A lady of

told me that she was originally thin and weak, with poor gastrointestinal tract, dyspepsia, frequent flatulence and fatigue. Later, after listening to the advice of elders and health experts on TV, he bid farewell to the once gluttonous cold drinks and stopped drinking all kinds of sweet drinks. Even fruits were greatly reduced. The three meals were fixed in fixed time and the warm food was eaten as much as possible. Half a year later, the stomach and intestines were much more comfortable, the weight was significantly increased, the face was better, and the fatigue problem was also improved.

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were heard by another nutritionist and asked me: is there any scientific truth? There is no change in the composition of the food, just the difference in the temperature of the cold and hot, will have such a big impact on digestion? Can it be that Chinese medicine is fooling you

I said: her physical improvement, of course, is not only the contribution of temperature, but also the role of changing wrong living habits and keeping away from sweet food and drink. However, without consulting the professional literature, you can easily conclude that food temperature has no effect on digestion and absorption, which is probably not a scientific attitude. I don’t know much about other ingredients, at least in the starch food that I’ve been focusing on for a long time, the effect of temperature is really very big. I don’t believe it. Let’s look at a research report published in nutrition research in 2004. The

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study recruited nine healthy young male volunteers to give them fresh potatoes cooked that day in the morning. The number of potatoes eaten every day is exactly the same. The only difference is that in some days, they eat hot potatoes. If the central temperature is 84 ℃, the subjects will eat them. In the other part of the day, they ate potatoes that were completely cooled to room temperature. Their central temperature was determined to be 26 degrees Celsius before they were given to the subjects.

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in theory, there is no difference in the nutritional composition between the two potato meals, but it is only one of them, and it is only one of them to be dried for 1 hour after cooking. The subjects who ate hot potatoes cut them into pieces with knives and forks, and ate them while drying. Although the actual imported temperature was higher than the body temperature, it could not reach the degree of scalding the mouth. However, the results of the test, but people were surprised — after eating hot potatoes,

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, the increase of postprandial blood glucose was significantly higher than that of eating cold potatoes, and the glycemic index was 122 and 78 respectively, which was more than 50% lower. However, the rise of postprandial blood insulin was also different, with postprandial insulin being 117 and 82 respectively. However, what is most surprising is that the rising trend of triglycerides after meals is completely different. Hot potatoes bring about a significant increase, while cool potatoes not only do not cause an increase, but also a very significant decrease (Najjar et al, 2004)!

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for starch food, the difficulty of digestion is not only related to the fiber content, but also related to the degree of gelatinization and aging of starch, as well as the hardness and viscosity of food, which have been scientifically proved for a long time. The gelatinization degree and aging degree of starch are strongly affected by temperature. Without enough temperature, starch can not be fully gelatinized, which is “immature”. Once the temperature is lowered after ripening, the starch molecules will gather again and return to the raw direction, resulting in changes such as viscosity decrease and hardness increase, which is called “aging and rejuvenation”. After the starch molecules regenerate, more “resistant starch” will be produced, that is, starch molecules that are not easy to be digested and absorbed by human beings. They are similar to dietary fiber. Only when they enter the large intestine can they be fermented by large intestinal microorganisms.

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have also been studied by Taiwan scholars. It has been found that there is a big difference between the method of determining resistant starch to evaluate the digestion characteristics of starch food and the data measured in human body. For example, brown rice (the whole grain of rice) has relatively high resistant starch content. It should be digested slowly and blood glucose response is low, but the measured blood glucose response is relatively high. According to the analysis of the researchers, this is because the extraction and determination temperature of resistant starch is room temperature, and there has been a certain degree of starch retrogradation in the extraction of resistant starch. However, when eating, the subjects ate just cooked hot brown rice, and the degree of starch gelatinization remained at a relatively high level (Lin et al, 2010). It has long been confirmed that cold rice digests more slowly than hot rice and has a lower blood glucose response. Our laboratory tests also found that, due to the structural differences of amylopectin, even the glutinous rice with almost no amylose has different blood glucose response after cold storage. The changes of Japonica glutinous rice are small, while the changes of indica glutinous rice are large. On the other hand, from the perspective of food fat, beef and mutton fat has a higher proportion of saturated fatty acids, and its melting point exceeds body temperature. Therefore, in the cold after eating, its fat appears solid, digestion speed will also be reduced.

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can be found from these analyses that it is beneficial and harmless for people with too good digestive capacity, obesity, hypertension, hyperlipidemia and hyperglycemia to eat some cool food and increase resistant starch, which can delay the rise of postprandial blood glucose and blood lipid, and improve intestinal flora. But on the contrary, for those with poor digestion ability and very thin body, if it is not easy to digest after cooking, it will make the digestive system worse. At the same time,

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also need to think of another problem: warm food is conducive to promoting blood circulation in the stomach, while food with significantly lower temperature, especially iced and frozen food, will temporarily constrict gastric blood vessels, inhibit local blood circulation, and reduce the secretion of digestive juice and the speed of gastrointestinal peristalsis. For those who are thin and weak, it is obviously not wise to use frozen food to cool their stomachs with less digestive juice secretion or lower digestive enzyme activity. Therefore, it is reasonable for this lady to improve her health after changing her eating habits.

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but here we also need to remind: first of all, if the gastrointestinal digestion function is strong, you don’t need to pay too much attention to whether the food is warm, as long as you don’t ice your teeth; second, even if you are thin and weak with dyspepsia, you don’t recommend eating hot food. You should blow the hot food until it’s not too hot, and then put it into your mouth when the mouth is not hot at more than 40 degrees. Otherwise, the mucous membranes in our mouth, esophagus and stomach, just like those barbecues, will be scalded and denatured, and increase the risk of cancer.

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: KDspe”

  1 Najjar N, Adra N, Hwalla N. Glycemic and insulinemic responses to hot vs cooled potato in males with varied insulin sensitivity[J]. Nutrition Research, 2004, 24(12): 993-1004.

  2 Lin M H A, Wu M C, Lu S, et al. Glycemic index, glycemic load and insulinemic index of Chinese starchy foods[J]. World journal of gastroenterology: WJG, 2010, 16(39): 4973.”

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