More than a third of adults in developed nations fail to sleep for the recommended 7 to 9 hours per night.
To understand why sleep is important we must understand what happens when we sleep, and what triggers it.
The circadian rhythm is our body’s innate way of regulating sleep through the release of key hormones and these control how alert or sleepy we feel at certain points throughout the day.
Meanwhile, adenosine, which is known commonly as ‘sleep pressure’, builds up continuously over the course of the day which, by bedtime, forces your brain and body to sleep.
Finally, melatonin, often referred to as the ‘sleep hormone’,’the hormone of darkness’ or ‘the vampire hormone’ due to its essential role in sleep essentially helps the timing of when sleep occurs. It is often released quickly into the bloodstream from 6pm onwards before reducing at 6am, depending on your individual circadian rhythm.
Typically, poor sleep is associated with negative health-related outcomes such as obesity, hypertension and cardiovascular disease. From an athletic or performance perspective there may be reduced cognitive function, negative impact on hormonal state, increases in fat storage and muscle wastage, drops in immune function and mood, fatigue and decreases in performance.
Processed Foods and Sleep
A diet that contains saturated and trans fats plus low volumes of fibre has been shown to reduce the quality of sleep. This, in essence, is a diet high in processed foods. A systematic review in 2020 showed that when ultra-processed foods were consumed on a regular basis (including daily consumption), it had a dramatic impact on several health factors, an increase in a sedentary lifestyle, poor school results, increased screen time and a significant decrease in sleep quality.
Caffeinated Drinks and Sleep
Caffeine is one of the most widely available stimulants worldwide. A stimulant is a substance that raises physiological or nervous activity within the body. Caffeine does this through blocking adenosine receptors from building up. With a half-life of roughly 6-7 hours, half of the caffeine contained in a cup of coffee is still in your blood after 6-7 hours. A 2013 study investigated caffeine’s impact on sleep when consumed 6, 3 and 0 hours before sleep and the results showed that even when caffeine was drunk 6 hours before bed, there was a significant decline in sleep quality and duration. So, if you were to drink a coffee at 16:00 with a 22:00 bedtime your sleep would be disrupted. Our best advice with caffeine is to avoid it after 16:00 in order to promote better sleep.
Sleep-Promoting Foods
Several foods have been shown to improve sleep quality through their positive effects on sleep hormones. Below are a few examples of foods that can promote a good night’s sleep.
Milk is generally considered ideal for helping sleep quality. Milk helps the release of large amounts of tryptophan from which melatonin is made. Improving blood melatonin levels have long been shown to improve the circadian rhythm of humans.
Oily fish, or more specifically omega-3 (unsaturated fat), has been shown to aid serotonin regulation. A 2014 study investigated eating 300g of oily fish 3 times per week on sleep quality over 6 weeks. The results showed that when omega-3 was regularly eaten, sleep efficiency and sleep quality improved. We personally would recommend an omega-3 supplement to obtain a regular intake of unsaturated fat as oily fish can be sporadic in its content.
Fruit has now been shown to have a positive influence on the circulation of several sleep hormones. Tart cherries and kiwifruit, in particular, have been shown to be of benefit through increasing melatonin concentrations. In particular, kiwifruits eaten 1 hour before bed have a significant impact on sleep quality through its high vitamin C and E content.
In conclusion, the consumption of certain nutrients can boost sleep quantity and quality. We strongly recommend avoiding processed foods, reducing caffeine intake after 16:00, drinking a glass of milk before bed and hitting your colour sets (two of each). We may also recommend considering an omega-3 supplement to boost the unsaturated fat content of your diet.