od smajliss » pon říj 14, 2013 15:46
Narazil jsem na velmi zajímavý článek o cukrech a konkrétně se zde vychvalovala fruktoza na úkor glukozy. Je to hodně dlouhý článek, tak tu dám jenom ty nejdůležitější úrývky, Některé jsou hodně zajímavé
fructose can by-pass the fatty acids' inhibition of glucose metabolism, to be oxidized when glucose can't, and if the metabolism of diabetes involves the oxidation of fatty acids instead of glucose, then we would expect there to be less than the normal amount of fructose in the serum of diabetics, although their defining trait is the presence of an increased amount of glucose. According to Osuagwu and Madumere (2008), that is the case. If a fructose deficiency exists in diabetes, then it is appropriate to supplement it in the diet.
fructose has some special functions, that aren't as well performed by glucose. It is the main sugar involved in reproduction, in the seminal fluid and intrauterine fluid, and in the developing fetus. After these crucial stages of life are past, glucose becomes the primary molecular source of energy, except when the system is under stress. It has been suggested
The placenta turns glucose from the mother's blood into fructose, and the fructose in the mother's blood can pass through into the fetus, and although glucose can move back from the fetus into the mother's blood, fructose is unable to move in that direction, so a high concentration is maintained in the fluids around the fetus.
Fructose has been known for many years to accelerate the oxidation of ethanol (by about 80%). Oxygen consumption in the presence of ethanol is increased by fructose more than by glucose (Thieden and Lundquist, 1967).
Besides protecting against the reductive stresses, fructose can also protect against the oxidative stress of increased hydrogen peroxide (Spasojevic, et al., 2009). Its metabolite, fructose 1,6-bisphosphate, is even more effective as an antioxidant.
Endotoxin absorbed from the intestine is one of the ubiquitous stresses that tends to cause free radical damage. Fructose, probably more than glucose, is protective against damage from endotoxin.
Many studies have found that sucrose is less fattening than starch or glucose, that is, that more calories can be consumed without gaining weight. During exercise, the addition of fructose to glucose increases the oxidation of carbohydrate by about 50% (Jentjens and Jeukendrup, 2005).
The addition of fructose to glucose "can markedly reduce hyperglycemia during intraportal glucose infusion by increasing net hepatic glucose uptake even when insulin secretion is compromised" (Shiota, et al., 2005).
Lipid peroxidation is involved in the degenerative diseases, and many publications argue that fructose increases it, despite the fact that it can increase the production of uric acid, which is a major component of our endogenous antioxidant system (e.g., Waring, et al., 2003).
When people were given a 300 calorie drink containing glucose, or fructose, or orange juice, those receiving the glucose had a large increase in oxidative and inflammatory stress (reactive oxygen species, and NF-kappaB binding), and those changes were absent in those receiving the fructose or orange juice (Ghanim, et al., 2007).
Several later studies show that fructose increases the excretion of phosphate in the urine, while decreasing the level in the serum. However, a common opinion is that it's only the phosphorylation of fructose, increasing the amount in cells, that causes the decrease in the serum; that could account for the momentary drop in serum phosphate during a fructose load, but--since there is only so much phosphate that can be bound to intracellular fructose--it can't account for the chronic depression of the serum phosphate on a continuing diet of fructose or sucrose.
Fructose affects the body's ability to retain other nutrients, including magnesium, copper, calcium, and other minerals. Comparing diets with 20% of the calories from fructose or from cornstarch, Holbrook, et al. (1989) concluded "The results indicate that dietary fructose enhances mineral balance." Ordinarily, things (such as thyroid and vitamin D) which improve the retention of magnesium and other nutrients are considered good, but the fructose mythology allows researchers to conclude, after finding an increased magnesium balance, with either 4% or 20% of energy from fructose (compared to cornstarch, bread, and rice), "that dietary fructose adversely affects macromineral homeostasis in humans." (Milne and Nielsen, 2000).
Another study compared the effects of a diet with plain water, or water containing 13% glucose, or sucrose, or fructose, or high fructose corn syrup on the properties of rats' bones: Bone mineral density and mineral content, and bone strength, and mineral balance. The largest differences were between animals drinking the glucose and the fructose solutions. The rats getting the glucose had reduced phosphorus in their bones, and more calcium in their urine, than the rats that got fructose. "The results suggested that glucose rather than fructose exerted more deleterious effects on mineral balance and bone" (Tsanzi, et al., 2008).
An older experiment compared two groups with an otherwise well balanced diet, lacking vitamin D, containing either 68% starch or 68% sucrose. A third group got the starch diet, but with added vitamin D. The rats on the vitamin D deficient starch diet had very low levels of calcium in their blood, and the calcium content of their bones was low, exactly what is expected with the vitamin D deficiency. However, the rats on the sucrose diet, also vitamin D deficient, had normal levels of calcium in their blood. The sucrose, unlike the starch, maintained claim homeostasis. A radioactive calcium tracer showed normal uptake by the bone, and also apparently normal bone development, although their bones were lighter than those receiving vitamin D.
In monkeys living in the wild, when their diet is mainly fruit, their cortisol is low, and it rises when they eat a diet with less sugar (Behie, et al., 2010).
Narazil jsem na velmi zajímavý článek o cukrech a konkrétně se zde vychvalovala fruktoza na úkor glukozy. Je to hodně dlouhý článek, tak tu dám jenom ty nejdůležitější úrývky, Některé jsou hodně zajímavé
fructose can by-pass the fatty acids' inhibition of glucose metabolism, to be oxidized when glucose can't, and if the metabolism of diabetes involves the oxidation of fatty acids instead of glucose, then we would expect there to be less than the normal amount of fructose in the serum of diabetics, although their defining trait is the presence of an increased amount of glucose. According to Osuagwu and Madumere (2008), that is the case. If a fructose deficiency exists in diabetes, then it is appropriate to supplement it in the diet.
fructose has some special functions, that aren't as well performed by glucose. It is the main sugar involved in reproduction, in the seminal fluid and intrauterine fluid, and in the developing fetus. After these crucial stages of life are past, glucose becomes the primary molecular source of energy, except when the system is under stress. It has been suggested
The placenta turns glucose from the mother's blood into fructose, and the fructose in the mother's blood can pass through into the fetus, and although glucose can move back from the fetus into the mother's blood, fructose is unable to move in that direction, so a high concentration is maintained in the fluids around the fetus.
Fructose has been known for many years to accelerate the oxidation of ethanol (by about 80%). Oxygen consumption in the presence of ethanol is increased by fructose more than by glucose (Thieden and Lundquist, 1967).
Besides protecting against the reductive stresses, fructose can also protect against the oxidative stress of increased hydrogen peroxide (Spasojevic, et al., 2009). Its metabolite, fructose 1,6-bisphosphate, is even more effective as an antioxidant.
Endotoxin absorbed from the intestine is one of the ubiquitous stresses that tends to cause free radical damage. Fructose, probably more than glucose, is protective against damage from endotoxin.
Many studies have found that sucrose is less fattening than starch or glucose, that is, that more calories can be consumed without gaining weight. During exercise, the addition of fructose to glucose increases the oxidation of carbohydrate by about 50% (Jentjens and Jeukendrup, 2005).
The addition of fructose to glucose "can markedly reduce hyperglycemia during intraportal glucose infusion by increasing net hepatic glucose uptake even when insulin secretion is compromised" (Shiota, et al., 2005).
Lipid peroxidation is involved in the degenerative diseases, and many publications argue that fructose increases it, despite the fact that it can increase the production of uric acid, which is a major component of our endogenous antioxidant system (e.g., Waring, et al., 2003).
When people were given a 300 calorie drink containing glucose, or fructose, or orange juice, those receiving the glucose had a large increase in oxidative and inflammatory stress (reactive oxygen species, and NF-kappaB binding), and those changes were absent in those receiving the fructose or orange juice (Ghanim, et al., 2007).
Several later studies show that fructose increases the excretion of phosphate in the urine, while decreasing the level in the serum. However, a common opinion is that it's only the phosphorylation of fructose, increasing the amount in cells, that causes the decrease in the serum; that could account for the momentary drop in serum phosphate during a fructose load, but--since there is only so much phosphate that can be bound to intracellular fructose--it can't account for the chronic depression of the serum phosphate on a continuing diet of fructose or sucrose.
Fructose affects the body's ability to retain other nutrients, including magnesium, copper, calcium, and other minerals. Comparing diets with 20% of the calories from fructose or from cornstarch, Holbrook, et al. (1989) concluded "The results indicate that dietary fructose enhances mineral balance." Ordinarily, things (such as thyroid and vitamin D) which improve the retention of magnesium and other nutrients are considered good, but the fructose mythology allows researchers to conclude, after finding an increased magnesium balance, with either 4% or 20% of energy from fructose (compared to cornstarch, bread, and rice), "that dietary fructose adversely affects macromineral homeostasis in humans." (Milne and Nielsen, 2000).
Another study compared the effects of a diet with plain water, or water containing 13% glucose, or sucrose, or fructose, or high fructose corn syrup on the properties of rats' bones: Bone mineral density and mineral content, and bone strength, and mineral balance. The largest differences were between animals drinking the glucose and the fructose solutions. The rats getting the glucose had reduced phosphorus in their bones, and more calcium in their urine, than the rats that got fructose. "The results suggested that glucose rather than fructose exerted more deleterious effects on mineral balance and bone" (Tsanzi, et al., 2008).
An older experiment compared two groups with an otherwise well balanced diet, lacking vitamin D, containing either 68% starch or 68% sucrose. A third group got the starch diet, but with added vitamin D. The rats on the vitamin D deficient starch diet had very low levels of calcium in their blood, and the calcium content of their bones was low, exactly what is expected with the vitamin D deficiency. However, the rats on the sucrose diet, also vitamin D deficient, had normal levels of calcium in their blood. The sucrose, unlike the starch, maintained claim homeostasis. A radioactive calcium tracer showed normal uptake by the bone, and also apparently normal bone development, although their bones were lighter than those receiving vitamin D.
In monkeys living in the wild, when their diet is mainly fruit, their cortisol is low, and it rises when they eat a diet with less sugar (Behie, et al., 2010).