Chinese traditional culture often uses “five” as a unit to explain the material world. The five elements are wood, fire, earth, metal and water; the five colors are blue, red, yellow, white and black; the five internal organs are liver, heart, spleen, lung and kidney; the five senses are eyes, tongue, mouth, nose and ears; the five flavors are sour, bitter, sweet, pungent and salty. Now let’s talk about the five flavors.
The reason why people can have a sense of taste is mainly due to the fact that there are a large number of taste buds distributed on the tongue and the oral mucosa. Each taste bud is composed of taste cells and supporting cells. When the aqueous solution of substances stimulates the taste buds, the sensation is transmitted to the brain through the taste nerve fibers, and people can then perceive various flavors.
The tongue is the organ of taste, capable of sensing sourness, sweetness, bitterness, spiciness and saltiness. Children have the most taste buds on their tongues, which is why they always enjoy their meals. As we age, our taste buds gradually decrease, so the elderly often find food tasteless.
The different parts of the tongue have varying sensitivities to taste. Sweetness is most sensitive at the tip of the tongue, bitterness at the back, saltiness at the tip and the sides, and sourness at the sides and the middle.
In the history of biological evolution, sour and salty tastes developed earliest, bitter and spicy tastes developed later, and sweet taste developed latest. Many mammals still lack the ability to taste sweet to this day.
Traditional Chinese medicine applies the five flavors in both theoretical and clinical practice. The “Suwen: Six Sections on the Manifestations of the Zang-Fu Organs” in the “Huangdi Neijing” states: “Heaven nourishes man with the five qi, and earth nourishes man with the five flavors… When the five flavors enter the mouth, they are stored in the stomach and intestines. The flavors are stored to nourish the five qi. When the qi is harmonious, life is born. The body fluids are formed together, and the spirit is born by itself.” The “Suwen: Manifestation of the Five Qi” in the “Huangdi Neijing” says: “Sour enters the liver, pungent enters the lung, bitter enters the heart, salty enters the kidney, and sweet enters the spleen. This is called the five entries.”
sour
The sour taste has the effects of promoting saliva secretion, quenching thirst, stimulating appetite and removing greasiness, and thus is favored by many people.
Sourness can greatly stimulate the secretion of saliva. Our stomach secretes gastric acid. The essence of gastric acid is hydrochloric acid, which plays a very important role in digesting food. A lack of gastric acid can cause indigestion. Some diseases, such as atrophic gastritis, pernicious anemia, and gastric cancer, are often caused by a lack of gastric acid. However, other diseases are caused by excessive gastric acid, such as hypertrophic gastritis and peptic ulcers.
Pregnant women often have a craving for sour foods such as apricots, plums and hawthorn. In the past, we were not clear about the reason. In recent years, through advanced radioimmunoassay techniques, the mystery has been revealed. It turns out that after a woman becomes pregnant, the placenta secretes a wonderful substance that can inhibit the secretion of gastric acid, reducing the secretion of gastric acid in pregnant women and greatly lowering the digestive activity of various enzymes, thereby affecting the normal digestive function of pregnant women, causing them to feel nauseous, vomit and lose their appetite. At this time, eating some acidic foods can improve these symptoms. This is also a protective response of the human body.
Taste is related to the temperature of food to some extent. Generally, the sourness becomes more intense as the temperature rises. Most fruits are both sweet and sour. At 10 to 15 degrees Celsius, the sweetness and sourness are best balanced, and the taste is the most enjoyable.
The properties of traditional Chinese medicine are classified into four natures and five flavors. The four natures are cold, hot, warm and cool, while the five flavors are sour, bitter, sweet, pungent and salty. Sour taste has the functions of astringency and consolidation, and is often used for spontaneous sweating, night sweats, diarrhea, enuresis and spermatorrhea. For instance, Schisandra chinensis can stop sweating and consolidate essence, and is used to treat spermatorrhea and night sweats; Prunus mume can astringe and consolidate the intestines, and is used to treat dysentery, abdominal pain.
Chemical analysis and pharmacological research on traditional Chinese medicine have revealed that many of them contain organic acids, including citric acid, salicylic acid, tartaric acid, malic acid, oxalic acid, folic acid, ascorbic acid, and succinic acid. Many of these organic acids have anti-rheumatic, anticoagulant, and antipyretic effects. Folic acid and ascorbic acid are vitamins and essential nutrients for the human body.
Bitterness
The bitterness in food is the taste presented by inorganic ions such as calcium, magnesium and ammonium. Unrefined table salt often contains a small amount of magnesium ions, so it has a slight bitter taste. The reason why seawater tastes bitter is also because of this. Tea, coffee and cocoa are bitter because they contain caffeine, theine and theobromine, which all belong to alkaloids and are soluble in hot water, having a very bitter taste.
Most traditional Chinese medicine decoctions are bitter. This is because alkaloids, saponins, cardiac glycosides and other substances widely present in plant-based Chinese medicines all have a strong bitter taste. Many Chinese medicines are both bitter and cold, known as bitter-cold medicines, such as Scutellaria baicalensis, Coptis chinensis, Phellodendron amurense, Rheum officinale, Gentiana scabra, Sophora flavescens, and Fraxinus rhynchophylla. They can treat various heat-related diseases (such as acute bacterial infections, etc.) and are hailed as “antibiotics of traditional Chinese medicine”.
The sensitivity of human taste is affected by the temperature of food. When coffee cools down, its bitterness intensifies; when soup cools down, its saltiness becomes more pronounced; sweet foods taste sweetest at around 37℃; while bitterness is lessened when the temperature is above 37℃, and increases as the temperature drops. Therefore, coffee is best consumed while hot, and traditional Chinese medicinal decoctions are also better taken while still warm.
According to traditional Chinese medicine, bitterness can purge and dry. Purging means inducing defecation, and drying means eliminating dampness. Therefore, it is often used for treating excess conditions, dampness-related disorders, or upward rebellions. For instance, rhubarb can purge fire and relieve constipation, treating intestinal stagnation and constipation; Phellodendron can dry dampness, purge fire, detoxify and reduce inflammation, treating dysentery and damp sores; Atractylodes can dry dampness and strengthen the spleen, etc.
There are also bitter-tasting Western medicines, but their purpose is not to clear heat; rather, they are called “bitter-tasting stomach-strengthening medicines” as they aim to strengthen the stomach. This is because the bitter taste stimulates the taste buds, which reflexively stimulates the secretion of gastric juice, thereby having the effect of strengthening the stomach and aiding digestion. They are often used in clinical practice to treat indigestion, loss of appetite, and other conditions.
Why is bitter gourd bitter? It’s because it contains quinine, which is the source of its bitterness. Bitter gourd is rich in nutrients and can remove heat toxins, relieve fatigue, clear the mind and improve eyesight, strengthen the body and boost sexual function. It is a precious bitter vegetable that can stimulate appetite.
Gan
Sweetness is the quality of tasting sweet. There are many sweet substances. Not only fructose, sucrose and lactose are sweet, but also some amino acids and saccharin have a sweet taste.
Many foods and non-foods have a sweet taste. The sweetness of a substance depends on its structure. For monosaccharides, the number of hydroxyl groups (-OH) they contain determines the degree of sweetness. Generally speaking, a monosaccharide with only one hydroxyl group is not sweet, and one with more than three hydroxyl groups has a slight sweetness. The more hydroxyl groups there are, the sweeter it is. In terms of sweetness identification, the sweetness of sucrose is generally taken as 100 units for comparison. Lactose is 15, maltose is 30, high-fructose corn syrup is 60, glucose is 75, and fructose is 150. Saccharin is 550 times sweeter than sucrose and is commonly used to prepare various foods. Saccharin has no nutritional value, and in recent years, its safety has also been questioned, so its use range and dosage should be strictly limited. The artificial organic compound glycyrrhizin is 250 times sweeter than sucrose, and shiso aldehyde oxime is 2000 times sweeter than sucrose, but both are toxic and cannot be eaten.
Licorice is not only a traditional Chinese medicine but also a non-toxic sweetener. The sodium salt of glycyrrhizic acid is extremely sweet, with a sweetness 200 times that of sucrose.
Mogroside is a new generation of natural sweetener, extracted from the mature fruits of Siraitia grosvenorii. Chemical research shows that mogroside is its main component. In addition, it also contains a certain amount of glucose and fructose, so it is very sweet. Long-term consumption of mogroside is non-toxic and harmless, making it an ideal sweet source to replace sucrose. Its sweetness is equivalent to 210 to 330 times that of sucrose. Mogroside will play a role in the preparation of candies, pastries, beverages, medicines, seasonings, etc., especially in health foods for children and the elderly.
The leaves of stevia can be used to extract stevioside. Stevioside is 300 times sweeter than sucrose and is also a good natural sweetener. It has a pure and delicious taste, and features high sweetness and low calories. It is very suitable for people with diabetes, obesity, hypertension, arteriosclerosis and other diseases to consume, and can replace sucrose.
In traditional Chinese medicine, sweetness is one of the five flavors. It can tonify, harmonize and moderate. It is often used for treating deficiency syndromes or alleviating acute pain. It can also neutralize the toxicity of drugs. For instance, Codonopsis pilosula can tonify qi, Rehmannia glutinosa can tonify blood, Jujube can relieve acute pain, and Glycyrrhiza uralensis can detoxify and harmonize various drugs.
Although sweet foods are delicious, they should not be consumed in excessive amounts. Overconsumption of sweet foods can lead to an overabundance of earth energy, which can then overpower water energy and damage the kidneys. This can result in a sallow complexion, chest tightness and shortness of breath, soreness and weakness in the waist and knees, and hair loss. Diabetic patients should avoid sugar, including white sugar, brown sugar, rock sugar, and honey. Patients who have a sweet tooth can consume sugar substitutes in moderation, such as the ones mentioned above, such as Luo Han Guo sweetener and inulin.
Xin
Spicy means hot. There are many spicy foods, such as chili peppers, scallions, leeks, mustard greens, garlic, ginger, Sichuan pepper, black pepper, star anise, cinnamon, and onions. However, the flavors of spiciness are not the same, nor are the parts of the human body they affect. The folk saying “Qin pepper burns the mouth, garlic burns the heart, and mustard burns the nasal sinuses” is a vivid illustration.
Among various spicy foods, scallion, garlic, ginger and chili are known as the “Four Spicy Flavors”, with chili being the representative of spiciness. Spiciness is related to temperature. When you feel that the chili is too spicy, drinking a mouthful of cold water immediately can relieve the spiciness. Capsaicin contained in chili can cause redness, blisters and even ulcers on sensitive tissues. When chili is eaten, it gives a spicy feeling in the mouth, a burning sensation in the stomach and a hot and spicy feeling at the anus when defecating. Therefore, patients with oral ulcers, ulcers in the stomach and duodenum, gastroenteritis, hemorrhoids and rectal prolapse should avoid eating chili.
In traditional Chinese medicine, spicy is called “Xin”. It is believed that Xin can disperse and promote circulation. “Disperse” means to disperse cold or heat, and “promote circulation” means to promote the circulation of qi and blood. For example, Perilla frutescens and Schizonepeta tenuifolia can disperse wind-cold, Pueraria lobata and Mentha can disperse wind-heat, Saussurea lappa and Lysimachia foenum-graecum can promote the circulation of qi, and Paeonia rubra and Ligusticum chuanxiong can promote the circulation of blood.
Salty
In daily life, the main source of saltiness is table salt, whose main component is sodium chloride, and it also contains a small amount of potassium chloride and minerals such as calcium and magnesium. The chloride ions in it are responsible for the salty taste. In the world, apart from chloride ions, other sodium and potassium salts containing sulfate, nitrate ions and organic acids also have a salty taste. For example, patients with kidney disease can use potassium malate instead of table salt as a seasoning, which not only maintains the salty flavor but also avoids aggravating edema and raising blood pressure due to sodium retention.
Life cannot do without salt, as sodium and chloride ions are the main electrolytes that constitute extracellular fluid and are the main components for maintaining crystal osmotic pressure, playing a significant role in maintaining normal blood volume. If there is a lack of salt in the human body, symptoms such as fatigue, dizziness, nausea, vomiting, accelerated heart rate, fine pulse, decreased blood pressure, muscle spasms, and even coma may occur. A lack of salt can also lead to a decrease in the body’s immunity.
However, excessive salt intake is also harmful and can lead to diseases such as hypertension. The “Chinese Dietary Guidelines (2022)” stipulates that the daily salt intake for each person should not exceed 5 grams. For healthy individuals, excessive salt intake beyond the kidney’s excretion capacity can cause edema and increase the burden on the heart and kidneys. For patients with kidney diseases, excessive salt intake can lead to edema or exacerbate it; for those with heart diseases, it can cause heart failure; for patients with liver cirrhosis, it can result in edema and ascites; for glaucoma patients, excessive salt intake can increase intraocular pressure and trigger acute glaucoma attacks; for patients with peptic ulcers and pregnancy-induced edema, excessive salt intake can also have adverse effects. Therefore, patients with the above-mentioned diseases should adopt a low-salt or salt-free diet.
According to traditional Chinese medicine theory, salty-tasting Chinese herbs have the effects of purging and promoting defecation, softening and dispersing hard lumps. They are often used for constipation, tuberculosis, and lumps. For instance, mirabilite purges, and oyster shell softens and disperses hard lumps, which can be used to treat scrofula. Additionally, saltiness enters the kidney, so for kidney disorders, salty-tasting Chinese herbs can be used as guiding herbs.
In conclusion, if we master the theory of the “Five Flavors” in traditional Chinese medicine, we can use it to maintain our health and become our own health assistants.
