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We have a body clock. Relentlessly and accurately, it synchronizes each physiological function to a twenty-four hour day. According to the time on this clock, known as the circadian rhythm, it more or less activates specific genes, so that our body works differently according to the flow of time. It is a refined mechanism, which has nothing to do with any magical formula: in fact our clock works on the basis of two factors.
The first factor – the one we know most about – is light: according to the quantity of light actually present, the circadian rhythm evaluates what time of the day it is. For this reason, being in the dark makes us feel sleepy, no matter what the time. A second factor, however, has only been discovered recently, and this has to do with our diet: the food we eat has an effect on our circadian clock. The study revealing it dates back to 2001 but at that time it was not yet quite clear which factors influenced this mechanism. A recent research just published in the prestigious Cell Reports, now explains how food affects the way the circadian rhythm works.
Dr. Makoto Akashi, together with his team at Yamaguchi University, has discovered that insulin plays a vital role in this process. Produced by the pancreas, insulin is a hormone responsible for a great many physiological processes, the most important of which is to regulate blood glucose levels. Thanks to the work of Akashi and his colleagues, however, we now know that it also affects the circadian rhythm, according to what we eat. We consume food which triggers the production of a certain quantity of insulin which, in its turn, interacts with our biological clock. The consequence of this process is important: by regulating what we eat and when we eat it, we can regulate our body clock and therefore improve our level of efficiency. To obtain these results, the Japanese team has evaluated the behaviour of the Per2 gene, which is the principal “switch” regulating the circadian rhythm. In brief, Akashi and his colleagues fed mice with different quantities of food and studied changes in the Per2 gene and, consequently, in the circadian rhythm. Apart from their scientific findings, the researchers also extracted some precious indications which help us understand how food influences our efficiency throughout the day.
For instance, to prevent jet-lag when you land late in the evening after a long-haul flight, Dr. Akashi recommends a meal rich in foods that stimulate the production of insulin, carbohydrates that is. In this way, Per2 is activated to a greater extent and the body clock is led to believe that it is facing a new day. On the contrary, when arriving in the morning, it is better to eat a breakfast that does not stimulate the production of insulin excessively. This research is still in the early stages and needs to be elaborated further but, as a general rule, we know that by regulating our carbohydrate intake (bearing in mind that sugar is a type of carbohydrate), we can accelerate or slow down our biological clock.
Akashi’s work offers a further proof that, in normal conditions, a carbohydrate-rich breakfast is the best way to start the day. Not only because it supplies an instant energy boost as soon as you wake up, but because it “resets” the body clock. An excess of carbohydrates in the evening would lead to a new reset, too close to the previous one to make us efficient and reactive: for this reason, the evening meal should be low in carbohydrates with a preference for protein-rich foods.
Handy tips aside, the importance of this research is that it helps us to understand and elaborate the correlation between diet and biological cycle in order to prevent various pathologies. Suffice it to say, for instance, that an irregular circadian rhythm contributes to heart diseases, diabetes and even cancer. Thanks to the work of the Yamaguchi University team, it could be possible to stay healthy… by eating.