Research shows that what we eat can directly affect the quality of our sleep, and that doesn’t just mean avoiding cheese and coffee at bedtime. Sleep needs obviously vary from individual to individual; the optimum average being between seven and nine hours. Sleep researchers discount the common myth that older people require less sleep; instead, the amount of sleep that an adult needs remains fairly constant. With advancing age, however, the nature of sleep changes and the incidence of sleep disorders rises. The degree of time spent in the deeper stages of sleep often lessens with age, and an older person is likely to awaken more frequently during the night.
A recent study shows a variation in the diet of those who slept well compared with those who struggled to get to sleep and suffered a disturbed night. Those who slept for less than five hours were found to have drunk less water, consumed fewer carbohydrates, had a diet containing less vitamin C and selenium (found in nuts, seeds and shellfish) but ate more green, leafy vegetables. Those who enjoyed better sleep consumed more carbohydrates (which increase the production of the relaxant tryptophan), less chocolate and tea and less choline (found in eggs and some meats). Scientists also point out that whilst everyone knows that eating a large meal just before bed is never advisable, in fact you should allow a three hour window between your last meal and hitting the sheets as it allows your body to relax and enables it to produce more of the sleep-inducing hormone melatonin. Eating a big meal near to bedtime will increase the blood flow to your digestive tract with the knock-on effect of stimulating your metabolism at a time when you need it to be slowing down. Going to bed hungry, however, is also a problem as your innate survival instincts will kick in and keep you awake so a small snack is better than nothing at all, but make sure what you consume is only a small amount and preferably carb-rich to help stimulate serotonin production, the natural chemical that promotes relaxation.
We are all aware of the downside of sleep deprivation, but few of us know that the better your sleep the fewer calories you are likely to consume the following day. The link between what we eat, our weight and our sleep patterns has emerged as an important part of managing weight problems. A lack of sleep has been found to result in an increased production of ghrelin, the ‘hunger hormone’, which can lead to over-eating. ‘We now know that short sleep duration is associated with weight gain and obesity, diabetes, and cardiovascular disease,’ explains Michael Grandner, researcher at the University of Pennsylvania’s Centre for Sleep. ‘If we can pinpoint the ideal mix of nutrients and calories to promote healthy sleep we have the potential to make a major dent in obesity and other cardiometabolic risk factors.’ Ideally, we should try and eat little and often, rather than large meals with long gaps in between, as this helps balance hormones.
Top tips for a restful night
- Avoid fatty meals. A recipe for disaster when it comes to getting a good night’s sleep, research shows those who indulge in a greasy takeaway in the evening are far more likely to have have their sleep disturbed.
- Alcohol makes you sleepy but studies show that whilst a few glasses increase deep sleep initially the alcohol will lead to disturbed sleep later – usually from the wee small hours. Alcohol is also a diuretic which means you are more likely to have to get up in the night too and increases the likelihood of snoring which restricts the airflow into the lungs and disturbs your sleep.
- Water is an essential in any healthy diet but research shows clearly that those who are even marginally dehydrated are likely to suffer a disturbed night.
- High levels of salt in processed foods and some takeaways can raise blood pressure and can also lead to dehydration which has a detrimental effect on sleep.
- Caffeine can linger in your system for up to 12 hours. Avoiding caffeine over the course of a day can lead to a better night’s sleep.
- Tyramine, found in cheese, but also in bacon, ham, avocado, raspberries, soy sauce and red wine, causes the release of the brain stimulant norepinephrine which can cause sleeplessness.