10-second takeaway: Sleep and nutrition are closely connected and should be taken together when approaching patients through a holistic lifestyle medicine lens. 

We all need sleep, no matter how inconvenient it sometimes may seem. There is a growing body of research linking sleep and our physical and mental health, with sleep deprivation increasing our risk for a variety of health conditions including cardiovascular disease, metabolic syndrome and even dementia. Even for those who feel they can tolerate less than the recommended 7-9 hours of sleep, there may be underlying health effects that are not immediately apparent. 

When a healthcare professional wants to assess sleep quality and “hygiene” for a patient, there are several lifestyle factors to consider including caffeine, alcohol and light exposure. These are well-established, widely understood components that patients themselves are probably already aware of. However, an often-overlooked factor is nutrition. As it turns out, there is a bi-directional association with sleep, meaning that what we eat can affect how we sleep, and how we sleep can affect what we choose to eat.

Learn more about the bi-directional relationship between nutrition and sleep in our webinar on “The Sleep-Food Complex” by Dr Josh Kovoor.

 

Why do we have such different sleep patterns? 

Sleep is inherently personal; we all have different sleep needs and preferences, whether it be a certain type of mattress, a warm shower or a mug of herbal tea. And just as any daytime activity can become a habit, our sleep patterns can develop into habits that can be difficult to change, which can create problems for patients with chronic sleep deprivation.

Evidence gathered from research suggests that we may all have sleep ‘chronotypes’ in which we are hard-wired (potentially genetically) to function better with a specific sleep-wake cycle that determines our preferences for bedtimes and waking times. This is the rationale behind “night owls” and people who self-identify as a “morning person”. Unfortunately, the 9-5 structure of our society means “night owls” who sleep later are forced to wake up early, leaving them sleep-deprived. Shift workers also get a bad deal when it comes to sleep, having to adapt to completely different sleeping patterns all the time, which could also lead to sleep deprivation.

There seems to be increasing awareness among some patient populations for sleep hygiene and the link between sleep and health. This may be due to increased research and conversation, as well as the rise in popularity of smartwatches and sleep apps. The concept of “sleep debt” is also quite popular, where a device calculates how much sleep you have missed and thus how much sleep you should catch up on to effectively “clear” the debt.

How does sleep deprivation affect nutrition?

We’ve all been there; searching for a quick, energy-dense meal after a long flight or a particularly poor night’s sleep. Multiple studies actually show consistent associations between short sleep duration and higher total energy intake as well as higher fat intake. There is also evidence to suggest lower overall diet quality and fruit intake. Of course, the occasional night of poor sleep is acceptable (and sometimes unavoidable!) but difficulties arise when individuals become chronically sleep-deprived, allowing these sub-optimal food and energy intakes to compound over time, leading to weight gain, obesity and associated diseases. 

So, what are the possible mechanisms for the association between sleep deprivation and poorer health?

• Some evidence suggests that short sleepers may have irregular eating patterns, with more energy-dense snacking at night
• Possible differences in appetite-related hormones 
• Increased energy intake simply because you are awake longer
• Poor decision-making when tired

How does nutrition affect sleep quantity and quality?

This topic has more nuance due to the specific effects food may have on each individual, but there are some general associations we can look at. Firstly, meal timing seems to play a role, with irregular mealtimes and late-night meals associated with poorer sleep quality. 

The composition of macronutrients in the diet may also play a role, with evidence linking higher fat intakes, insufficient or excess protein and high glycaemic index with poor sleep. On the contrary, a diet rich in seafood and vegetables has been linked to better sleep, with some evidence supporting the Mediterranean diet for sleep. Furthermore, long-term inadequate nutrition may heighten inflammation in the body, which is linked to insomnia.

What can you advise your patients? 

The stresses of modern lifestyle, combined with physical and mental health conditions, mean many patients will be experiencing sub-optimal sleep quality and quantity. So here are some tips to help patients with their sleep and nutrition:

• Try to prioritise sleep by blocking out calendar time in the evening for screen-free relaxation
• Give sleep apps a go and see if they work for you
• Try to eat earlier as late meals can impair sleep quality 
• Make a food diary if you are struggling with sleep and nothing else is helping- maybe there are opportunities to eat food that will support good sleep?
• Have healthy meals prepared in the fridge and freezer, so that you can grab and go or quickly heat them up. Hearty meals like a bolognese sauce or chicken pie may be good options over a salad, so if you are craving high-energy and high-fat foods, you can satisfy this craving without compromising on nutrition.

 

Key takeaways

• Sleep deprivation is linked to various health conditions (including cardiovascular disease, metabolic syndrome, and dementia) and even those who tolerate less sleep may face hidden health effects.
• Nutrition and sleep influence each other; poor sleep can lead to unhealthy eating habits, and poor nutrition can impact sleep quality and quantity.
• Healthcare professionals should explore sleep hygiene alongside nutrition to provide holistic care for patients

 

 

Learn more about the bi-directional relationship between nutrition and sleep in our webinar on “The Sleep-Food Complex” by Dr Josh Kovoor. Looking for more high-quality lifestyle medicine education? Make sure to explore our free CME-accredited webinars and the latest series of our Nutritank podcast.

 

About the author

Lizzie Davies is a final-year student dietitian at King’s College London. Her current interests in dietetics include women’s health and cystic fibrosis. In her spare time, she loves to bake and cook, and volunteers in the charity sector. Find her on Instagram @lizziedietetics. 

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