"Adults eat no more than 300 grams of lychees per day, children do not exceed 5" advice
It is based on "lychees contain a lot of sugar, mainly fructose; Eating a large amount of lychee, fructose accumulates in the blood, stimulates a large amount of insulin secretion, causing blood sugar to drop rapidly below normal values, resulting in hypoglycemic lychee disease", as explained by the doctor below.
In medicine, the transient hypoglycemia induced by eating high-sugar foods on an empty stomach is called "reactive hypoglycemia", which in the past was also called "bait hypoglycemia".
However, the theory that lychee disease is "bait hypoglycemia" lacks scientific evidence to support it, and there are at least a few fatal errors that cannot be justified; And as early as the 1960s, it was already denied by scientific experiments conducted on the mainland.
Eating any simple high-sugar food on an empty stomach may induce reactive hypoglycemia
One problem is that on an empty stomach, healthy people eating simple high-sugar foods (only sugar and no protein, starchy components), especially drinking high-sugar beverages, may induce the emergence of "reactive hypoglycemia".
However, different people have different tolerances to hypoglycemia, and some sensitive people will have "low blood sugar" symptoms such as hunger, panic, and sweating; Others can feel nothing at all.
Instead of eating a lot of lychees on an empty stomach, this "reactive hypoglycemia" will be eaten.
The truth is that eating a high-fructose diet has relatively smoother blood sugar levels
Another problem is that, contrary to the "bait hypoglycemia" theory of lychee disease, after eating a high fructose diet, the blood sugar level in the body is more stable than eating high-glucose foods, but it is not easy to occur "reactive hypoglycemia".
This is because, first, fructose is not easily absorbed.
Fructose and glucose are both absorbed in the small intestine by specialized transporter transporters.
The difference is that the carrier that transports glucose into the intestinal epithelial cells is glucose transporter 1 (GLUT1), and the carrier of fructose is GLUT5; The CELLS are then transported by GLUT2 into the blood vessels.
GluT5 is relatively inefficient in transport compared to GLUT1 and relies on the presence of glucose to work.
The study found that the human body cannot absorb high-purity fructose alone, which is why 95% high-fructose corn syrup acts as a laxative (cannot be absorbed and enters the colon causing osmotic diarrhea).
If fructose is present at the same time as glucose, it can be transported and absorbed; The ratio of fructose to glucose is 1:1, and the absorption efficiency is the highest, almost indistinguishable from the absorption of glucose.
This means that if lychees mainly contain fructose, these fructose are not easily absorbed, and they will not lead to reactive hypoglycemia, which can only induce diarrhea due to osmotic diarrhea.
Importantly, after the fructose is absorbed into the bloodstream, it does not remain in the blood in large quantities, but is almost all "detained" by the liver and metabolized in the liver.
What's more, fructose also does not directly stimulate islet cells to secrete insulin.
At the same time, fructose metabolism in the liver has multiple reversals, most of which are directly converted into fat (triglycerides, which is also the principle that long-term eating high fructose diet is prone to hypertriglyceridemia and fatty liver); Partially converted directly into hepatic glycogen stores; Only about 17% is gradually converted into glucose released into the bloodstream.
Therefore, compared with eating pure glucose and eating a high-fructose diet, the rise in blood glucose after a meal is more slow and smaller, and the risk of "reactive hypoglycemia" that may be triggered by this is smaller.
The ratio of fructose to glucose in lychee is 1:1
At present, the vast majority of domestic "science popularization" on the pathogenesis of lychee disease has made the most basic mistake, that is, they all "wishfully" believe that the sugar in lychees is mainly only fructose, and the high fructose of lychees is the root cause of lychee disease.
The truth is that lychees contain sugars including fructose, glucose, and sucrose.
Although the sugar content varies at different stages of ripening, the ratio of fructose to glucose is almost always maintained at a level of 1:1, and mature lychees gradually saccharify (become sweeter) mainly because sucrose is converted into sweeter fructose.
Moreover, since 1 molecule of sucrose is the condensation of 1 molecule of fructose and 1 molecule of glucose, no matter how the sugar content in the lychee changes, the ratio of fructose to glucose that is eventually absorbed into the body is still maintained at a 1:1 level.
Therefore, the cornerstone argument that "lychee mainly contains a lot of fructose" in the domestic science of lychee disease is completely wrong.
Drinking 1 bottle of Coca-Cola can also eat lychee disease?
As mentioned above, regardless of the amount of sucrose in lychees, the final absorption into the bloodstream must be 1:1 fructose and glucose.
Therefore, in terms of the absorption of sugar and the metabolism after absorption, eating lychees is no different from eating white sugar (mainly sucrose).
Studies have known that the sugar content of mature lychees is between 15% and 16%, and 300 grams of lychees contain 45 grams of total sugar, of which fructose and glucose are about 17 grams each, and sucrose is 11 grams.
In this way, eating 300 grams of lychees absorbs sugar into the bloodstream is exactly the same as eating 1 two (45 grams) of white sugar.
If lychee disease can occur by eating more than 300 grams of lychee per day, then eating more than 1 or 2 sugars can also eat lychee disease.
Taking Coca-Cola as an example, its sugar content is 10.6 grams /100 ml, and the sugar content of 500 ml is 53 grams, which has exceeded the sugar content of 300 grams of lychees.
This means that if eating more than 300 grams of lychee per day will cause lychee disease, then drinking 1 bottle of Coca-Cola a day will also induce lychee disease.
Eating a large piece of watermelon will eat lychee disease?
Assuming that eating a large number of lychees to eat lychee disease is really due to the high proportion of fructose, then eating apples, eating watermelon and other fructose: sweet fruits with a higher glucose ratio should be easier to eat lychee disease.
Taking watermelon as an example, the total sugar content of lychee is 15%, and the total sugar content of watermelon is 6%-9%.
Even at 6%, 750 grams (1 and a half pounds, a large piece) of watermelon has more sugar than 300 grams of lychees, and the fructose in them is more than that of lychees.
In summer, an adult eating 750 grams of watermelon a day can be said to be the daily routine of most people, why not eat lychee disease?
The reason is very simple, the current domestic epidemic of lychee disease is caused by high fructose in lychee is wrong.
1965 Chinese Medical Journal: Children eat 3 kilograms of lychees a day, and they can't eat lychee disease even for 3 days
In fact, as early as 1965, in a research paper on lychee disease published in the Chinese Medical Journal, the authors had already proved through experiments that even children who had already experienced lychee disease could not eat and starve lychee disease hypoglycemia by eating 3 kilograms of lychee disease every day, eating for 3 days, and being hungry for another 20 hours.
The authors make it clear that "lychee disease is not bait hypoglycemia.".
That is to say, the pathogenesis of litchi disease, which is currently prevalent in China, has been denied by the mainland scientific research as early as half a century ago.