marți, 30 noiembrie 2010
joi, 18 noiembrie 2010
miercuri, 10 noiembrie 2010
joi, 21 octombrie 2010
sâmbătă, 16 octombrie 2010
insulin
ultima parte dintr-o serie de articole interesante despre insulina aici
The bottom line is that insulin does not deserve the bad reputation that it has been given, and the “carbohydrates drive insulin which drives fat storage” mantra is wrong. To summarize:
Insulin suppresses appetite; it does not increase it
A high carbohydrate diet does not cause chronically high insulin levels
Protein is insulinemic, and in certain cases, can be just as insulinemic as carbohydrate
Contrary to popular belief, glucagon does not “cancel out” the suppression of lipolysis by insulin when protein is ingested
The insulinemic effects of protein are due to a direct stimulatory effect on the pancreas, and not because the protein is converted to glucose
The combination of protein and carbohydrate can produce greater insulin secretion than either one alone, yet high protein, moderate-to-high carbohydrate diets are very effective for weight loss
Very high carbohydrate diets have been demonstrated to produce weight loss when people are in an energy deficit
Dairy is extremely insulinemic, just as insulinemic as white bread, yet does not promote weight gain in the absence of an energy surplus. This is supported by a very large number of studies, including animal studies, observational studies, and randomized controlled trials.
Insulin is not required for fat storage
Insulin levels are not predictive of weight gain or weight loss in the majority of prospective studies
Exenatide restores rapid phase insulin release in diabetics, yet causes weight loss
The effects of insulin injection cannot be compared to normal physiological insulin release, since amylin is co-secreted with insulin from the pancreas
Insulin mainly functions as an inhibitory hormone rather than a storage hormone, acting as a brake on many important physiologic processes
A type I diabetic without insulin becomes hyperglycemic because of overproduction of glucose by the liver, not because insulin can’t get into cells
Insulin enhances the uptake of glucose into cells, but is not required for it
Insulin regulates blood sugar after a meal both by stopping the liver from producing glucose and enhancing glucose uptake into cells.
In a fasted state, insulin regulates blood sugar by controlling glucose production of the liver, not by affecting the uptake of glucose into cells
You cannot simply look at the temporary effects of insulin on lipolysis and glucose storage. You have to address what is happening over a 24-hour period; body fat will not increase if there is no overall energy surplus.
The bottom line is that insulin does not deserve the bad reputation that it has been given, and the “carbohydrates drive insulin which drives fat storage” mantra is wrong. To summarize:
Insulin suppresses appetite; it does not increase it
A high carbohydrate diet does not cause chronically high insulin levels
Protein is insulinemic, and in certain cases, can be just as insulinemic as carbohydrate
Contrary to popular belief, glucagon does not “cancel out” the suppression of lipolysis by insulin when protein is ingested
The insulinemic effects of protein are due to a direct stimulatory effect on the pancreas, and not because the protein is converted to glucose
The combination of protein and carbohydrate can produce greater insulin secretion than either one alone, yet high protein, moderate-to-high carbohydrate diets are very effective for weight loss
Very high carbohydrate diets have been demonstrated to produce weight loss when people are in an energy deficit
Dairy is extremely insulinemic, just as insulinemic as white bread, yet does not promote weight gain in the absence of an energy surplus. This is supported by a very large number of studies, including animal studies, observational studies, and randomized controlled trials.
Insulin is not required for fat storage
Insulin levels are not predictive of weight gain or weight loss in the majority of prospective studies
Exenatide restores rapid phase insulin release in diabetics, yet causes weight loss
The effects of insulin injection cannot be compared to normal physiological insulin release, since amylin is co-secreted with insulin from the pancreas
Insulin mainly functions as an inhibitory hormone rather than a storage hormone, acting as a brake on many important physiologic processes
A type I diabetic without insulin becomes hyperglycemic because of overproduction of glucose by the liver, not because insulin can’t get into cells
Insulin enhances the uptake of glucose into cells, but is not required for it
Insulin regulates blood sugar after a meal both by stopping the liver from producing glucose and enhancing glucose uptake into cells.
In a fasted state, insulin regulates blood sugar by controlling glucose production of the liver, not by affecting the uptake of glucose into cells
You cannot simply look at the temporary effects of insulin on lipolysis and glucose storage. You have to address what is happening over a 24-hour period; body fat will not increase if there is no overall energy surplus.
luni, 11 octombrie 2010
miercuri, 29 septembrie 2010
low carb diets study on mortality
Low-carbohydrate diets and all-cause and cause-specific mortality: two cohort studies.
Fung TT, van Dam RM, Hankinson SE, Stampfer M, Willett WC, Hu FB.
Harvard School of Public Health, Boston, Massachusetts 02115, USA.
Comment in:
* Ann Intern Med. 2010 Sep 7;153(5):337-9.
Abstract
BACKGROUND: Data on the long-term association between low-carbohydrate diets and mortality are sparse.
OBJECTIVE: To examine the association of low-carbohydrate diets with mortality during 26 years of follow-up in women and 20 years in men.
DESIGN: Prospective cohort study of women and men who were followed from 1980 (women) or 1986 (men) until 2006. Low-carbohydrate diets, either animal-based (emphasizing animal sources of fat and protein) or vegetable-based (emphasizing vegetable sources of fat and protein), were computed from several validated food-frequency questionnaires assessed during follow-up.
SETTING: Nurses' Health Study and Health Professionals' Follow-up Study.
PARTICIPANTS: 85 168 women (aged 34 to 59 years at baseline) and 44 548 men (aged 40 to 75 years at baseline) without heart disease, cancer, or diabetes.
MEASUREMENTS: Investigators documented 12 555 deaths (2458 cardiovascular-related and 5780 cancer-related) in women and 8678 deaths (2746 cardiovascular-related and 2960 cancer-related) in men.
RESULTS: The overall low-carbohydrate score was associated with a modest increase in overall mortality in a pooled analysis (hazard ratio [HR] comparing extreme deciles, 1.12 [95% CI, 1.01 to 1.24]; P for trend = 0.136). The animal low-carbohydrate score was associated with higher all-cause mortality (pooled HR comparing extreme deciles, 1.23 [CI, 1.11 to 1.37]; P for trend = 0.051), cardiovascular mortality (corresponding HR, 1.14 [CI, 1.01 to 1.29]; P for trend = 0.029), and cancer mortality (corresponding HR, 1.28 [CI, 1.02 to 1.60]; P for trend = 0.089). In contrast, a higher vegetable low-carbohydrate score was associated with lower all-cause mortality (HR, 0.80 [CI, 0.75 to 0.85]; P for trend
LIMITATIONS: Diet and lifestyle characteristics were assessed with some degree of error. Sensitivity analyses indicated that results were probably not substantively affected by residual confounding or an unmeasured confounder. Participants were not a representative sample of the U.S. population.
CONCLUSION: A low-carbohydrate diet based on animal sources was associated with higher all-cause mortality in both men and women, whereas a vegetable-based low-carbohydrate diet was associated with lower all-cause and cardiovascular disease mortality rates.
Fung TT, van Dam RM, Hankinson SE, Stampfer M, Willett WC, Hu FB.
Harvard School of Public Health, Boston, Massachusetts 02115, USA.
Comment in:
* Ann Intern Med. 2010 Sep 7;153(5):337-9.
Abstract
BACKGROUND: Data on the long-term association between low-carbohydrate diets and mortality are sparse.
OBJECTIVE: To examine the association of low-carbohydrate diets with mortality during 26 years of follow-up in women and 20 years in men.
DESIGN: Prospective cohort study of women and men who were followed from 1980 (women) or 1986 (men) until 2006. Low-carbohydrate diets, either animal-based (emphasizing animal sources of fat and protein) or vegetable-based (emphasizing vegetable sources of fat and protein), were computed from several validated food-frequency questionnaires assessed during follow-up.
SETTING: Nurses' Health Study and Health Professionals' Follow-up Study.
PARTICIPANTS: 85 168 women (aged 34 to 59 years at baseline) and 44 548 men (aged 40 to 75 years at baseline) without heart disease, cancer, or diabetes.
MEASUREMENTS: Investigators documented 12 555 deaths (2458 cardiovascular-related and 5780 cancer-related) in women and 8678 deaths (2746 cardiovascular-related and 2960 cancer-related) in men.
RESULTS: The overall low-carbohydrate score was associated with a modest increase in overall mortality in a pooled analysis (hazard ratio [HR] comparing extreme deciles, 1.12 [95% CI, 1.01 to 1.24]; P for trend = 0.136). The animal low-carbohydrate score was associated with higher all-cause mortality (pooled HR comparing extreme deciles, 1.23 [CI, 1.11 to 1.37]; P for trend = 0.051), cardiovascular mortality (corresponding HR, 1.14 [CI, 1.01 to 1.29]; P for trend = 0.029), and cancer mortality (corresponding HR, 1.28 [CI, 1.02 to 1.60]; P for trend = 0.089). In contrast, a higher vegetable low-carbohydrate score was associated with lower all-cause mortality (HR, 0.80 [CI, 0.75 to 0.85]; P for trend
LIMITATIONS: Diet and lifestyle characteristics were assessed with some degree of error. Sensitivity analyses indicated that results were probably not substantively affected by residual confounding or an unmeasured confounder. Participants were not a representative sample of the U.S. population.
CONCLUSION: A low-carbohydrate diet based on animal sources was associated with higher all-cause mortality in both men and women, whereas a vegetable-based low-carbohydrate diet was associated with lower all-cause and cardiovascular disease mortality rates.
joi, 16 septembrie 2010
marți, 14 septembrie 2010
luni, 6 septembrie 2010
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