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Do you eat breakfast every morning? What do you usually eat?
Some people sleep until just before they leave for work or school, and others just have coffee, but this is a waste because it misses an opportunity to promote wakefulness.
This article discusses the importance of breakfast and what you should keep in mind.
Benefits of chewing your breakfast thoroughly
Some people skip breakfast or eat something quick, but eating breakfast properly is very important.
Eating breakfast stimulates the taste buds and brain, and the act of eating and chewing "promotes wakefulness." In addition to providing "energy replenishment" for daytime activities, it also offers "circadian rhythm resetting effects" similar to exposure to sunlight, "obesity prevention effects," and even "memory-boosting effects."
Breakfast offers so many benefits. Moreover, using ingredients for breakfast that require thorough chewing can be even more effective.
Why focus on chewing your breakfast?
I've already mentioned the effects, but I'd like to explain them in more detail.
Promotes wakefulness
Eating breakfast stimulates the taste buds, and the act of eating and chewing further activates the brain.
Just as good wakefulness leads to good sleep, sleep and wakefulness are two sides of the same coin, so it's important to be active during the day and achieve good wakefulness.
By the way, it's a good idea to lightly clean your tongue before meals to properly perceive the five basic tastes: salty, sour, bitter, sweet, and umami (※1).
Taste stimuli are transmitted to the brain via taste buds (a collection of chemosensitive epithelial cells and afferent neurons) located in the papillae on the surface of the tongue (※2).
You may have noticed that your tongue surface sometimes appears white. This is due to a buildup of detached mucosal cells, bacteria, food debris, and remnants of white blood cells, forming "tongue coating" or "fur." When the tongue coating becomes thick, it can hinder the transmission of stimuli to the taste buds, so cleaning is recommended (※1).
Furthermore, an increase in core body temperature is a condition for wakefulness, and eating causes an increase in body temperature. For more details on core body temperature, please refer to another article.
Energy replenishment
Food is taken into the body, broken down, and absorbed to become energy. The brain is active even during sleep, leading to energy depletion in the morning. Therefore, to be active during the day, it is essential to replenish energy at the start of the day.
When deprived of nutrients, the body initially uses glycogen (polysaccharides) in muscle cells and the liver as an energy source, which is consumed in just one day. Next, fat and proteins stored in fat cells are used (gluconeogenesis: the use of amino acids for energy) (※3).
A decrease in muscle mass reduces basal metabolism, making it harder to lose weight in the long term. Additionally, since protein is the raw material for skin and hair, a deficiency can make one appear older.
Another purpose of food intake is to acquire substances that humans cannot produce internally (essential nutrients; for example, nine essential amino acids, specific vitamins, and inorganic salts).
For instance, if vitamin C, abundant in citrus fruits, is not adequately consumed, it can lead to anemia, scurvy, and impaired bone formation (※4).
Serotonin, which is related to mood, and melatonin, the sleep hormone synthesized from serotonin, are both synthesized from the essential amino acid tryptophan. While essential amino acids can be obtained through a balanced diet including protein, individuals with imbalanced diets should be cautious.
Resetting the body clock
The human circadian rhythm is said to be "24.2 hours," and adjustments to the light-dark cycle are made through stimuli such as temperature changes and light.
If no adjustment is made, a free-running state occurs, and the rhythm gradually shifts backward. Eating, accompanied by changes in body temperature and hormone secretion, has the effect of resetting the body clock, similar to exposure to sunlight.
Obesity prevention
In recent years, metabolic syndrome, known as a risk factor for obesity (characterized by visceral fat accumulation, elevated fasting blood glucose, serum lipids, and blood pressure above certain levels) (※5), has been on the rise.
A 2006 Ministry of Health, Labour and Welfare survey estimated that one in two men and one in five women aged 40-74 are considered to be in the preliminary stage of metabolic syndrome (※6). Furthermore, eating breakfast has an obesity prevention effect. Some people skip breakfast to diet, but this is counterproductive. From now on, eat breakfast.
As an actual research example, I will introduce a mouse experiment conducted at SCN Lab on "chewing and circadian rhythm and sleep."
In a comparison between mice fed solid food and those fed powdered food, the mice fed powdered food that did not chew gained weight steadily more than those fed solid food who chewed (※7).
Cortisol is a type of adrenal corticosteroid hormone, and its main functions include fat mobilization, increase in blood sugar levels, and adaptation to stress (※7).
Fat mobilization refers to the hydrolysis of stored fat in fat cells into fatty acids and glycerol, which are then released into the bloodstream; in essence, it means the breakdown of fat. The fluctuation in cortisol secretion peaks within one hour after waking (Car: cortisol awakening response; recently attracting attention as an indicator of daily stress) and follows a cycle of monotonically decreasing from early morning to night (※8).
In other words, it indicates that fat is most easily broken down in the morning.
Incidentally, it is thought that the high secretion level in the early morning converts the body's sugar, which tends to be in short supply after being consumed during sleep, into energy, thereby preventing a drop in blood sugar levels upon waking.
Memory enhancement
At schools, we are often told to "chew your food well" and "skipping breakfast will lower your grades," and this is actually true. Eating breakfast is said to improve memory.
In the aforementioned mouse experiment, neurogenesis (the birth of new nerve cells in the brain) was observed in the hippocampus, which is responsible for memory, in mice that were given solid food and chewed thoroughly. In contrast, a decrease in nerve cell regeneration was observed in mice that were given powdered food and did not chew.
Incidentally, the hippocampus is a part of the limbic system, a crucial area often called the commander of memory.
New memories are stored in the hippocampus, while old memories are stored in the cerebral cortex (※7). Although it was previously believed that the brain would only deteriorate with age, it has now been confirmed that neurogenesis occurs even in adults. This means that even as we age, our brains can remain youthful depending on our mindset.
Clear distinction between day and night
In the aforementioned mouse experiment, mice that were given solid food and chewed thoroughly showed a clear distinction between day and night in their sleep and activity patterns.
The results suggest that chewing is important for forming active and resting rhythms.
What should I eat?
Since chewing well enhances the effects, we recommend ingredients and menus that require thorough chewing.
For example, if you're a cereal eater, granola, which has a chewy texture, is more effective than cornflakes or fruit granola.
For rice eaters, mixed grain rice is more effective than white rice, as it contains more nutrients and requires more chewing. You can also try cutting vegetables slightly larger for stir-fries or stews.
Also, warm soups raise body temperature, promoting wakefulness. If possible, adding a warm soup can be even more effective.
【References】
※1: Oral Hygiene Research, 6. Taste and Tongue Coating
※2: Raven/Johnson Biology (Vol. 2) 7th Edition, p975
※3: Role of Nutrients (Supervised by Professor Yoshiaki Tanaka, Medical Safety Management Department, Kurume University School of Medicine)
※4: Raven/Johnson Biology (Vol. 2) 7th Edition, p903-904
※5:Ministry of Health, Labour and Welfare, e-Health Net, What is Metabolic Syndrome?
※6:Ministry of Health, Labour and Welfare, Status of Individuals with or at Risk of Metabolic Syndrome
※6: Anegawa,E., et al., Chronic powder diet after wearning induces sleep, behavioral, neuroanatomical, and neurophysiological changes in mice. PLoS One, 2015. 10(12):p.e0143909
※7: Raven/Johnson Biology (Vol. 2) 7th Edition, p995
※8: Nomura et al., Transdermal Evaluation of Cortisol Awakening Response by Microneedle Puncture Method. Life Support Vol. 24 No. 24, 2012.
※9: Raven/Johnson Biology (Vol. 2) 7th Edition, p957-958
