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Age and amino acids
Maintaining muscle mass and physical function is fundamental to promoting health and independence with age. It has particular relevance for the prevention of falls, fracture and disability which may have life-threatening implications for elderly individuals. The identification of effective nutritional treatments for age-related sarcopenia (age-dependent loss of muscle mass) represents an ongoing challenge.

We have already discussed here that essential amino acids (EAA) and especially leucine could be of benefit to an aging individual, especially considering a positive balance of costs and benefits of EAA. A recent clinical work published after our LinkedIn summary (see here, in August 2015) has compared the efficacy of EAAs enriched with different amounts of leucine on muscle mass and physical performance in elderly men and women. In line with our assumptions, the authors hypothesized that an increase in the proportion of leucine in a modified mixture of EAAs would be of greater benefit than a standard mixture of EAAs or a placebo. For study itself; see: www.ncbi.nlm.nih.gov/pubmed/26081485

The authors found that twice-daily supplementation of EAAs containing 20% or 40% leucine improved the key aspects of functional status and at the higher level improved lean tissue mass. Since elderly rarely care about their muscle mass, the improvement in functionality is the key message. Among the tricky points of the study was the app. 79% adherence, indicating that the taste and texture could be a hurdle when implementing leucine-rich EAA diet for elderly people. This point aside, the referenced study further confirmed prophylactic role of EAAs and in particular leucine for the treatment of sarcopenia. Twice-daily supplementation with 0.21 g/kg/day EAAs (with 40% content of leucine) alongside a diet providing adequate protein is the best recommendation nutritional science can right now provide…

Branched-Chain Amino Acids in elderly
Sarcopenia, the gradual loss of lean muscle mass associated with middle- and especially high-age, contributes to the fragility of an aging person. There is no clear consensus on how to blunt the process, but it is reasonable to claim that absence of chronic disease in a combination with physical activity and a healthy diet rich high-quality protein are the key factors.

Because the anabolic capacity of skeletal muscle decreases with age and there is no apparent harm associated with protein intake above the Recommended Dietary Allowance (RDA, the current RDA is 0.83 g protein/kg body weight/day), high protein diets were already proposed for elderly adults (Wolfe, Br J Nutr 2012;108:S88-S93).

However, the quality of long-term ingested dietary protein in terms of essential amino acids content, and especially leucine content, comes up as more important than quantity of the protein eaten (Paddon-Jones, Exp Gerontol. 2006;41(2):215-219).

Leucine and the two other branched-chain amino acids (BCAA) belong to the most studied group of amino acids with respect to muscular functions in both young and elderly humans. The unique role of leucine as the trigger of muscle synthesis is well studied (e.g. Valerio, Aging 2011;3:464-478). Clinical data support leucine central role in muscle protein synthesis, nitrogen provision for synthesis of other amino acids, as well as its role as an insulin stimulant.

Importantly, the beneficial effects of leucine were identified in both young and elderly humans. Among others, Koopman and colleagues reported that ingesting whey protein and 13 g leucine following physical activity resulted in similar increases in muscle strength/mass and body protein balance in young and eldely men (Koopman, Am J Clin Nutr 2006;84:623-632). Similar results, in addition to an enhanced rate of skeletal muscle synthesis, were obtained with another larger group of elderly adults supplementing for two weeks their normal diet with 12 g leucine per day (Casperson, Clin Nutr. 2012;31(4):512-519).

A different approach often used in clinical research involves the administration of a mixture of all nine essential amino acids in addition to extra high leucine doses. From a summary of all comparable trials, one could deduce that the minimum dose of leucine to stimulate muscle growth and strength in the elderly was at least 3 g leucine (i.e., Paddon-Jones, Curr Opin Clin Nutr Metab Care 2009;12:86-90).

It is also of value to note that leucine and BCAA mixtures have been reported to exert beneficial effects on body weight and body fat control in middle-aged individuals (Qin, J Nutr 2011;141:249-254). These epidemiological data on the importance of leucine in body weight management were further supported by interventional findings (i.e., Zanchi, Med Hypotheses 2012;79:883-888).

Taken together, clinical results have been very promising and demonstrated the key role of leucine and other branched-chain amino acids (BCAA) in tackling muscle loss in elderly, although it is important to note that physical activity, glucose metabolism and background intake of dietary protein are also very important factors.

Amino acids nutritional supplement formulations for elder people health; a suggestion for a different investigation approach

Amino acids are well known to exhibit significant health boost effects when taken in optimum quantities and their lack has been correlated with various negative effects including psychological disturbances, loss of muscular and bone mass, and others. Of special attention is the positive effect that they may provoke on specific population groups that suffer from known health problems, such as elderly people. Several studies have been published on the subject, and major guidelines are presented here.

In relevant research works, different amino acids have been supplied to patients at different combinations, contents and rates. Such recipes include any of the following amino acids:
– L-Leucine
– L-Lysine
– L-Isoleucine
– L-Valine
– L-Threonine
– L-Cysteine
– L-Histidine
– L-Phenylalanine
– L-Methionine
– L- Tyrosine
and others. Supplying amino acids as nutritional supplements has been proved to increase health of elderly people in terms of reducing mild depression and increasing muscle strength. Long term effects should also be investigated since it is possible that they could reveal other improvements related to energy transfer, organ functionality, improvement of cardio vascular status, and others.

Up to now, most studies have focused on multi amino acids mixtures, trying to simulate a ‘complete’ nutritional approach effect on the health of older people. However, the opposite approach might provide a better and more efficient way to investigate specific effects of essential amino acids on health of older people. Different studies have revealed the synergistic effects of amino acids, but single amino acids effects are well established as well. A viable and promising technique would be to investigate combinations of amino acids in increasing number of components, thus advancing to the next greater group of amino acids only when conclusions are reached for a specific combination. Such a work would be based on probabilities theory and potential calculations of a number of given amino acids. Different methodologies exist to investigate such processes, for example Monte Carlo statistical approaches. Working with such methodologies can lead to better understanding of published experimental results and better estimations on health improvement of older people.

Optimization of nutritional supplements composition is less likely to be successful when a large number of amino acids are utilized simultaneously. On the other hand, an additive technique, starting at a low number of amino acids can provide significant advances in the search for such optimum formulations. The methodology of addition should follow a ‘gradient’ measurement of effects, focusing on the largest changes towards required properties. Using published results on low numbers of components can increase the rate of this trial and error procedure. An important advantage of such a technique is that masking effects can be avoided, since addition of components is a step by step procedure. A similar approach would be characterized as reducing the components of a mixture of numerous components to investigate the effects of each compound in the mixture. Both techniques are expected to be used in a larger extend by the scientific community.

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