(TESTO IN ITALIANO SOTTO)
A daily intake of high
glycemic index carbohydrates is associated with an increased risk of
coronaropathy, obesity, diabetes and cardiovascular pathologies.
It seems that caloric
restriction benefits could be associated with the insulin resistance
prevention.
Impaired glucose tolerance
is associated with carotid atherosclerosis and with high
cardiovascular risk (while a normal glucose tolerance and a plasma
glucose within the normal range are not).
Insulin/glycemia excess
and insulin resistance are associated with coronary heart disease,
carotid atherosclerosis and cardiovascular risk.
Insulin-resistance is
associated with cardiovascular disease independently of all classic
and several nontraditional risk factors.
Insulin-resistance could
be an important target to reduce cardiovascular disease risk.
High glycemic index
carbohydrates produce substantial increases in blood glucose and
insulin levels after ingestion. Their insulin stimulation is so
strong that after their ingestion blood sugar levels begin to decline
rapidly due to an exaggerated increase in insulin secretion.
According to these data,
we can conclude that the pluridecennial daily intake of high glycemic
carbohydrates (that is typical of most people) could be strongly
associated with these pathologies.
Furthermore a low-glycemic
index carbohydrates based diet could be useful for their prevention
and treatment.
COMMENTO IN ITALIANO:
(e sotto)
Sources:
Diabetes Care. 2007
Feb;30(2):318-24.
Insulin resistance as
estimated by homeostasis model assessment predicts incident
symptomatic cardiovascular disease in caucasian subjects from the
general population: the Bruneck study.
Bonora E, Kiechl S,
Willeit J, Oberhollenzer F, Egger G, Meigs JB, Bonadonna RC, Muggeo
M.
Endocrinologia e Malattie
del Metabolismo, Ospedale Maggiore, Piazzale Stefani 1, 37126 Verona,
Italy. enzobonora@virgilio.it
Abstract
OBJECTIVE:
The purpose of this study
was to evaluate whether insulin resistance is associated to
cardiovascular disease (CVD) and to understand whether this
association can be explained by traditional and novel CVD risk
factors associated with this metabolic disorder.
RESEARCH DESIGN AND
METHODS:
We examined a sample
representative of the population of Bruneck, Italy (n = 919; aged
40-79 years). Insulin-resistant subjects were those with a score in
the top quartile of the homeostasis model assessment (HOMA) for
insulin resistance (HOMA-IR). Risk factors correlated with insulin
resistance included BMI, A1C, HDL cholesterol, triglycerides, blood
pressure, high-sensitivity C-reactive protein (hsCRP), fibrinogen,
oxidized LDL, vascular cell adhesion molecule-1 (VCAM-1), and
adiponectin. Subjects without CVD at baseline were followed up for 15
years for incident CVD, a composite end point including fatal and
nonfatal myocardial infarction and stroke, transient ischemic attack,
and any revascularization procedure.
RESULTS:
During follow-up, 118
subjects experienced a first symptomatic CVD event. Levels of HOMA-IR
were higher at baseline among subjects who developed CVD (2.8)
compared with those remaining free of CVD (2.5) (P < 0.05). Levels
of HOMA-IR also were significantly correlated (P < 0.05) with most
CVD risk factors we evaluated. In Cox proportional hazard models,
insulin-resistant subjects had an age-, sex-, and smoking-adjusted
2.1-fold increased risk (95% CI 1.3-3.1) of incident symptomatic CVD
relative to non-insulin-resistant subjects. After sequential
adjustment for physical activity and classic risk factors (A1C, LDL
cholesterol, and hypertension) as well as BMI, HDL cholesterol,
triglycerides, and novel risk factors, including fibrinogen, oxidized
LDL, hsCRP, VCAM-1, and adiponectin, the association between HOMA-IR
and incident CVD remained significant and virtually unchanged (hazard
ratio 2.2 [95% CI 1.4-3.6], P < 0.001).
CONCLUSIONS:
HOMA-estimated insulin
resistance is associated with subsequent symptomatic CVD in the
general population independently of all classic and several
nontraditional risk factors. These data suggest that insulin
resistance may be an important target to reduce CVD risk.
Diabetes Care. 2003
Apr;26(4):1251-7.
Carotid atherosclerosis
and coronary heart disease in the metabolic syndrome: prospective
data from the Bruneck study.
Bonora E, Kiechl S,
Willeit J, Oberhollenzer F, Egger G, Bonadonna RC, Muggeo M; Bruneck
study.
Division of Endocrinology
and Metabolic Diseases, University of Verona Medical School, Verona,
Italy. enzobonora@virgilio.it
Abstract
OBJECTIVE:
The present study aimed at
prospectively evaluating carotid atherosclerosis and coronary heart
disease (CHD) in subjects with the metabolic syndrome.
RESEARCH DESIGN AND
METHODS:
Within a prospective
population-based survey examining 888 subjects aged 40-79 years, 303
subjects were identified as fulfilling World Health Organization
(WHO) criteria and 158 as fulfilling the National Cholesterol
Education Program (NCEP)-Adult Treatment Panel (ATP)-III criteria for
diagnosing the metabolic syndrome. The 5-year change in carotid
status, as assessed by echo-duplex scanning, and incident fatal and
nonfatal CHD, as assessed by medical history and death certificates,
were compared in subjects with the metabolic syndrome and in the rest
of the sample (control subjects).
RESULTS:
Compared with the control
subjects, subjects with the metabolic syndrome by WHO criteria had an
increased 5-year incidence and progression of carotid
atherosclerosis: 51 vs. 35% developed new plaques (P = 0.021) and 34
vs. 19% developed carotid stenosis >40% (P = 0.002) after
adjusting for several confounders. Subjects with the metabolic
syndrome by these criteria also had an increased incidence of CHD
during follow-up: 8 vs. 3% in control subjects (P = 0.012). Similar
results were found when the NCEP-ATPIII criteria were used.
CONCLUSIONS:
Subjects with the
metabolic syndrome are at increased risk for both progressive carotid
atherosclerosis and CHD.
Crit Rev Food Sci Nutr.
2003;43(4):357-77.
Low-glycemic-load
diets: impact on obesity and chronic diseases.
Bell SJ, Sears B.
Sears Labs, 222 Rosewood
Drive, Suite 500, Danvers, Massachusetts 01923, USA.
sbell@searslabs.com
Abstract
Historically,
carbohydrates have been thought to play only a minor role in
promoting weight gain and in predicting the risk of development of
chronic disease. Most of the focus had been on reducing total dietary
fat. During the last 20 years, fat intake decreased, while the number
of individuals who were overweight or developed a chronic conditions
have dramatically increased. Simultaneously, the calories coming from
carbohydrate have also increased. Carbohydrates can be classified by
their post-prandial glycemic effect, called the glycemic index or
glycemic load. Carbohydrates with high glycemic indexes and high
glycemic loads produce substantial increases in blood glucose and
insulin levels after ingestion. Within a few hours after their
consumption, blood sugar levels begin to decline rapidly due to an
exaggerated increase in insulin secretion. A profound state of hunger
is created. The continued intake of high-glycemic load meals is
associated with an increased risk of chronic diseases such as
obesity, cardiovascular disease, and diabetes. In this review, the
terms glycemic index and glycemic load are defined, coupled with an
overview of short- and long-term changes that occur from eating diets
of different glycemic indexes and glycemic loads. Finally, practical
strategies for how to design low-glycemic-load diets consisting
primarily of low-glycemic carbohydrates are provided.
Diabetologia. 2000
Feb;43(2):156-64.
Impaired glucose
tolerance, Type II diabetes mellitus and carotid atherosclerosis:
prospective results from the Bruneck Study.
Bonora E, Kiechl S,
Oberhollenzer F, Egger G, Bonadonna RC, Muggeo M, Willeit J.
Department of
Endocrinology and Metabolic Diseases, University of Verona Medical
School, Italy.
Abstract
AIMS/HYPOTHESIS:
Cardiovascular disease is
a well-known severe complication of impaired glucose tolerance and
Type II (non-insulin-dependent) diabetes mellitus. The independent
contribution of glucose intolerance to cardiovascular disease and the
underlying pathogenic mechanisms are still, however, not clear.
METHODS:
In this prospective
population-based study, 826 subjects aged 40-79 years underwent high
resolution duplex ultrasound examinations of carotid arteries and
extensive clinical and laboratory screenings for potential vascular
risk factors at baseline and 5 years later. The ultrasound protocol
involved measurements of maximum axial diameter of atherosclerotic
plaques, if any, in common and internal carotid arteries on both
sides and enable differentiation of two main stages in carotid artery
disease, termed early non-stenotic and advanced stenotic
atherosclerosis. Intima-media thickness was assessed at the follow-up
examination.
RESULTS:
Type II diabetes and, to a
lesser extent, impaired glucose tolerance were found to be
statistically significant risk predictors of 5-year changes in
carotid atherosclerosis. These associations were in part independent
of other vascular risk factors typically clustering with glucose
intolerance. Both impaired glucose tolerance and Type II diabetes
mellitus were not independently related to early non-stenotic
atherosclerosis. In contrast, Type II diabetes mellitus was the
strongest single risk predictor of advanced stenotic atherosclerosis
[odds ratio 5.0 (95% confidence intervals 2.3-11.1)] and impaired
glucose tolerance was of relevance as well [odds ratio 2.8 (1.2-6.4)]
(p < 0.001).
CONCLUSION/INTERPRETATION:
Impaired glucose tolerance
and, to a greater extent, Type II diabetes were strong independent
predictors of advanced carotid atherosclerosis in our prospective
population-based study.
Diabetes Care. 1999
Aug;22(8):1339-46.
Plasma glucose within
the normal range is not associated with carotid atherosclerosis:
prospective results in subjects with normal glucose tolerance from
the Bruneck Study.
Bonora E, Kiechl S,
Willeit J, Oberhollenzer F, Egger G, Bonadonna R, Muggeo M.
Department of
Endocrinology and Metabolic Diseases, University of Verona Medical
School, Italy.
Abstract
OBJECTIVE:
There is substantial
evidence that glucose intolerance is associated with an increased
risk of cardiovascular disease. However, it is not well established
whether plasma glucose is independently related to atherosclerosis
when glucose tolerance is normal and, if so, to which stage of the
complex atherosclerotic process.
RESEARCH DESIGN AND
METHODS:
We prospectively examined
the status of carotid arteries in 625 subjects aged 40-79 years who
were randomly selected from the general population and had normal
glucose tolerance (according to World Health Organization criteria)
both at baseline and at 5 years of follow-up. All subjects had
high-resolution echo-duplex evaluation of the common and internal
carotid arteries (eight regions of interest on both sides) in 1990
and 1995 to detect the change in carotid status over time. The
occurrence of new plaques in previously normal segments was termed
"incident nonstenotic" or "early atherosclerosis,"
and the occurrence of stenosis in >40% of previously normal
segments was termed "incident stenotic" or "advanced
atherosclerosis." In addition, we evaluated the changes in the
atherosclerosis score (the sum of all plaques) during the follow-up,
and we measured intimal-medial thickening (IMT) in the common carotid
artery in 1995. In all subjects, several candidate risk factors were
assessed: sex, age, BMI, waist-to-hip ratio, glucose, HbA1c, insulin,
urate, lipids, apolipoproteins A1 and B, blood pressure,
lipoprotein(a), fibrinogen, antithrombin III, factor V Leiden
mutation, ferritin, leukocyte count, smoking, alcohol intake,
physical activity, and socioeconomic status. Fasting plasma glucose
(FPG), plasma glucose 2 hr after the glucose load (2-h PG), and HbA1c
concentrations in 1990 and 1995 were averaged in each subject to
obtain an estimate of long-term glucose exposure of the arterial
wall.
RESULTS:
Linear or logistical
regression analyses indicated that neither baseline glucose and HbA1c
levels nor mean FPG, mean 2-h PG, or mean HbA1c in 1990 and 1995 were
independently related to IMT, a 5-year change in the atherosclerotic
score, incident nonstenotic (early) atherosclerosis, or incident
stenotic (advanced) atherosclerosis. Likewise, subjects with FPG
levels above the median and subjects in the new category of "impaired
fasting glucose" did not have an increased occurrence or
progression of atherosclerosis. All results were consistent before
and after adjustment for other vascular risk factors and possible
confounders.
CONCLUSIONS:
These results suggest that
plasma glucose levels within the normal range (<7.8 mg/dl both at
FPG and 2-h PG) are not independently related to any stage of
atherosclerosis.
Diabetes. 1998
Oct;47(10):1643-9.
Prevalence of insulin
resistance in metabolic disorders: the Bruneck Study.
Bonora E, Kiechl S,
Willeit J, Oberhollenzer F, Egger G, Targher G, Alberiche M,
Bonadonna RC, Muggeo M.
Division of Endocrinology
and Metabolic Diseases, University of Verona Medical School and
Azienda Ospedaliera di Verona, Italy.
Abstract
The prevalence of insulin
resistance in the most common metabolic disorders is still an
undefined issue. We assessed the prevalence rates of insulin
resistance in subjects with impaired glucose tolerance (IGT), NIDDM,
dyslipidemia, hyperuricemia, and hypertension as identified within
the frame of the Bruneck Study. The study comprised an age- and
sex-stratified random sample of the general population (n = 888; aged
40-79 years). Insulin resistance was estimated by homeostasis model
assessment (HOMA(IR)), preliminarily validated against a
euglycemic-hyperinsulinemic clamp in 85 subjects. The lower limit of
the top quintile of HOMA(IR) distribution (i.e., 2.77) in nonobese
subjects with no metabolic disorders (n = 225) was chosen as the
threshold for insulin resistance. The prevalence of insulin
resistance was 65.9% in IGT subjects, 83.9% in NIDDM subjects, 53.5%
in hypercholesterolemia subjects, 84.2% in hypertriglyceridemia
subjects, 88.1% in subjects with low HDL cholesterol, 62.8% in
hyperuricemia subjects, and 58.0% in hypertension subjects. The
prevalence of insulin resistance in subjects with the combination of
glucose intolerance (IGT or NIDDM), dyslipidemia
(hypercholesterolemia and/or hypertriglyceridemia and/or low HDL
cholesterol), hyperuricemia, and hypertension (n = 21) was 95.2%. In
isolated hypercholesterolemia, hypertension, or hyperuricemia,
prevalence rates of insulin resistance were not higher than that in
nonobese normal subjects. An appreciable number of subjects (n = 85,
9.6% of the whole population) was insulin resistant but free of IGT,
NIDDM, dyslipidemia, hyperuricemia, and hypertension. These results
from a population-based study documented that 1) in
hypertriglyceridemia and a low HDL cholesterol state, insulin
resistance is as common as in NIDDM, whereas it is less frequent in
hypercholesterolemia, hyperuricemia, and hypertension; 2) the vast
majority of subjects with multiple metabolic disorders are insulin
resistant; 3) in isolated hypercholesterolemia, hyperuricemia, or
hypertension, insulin resistance is not more frequent than can be
expected by chance alone; and 4) in the general population, insulin
resistance can be found even in the absence of any major metabolic
disorders.
Stroke. 1997
Jun;28(6):1147-52.
Relationship between
insulin and carotid atherosclerosis in the general population. The
Bruneck Study.
Bonora E, Willeit J,
Kiechl S, Oberhollenzer F, Egger G, Bonadonna R, Muggeo M.
Department of
Endocrinology and Metabolie Diseases, University of Verona (Italy)
Medical School, Italy.
Abstract
BACKGROUND AND PURPOSE:
Although several studies
have investigated the association between insulin and coronary heart
disease, the relationship between this hormone and carotid
atherosclerosis is not well established.
METHODS:
As a part of a
population-based survey on atherosclerosis and its risk factors,
serum insulin was measured at fasting (n = 888) and at 2 hours after
an oral glucose load (n = 811; known diabetic subjects were
excluded). The study population comprised an age- and sex-stratified
random sample of men and women aged 40 to 79 years. Atherosclerosis
in the common and internal carotid arteries was assessed twice (in
1990 and 1995) by duplex sonography. Progression during the 5-years
follow-up was defined by an increase in the atherosclerosis score of
more than the doubled measurement error (> 27%) or by the
occurrence of new plaques. Subjects were stratified in quintiles
according to baseline serum insulin at fasting or 2 hours after
glucose loading.
RESULTS:
Logistic regression
analysis revealed a significant association of carotid
atherosclerosis with both low and high insulin (U-shaped relation).
This finding was found before and after adjustment for several
covariates (sex, age, body mass index, glucose tolerance,
triglycerides, apolipoproteins Al and B, fibrinogen, blood pressure
status, behavioral variables, and socioeconomic status). This
relation applied equally to fasting and postglucose insulin and was
more pronounced in the prospective analysis than in the
cross-sectional analysis.
CONCLUSIONS:
We conclude that both
"hypoinsulinemia" and hyperinsulinemia are independent risk
indicators of carotid atherosclerosis.
J Gerontol A Biol Sci
Med Sci. 1995 May;50(3):B142-7.
Long-term dietary
restriction in older-aged rhesus monkeys: effects on insulin
resistance.
Bodkin NL, Ortmeyer HK,
Hansen BC.
School of Medicine,
Department of Physiology, University of Maryland at Baltimore, USA.
Abstract
Long-term dietary
restriction to maintain constant body weight in adult rhesus monkeys
prevents the development of impaired glucose tolerance,
hyperglycemia, and noninsulin-dependent diabetes mellitus. We sought
to determine whether these positive antidiabetogenic effects of
reduced calorie intake with maintenance of normal lean body weight
might be mediated through prevention of the development of insulin
resistance. Insulin-stimulated glucose uptake was assessed by the
euglycemic hyperinsulinemic clamp technique in seven older-aged
rhesus monkeys (20.7 +/- 0.6 years) who had been dietary restricted
for 9 +/- 2 years. Results were compared to seven ad libitum-fed
nondiabetic monkeys of similar age (21.0 +/- 1.3 years). Results
showed that the dietary restricted monkeys had significantly higher
in vivo insulin action compared to the ad libitum-fed group (14.06
+/- 2.4 vs 7.75 +/- 0.9 mg/kg FFM/min, respectively; p < .03). We
conclude that long-term dietary restriction is an effective means of
mitigating the development of significant insulin resistance in
older-aged rhesus monkeys, and may be the mechanism underlying the
prevention of Type II diabetes in this model.
COMMENTO IN ITALIANO:
La connessione tra
insulina e le patologie diffuse.
Un apporto giornaliero di
carboidrati ad alto indice glicemico è associato con aumentato
rischio di coronaropatia, obesità, diabete e patologie
cardiovascolari.
Sembra che i benefici
della restrizione calorica siano associati alla prevenzione
dell'insulino-resistenza.
La ridotta tolleranza al
glucosio è associata con aterosclerosi carotidea a con elevato
rischio cardiovascolare (mentre la normale tolleranza al glucosio ed
il livello di glucosio plasmatico nei limiti del range normale non lo
sono).
L'eccesso di
insulina/glicemia e la resistenza all'insulina sono associati con la
malattia coronarica, l'aterosclerosi carotidea ed il rischio
cardiovascolare.
L'insulinoresistenza è
associata con la patologia cardiovascolare indipendentemente da tutti
gli altri numerosi fattori di rischio classici e non tradizionali.
Agire
sull'insulinoresistenza potrebbe essere un importante obiettivo per
ridurre il rischio cardiovascolare.
I carboidrati ad alto
indice glicemico producono un sostenziale incremento nei livelli
ematici di glucosio ed insulina. La loro stimolazione insulinica è
così forte che dopo l'ingestione di tali tipi di carboidrati i
livelli ematici di glucosio iniziano a diminuire rapidamente.
In base a questi dati
possiamo concludere che l'apporto quotidiano pluridecennale di
carboidrati ad alto indice glicemico (che è tipico della maggior
parte della popolazione) potrebbe essere fortemente associato con le
suddette patologie.
Inoltre, un dieta basata
su carboidrati a basso indice glicemico potrebbe essere molto utile
per la prevenzione ed il trattamento di esse.
