2. Fruits
Fruits can be divided into the fresh and preserved varieties. Fresh fruits, such as apples, pears, peaches, haws, grapes, pineapples and bananas are the ones most commonly used in clinical practice; and the fruits of the latter group are prepared from the fresh fruits, including candied dates, dried persimmons and raisins.
The important nutritive components of fresh fruits are the vitamins (chiefly vitamin C) and inorganic salts. As analyzed by nutriologists, the content of vitamin C in fresh dates is as high as 540 gm %, and it can be 30-100 times this amount in other fruits and ordinary vegetables. The content of vitamin C is even higher in wild jujubes, sometimes reaching 850-1170 mg %. The absorptive ratio of vitamin C in the intestines may reach 86.3%. Haws, tangerines and lemons are also rich in vitamin C. Red and yellow fruits, like apricots, oranges and tangerines, contain more carotin and inorganic salts, including calcium, phosphorus and iron.
Through the process of manufacture, preserved fruits may lose many of their vitamins, but the relative contents of proteins, carbohydrates and inorganic salts are increased after the marked loss of water from fresh fruits. For example, the contents of protein and carbohydrate in grapes are 0.7 % and 11.5 %, but in raisins they are raised to 4.1 % and 78.7 % respectively.
The iron and copper in fruits are useful for the production of hemoglobins in anemic patients. The high content of potassium and low content sodium in fruits can produce a diuretic effect. Organic acids such as malic acid and citric acid can stimulate secretion of gastric acid and improve the digestion. Succinic acid contained in unripe fruits can produce a strong stimulation effect in the stomach and intestines.
Fruits can have a remarkable therapeutic effect. For example, haws can dilate blood vessels, lower blood pressure and blood cholesterol level, improve the heart function, inhibit and kill bacteria and improve the digestion. According to pharmacological studies, haws contain many flavone glycosides and complicated di- or polyflavanoids. The toxicity of polyflavanoids is low, and it can produce an apparent hypotensive and cordial effect. Flavone and derivatives of flavanoid can dilate coronary arteries and produce a sedative effect. The fresh fruits and leaves of haws contain the precursor of diflavanoid, anthocyanidin, and catecuric acid and anthocyanidin may be produced after hydrolysis to improve contraction of the myocardium, increase blood flow in the coronary artery and prevent arrhythmia. According to in vitro bacteriostatic experiments, haws can produce a strong inhibitory effect on Flexner's coli and Bacillus pyocyaneus. Recently, it has been discovered that haws can increase secretion of amylase and lipase in the stomach, and promote digestion.
Apples can both stop diarrhea and promote bowel movement mild diarrhea (except bacillary dysentery) can be stopped a few days after the intake of apple paste alone. The organic acids and tannic acid in apples can produce an astringent effect, and the pectine and cellulose in apples can absorb bacterial toxin to stop diarrhea; but the organic acids and cellulose can stimulate intestine and promote the motility of the stomach and intestines to treat constipation.
According to clinical observations, the increase of urine sugar in diabetic patients after eating bananas is not a remarkable as after the intake of other fruits. The ratio of glucose and fructose in banana is 1:1, making them suitable for treating fatty diarrhea and intoxic indigestion. The abundant minerals in bananas are useful for correcting the disturbance of water and electrolyte metabolism. The 5- serotonin in bananas can reduce gastric acid and protect gastric mucosa from the stimulation of gastric acid. However, the overeating of bananas may cause dysfunction of the digestive system. Pears contain vitamin C, sugar, calcium, phosphorus and sodium, and they can be used with the correspondent specific medicines to treat pulmonary tuberculosis, acute or chronic bronchitis and upper respiratory infection with dryness and pain in throat, expectoration of profuse yellow sticky sputum and discharge of dark urine in short streams.
Ripe fruits contain more digestible sugar, like glucose, and are beneficial for the liver. Patients with liver disease should eat more sweet fruits. Sour fruits, like plums, apricots, oranges and tangerines can cause spasms in the biliary tract, so patients with diseases of the liver or gallbladder should avoid eating sour fruits.
