily absorbed.

And is there anything to reduce or avoid?

Apart from the refined carbohydrates mentioned above, the other biggie is caffeine. Although in the short-term, a hot cup of coffee can give you an energy boost and make you feel more alert, if you are relying on caffeine to get you through the day, it could be having a detrimental effect on your sleep. Caffeine has a half-life (meaning it stays in your system) of up to 8 hours (6) - this means that your 4pm pick-me-up could still be keeping you wired come 11pm - hello restless sleep. This can then leave you stuck in a vicious cycle of having more caffeine the next day due to poor sleep the night before, and so it continues. Reducing your caffeine intake is one of the quickest ways to improve sleep quality. Try swapping tea and coffee for matcha (rich in l-theanine which promotes relaxation and deep sleep (6)) or caffeine-free herbal teas, and have caffeine earlier in the day. If you have a lot of caffeine during the day, reduce your intake slowly to reduce the chance of caffeine withdrawal symptoms.

If you experience issues with sleep length or quality, try a few of these suggestions and see if they help you. I’d love to hear how you get on with them and as always if you have any questions, please drop them in the comments.

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  1. Shechter, A. et al. 2010. Sleep, hormones and circadian rhythms throughout the menstrual cycle in healthy women and women with premenstrual dysphoric disorder. International Journal of Endocrinology, e259345

  2. EU Science Hub. 2020. Dietary fats. Available at: (Accessed: 23rd October 2020)

  3. Nagashima, S. et al. 2017. Can tryptophan supplement intake at breakfast enhance melatonin secretion at night? Journal of Physiological Anthropology, 36:20

  4. Roder, P.V et al. 2016. Pancreatic regulation of glucose homeostasis.Experimental & Molecular Medicine, 48:e219

  5. Kim, S et al. 2019. GABA and L-theanine mixture decreases sleep latency and improves NREM sleep. Pharmaceutical Biology, 57:65-73

  6. O’Callaghan, F et al. 2018. Effects of caffeine on sleep quality and daytime functioning. Risk Management and Healthcare Policy, 11:263-271