lunedì 16 luglio 2012

Harms of hydrogenated oils

(TESTO IN ITALIANO SOTTO)

Hydrogenated fatty acids (contained in hydrogenated and partially-hydrogenated oils/vegetable fats):

1) inhibit desaturation of fatty acids!

2) increase Low-Density Lipoproteins (LDL: “bad” cholesterol)

3) decrease High-Density Lipoproteins (HDL: “good” cholesterol)

4) increase the Total Cholesterol / HDL ratio (bad!)

Summarizing, hydrogenated fatty acids can seriously impair our health.
Let's control ingredients of packed foods before buying them.


COMMENTO IN ITALIANO:
(e sotto)


Source:

Health effects of trans fatty acids.

A Ascherio and
W C Willett
Author Affiliations
Department of Nutrition, Harvard School of Public Health, Boston, MA 02115, USA.

Abstract
trans Fatty acids are formed during the process of partial hydrogenation in which liquid vegetable oils are converted to margarine and vegetable shortening. Concern has existed that this process may have adverse consequences because natural essential fatty acids are destroyed and the new artificial isomers are structurally similar to saturated fats, lack the essential metabolic activity of the parent compounds, and inhibit the enzymatic desaturation of linoleic and linolenic acid. In the past 5 y a series of metabolic studies has provided unequivocal evidence that trans fatty acids increase plasma concentrations of low-density-lipoprotein cholesterol and reduce concentrations of high-density-lipoprotein (HDL) cholesterol relative to the parent natural fat. In these same studies, trans fatty acids increased the plasma ratio of total to HDL cholesterol nearly twofold compared with saturated fats. On the basis of these metabolic effects and the known relation of blood lipid concentrations to risk of coronary artery disease, we estimate conservatively that 30,000 premature deaths/y in the United States are attributable to consumption of trans fatty acids. Epidemiologic studies, although not conclusive on their own, are consistent with adverse effects of this magnitude or even larger. Because there are no known nutritional benefits of trans fatty acids and clear adverse metabolic consequences exist, prudent public policy would dictate that their consumption be minimized and that information on the trans fatty acid content of foods be available to consumers.

Gli acidi grassi idrogenati (contenuti negli oli - o grassi vegetali - idrogenati o parzialmente idrogenati):

1) inibiscono la desaturazione degli acidi grassi!

2) aumentano l'LDL (colesterolo cattivo)

3) diminuiscono l'HDL (colesterolo buono)

4) aumentano il rapporto Colesterolo Totale / HDL (il che è male)

In conclusione, i grassi idrogenati possono seriamente danneggiare la nostra salute.
Controlliamo sempre gli ingredienti degli alimenti confezionati prima di acquistarli.

sabato 14 luglio 2012

The classification of carbohydrate sources based on their real “speed” (glycemic index) is useful.

(TESTO IN ITALIANO SOTTO)

1) During the last 20 years:
- fat intake decreased;
- while the number of individuals who were overweight or developed a chronic conditions have dramatically increased;
- the calories coming from carbohydrate have also increased;

2) The classification of carbohydrate sources based on the glycemic index is useful and can really “measure” the effects in the body;

3) High glycemic index carbohydrates cause:
- a strong increase of haematic glucose;
- a strong increase of haematic insulin;

4) Daily intake of high glycemic index carbohydrates is associated with an increased risk of chronic diseases such as obesity, cardiovascular disease, and diabetes.

Summarizing, we can get further benefits through a low-glycemic index diet: a diet that will take account of these parameters too, in addition to calories and grams.


COMMENTO IN ITALIANO:
(e sotto)

Source:


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.

PMID: 12940416



La classificazione delle fonti di carboidrati basata sulla loro reale “velocità” (indice glicemico) è utilissima.

1) Negli ultimi 20 anni:
- l'apporto di grasso è diminuito
- mentre il numero di individui sovrappeso o che hanno sviluppato patologie croniche è aumentato dramaticamente;
- le calorie provenienti dai carboidrati sono anche aumentate (tra l'altro il boom di prodotti light senza grassi o con ridotto contenuto di grassi è un fenomeno degli ultimi 10-15 anni);

2) La classificazione delle fonti di carboidrati basata sull'indice glicemico è utile e può realmente “misurare” gli effetti dell'alimento (anche ormonali!!) nel corpo;

3) I carboidrati ad alto indice glicemico causano:
- un forte incremento del glucosio ematico;
- un forte incremento dell'insulina ematica;

4) L'apporto quotidiano di carboidrati ad alto indice glicemico è associato con un accresciuto rischio di malattie croniche come obesità, malattie cardiovascolari e diabete.

In conclusione, possiamo ottenere importanti ulteriori benefici per mezzo di una alimentazione a basso indice glicemico, che tenga conto, quindi, anche di questi parametri, oltre che di grammi e calorie.

venerdì 13 luglio 2012

Psyllium fiber supplementation benefits

(TESTO IN ITALIANO SOTTO)

Psyllium fiber reduces hypercholesterolemia and improves glycemic control.
Even if this study was made on men with type 2 diabetes, this kind of fiber could be useful for healthy people too, expecially in a body-fat control strategy.

COMMENTO IN ITALIANO:
(e sotto)


Source:

Am J Clin Nutr. 1999 Oct;70(4):466-73.
Effects of psyllium on glucose and serum lipid responses in men with type 2 diabetes and hypercholesterolemia.
Anderson JW, Allgood LD, Turner J, Oeltgen PR, Daggy BP.

Veterans Affairs Medical Center, the University of Kentucky, Lexington 40511, USA. Jwandersmd@aol.com

Abstract

BACKGROUND:
Water-soluble dietary fibers decrease postprandial glucose concentrations and decrease serum cholesterol concentrations. This study examined the effects of administering psyllium to men with type 2 diabetes.

OBJECTIVE:
The objective was to evaluate the safety and effectiveness of psyllium husk fiber used adjunctively to a traditional diet for diabetes in the treatment of men with type 2 diabetes and mild-to-moderate hypercholesterolemia.

DESIGN:
After a 2-wk dietary stabilization phase, 34 men with type 2 diabetes and mild-to-moderate hypercholesterolemia were randomly assigned to receive 5.1 g psyllium or cellulose placebo twice daily for 8 wk. Serum lipid and glycemic indexes were evaluated biweekly on an outpatient basis and at weeks 0 and 8 in a metabolic ward.

RESULTS:
In the metabolic ward, the psyllium group showed significant improvements in glucose and lipid values compared with the placebo group. Serum total and LDL-cholesterol concentrations were 8.9% (P < 0.05) and 13.0% (P = 0.07) lower, respectively, in the psyllium than in the placebo group. All-day and postlunch postprandial glucose concentrations were 11.0% (P < 0.05) and 19.2% (P < 0.01) lower in the psyllium than in the placebo group. Both products were well tolerated, with no serious adverse events related to treatment reported in either group.

CONCLUSION:
The addition of psyllium to a traditional diet for persons with diabetes is safe, is well tolerated, and improves glycemic and lipid control in men with type 2 diabetes and hypercholesterolemia.

PMID: 10500014




Benefici dell'integrazione con fibra di Psyllium

La fibra di Psyllium riduce l'ipercolesterolemia e migliora il controllo glicemico.
Anche se questo studio è stato fatto su diabetici di tipo 2, questo tipo di fibra può essere molto utile anche negli individui sani, specialmente se inserita nelle strategie di controllo del grasso corporeo.

giovedì 12 luglio 2012

Further benefits of low-glycemic index diets

(TESTO IN ITALIANO SOTTO)

Optimizing a diet not only in its calorie intake, but in its macronutrients composition, proportion and absorption speed too, may give us further benefits. A low-glycemic index diet optimizes the energetic metabolism, reduces the catabolism and reduces the need of food too, if compared with a diet containing more high-glycemic index carbohydrates. It is important to underline that this happens despite the diets had similar total energy, energy density, and fiber contents.

This result is pertinent to the expectations, due to the antilipolytic and lipogenetic effects of insulin peak.
This means that we can get important further benefits with a low-glycemic index diet.

(e sotto)

Source:
http://www.ncbi.nlm.nih.gov/pubmed/10731495
1. Am J Clin Nutr. 2000 Apr;71(4):901-7.
Dietary composition and physiologic adaptations to energy restriction.
Agus MS, Swain JF, Larson CL, Eckert EA, Ludwig DS.

Division of Endocrinology, Department of Medicine, Children's Hospital, Boston,
and the General Clinical Research Center, Brigham and Women's Hospital, Boston,
MA 02115, USA.

BACKGROUND: The concept of a body weight set point, determined predominantly by
genetic mechanisms, has been proposed to explain the poor long-term results of
conventional energy-restricted diets in the treatment of obesity.
OBJECTIVE: The objective of this study was to examine whether dietary composition
affects hormonal and metabolic adaptations to energy restriction.
DESIGN: A randomized, crossover design was used to compare the effects of a
high-glycemic-index (high-GI) and a low-glycemic-index (low-GI) energy-restricted
diet. The macronutrient composition of the high-GI diet was (as percent of
energy) 67% carbohydrate, 15% protein, and 18% fat and that of the low-GI diet
was 43% carbohydrate, 27% protein, and 30% fat; the diets had similar total
energy, energy density, and fiber contents. The subjects, 10 moderately
overweight young men, were studied for 9 d on 2 separate occasions. On days -1 to
0, they consumed self-selected foods ad libitum. On days 1-6, they received an
energy-restricted high- or low-GI diet. On days 7-8, the high- or low-GI diets
were consumed ad libitum.
RESULTS: Serum leptin decreased to a lesser extent from day 0 to day 6 with the
high-GI diet than with the low-GI diet. Resting energy expenditure declined by
10.5% during the high-GI diet but by only 4.6% during the low-GI diet (7.38 +/-
0.39 and 7.78 +/- 0.36 MJ/d, respectively, on days 5-6; P = 0.04). Nitrogen
balance tended to be more negative, and energy intake from snacks on days 7-8 was
greater, with the high-GI than the low-GI diet.
CONCLUSION: Diets with identical energy contents can have different effects on
leptin concentrations, energy expenditure, voluntary food intake, and nitrogen
balance, suggesting that the physiologic adaptations to energy restriction can be
modified by dietary composition.

PMCID: PMC2905862
PMID: 10731495 [PubMed - indexed for MEDLINE]



Ulteriori vantaggi delle diete a basso indice glicemico

Si è visto che agendo non solamente sulla quota calorica, ma anche sul tipo di macronutrienti ingeriti (rapporto tra di loro e differente velocità di assorbimento), una dieta ipocalorica a basso indice glicemico ottimizza il metabolismo energetico, riduce il catabolismo e riduce il bisogno di cibo se paragonata con una dieta con più carboidrati ad alto indice glicemico.
E' importante sottolineare anche il fatto che le due diete avevano similare contenuto calorico e di fibre.

Risultato pertinente con le aspettative, dato l'effetto antilipolitico e lipogenetico del picco insulinico.
Ciò significa che possiamo ottenere importanti benefici ulteriori da una dieta a basso indice glicemico.

mercoledì 11 luglio 2012

Let's start...

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