By doctor Francesco Casillo
Introduction
Culture, tradition (religious, mystical, superstitious, folkloristic, etc.) are spatial-temporal cases that weave a large part of the plot of the relational-social aspects of the individual, conditioning their fate.
Unfortunately, there are many "myths" of our sector ...
"A lie told enough times becomes a truth" - reads a quote attributed to the Russian revolutionary Lenin. The efficacy and power of this statement has been recognized by leader political for eons, since it is such as to make the beliefs that they want to be assimilated as truth take hold in the minds of the people.
But as Kennedy said in 1962 to the "Commencement Address"At Yale University, the greatest enemy of truth is not the lie but the" myth ", since it is persistent, persuasive and unrealistic. And the most serious problem is when the myth permeates the classes of scientific rank , automatically becomes a law, in reference to which public opinion relates and, therefore, behaves! And here the "mythological" examples would follow in extensive review.
In this "Dossier Pseudo-Truth" we will try to bring to the attention of the readers the main issues most debated within the body-building and sport in general, linked to nutritional aspects and not only, to highlight - through the appropriate literature reported in the extensive bibliographic references - how many of the beliefs, not only popular, but also medical (media) -scientific are unfortunately dictated from opinions, beliefs, hearsay, hypotheses and anything else that has no connection with science, with concrete facts and statistical significance ... - and yet they represent the most widespread "knowledge" and permeating the knowledge of the masses and (pseudo) specialists!
High-protein diet and loss of bone mineral
It is now widely known that proteins can be deleterious to bone health, based on the association that hypercalciuria - induced by their intake - is the result of bone calcium mobilization.
He later came to scientific knowledge that the main source of hypercalciuria is the intestine. Subsequent studies revealed that reduced protein intake induces a reduced intestinal absorption of calcium, an event associated with increased levels of parathyroid hormone. Therefore, the assumption that hyperprotein diet-induced hypercalciuria was associated with bone mineral loss was revisited. And even the opposite emerged.
Studies on postmenopausal women aged 50 to 75, and another study on men and women aged 50 and over, were conducted to evaluate the effect on calcium levels and bone metabolism caused by an increase in protein (from meat) from 0.94 to 1.62 and 0.78 to 1.55g per kg of body weight after 5 and up to 9. The results of the two studies reported no hypercalciuria, much less any decrease in calcium retention.
In the first study, the initial renal acid excretion reported by the high-protein group decreased significantly over time and no marker bone metabolism underwent variations. In the second, however, a decreased urinary excretion of the "N-telopeptide (marker bone resorption) and an increase in IGF-1 (somatomedin favoring anabolism, also of a bone nature).
If yesterday losing weight was the prerogative of counting caloric, not long ago it was the glycemic index, whereas very recently it was a virtue of the glycemic load; today the PRAL ("Potential Renal Acid Load", i.e. renal acid load potential) has become a reference for monitoring food quality selection, in order to avoid renal acid loads responsible for bone mineral loss. Beyond the nutritional fads and recent scientific discoveries - which instead of adding to the known baggage of knowledge seem to almost suppress it to excel, as if they represented absolute and indisputable truths -, the body-builder type "does not lie" about the correctness and healthiness of the lifestyle choices undertaken, since its morphological structure is nothing "other than the mere phenotyping of full organic health in toto.
A recent publication, which comes to further confirmation and validation of the aforementioned studies, is that of 2011 of "Journal of Nutrition". The study aimed to determine the effects of a high-protein and high PRAL diet on calcium absorption and retention levels, as well as on marker bone metabolism. To this end, the hyperproteic diet with high PRAL (HPHP) was compared with the hypoproteic diet with low PRAL (LPLP). The HPHP diet showed higher IGF-1 values and decreased parathyroid hormone values compared to the LPLP diet.
Furthermore, the HPHP diet reported higher values in calcium absorption and also in excretion compared to the LPLP diet, but the net difference between absorbed and excreted calcium values did not differ between the two approaches. The HPHP protocol did not result in changes in the marker bone metabolism. And the increase in calcium uptake observed in HPHP offsets its excretion. In addition to this, the increased levels of IGF-1, the decreased concentrations of parathyroid hormone and the simultaneous stability of the marker of bone metabolism indicate that the high-protein approach is not responsible for negative implications on bone health.
Another recent study on 8 bodybuilder d "elite denies the "absoluteness of the causal relationship" high-protein approach and metabolic acidosis. "The eight athletes, aged between 18 and 25, were recruited from those who had at least a training period of more than 2 years in sight. preparations for competitive events and which have also reported several victories in national championships (therefore these are not novice subjects included in the study, but athletes with high turnover protein).
Their protein intake consisted of 4.3g ± 1.2g of protein per kilo of body weight per day, in a caloric context of 5621.7kcal +/- 1354.7kcal per day. Their supplemental plan also included quantities of vitamin and mineral supplements (calcium and potassium) significantly higher than the normally recommended doses.
The proportion of the ratios between the macronutrients within the daily caloric body was set as follows: 34% carbohydrates, 30% proteins, 36% fats. The proportions of the ratios between the macronutrients deriving solely from the supplements were as follows: 14% carbohydrates, 66 % protein, 20% fat; and 28% of the total daily protein intake came from protein-based supplements.
At the beginning of the study it was assumed that the protein intake five times higher than that recommended for the general population (0.8g per kilo of body weight) could induce serious homeostatic alterations in the delicate acid-base balance.
At the end of the study, the obviousness in detecting phenomena of metabolic acidosis in response to high protein loads failed.
This study confirms how much the effects of a macronutrient (in this case proteins) cannot be given as absolute and in every circumstance, but must always be contextualized and above all verified in a cause-effect relationship such as conditio sine qua non for the knowledge of their real metabolic impact.
Any other way of observing and conceiving is skimmed of feedback objective remains indifferent, speculative and sterile with respect to the real effects induced by specific stimuli, in this case biochemical-nutritional.
The authors hypothesize that, most likely, physical exercise in combination with "buffers" such as potassium and calcium helped prevent the phenomena of acidosis resulting from high protein consumption.
Therefore proteins are not primarily responsible for effects ... but the nutritional context and the overall lifestyle in which they are inserted represents the determinant of the ultimate effects, positive or negative respectively.
Other articles on "High Protein Diet and Bone Mineral Loss"
- High-protein diet and kidney damage
- High Testosterone and Prostate Cancer Risk
- High Transaminases in Sports and Liver Health
- Testosterone and health problems
