Eat, eat well but also eat healthy. Nutrition is certainly one of the most precious pleasures we have but at the same time it can also become an ally for our health to strengthen the immune system, support memory, counteract overweight, prevent cellular degeneration and yes, even the insomnia and sleep disturbances. A few weeks ago a review was published that focuses on the link between nutrition and sleep quality with the aim of understanding which are the best habits to ensure a good restful sleep, but let's try to understand better (Bulman et al, Beverages, 2021).
Why it is important to sleep well
A good sleep, understood both in terms of the quality and the duration of the hours spent in bed while asleep, is essential to ensure the correct functioning of a wide range of biological processes. First of all, sleeping well protects the heart, then supports memory and cognitive function, stimulates the immune system and regulates the metabolism. Sleep problems can result in mood changes, cognitive decline, anxiety, depression but also metabolic syndrome, which is a condition in which at least three of these factors exist at the same time such as abdominal circumference higher than 88 cm for women and 102 for men, hypertension, hyperglycemia, high triglycerides and low good cholesterol. Hence, improving sleep quality has benefits on several aspects of life.
The bedtime diet
Food and some drinks can help improve the quality of sleep thanks to the particular substances they contain. A diet capable of providing tryptophan, an essential amino acid for the production of serotonin, also called the happy hormone, and melatonin, an important hormone to regulate the sleep-wake rhythm, has proved to be helpful. Tryptophan is contained in milk and dairy products, poultry, fish, eggs, squash, nuts, green leafy vegetables and some fruits such as plums, kiwi fruits and tomatoes.
Drinks, milk and honey
There are also drinks capable of improving the quality of sleep. These drinks are based on powerful active ingredients or on a synergy of these. For example, a cup of milk drunk before bed has shown mixed results on possible sleep benefits. Instead, a cup of milk with the addition of a spoonful of honey brought measurable benefits in the quality of sleep already after three days of intake. This is due to the ability of honey to make the tryptophan in milk more readily available and to reach the brain in higher quantities. Honey also shows anti-inflammatory and antioxidant properties capable of counteracting oxidative stress with possible beneficial effects also on sleep. However, be careful if you need to keep your blood sugar under control. In case of lactose intolerance, it is possible to replace cow's milk with vegetable milk. For example, almond milk appears to help improve sleep quality.
Chamomile
The bedtime drink par excellence is definitely chamomile. But is it just a matter of tradition or is there also a scientific basis? The sleep-inducing properties of chamomile can be traced back to a substance contained in it, apigenin, which easily reaches the brain where it stimulates the action of GABA receptors, which are neurotransmitters capable of reducing stress and anxiety. However, apigenin is poorly water-soluble, so the amount of apigenin is reduced in chamomile tea. This is why scientific studies have found scant and often disagreeing evidence of chamomile's ability to improve sleep quality and reduce insomnia.
Green tea
Green tea contains L theanine, a substance with a calming action and capable of inducing a good restful sleep. However, to ensure a relaxing action by drinking a cup of green tea, it is necessary to choose varieties with low caffeine content, which otherwise would counteract the action of L theanine. Green teas low in caffeine are, for example, bancha or kukicha green tea. It was observed that after two weeks of consuming low-caffeine green tea, nighttime awakenings were effectively reduced and the length of time spent in bed while asleep increased in the study participants.
