From the perspective of modern medicine, qi deficiency as discussed in Donguibogam is deeply connected to our body's complex energy metabolism system. In particular, the digestive system, endocrine system, and nervous system work organically to regulate taste and appetite, and when this balance is disrupted, symptoms like qi deficiency can appear.
First, feeling hunger and satiety is not a simple sensation, but the result of constant signaling back and forth between the brain and the gut. In the hypothalamus, there is a center that regulates appetite, and it is influenced by two important hormones: ghrelin and leptin. Ghrelin is secreted by the stomach and sends a signal of 'I am hungry' to the brain to stimulate appetite, whereas leptin is secreted by adipocytes and sends a signal of 'I am full, stop eating' to suppress appetite. However, if hormonal balance is disrupted by factors like stress, irregular meals, or sleep deprivation, an error occurs in this signaling system. Just like a communication failure, the brain becomes unable to accurately perceive the true condition of the gut. As a result, even though the body lacks energy, problems such as having no appetite or conversely feeling constant hunger can occur.
Furthermore, beyond being a simple digestive organ, our gut is the center of the nervous system and immune system to the extent that it is called the 'second brain.' Countless microorganisms reside inside the gut, and research results are pouring out showing that the health of this gut microbiota determines appetite, digestion, and even mood. The proliferation of harmful bacteria or a decrease in beneficial bacteria can increase intestinal mucosal permeability, causing leaky gut syndrome, which can lead to chronic inflammation and bring about chronic fatigue and malabsorption. If the gut is not healthy, its ability to properly break down food and absorb nutrients declines; thus, no matter how well one eats, nutrients cannot be absorbed by the body, ultimately leading into a state of qi deficiency.
Stress cannot be overlooked either. Cortisol, a stress hormone, interferes with intestinal peristalsis and suppresses the secretion of digestive enzymes. As the saying goes, 'feeling like a stone is sitting in the epigastrium,' everyone has likely experienced indigestion and a sharp loss of appetite when nervous or anxious. This happens because stress affects the autonomic nervous system, directly impacting digestive function. Because the gut and the brain are connected through a highway called the gut-brain axis, stress signals sent from the brain are immediately transmitted to the gut, and conversely, signs of abnormality in gut health can be sent to the brain, causing psychological problems like depression or anxiety. Ultimately, qi deficiency is not merely a state of not feeling hungry, but a red flag indicating an emergency in the whole body's energy system where the brain, gut, hormones, and our emotions are intricately intertwined.
