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Insulin and insulinemic index.
The constant level of glucose in the blood is maintained with the help of hormones of the pancreas - insulin and glucagon.
Insulin - a hormone of protein nature, formed by beta cells, the so-called islets of the pancreas.
The intensity of insulin release depends on many factors, but primarily on the level of glucose (sugar) of the blood. The action of insulin is aimed at decreasing the glucose level in the blood, strengthening the permeability of the cellular membranes of various tissues for it.
The biochemistry of our body is arranged so that as soon as sugar enters the blood (glucose), the level of insulin also rises. The utilization of glucose should occur directly in the cells. Scientists suggest that in our distant ancestors, food rich in carbohydrates came across quite rarely and seasonally. Nature compensated for the uncontrolled synthesis of insulin, in order to ensure the fullest assimilation of the most effective "fuel" in reserve. That's why, using carbohydrates, whether you want it or not, you launch an evolutionarily ancient biochemical reaction of synthesis and deposition of energy material for a rainy day. Initially entering the blood, insulin promotes the conversion of glucose into glycogen, but when there is not enough space for glycogen in the liver and muscles, glucose directly turns into fats, which are deposited in the "bins" of subcutaneous fat. This conveyor of fat synthesis literally does not stop at a constant intake of glucose (sugar) into the blood.
In this case, insulin has the feature of causing an ongoing feeling of hunger, a feeling of malnutrition, and the person is so used to suppress this condition by the ingestion of carbohydrate food that becomes dependent on it as a drug. A condition when you need to eat something carbohydrate every 2-3 hours to feel normal. And often with an "overdose" of carbohydrates from the islet part of the pancreas will be thrown out an excessively large amount of insulin. As a result, after half an hour the glucose level will decrease again, and quite sharply. There will come a condition, which is called reactive hypoglycemia. It is accompanied by weakness, a decrease in physical and mental performance, and most importantly again sharply increases appetite, demanding another "dose".
As you know, in India and China, the elite used exotic drugs. Among these drugs was what we now call food sugar. This drug is very similar to today's cocaine. Perhaps the impact of sugar as a drug is somewhat exaggerated. But between them there are several obvious similarities: sugar, like cocaine, is a plant extract, purified to a chemically pure state, i.e. does not contain vitamins, minerals, proteins or fiber.
Think about it!
It has long been noted that when using different types of products, the concentration of glucose in the blood, and, consequently, the response of insulin increases in different degrees and at different rates. This allowed in 1981, Dr. David Jenkins, a professor at the University of Toronto in Canada, for the first time to introduce the concept of a glycemic index. The ability of carbohydrates to cause an increase in blood sugar (hyperglycemia) is determined by the glycemic index. This index will be higher, the higher the hyperglycemia caused by the breakdown of carbohydrates, with the glycemic glucose index taken as 100. The higher this index for foods, the more sugar will be in the blood when they are consumed.
David Jenkins tried in this way to determine which food is most beneficial for people with diabetes. Later, the term was popularized by M. Montignac, and in 1997, scientists at Harvard University, led by Walter Willett, studying the relationship between the consumption of foods with a high glycemic index and the risk of type 2 diabetes (insulin-independent), found that this connection is directly is proportional.
And more recently, Janette Brand-Miller of the University of Sydney, observed that the pancreas in some cases releases too much insulin in response to consumption of certain types of foods with a low glycemic index. And then she introduced, in addition to the glycemic index, which characterizes the rate of increase in blood glucose, a new index - insulinemic, which characterizes the rate of insulin release in response to food. This indicator more accurately reflects the real picture and, by the way, it turned out that in most cases, both these indexes correspond to each other - the more one, the more and the other. In normal practice, the glycemic index characterizes the rate of increase in blood sugar level in response to consumption of the amount of a product containing 50 g of carbohydrates. Jeanette Brand-Miller applied a slightly different approach.
First, for the product for comparison, she took not white sugar but white bread. Its glycemic index is conditionally taken as 100.
Secondly, for the experiments and for the calculation of both insulinemic and glycemic indices, not portions of the product containing 50 g of carbohydrates were used, but portions of products giving the same amount of energy: 1000 kilojoules (240 kcal).
An example of some products, the insulinemic response of the body to which is stronger than glycemic:
(The first figure is glycemic, the second figure is the insulinemic index of products by G. Brand-Miller).
• Croissant - 74 and 79
• Cupcake - 65 and 82
• Cookies «Doughnuts» - 63 and 74
Cookies Cookies - 74 and 92
• Mars bars - 79 and 112
• Peanuts - 12 and 20
• Yogurt - 62 and 115
• Ice cream - 70 and 89
• Potato chips - 52 and 61
• White bread - 100 and 100
• French loaf - 71 and 74
• Beef - 21 and 51
• Fish - 28 and 59
• Bananas - 79 and 81
• Grapes - 74 and 82
• Apples - 50 and 59
• Oranges - 39 and 60
These numbers I give only for a general comparison. There are entire lists and tables of such products, but they are more useful to dietitians, since the very concept of the glycemic and insulinemic index of products is very relative.
These indices can vary under the influence of various factors. These factors include culinary processing of products, as well as the interaction of different products among themselves. Patients suffering from obesity, it is sufficient to have a general idea of the mechanisms of the influence of various products on the production of insulin and take into account these indices in just a few types of the most frequently used products.
I often ask a question from many of my patients: "Why can we eat fruit containing fructose and absolutely forbade fructose itself in its pure form?"
Fructose is found in a wide variety of fruits and honey, as well as the so-called "inverse syrups". Because of the low glycemic index (31 in relation to white bread) and strong sweetness, it has long been regarded as an alternative to sucrose. Unlike glucose, fructose can penetrate from the blood into the tissue cells without the participation of insulin. For this reason, it is recommended as the safest source of carbohydrates for diabetics.
Part of the fructose enters the liver cells, which turn it into glucose, so fructose is also capable of raising blood sugar, although to a much lesser extent than other simple sugars. But fructose is much faster than glucose, can turn into fat!
Are you surprised?
In experiments on rats, researchers at the University of Florida have determined that fructose is one of the links in a biochemical chain reaction leading to an increase in body weight and the development of other signs of metabolic syndrome, a precursor of type II diabetes mellitus.
Fructose increases the level of uric acid in the blood, which reduces the activity of insulin, which regulates the processes of storing and consuming carbohydrates in the body.
Frequent increases in uric acid levels can cause metabolic syndrome, including obesity, increased cholesterol levels in the blood and, as a consequence, high blood pressure.
And all because fructose is the natural sugar contained in fruits (although some fruits such as oranges and grapes also contain a large amount of glucose) - is processed in the liver not into glycogen (a special substance that is used to cover energy costs caused by muscle work ), but into fat! Getting into the body, fructose passes a special enzyme - fructokinase-1. And he is responsible for processing the incoming carbohydrates into the body and decides what to convert the carbohydrates to: glycogen or fat. Complex carbohydrates such as oatmeal, macaroni, wild rice, having got into the body, turn mainly into glycogen, and in this form are deposited in the liver and muscles. This happens until there is a free space in the "store rooms" of your body, and only then these carbohydrates will be processed into fat (according to scientific data, the human body is able to store about 250,400 grams of carbohydrates in the form of glycogen). Fructose, however, almost completely turns the liver into fat, which, when ingested, is immediately absorbed by the fat cells.
Little of! When entering the blood, glucose usually passes unhindered through the liver - this peculiar filter of the body and is sent from there straight to the muscles. What happens if a part of the fructose your body gets into the liver and turns into glycogen? And the fact that your wise organism will say "no" to any other incoming carbohydrates and block their intake, both to the liver and to the muscles through the liver. As a result, unclaimed complex carbohydrates will turn not into precious muscle glycogen, which is capable of providing a powerful burst of energy, but in hateful fat!
Recently, in a study published in the journal Hepatology, rats were fed a sugar solution containing glucose in one case, in another fructose. Feeding rats with fructose led to two serious consequences: increased production of fats in the liver and a decrease in the effectiveness of protein leptin (in addition to other functions, leptin is responsible for fat metabolism).
The study revealed that some of the negative properties of fructose were the result of impairment of the receptor function, known as alpha-polyphosphoric acid. This receptor is present in the human body, and its activity in humans is less than in rats. As a result, one of the authors of the study suggested that the effect of fructose on humans should cause even worse consequences than those observed in rats. It seems that there is every reason to believe that the use of fructose can contribute to the growth of the obesity process observed in the world.
Therefore, fructose is not considered a healthy food supplement. The use of a large number of soft drinks containing fructose is more conducive to obesity than the use of other sweeteners.
At one time, such work was carried out: the researchers offered experimental mice a choice of water, a solution of fructose and soft drinks with fructose. In mice - lovers of fructose-containing beverages, there was a more significant increase in weight, even with a decrease in the overall kallorazha ration. In these mice, not only weight gain was noted, but, most notably, this increase was 90% due to adipose tissue.
It is also proved that some hormones that react to glucose (leptin, insulin, etc.) do not perform their normal functions when using fructose. The appearance of obesity is explained not only by the high calorie content of fructose, but also by the changes in metabolism that contribute to the accumulation of fat.
Let's imagine two oranges. We simply clean one, eat it, and squeeze out juice from another and drink it.
What happens when this juice gets to us in the stomach, and then the intestines. The fructose contained in it in the liquid form will immediately absorb and become glucose. If we just eat an orange, our body will have to take the time and effort to extract fructose from it. Her intake into the blood will not be so rapid as from the juice. Insulin for the recovery of the resulting glucose will be allocated gradually and little by little.
Fans of fructose should also know that it is caloric as a sugar - 2.5 times sweeter than glucose and 1.7 - sucrose. For this reason, a number of specialists associate the epidemic of obesity in the US with the use of fructose.
We have been talking about carbohydrates for so long and their ability to influence the production of insulin, which involuntarily raises the question, and what is the relationship between insulin production and the accumulation of fats.
It turns out that in humans the process of accumulation or not accumulation of reserve fat in the body is directly connected with the release of this remarkable hormone. Insulin is secreted by the pancreas and performs a vital role in the metabolism, promoting the penetration of nutrients into the cell. And although his main natural purpose is to remove carbohydrates from the blood, in some cases he takes a direct part in the deposition of fats. Why and how does this happen? Let's understand.
So, the normal reaction of the body to increase blood glucose is the release of insulin, which affects glucose (that is, sugar), helping it penetrate into the tissues of the body. It's good. Glucose immediately satisfies the energy needs of the body. And it's great! It seems, on this all !? Sugar in the blood "decreased" - insulin should not be allocated more.
But, as it turned out, some people have insulin in the blood always too much. This is associated with the loss of sensitivity to it by the receptors of the body (insulin resistance). Remember what I wrote at the beginning of this chapter.
Sometimes heredity is guilty, sometimes chromium deficiency, but more often - love of sweet life, that is, to easily assimilated carbohydrates. For several years of constant consumption of a large number of products that have a high glycemic or insulinemic index, the pancreas is trained to throw out endless streams of insulin, and the body eventually loses its sensitivity to it. In this case, even despite the decrease in glucose (sugar) in the blood, insulin continues to be released into the blood, as its regulation is disrupted.
Quite simple and fairly accurate criterion for determining the presence of pancreatic pathology and loss of receptor sensitivity to insulin is associated with the distribution of fat. It is defined as the ratio of the lengths of the circumference of the waist and hips. However, as it was established in recent studies, the situation with abdominal fat accumulation is characterized more precisely by the circumference of the waist circumference.
Dr. Gerald M. Riven and colleagues at Stanford University School of Medicine suggested that the BMI and waist circumference may be equally effective for identifying patients with insulin resistance (insensitivity). In this case, the risk group can include those patients whose waist circumference in men exceeded 94 cm, and in women 80 cm. Want to measure your waist? I'll wait. Although for many, the big question is where to look for this very waist.
Scientists rated 260 apparently healthy volunteers, 133 of whom were classified as obese. They found that insulin sensitivity and associated metabolic cardiovascular risk factors are directly related to the increase in obesity, regardless of whether it was used as an excess weight index - BMI or waist circumference.
So, suppose you have latent or obvious resistance (insensitivity) to insulin. In this case, the blood constantly high concentration of this hormone, and you decided to treat yourself, say, cream cake. What will happen? And what will happen is that - immediately satisfying energy needs at the expense of sugar, your body will immediately try to postpone fats (fat cream) in reserve. And he will do it very successfully thanks to a huge amount of the same insulin. After all, the fat stores of the body are huge. As this happens on a more subtle level, I will try to explain easily.
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Insulin and insulinemic index.
A whole generation of scientists tried to isolate insulin from the islets of Langerhans. Success finally came to the 30-year-old Canadian physician Frederick Grant Bunting, who in the summer of 1921 worked at the University of Toronto, trying to solve this problem. He was assisted by a 21-year-old doctor, Charles Herbert West. Banting and Best took the decisive step: they bandaged the excretory duct of the pancreas
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