X Esperti: Calcio-osteoporosi-acidita' Delle Proteine

[shernon]

La più importante causa dell'osteoporosi - problema attualissimo che interessa principalmente le donne - deve essere individuata nella dieta. L'osteoporosi non è infatti conseguente a carenza di calcio nella dieta, ma ad un eccesso di acidità, che costringe l'organismo a ricavare il calcio dalle ossa. È vero che i prodotti caseari contengono una grande quantità di calcio, ma è altrettanto vero che chi assume molto calcio tramite i latticini presenta livelli di osteoporosi più alti.

La sopravvivenza del pregiudizio sul calcio è da ascriversi principalmente ad un'impostazione quantitativa superficiale.
Moderne ricerche hanno dimostrato come le popolazioni che assumono minori quantità di calcio presentino un'ossatura più forte, probabilmente perché chi mangia cibi molto ricchi di calcio ingerisce allo stesso tempo cibi a reazione acida, che sottraggono calcio al corpo. Il formaggio, per esempio, è molto ricco di calcio ed è anche fortemente proteico e, se mangiato in eccesso o assieme a una grande quantità di altri cibi proteici, provoca la perdita di calcio e di altri minerali alcalini.

A causa dell'eccessivo consumo di cibi a reazione acida, si perdono quindi calcio e altri minerali alcalini. La mancanza di calcio ha perciò pochissima relazione con l'assunzione alimentare dello stesso, se non addirittura nessuna (eccetto che in caso di denutrizione). La più vasta indagine mondiale sull'alimentazione dimostra come il livello di osteoporosi (come pure di molte altre malattie) sia maggiore in popolazioni che assumono grandi quantità di calcio tramite latticini. Nutrendosi di prodotti caseari e assumendo calcio in compresse non si previene l'osteoporosi, l'unico modo per non incorrervi è non causarla.
In base a numerose e diversificate indagini mediche a livello mondiale si è stabilito come l'osteoporosi abbia poco a che vedere con l'assunzione di calcio, mentre essa risulta connessa all'assunzione di proteine: Il British Medical Journal riferisce come l'assunzione di calcio sia completamente irrilevante rispetto alla perdita ossea. Nel 1970 l'American Journal of Clinical Nutrition dichiarava: "L'osteoporosi è una malattia causata da una quantità di fattori, il più importante dei quali è l'eccessiva assunzione di proteine."

FONTE: http://www.ivu.org/italian/trans/avs-calcium.html



pareri?

[max_power]

Che è vero e lo sapevo già da tempo.

Ma se già i miti dell'alimentazione sono duri a morire, i miti della medicina lo sono ancor di più.

[shernon]

quindi una dieta iperproteica come la nostra nel tempo puo avere conseguenze legate all osteoporosi ?

[shernon]

altro articolo interessante sull'argomento:

Sanihelp.it - NEW YORK, (Reuters Health) – Gli uomini che assumono alte quantità di latte, gelato e formaggio potrebbero essere maggiormente a rischio di sviluppare un cancro alla prostata rispetto ai loro coetanei che seguono una dieta a prodotti caseari ridotti e quindi a meno contenuto di calcio.

Uno studio effettuato su circa 21.000 uomini in un arco di tempo di 11 anni, ha rilevato che soggetti che ingerivano più di 600 milligrammi di calcio al giorno con una dieta ricca in latticini, avevano il 32% di probabilità in più di sviluppare un cancro alla prostata rispetto a quelli che assumevano una dose di calcio giornaliero di 150 mg.
Una assunzione di 500 mg di calcio al giorno, è stato associato ad un incremento del 16% di rischio di cancro prostatico.

Un’assunzione massiccia di calcio, in particolare quello contenuto in prodotti caseari, può sopprimere i livelli di vitamina D nel sangue.
La Dott.ssa June M. Chan, autore dello studio afferma che oltre ad essere un importante elemento nutrizionale, la vitamina D è un ormone che favorisce la protezione contro il cancro alla prostata prevenendo la proliferazione delle cellule tumorali.

I risultati, pubblicati sull’American Journal of Clinical Nutrition, confermano precedenti studi che correlano il cancro della prostata con un consumo elevato di latticini.

Naturalmente non tutti concordano su queste conclusioni. Alcuni esperti ed il Consiglio Nazionale sui Prodotti Caseari ritengono insufficienti le prove che legano il consumo di prodotti caseari con il tumore alla prostata.

[ANMARYA]

La più importante causa dell'osteoporosi - problema attualissimo che interessa principalmente le donne - deve essere individuata nella dieta. L'osteoporosi non è infatti conseguente a carenza di calcio nella dieta, ma ad un eccesso di acidità, che costringe l'organismo a ricavare il calcio dalle ossa. È vero che i prodotti caseari contengono una grande quantità di calcio, ma è altrettanto vero che chi assume molto calcio tramite i latticini presenta livelli di osteoporosi più alti.

La sopravvivenza del pregiudizio sul calcio è da ascriversi principalmente ad un'impostazione quantitativa superficiale.
Moderne ricerche hanno dimostrato come le popolazioni che assumono minori quantità di calcio presentino un'ossatura più forte, probabilmente perché chi mangia cibi molto ricchi di calcio ingerisce allo stesso tempo cibi a reazione acida, che sottraggono calcio al corpo. Il formaggio, per esempio, è molto ricco di calcio ed è anche fortemente proteico e, se mangiato in eccesso o assieme a una grande quantità di altri cibi proteici, provoca la perdita di calcio e di altri minerali alcalini.

A causa dell'eccessivo consumo di cibi a reazione acida, si perdono quindi calcio e altri minerali alcalini. La mancanza di calcio ha perciò pochissima relazione con l'assunzione alimentare dello stesso, se non addirittura nessuna (eccetto che in caso di denutrizione). La più vasta indagine mondiale sull'alimentazione dimostra come il livello di osteoporosi (come pure di molte altre malattie) sia maggiore in popolazioni che assumono grandi quantità di calcio tramite latticini. Nutrendosi di prodotti caseari e assumendo calcio in compresse non si previene l'osteoporosi, l'unico modo per non incorrervi è non causarla.
In base a numerose e diversificate indagini mediche a livello mondiale si è stabilito come l'osteoporosi abbia poco a che vedere con l'assunzione di calcio, mentre essa risulta connessa all'assunzione di proteine: Il British Medical Journal riferisce come l'assunzione di calcio sia completamente irrilevante rispetto alla perdita ossea. Nel 1970 l'American Journal of Clinical Nutrition dichiarava: "L'osteoporosi è una malattia causata da una quantità di fattori, il più importante dei quali è l'eccessiva assunzione di proteine."

FONTE: http://www.ivu.org/italian/trans/avs-calcium.html



pareri?

stai entrando in menopausa?

[spot86]

riporto degli studi interessanti (di alcuni solo l'abstract) sulla questione che hai sollevato:

Diet, evolution and aging--the pathophysiologic effects of the post-agricultural inversion of the potassium-to-sodium and base-to-chloride ratios in the human diet.Frassetto L, Morris RC Jr, Sellmeyer DE, Todd K, Sebastian A.
University of California, San Francisco 94143, USA.
Theoretically, we humans should be better adapted physiologically to the diet our ancestors were exposed to during millions of years of hominid evolution than to the diet we have been eating since the agricultural revolution a mere 10,000 years ago, and since industrialization only 200 years ago. Among the many health problems resulting from this mismatch between our genetically determined nutritional requirements and our current diet, some might be a consequence in part of the deficiency of potassium alkali salts (K-base), which are amply present in the plant foods that our ancestors ate in abundance, and the exchange of those salts for sodium chloride (NaCl), which has been incorporated copiously into the contemporary diet, which at the same time is meager in K-base-rich plant foods. Deficiency of K-base in the diet increases the net systemic acid load imposed by the diet. We know that clinically-recognized chronic metabolic acidosis has deleterious effects on the body, including growth retardation in children, decreased muscle and bone mass in adults, and kidney stone formation, and that correction of acidosis can ameliorate those conditions. Is it possible that a lifetime of eating diets that deliver evolutionarily superphysiologic loads of acid to the body contribute to the decrease in bone and muscle mass, and growth hormone secretion, which occur normally with age? That is, are contemporary humans suffering from the consequences of chronic, diet-induced low-grade systemic metabolic acidosis? Our group has shown that contemporary net acid-producing diets do indeed characteristically produce a low-grade systemic metabolic acidosis in otherwise healthy adult subjects, and that the degree of acidosis increases with age, in relation to the normally occurring age-related decline in renal functional capacity. We also found that neutralization of the diet net acid load with dietary supplements of potassium bicarbonate (KHCO3) improved calcium and phosphorus balances, reduced bone resorption rates, improved nitrogen balance, and mitigated the normally occurring age-related decline in growth hormone secretion--all without restricting dietary NaCl. Moreover, we found that co-administration of an alkalinizing salt of potassium (potassium citrate) with NaCl prevented NaCl from increasing urinary calcium excretion and bone resorption, as occurred with NaCl administration alone. Earlier studies estimated dietary acid load from the amount of animal protein in the diet, inasmuch as protein metabolism yields sulfuric acid as an end-product. In cross-cultural epidemiologic studies, Abelow found that hip fracture incidence in older women correlated with animal protein intake, and they suggested a causal relation to the acid load from protein. Those studies did not consider the effect of potential sources of base in the diet. We considered that estimating the net acid load of the diet (i. e., acid minus base) would require considering also the intake of plant foods, many of which are rich sources of K-base, or more precisely base precursors, substances like organic anions that the body metabolizes to bicarbonate. In following up the findings of Abelow et al., we found that plant food intake tended to be protective against hip fracture, and that hip fracture incidence among countries correlated inversely with the ratio of plant-to-animal food intake. These findings were confirmed in a more homogeneous population of white elderly women residents of the U.S. These findings support affirmative answers to the questions we asked above. Can we provide dietary guidelines for controlling dietary net acid loads to minimize or eliminate diet-induced and age-amplified chronic low-grade metabolic acidosis and its pathophysiological sequelae. We discuss the use of algorithms to predict the diet net acid and provide nutritionists and clinicians with relatively simple and reliable methods for determining and controlling the net acid load of the diet. A more difficult question is what level of acidosis is acceptable. We argue that any level of acidosis may be unacceptable from an evolutionarily perspective, and indeed, that a low-grade metabolic alkalosis may be the optimal acid-base state for humans.

Dietary protein: an essential nutrient for bone health.Bonjour JP.
Service of Bone Diseases, University Hospital, Rue Micheli-Du-Crest, 1211 Geneva, Switzerland. Jean-Philippe.Bonjour@medecine.unige.ch.
Nutrition plays a major role in the development and maintenance of bone structures resistant to usual mechanical loadings. In addition to calcium in the presence of an adequate vitamin D supply, proteins represent a key nutrient for bone health, and thereby in the prevention of osteoporosis. In sharp opposition to experimental and clinical evidence, it has been alleged that proteins, particularly those from animal sources, might be deleterious for bone health by inducing chronic metabolic acidosis which in turn would be responsible for increased calciuria and accelerated mineral dissolution. This claim is based on an hypothesis that artificially assembles various notions, including in vitro observations on the physical-chemical property of apatite crystal, short term human studies on the calciuric response to increased protein intakes, as well as retrospective inter-ethnic comparisons on the prevalence of hip fractures. The main purpose of this review is to analyze the evidence that refutes a relation of causality between the elements of this putative patho-physiological "cascade" that purports that animal proteins are causally associated with an increased incidence of osteoporotic fractures. In contrast, many experimental and clinical published data concur to indicate that low protein intake negatively affects bone health. Thus, selective deficiency in dietary proteins causes marked deterioration in bone mass, micro architecture and strength, the hallmark of osteoporosis. In the elderly, low protein intakes are often observed in patients with hip fracture. In these patients intervention study after orthopedic management demonstrates that protein supplementation as given in the form of casein, attenuates post-fracture bone loss, increases muscles strength, reduces medical complications and hospital stay. In agreement with both experimental and clinical intervention studies, large prospective epidemiologic observations indicate that relatively high protein intakes, including those from animal sources are associated with increased bone mineral mass and reduced incidence of osteoporotic fractures. As to the increased calciuria that can be observed in response to an augmentation in either animal or vegetal proteins it can be explained by a stimulation of the intestinal calcium absorption. Dietary proteins also enhance IGF-1, a factor that exerts positive activity on skeletal development and bone formation. Consequently, dietary proteins are as essential as calcium and vitamin D for bone health and osteoporosis prevention. Furthermore, there is no consistent evidence for superiority of vegetal over animal proteins on calcium metabolism, bone loss prevention and risk reduction of fragility fractures.

Eicosapentaenoic acid and docosahexaenoic acid supplementation increases calcium balance
M. C. Kruger Ph.D., H. Coetzer B.Sc., R. de Winter Biol.Tech. and N. Claassen M.Sc.
Department of Physiology, University of Pretoria, PO Box 2034, Pretoria, South Africa
Accepted 9 September 1994. ; Available online 23 December 1999.
Abstract

Sprague Dawley rats were supplemented with either fish oil, evening primrose oil or sunflower oil (control) for 12 weeks. Calcium balance and fatty acid analyses of plasma and intestinal membranes were performed at week 12. Fish oil decreased faecal calcium excretion significantly leading to an increased calcium balance (p < 0.05). Increased unsaturation of the intestinal membranes in the fish oil group may facilitate calcium absorption.

Huth PJ et. al. Major scientific advances with dairy foods in nutrition and health. J Dairy Sci. (2006) 89:1207-21.
A large body of scientific evidence collected in recent decades demonstrates that an adequate intake of calcium and other nutrients from dairy foods reduces the risk of osteoporosis by increasing bone acquisition during growth, slowing age-related bone loss, and reducing osteoporotic fractures. These results have culminated in the new (2005) Dietary Guidelines for Americans that now recommend 3 servings of milk products per day to reduce the risk of low bone mass and contribute important amounts of many nutrients that may have additional health attributes beyond bone health. A number of animal, observational, and clinical studies have shown that dairy food consumption can help reduce the risk of hypertension. Clinical trials indicate that the consumption of recommended levels of dairy products, as part of a healthy diet, can contribute to lower blood pressure in individuals with normal and elevated blood pressure. Emerging data also indicate that specific peptides associated with casein and whey proteins can significantly lower blood pressure. In addition, a growing body of evidence has provided support for a beneficial effect of dairy foods on body weight and the loss of bodyfat. Clinical studies have demonstrated that during caloric restriction, body weight and bodyfat loss occurs when adequate calcium is provided by supplements and that this effect is further augmented by an equivalent amount of calcium supplied from dairy foods. Several studies support a role for calcium, vitamin D, and dairy foods against colon cancer. Additionally, conjugated linoleic acid, a fatty acid found naturally in dairy fat, confers a wide range of anticarcinogenic benefits in experimental animal models and is especially consistent for protection against breast cancer.
Lyle McDonald’s comment: Somewhere along the way, milk got a bad reputation among bodybuilders; it was said to make you fat and smooth. This attitude against milk has carried over into the fitness realm too and you will still see people removing milk from their diet when it's time to lean out. I used to get the occasional question about "When should I take dairy out of my diet?" In some circles, milk/dairy is considered an 'unclean' food (I don't want to get into the whole clean vs. unclean discussion here).
But is this attitude reasonable; more importantly, where did it come from? Here's my best guess. Back in the olden days of bodybuilding, lifters would routinely bulk up by lifting heavily and drinking gallons per day of whole milk (along with everything else that wasn't nailed down). This put on size but also a lot of fat. When it was time to diet, people would start to remove whole categories of foods from their diets. Ignorant of calories and dietary fat, I suspect that the removal of whole milk (containing a ton of each) let people lean up. Hence milk got its bad reputation; if you didn't drink it on a diet, you got leaner faster. If anyone else has a better idea where milk got its negative reputation from, please send me feedback.
Additionally, milk and other dairy products can contain quite a bit of sodium which can cause water retention. I suspect this is where its reputation for making people smooth comes from.
Finally, some people show a true allergy to dairy products although it's prevalance is only estimated at 1-3%. This should be contrasted to a milk intolerance (such as lactose intolerance), which is what causes people to get gassy (or diarrhea) due to undigested milk sugar. Rather, I'm talking about a true allergic/immunological response; this can cause a cortisol/immune system response in susceptible people. This tends to cause major water retention and can probably impair fat loss. Clearly, individuals who show a true immune system response to dairy should avoid it. Individuals with lactose intolerance can use the lactose removed milk (such as Lactaid).
I won't even get into the true anti-milk nutter groups, can't be bothered.
As you might guess, I do not subscribe to this particular belief. Hence the choice of this week's paper which is a review of the potential benefits of dairy foods in human health. There's really not much for me to add to what's written above in the paper's abstract but I would like to bring to everyone's attention the comments on increased fat loss when calcium (and especially dairy calcium) is added to the diet. I want to note that the research on this isn't quite as clear as the abstract above makes it sound; many papers have shown an effect of calcium, while others have not. A lot of it may have to do with whether you're fixing a true deficiency or supplementing above normal levels; fixing deficiencies tends to have a greater impact on everything than taking mega-doses.
But it does appear that dairy calcium improves fat loss on a diet, at least when you're looking at folks with sub-optimal intakes. And a bodybuilder/fitness type who is steadfastly avoiding all dairy and eating a small subset of foods (chicken breast, broccoli, maybe some oats) is at risk for a deficiency.
Add to this the critical importance of calcium for bone health, especially in women. And the fact that dairy calcium is best absorbed. Add to that the other potential health benefits listed above. Add to that the fact that dairy protein (which is a mix of both casein and whey) is extremely high quality, that casein protein takes a while to digest (this helps with both fullness on a diet and may exert an anti-catabolic effect) and, honestly, I think dairy should be a part of a diet. The fat and calorie issue is totally obviated now that low or non-fat products are available.
And the sodium issue? Well, first and foremost, if you're eating normal amounts of sodium in the first place, you don't get water retention when you eat a little more. As well, water retention is only an issue on contest day anyhow. Dairy should probably be dropped a few days out from your show so that you can deal with sodium/water retention issues but I see no need to avoid it steadfastly prior to that.

[shernon]

menopausa no, ma sto in iperproteica da tempo come del resto molti altri del forum e sportivi nella vita di tutti i giorni

[shernon]

ecco spot86 questa contraddice tutto quello che ho postato:

"Consequently, dietary proteins are as essential as calcium and vitamin D for bone health and osteoporosis prevention. Furthermore, there is no consistent evidence for superiority of vegetal over animal proteins on calcium metabolism, bone loss prevention and risk reduction of fragility fractures."

adesso....CHI HA RAGIONE????

[max_power]

stai entrando in menopausa?

Prego evitare OT.

[spot86]

ecco spot86 questa contraddice tutto quello che ho postato:

"Consequently, dietary proteins are as essential as calcium and vitamin D for bone health and osteoporosis prevention. Furthermore, there is no consistent evidence for superiority of vegetal over animal proteins on calcium metabolism, bone loss prevention and risk reduction of fragility fractures."

adesso....CHI HA RAGIONE????

eheh...

è il bello di queste cose

"tutto e il contrario di tutto"

bisognerebbe valutare quale sia lo studio/fonte + attendibile...ed affidarsi a quello...di + non si può fare...temo...

[max_power]

adesso....CHI HA RAGIONE????

Tutti e nessuno. In uno studio le variabili sono molte: condizioni di studio, parametri di studio differenti. Ecco perchè molte volte i risultati di uno studio non sono del tutto in sintonia.

[shernon]

xo notavo che quasi tutti i siti italiani tendono a scrivere questa stessa cosa..mentre in america, dove dicono che il consumo di calcio è minore, sono molto contradditori i studi..

alla fine non sai a chi devi tener conto e questo è veramente un problema...

[spot86]

xo notavo che quasi tutti i siti italiani tendono a scrivere questa stessa cosa..mentre in america, dove dicono che il consumo di calcio è minore, sono molto contradditori i studi..

alla fine non sai a chi devi tener conto e questo è veramente un problema...

diciamo che generalmente in Italia siamo + attaccati a falsi miti passati e remoti...imho

[max_power]

alla fine non sai a chi devi tener conto e questo è veramente un problema...

Sicuramente in termini di ricerca l'America è molto più avanti di noi, non c'è neanche paragone.

[zajka]

La più importante causa dell'osteoporosi - problema attualissimo che interessa principalmente le donne - deve essere individuata nella dieta.

una gran cavolata.E' risaputo che le cause dell'osteoporosi femminile in età avanzata sono dovute alle questioni ormonali e non alla dieta