Elder people need to maintain muscle mass for optimal health, as most lose muscle mass as they age and are less efficient at using dietary protein to build muscle. This condition is known as sarcopenia and is a characteristic of normal human aging. To make matters worse, older adults typically eat less protein than younger people, despite studies in the general population showing they should eat more. Heart failure is a serious medical condition in which the heart does not pump blood as it should. This means that the blood does not supply enough oxygen and nutrients to the body to allow it to function normally. Little is known about the impact of low protein intake in patients with congestive heart failure (chronic heart failure), a condition that becomes more common with age. Suffice it to say that about one in ten people aged 70 have heart failure. However, in the past, it was common belief that patients with chronic heart failure should not overdo the intake of dietary proteins, in order not to affect heart hypertrophy and dilation that could worsen the hemodynamic picture.
So, this conceptual situation has persisted for at least 60-70 years but it seems to be changing. Heart failure patients who consume more protein live longer, according to recent research that was previously presented at Heart Failure 2018, the annual World Congress of the European Society of Cardiology. This study investigated the association between protein intake and survival in 2,281 patients with heart failure in the BIOSTAT-CHF study, conducted in 11 countries in Europe. The mean age of the patients in this analysis was 68 years and 27% were female. Daily protein intake was estimated from urine excretion, corrected for clinical parameters such as creatinine and body mass index (BMI). The patients were divided into four groups based on the amount of protein they consumed, then the association with mortality was evaluated. The average protein intake was 53g per day, from 40g in the lowest quartile to 70g in the highest. At the end of the median follow-up period of 21 months, 31% of patients in the lowest protein intake quartile (40g or less per day) had died compared with 18% of patients in the highest protein intake quartile ( 70gr or more per day).
Dopo aggiustamento per più fattori confondenti, tra cui età e funzionalità renale, i pazienti nel più basso quartile di assunzione di proteine avevano un rischio di morte del 46% più alto rispetto a quelli nel più alto quartile di assunzione di proteine La conclusione è stata che un apporto proteico più elevato è associato in modo indipendente a una migliore sopravvivenza. Lo studio non ha esaminato le cause di questo collegamento, ma è probabile che la proteina alimentare costruisca la massa muscolare che è benefica per la salute in questi pazienti. Nello scompenso cardiaco, generalmente si ritiene che la perdita di massa muscolare derivi dall’atrofia da poco uso in un paziente che si stanca facilmente, è sotto terapia antipertensiva e generalmente ha come comorbidità di fondo un diabete o un’osteoartrosi diffusa. Queste condizioni impattano ancor di più nella progressione dello scompenso cardiaco, poiché possiedono una componente infiammatoria cronica più o meno silente. Questa, tuttavia, può influire sulla funzionalità cardiaca in modo diretto. Tutti i cardiologi, sia ricercatori che clinici, sanno che le citochine infiammatorie (IL-1, IL-6, TNF-alfa, ecc.) hanno attività catabolizzante sui muscoli. Esse, cioè, attivano i sistemi di proteolisi ovvero di scissione enzimatica delle proteine.
This obviously does not spare the heart, which in chronic heart failure is dilated and has thinned walls. The coexistence of chronic inflammatory situations both manifestly (osteoarthritis, rheumatoid arthritis, etc.) and in a silent way (such as diabetes) can contribute to the loss of cardiac muscle mass in an unconscious way. To prevent the loss of muscle mass in the chronic decompensated person, the possibilities of intervening through controlled physical exercise have been studied. In spite of significant results in terms of either survival or quality of life, physical activity is not always an option that is applicable to all cohorts or types of decompensated patients. Much more recently, the possibility of associating a greater dietary protein intake with physical exercise has been considered. In fact, scientists from the Reynolds Institute on Aging, University of Arkansas for Medical Sciences, found that individuals with still partially compensated heart failure who consume about 1.2 g of protein/kg/day, can benefit both physically and cardiovascularly from a exercise program that most consider likely to be insufficient to promote significant physiological adaptations.
Protein supplementation alone failed to improve physical performance. However, when combined with light exercise, there was a significant improvement in some (6 minutes of walking, 10m walking speed, quadriceps strength), but not in all physical function measurements. The amount of protein that each individual in each phase of his life should normally introduce is universally estimated at around 0.8g/kg of body weight. However, this amount can rise during adolescence (due to body development) and old age (due to the opposite phenomenon, i.e. greater loss). Those who are chronic heart disease and have malnutrition are both more likely to be hospitalized and short-term hospital readmission if food supplementation was not sufficient during hospitalization. This is the conclusion of a meta-analysis published in 2020 by Habaybeh et al. It must be considered, however, that in addition to the lack of proteins, the literature data also point to the association between reduced intake of certain nutrients and the onset of heart failure. For example, Japanese studies have confirmed that at least 30% of heart failures is attributable to taurine deficiency and correctable by the administration of this metabolite.
Other studies have pointed to the chronic and underestimated deficiency of certain minerals such as zinc and selenium. These two trace elements become part of important metabolic enzymes and protect against the action of free radicals and oxidative stress. Without going into the merits of these mechanisms, we only remember that zinc and selenium are very abundant in foods with high protein density such as milk and derivatives, animal meats, eggs and legumes. Excess cholesterol and triglycerides may well increase the risk of heart disease, but lack of protective factors for incorrect dietary beliefs apparently does not seem to be outdone.
- a cura del Dr. Gianfrancesco Cormaci, PhD, specialista in Biochimica Clinica.
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