By Dr. Francesco Casillo
Introduction
Culture, tradition (religious, mystical, superstitious, folkloristic, etc.) are spatio-temporal cases that weave a good part of the plot of the relational-social aspects of the individual, conditioning their destiny.
Unfortunately, there are many "myths" in our sector ...
"A lie told a sufficient number of times becomes a truth" - reads a quote attributed to the Russian revolutionary Lenin. The efficacy and power of this affirmation has been recognized by political leaders for eons, since it is such as to make the beliefs that they want to be assimilated as truth captured in the minds of the people .
But as Kennedy said in 1962 at the " Commencement Address " at Yale University, the greatest enemy of truth is not the lie but the "myth", because it is persistent, persuasive and unrealistic . And the most serious problem is when the myth, permeating between the classes of scientific rank, automatically becomes a law, in reference to which the public opinion relates and, therefore, behaves! And here the "mythological" examples would follow extensively.
In this "Pseudo-truth Dossier" we will try to bring to the attention of the readers the main topics most discussed in body-building and sport in general, linked to nutritional aspects and more, to highlight - through the appropriate literature reported in the extensive bibliographic references - like many of the beliefs, not only popular, but also medical (media) - scientific are unfortunately dictated by 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 permeate the knowledge of the masses and (pseudo) specialists!
High protein diet and bone mineral loss
It is now known that large-scale proteins can be detrimental to bone health, based on the association that hypercalciuria - induced by their intake - is the result of the mobilization of bone calcium (1, 2).
Later it turned to scientific knowledge that the main source of hypercalciuria is the intestine. Subsequent studies revealed that reduced protein intake leads to reduced intestinal calcium absorption, an event associated with increased parathormone levels (3, 4). Thus, the assumption that hypercalciuria induced by high protein diet was associated with bone mineral loss was revisited. And the opposite emerged.
Studies on menopausal women aged 50 to 75, and another study on men and women aged 50 and older, were conducted to evaluate the effect on calcium levels and bone metabolism caused by a protein increase (from meat) from 0.94 to 1.62 and from 0.78 to 1.55 g per kg of body weight respectively, after 5 and up to 9 weeks. The results of the two studies reported no hypercalciuria, let alone a decrease in calcium retention (5, 6).
In the first study, the initial renal acid excretion reported by the high protein group decreased significantly over time and no markers of bone metabolism underwent variations. In the second case, however, there was a decreased urinary excretion of the N-telopeptide ( marker of bone resorption) and an increase in IGF-1 (somatomedin favoring anabolism, including bone in nature).
If losing weight yesterday was the prerogative of calorie counting, recently it was the glycemic index, where very recently it was the virtue of the glycemic load; today the PRAL ( "Potential Renal Acid Load", or renal acid loading potential) has become a reference point for monitoring qualitative food selection, in order to avoid renal acid loads responsible for bone mineral loss. Beyond the nutritional fashions and the recent scientific findings - which instead of adding to the known wealth of knowledge seem almost to suppress it to excel, as if they represented absolute and unquestionable truths -, the body-builder type "does not lie" on the correctness and healthiness of the lifestyle choices undertaken, as its morphological structure is nothing but the mere phenotyping of full organic health in its entirety .
A recent publication, which leads to further confirmation and validation of the aforementioned studies, is that of the 2011 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 markers of bone metabolism. To this end the hyperprotein diet with high PRAL (HPHP) was compared with the low PRAL low protein diet (LPLP). The HPHP diet showed higher IGF-1 values and decreasing parathormone values compared to the LPLP diet.
Furthermore, the HPHP diet reported higher values in calcium absorption and also in excretion than 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 markers of bone metabolism. And the increase in calcium absorption observed in HPHP compensates for its excretion. In addition to this, the increased levels of IGF-1, the decreased concentrations of parathormone and the simultaneous stability of bone metabolism markers indicate that the hyperprotein approach is not responsible for negative effects on bone health (7).
Another recent study of 8 elite bodybuilders denies the absoluteness of the causal relationship "hyperprotein approach and metabolic acidosis" (72). The eight athletes, aged between 18 and 25, were recruited from among those who had at least a training period of more than 2 years behind them in preparation for competitive events and who also reported several victories in at the national championships (therefore it is not a question of novice subjects included in the study, but of athletes with high protein turnover ).
Their protein intake consisted of 4.3g ± 1.2g of protein per kilogram of body weight per day, in a caloric context of 5621.7kcal +/- 1354.7 kcal per day. Their supplementary plan also included amounts of supplements based on vitamins and minerals (calcium and potassium) significantly higher than the normally recommended doses.
The ratio of the ratios between the macronutrients within the daily caloric shell was thus set: 34% carbohydrates, 30% proteins, 36% fats. The proportions of the ratios between the macronutrients deriving only from the supplements were the following: 14% carbohydrates, 66% proteins, 20% fats; and 28% of the total daily protein intake derived 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 (0.8 g of body weight) could induce serious homeostatic alterations within the delicate acid-base balance.
At the end of the study, the obviousness in finding phenomena of metabolic acidosis in response to high protein loads failed .
This study confirms how the effects of a macronutrient (in this case the proteins) cannot be given for absolute and in all circumstances, but must always be contextualized and above all verified in a cause-effect relationship as a sine qua non condition for the knowledge of their real metabolic impact.
Any other way of observing and conceiving is skimmed by objective feedback remains unqualified, speculative and sterile with respect to the real effects induced by precise stimuli, in this case biochemical-nutritional.
The authors hypothesize that, very probably, the physical exercise in combination with "tampons" such as potassium and calcium helped to prevent the phenomena of acidosis resulting from high protein consumption.
So they are not primarily the proteins responsible for effects ... but the nutritional context and the overall lifestyle in which they are inserted represents the determinant of the ultimate, positive or negative effects respectively.
