How does our diet influence our sleep?
To sleep well, we need to synthesise a hormone called melatonin. Melatonin itself is dependent on a sufficient level of serotonin, called the “serenity hormone”.
The synthesis of serotonin in our brains requires the intake of an amino acid — tryptophan — through our diets. This amino acid is contained in foods such as dairy products, eggs, fish, poultry, chocolate, and almonds. Be careful, however, with the method of cooking chosen as this amino acid is sensitive to heat. It is preferable to use low-temperature cooking methods, such as steaming.
In order for tryptophan to be transformed into serotonin and then into melatonin, it also requires the intervention of essential vitamins and minerals: Vitamins B3, B5, B6, B9, B12, vitamin C, iron, copper, and the amino acid methionine. A diversified diet with animal and vegetable proteins and one that is rich in colourful vegetables and fruits will allow for the contribution of these co-factors. As far as iron is concerned, animal proteins provide iron that is better assimilated than vegetable proteins. B12 is also only found in foods of animal origin. For lacto-vegetarians and vegans, it will thus be necessary to analyse and supplement according to deficiencies.
Consuming complex carbohydrates and wholegrain products or legumes in the second half of the day promotes the synthesis of serotonin. Thus, a dinner rich in wholegrain cereals, such as wholegrain rice or pasta, or rich in legumes, such as lentils, chickpeas, or coloured beans, will help you sleep better. But, they should be accompanied by a good portion of vegetables. For the latter, which will make up half of your plate, think about colour and variety so that they will provide the vitamins and minerals essential for these chemical reactions.
Wholegrain cereals have the advantage of being rich in fibre, which acts on satiety, and in vitamins and minerals (B-group vitamins, magnesium, zinc, iron, selenium, and the antioxidant vitamin E).
Legumes are remarkably interesting for their richness in fibre, vegetable proteins, vitamins, and minerals. We can recommend green or coral lentils, chickpeas, split peas, beans, and dried beans in various colours.
If you feel a little hungry around 5 pm, the ideal snack to promote good sleep will consist of a small handful of almonds, fresh or dried fruit, and a square of dark chocolate with a minimum of 70% cocoa. This snack will increase the assimilation of tryptophan, an amino acid precursor of serotonin.
We can also promote digestion in the evening — and, therefore, better our sleep — by choosing detoxifying foods that help our liver to process waste, such as artichokes, turmeric accompanied by pepper and a good vegetable oil rich in omega 3 to optimise its absorption, broccoli, rosemary, and black radish. As liver cells regenerate at night, these foods will be beneficial for your sleep.
Are there foods and drinks to avoid or limit in the evening?
Yes, indeed, there are some foods to avoid in the evening. Remember also that all meals rich in fat, such as red meat, delicatessen, cheese, and fast food, are difficult to digest and take a long time to be fully digested. They will inevitably disturb your sleep. Also note that ultra-processed products rich in hydrogenated fats are not only unfavourable to our health but also to our sleep.
Chocolate rich in cocoa is good due to its high magnesium content and antioxidant properties but it also acts as a stimulant and should be avoided in the evening.
Do not forget that dinner should be the lightest meal of the day, not only to not store fat but also to sleep well.
As for drinks, it is recommended to avoid coffee and tea after 3pm as they can delay our sleep. Alcohol is a false friend that gives us the impression that it helps us fall asleep but it actually affects the quality of our sleep by reducing the phases of deep sleep and increasing night-time awakenings.
In short, our diet plays a crucial role in the quality of our sleep. By making the right choices at the right times of the day, you will positively influence the quality of your sleep. Always think about eating a range of colours. Investing in your diet also means investing in your sleep and, therefore, in your long-term health.
Muriel Bouquier Ouziel is a nutritionist, pharmacist, and micro-nutrition and healthy-eating specialist.
She lives in London and offers tailor-made nutritional and micro-nutritional assessments and support.
Muriel offers face-to-face and Skype consultations.