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La cuisson réduit-elle ou augmente t’elle la digestibilité du gluten?

30/07/2015 | Etudes Anti-âge

 

The digestibility of gluten proteins is reduced by baking and enhanced by starch digestion
Frances Smith   Molecular Nutrition & Food Research   Issue Cover image for Vol. 59 Issue 7

Resistance of proteins to gastrointestinal digestion may play a role in determining immune-mediated adverse reactions to foods. However, digestion studies have largely been restricted to purified proteins and the impact of food processing and food matrices on protein digestibility is poorly understood.

Methods and results
: Digestibility of a total gliadin fraction (TGF), flour (cv Hereward) and bread was assessed using in vitro batch digestion with simulated oral, gastric and duodenal phases. Protein digestion was monitored by SDS-PAGE and immunoblotting using monoclonal antibodies specific for celiac-toxic sequences (QQSF, QPFP) and starch digestion by measuring undigested starch. Whereas the TGF was rapidly digested during the gastric phase the gluten proteins in bread were virtually undigested and digested rapidly during the duodenal phase only if amylase was included. Duodenal starch digestion was also slower in the absence of duodenal proteases.

Conclusions
The baking process reduces the digestibility of wheat gluten proteins, including those containing sequences active in celiac disease. Starch digestion affects the extent of protein digestion, probably because of gluten-starch complex formation during baking. Digestion studies using purified protein fractions alone are therefore not predictive of digestion in complex food matrices.

Comment prendre ses oméga 3 de manière optimale?

29/07/2015 | Etudes Compléments alimentaires et Etudes Perte de poids et Etudes Anti-âge

 

Petite dose tous les jours ou grosses doses peu fréquentes?

What Is the Most Effective Way of Increasing the Bioavailability of Dietary Long Chain Omega-3 Fatty Acids—Daily vs. Weekly Administration of Fish Oil?
Nutrients 2015, 7(7), 5628-5645;  Samaneh Ghasemifard

The recommendations on the intake of long chain omega-3 polyunsaturated fatty acids (n-3 LC-PUFA) vary from eating oily fish (“once to twice per week”) to consuming specified daily amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (“250–500 mg per day”). It is not known if there is a difference in the uptake/bioavailability between regular daily consumption of supplementsvs. consuming fish once or twice per week. In this study, the bioavailability of a daily dose of n-3 LC-PUFA (Constant treatment), representing supplements, vs. a large weekly dose of n-3 LC-PUFA (Spike treatment), representing consuming once or twice per week, was assessed. Six-week old healthy male Sprague-Dawley rats were fed either a Constant treatment, a Spike treatment or Control treatment (no n-3 LC-PUFA), for six weeks. The whole body, tissues and faeces were analysed for fatty acid content.

The results showed that the major metabolic fate of the n-3 LC-PUFA (EPA+docosapentaenoic acid (DPA) + DHA) was towards catabolism (β-oxidation) accounting for over 70% of total dietary intake, whereas deposition accounted less than 25% of total dietary intake. It was found that significantly more n-3 LC-PUFA were β-oxidised when originating from the Constant treatment (84% of dose), compared with the Spike treatment (75% of dose). Conversely, it was found that significantly more n-3 LC-PUFA were deposited when originating from the Spike treatment (23% of dose), than from the Constant treatment (15% of dose).

These unexpected findings show that a large dose of n-3 LC-PUFA once per week is more effective in increasing whole body n-3 LC-PUFA content in rats compared with a smaller dose delivered daily.

Compared with daily, weekly n-3 PUFA intake affects the incorporation of eicosapentaenoic acid and docosahexaenoic acid into platelets and mononuclear cells in humans.
J Nutr. 2014 May;144(5):667-72.        Browning LM

Consumption of oily fish is sporadic, whereas controlled intervention studies of n-3 (ω-3) fatty acids usually provide capsules containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) as a daily dose. This methodologic study explored whether there are differences in the short-, medium-, and long-term incorporation of EPA and DHA into blood plasma and cells with the provision of identical amounts of EPA and DHA, equivalent to 2 oily fish servings per week (or 6.54 g/wk EPA and DHA), either intermittently (i.e., 1 portion twice per week) or continuously (i.e., divided into daily amounts). The study was part of a randomized, double-blind controlled intervention lasting 12 mo, with participants stratified by age and sex. There were 5 intervention groups, 2 of which are reported here: the 2 intermittent portions (2I) and 2 continuous portions (2C) groups. EPA and DHA were measured in plasma phosphatidylcholine, platelets, and blood mononuclear cells (MNCs) at 9 time points. Sixty-five participants completed the study (2I group, n = 30, mean age of 49.2 y; 2C group, n = 35, mean age of 50.6 y). The incorporation pattern over the 12-mo intervention was different between the 2 groups in all samples (P

< 0.0001, time × treatment interaction).

At the end of the 12-mo intervention, the 2C group had higher EPA, DHA, and EPA + DHA in platelets (all P < 0.01) and higher EPA and EPA + DHA in MNCs (both P < 0.05) compared with the 2I group. No significant differences were shown for plasma phosphatidylcholine EPA (P = 0.1), DHA (P = 0.15), EPA + DHA (P = 0.07), or MNC DHA (P = 0.06). In conclusion, the pattern of consumption does affect the incorporation of EPA and DHA into cells used as biomarkers of intake. The differences identified here need to be considered in the design of studies and when extrapolating results from continuous capsule-based intervention studies to dietary guidelines for oily fish consumption.

Vivre plus longtemps ou avoir des muscles?

28/07/2015 | Etudes Anti-âge

 

Impacts of metformin and aspirin on life history features and longevity of crickets: trade-offs versus cost-free life extension?
AGE April 2015, 37:31   Harvir Hans

We examined the impacts of aspirin and metformin on the life history of the cricket Acheta domesticus (growth rate, maturation time, mature body size, survivorship, and maximal longevity). Both drugs significantly increased survivorship and maximal life span. Maximal longevity was 136 days for controls, 188 days (138 % of controls) for metformin, and 194 days (143 % of controls) for aspirin. Metformin and aspirin in combination extended longevity to a lesser degree (163 days, 120 % of controls). Increases in general survivorship were even more pronounced, with low-dose aspirin yielding mean longevity 234 % of controls (i.e., health span). Metformin strongly reduced growth rates of both genders (

<60 % of controls),

whereas aspirin only slightly reduced the growth rate of females and slightly increased that of males. Both drugs delayed maturation age relative to controls, but metformin had a much greater impact (>140 % of controls) than aspirin (~118 % of controls). Crickets maturing on low aspirin showed no evidence of a trade-off between maturation mass and life extension. Remarkably, by 100 days of age, aspirin-treated females were significantly larger than controls (largely reflecting egg complement). Unlike the reigning dietary restriction paradigm, low aspirin conformed to a paradigm of “eat more, live longer.” In contrast, metformin-treated females were only ~67 % of the mass of controls.

Our results suggest that hormetic agents like metformin may derive significant trade-offs with life extension, whereas health and longevity benefits may be obtained with less cost by agents like aspirin that regulate geroprotective pathways.

Comment retirer l’arsenic du riz?

27/07/2015 | Etudes Perte de poids et Etudes Anti-âge

 

Le riz est la céréale le plus riche en arsenic (10 fois plus que les autres). Le riz complet est 10 à 20 fois plus riche que le riz blanc
(n’oublions pas que le riz, c’est le secret des sumo pour prendre rapidement du poids et du ventre)

Avec les cuiseur de riz dans lesquels ont met peu d’eau, on est exposé à 100% de l’arsenic. En rinçant à fond son riz cuit, on retire la moitié de l’arsenic. En cuisant avec un percolateur on en retire aussi 50%

Rethinking Rice Preparation for Highly Efficient Removal of Inorganic Arsenic Using Percolating Cooking Water
Manus Carey     PLOS Published: July 22, 2015

A novel way of cooking rice to maximize the removal of the carcinogen inorganic arsenic (Asi) is presented here. In conventional rice cooking water and grain are in continuous contact, and it is known that the larger the water:rice cooking ratio, the more Asi removed by cooking, suggesting that the Asi in the grain is mobile in water. Experiments were designed where rice is cooked in a continual stream of percolating near boiling water, either low in Asi, or Asi free. This has the advantage of not only exposing grain to large volumes of cooking water, but also physically removes any Asi leached from the grain into the water receiving vessel. The relationship between cooking water volume and Asi removal in conventional rice cooking was demonstrated for the rice types under study. At a water-to-rice cooking ratio of 12:1, 57±5% of Asi could be removed, average of 6 wholegrain and 6 polished rice samples. Two types of percolating technology were tested, one where the cooking water was recycled through condensing boiling water steam and passing the freshly distilled hot water through the grain in a laboratory setting, and one where tap water was used to cook the rice held in an off-the-shelf coffee percolator in a domestic setting. Both approaches proved highly effective in removing Asi from the cooking rice, with up to 85% of Asi removed from individual rice types. For the recycled water experiment 59±8% and 69±10% of Asi was removed, on average, compared to uncooked rice for polished (n=27) and wholegrain (n=13) rice, respectively. For coffee percolation there was no difference between wholegrain and polished rice, and the effectiveness of Asi removal was 49±7% across 6 wholegrain and 6 polished rice samples. The manuscript explores the potential applications and further optimization of this percolating cooking water, high Asi removal, discovery.

Trop de sel: néfaste pour la masse osseuse des seniors

26/07/2015 | Etudes Perte de poids et Etudes Anti-âge

 

Association of urinary sodium/creatinine ratio with bone mineral density in postmenopausal women: KNHANES 2008–2011
Endocrine August 2015, Volume 49, Issue 3, pp 791-799     Sung-Woo Kim

Accumulating evidence shows that high sodium chloride intake increases urinary calcium excretion and may be a risk factor for osteoporosis. However, the effect of oral sodium chloride intake on bone mineral density (BMD) and risk of osteoporosis has been inadequately researched. The aim of the present study was to determine whether urinary sodium excretion (reflecting oral sodium chloride intake) associates with BMD and prevalence of osteoporosis in postmenopausal women. This cross-sectional study involved a nationally representative sample consisting of 2,779 postmenopausal women who participated in the Korea National Health and Nutritional Examination Surveys in 2008–2011. The association of urinary sodium/creatinine ratio with BMD and other osteoporosis risk factors was assessed. In addition, the prevalence of osteoporosis was assessed in four groups with different urinary sodium/creatinine ratios. Participants with osteoporosis had significantly higher urinary sodium/creatinine ratios than the participants without osteoporosis. After adjusting for multiple confounding factors, urinary sodium/creatinine ratio correlated inversely with lumbar spine BMD (P = 0.001). Similarly, when participants were divided into quartile groups according to urinary sodium/creatinine ratio, the average BMD dropped as the urinary sodium/creatinine ratio increased. Multiple logistic regression analysis revealed that compared to quartile 1, quartile 4 had a significantly increased prevalence of lumbar spine osteoporosis (odds ratios 1.346, P for trend = 0.044).

High urinary sodium excretion was significantly associated with low BMD and high prevalence of osteoporosis in lumbar spine. These results suggest that high sodium chloride intake decreases lumbar spine BMD and increases the risk of osteoporosis in postmenopausal women.

NGF, algésie et mal au dos

22/07/2015 | Etudes sur les hormones et Echauffement et blessures et Etudes Musculation

 

Comparison of nerve growth factor–induced sensitization pattern in lumbar and tibial muscle and fascia
Benjamin Weinkauf     Muscle & Nerve Volume 2015 52, Issue 2, pages 265–272, August

Nerve growth factor (NGF) induces profound hyperalgesia
. In this study we explored patterns of NGF sensitization in muscle and fascia of distal and paraspinal sites.

Methods: We injected 1 µg of NGF into human (n = 8) tibialis anterior and erector spinae muscles and their fasciae. The spatial extent of pressure sensitization, pressure pain threshold, and mechanical hyperalgesia (150 kPa, 10 s) was assessed at days 0.25, 1, 3, 7, 14, and 21. Chemical sensitization was explored by acidic buffer injections (pH 4, 100 µl) at days 7 and 14.

Results: The mechanical hyperalgesia area was larger in tibial fascia than in muscle. Pressure pain thresholds were lower, tonic pressure pain ratings, and citrate buffer evoked pain higher in fascia than in muscle.

Conclusions: Spatial mechanical sensitization differs between muscle and fascia. Thoracolumbar fasciae appear more sensitive than tibial fasciae and may be major contributors to low back pain, but the temporal sensitization profile is similar between paraspinal and distal sites.

Plus de muscle = plus de graisse intra-musculaire

19/07/2015 | Etudes Perte de poids et Etudes Anti-âge

 

Tout va bien jusqu’à ce que tu te mettes au régime!
Skeletal muscle size is a major predictor of intramuscular fat content regardless of age
European Journal of Applied Physiology August 2015, Volume 115, Issue 8, pp 1627-1635   Hiroshi Akima

Skeletal muscles of older individuals have a larger amount of intramuscular adipose tissue (IntraMAT) than those of younger individuals. It is not understood how aging affects the IntraMAT content of individual muscles of the thigh. We assessed the relationship between IntraMAT content and skeletal muscle cross-sectional area (CSA), subcutaneous adipose tissue CSA, biochemical blood profiles, and physical activity.

Methods

Fifteen older (70.7 ± 3.8 years) and 15 younger (20.9 ± 0.3 years) men and women participated in this study. Magnetic resonance imaging of the right thigh was taken to measure IntraMAT content and skeletal muscle CSA for the quadriceps femoris (QF), hamstrings (HM), adductor (AD) muscle groups and subcutaneous adipose tissue CSA of the thigh. Fasting blood samples were collected to measure plasma lipids, adiponectin, and HbA1c levels.

Results

IntraMAT content in QF, HM, and AD for the Older group was significantly higher than in the Younger group. However, skeletal muscle CSA normalized by body weight (skeletal muscle CSA/bw) in the QF (P < 0.001) and total thigh (P < 0.01) were significantly lower in the Older group compared with the Younger group.There were no significant differences in HM and AD. Stepwise regression analysis with IntraMAT content as a dependent variable revealed that skeletal muscle CSA/bw of the thigh was the only predictive variable for IntraMAT content in Older and Younger groups.

Conclusion

These results suggest that skeletal muscle size could be a major determinant of IntraMAT content regardless of age.

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