9) CONTROLLING BLOOD SUGAR WITH DIET
d) Protein Poisoning by Fruit Sugar
The major sugar found in fruit is a sugar called fructose. In a nutshell, this fruit sugar (fructose) is a very damaging sugar and should be avoided by individuals with type 2 diabetes. Unfortunately most of the literature is not up with the latest research and still recommends that individuals with type 2 diabetes eat a diet "rich in fruits and vegetables". Fructose is especially damaging when it is in the form of "high fructose corn syrup", a major commercial sweetener found in soft drinks and prepared sweets. Fructose in this form is very rapidly absorbed by the body and the liver can't react fast enough to stop major damage.
"Protein poisoning" (Glycation) is the major route whereby the body is damaged by type 2 diabetes and fructose "poisons" (glycates) protein at ten times the rate of blood sugar. But fructose doesn't register on blood sugar blood meters. If a person with type 2 diabetes eats too much fructose their "finger pick" blood sugar testing will not correlate with the A1c test. Testing of the blood (glucose) sugar level is meant to be indicative of the really meaningful blood test, the A1c test which is done in a Doctor's office. A1c measures the total protein poisoning ("glycation") of the blood (both fructose and glucose induced), which is the important measure as far as the health of the individual. Fructose can raise the A1c considerably without raising the blood sugar proportionately. If a person with diabetes eats too much fructose, the blood sugar tests can be consistently low and the A1c can then come in high. And at this point the blood sugar meter generally gets blamed.
But if fructose glycates proteins at ten times the rate of blood sugar, is fructose ten times worse than blood sugar or is it benign? The laboratory research seems to say that the actual truth lies somewhere in the middle, fructose in slowly digested fruit isn't going to kill you but its consumption should be low to moderate. I.e. don't go overboard on the fruit, keeping consumption to less than two fruit per day. The argument about fructose is a little difficult to follow but it can be sorted out. It all has to do with the mechanism of glycation, where a sugar harms a protein, i.e. "poisons" a protein, by reacting with the protein. It takes time for both blood sugar and fructose to "poison" protein in the body.
Fructose only remains in the blood stream about one eighth of the time that blood sugar remains in the blood stream as fructose is rapidly metabolized by the liver. Add it all up, and consuming fructose results in about 25% more "protein poisoning" than consuming blood sugar (glucose). This 25% is exactly what was found in a very well done study in rats in 1998 (Boaz Levi and Moshe J. Werman, "Long-Term Fructose Consumption Accelerates Glycation and Several Age-Related Variables in Male Rats"). So fructose is only a little worse than blood sugar (glucose) when it comes to its effect on the body of an individual with type 2 diabetes. But then blood sugar (glucose) is a real bad actor in the body of someone with type 2 diabetes so fructose ("fruit sugar") definitely needs to be avoided by those with type 2 diabetes. The technical explaination as to why fructose is so bad is:
Makoto et al:
"We examined the role of fructose in the development of diabetic complications. Glycation (Maillard reaction), a non-enzymatic binding reaction between protein and sugar, is considered to be a pathogenic factor of diabetic complications, aging, and arteriosclerosis. Compared with glucose, fructose increased the fluorescence intensity and the cross-linking of glycated collagen, and promoted the polymerization of proteins. Therefore fructose accelerated the production of advanced glycation end-products more than glucose. In addition, fructose enhanced the reactive oxygen or oxygen radical generation and the associated degeneration of proteins and lipids. These actions of fructose appeared to be due to the formation of dicarbonyl compounds such as 3-deoxyglucosone, a highly reactive intermediate product formed in the advanced glycation stage. These results suggest that fructose is closely involved not only in glycation but also in the polyol pathway and peroxidation reactions through free radical formation. Thus, fructose is considered to be a more critical reducing sugar associate with the progression of diabetic complications than it has been thought until now."
We would tend to discount this research as being too preliminary except for the fact that it dovetails with what our ancestors ate 50,000 years ago. The fruit they ate was much coarser, with 25 times the fiber level of what we eat today and much less fructose per fruit. On this basis, we have to give fructose "protein poisoning" or glycation some weight and we recommend individuals with type 2 diabetes avoid at least some fruits (especially dried fruits) completely or severely limit the amounts of fruit. It is well established that fiber slows down the absorption of sugars such as fructose and would prevent high levels of fructose in the blood, thus preventing some of the "protein poisoning". All fruits are not made equal in this regard. We recommend a maximum of only one fruit per day (personally we avoid all fruit), avoiding oranges, grapes, apricots, melons, pineapple, banana and all "tropical" fruit (guava, kiwi, etc). A complete list follows in the next subchapter.
Current Chapter: 9) CONTROLLING BLOOD SUGAR WITH DIET
a) Blood Sugar Control
b) Individualized Reactions
c) What a Diary Tells a Person with Diabetes
d) Protein Poisoning by Fruit Sugar
e) What are "Acceptable Fruits"
f) Other Sugars
g) Best Mix of Protein, Carbohydrates, and Fats
h) Low Carbohydrate Diets
i) Fitting the Diet to the Individual
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