Amino Acids for Healthy Aging

As we get older, we start to lose muscle mass. This natural process is called sarcopenia, and it affects everyone. If nothing is done about it, sarcopenia can make it difficult to perform everyday activities or to go out, and can greatly increase the risk of falls or broken bones. In short, sarcopenia can make it harder for older people to live independently and enjoy a good quality of life.

Along with safe, effective and appropriate exercise, good nutrition is essential for fighting sarcopenia. Nutritionists recommend eating meals consisting of high-quality proteins–especially animal proteins like meat, fish, eggs, and milk–that contain all nine essential amino acids.

Amino acids are also being closely studied as part of a nutritional strategy to combat sarcopenia. Research shows that combining exercise with amino acid supplementation increases muscle mass and strength.

Muscle protein is synthesized from amino acids. A particularly important role is played by branched-chain amino acids or BCAAs, which stimulate muscle growth and provide energy during exercise.

Amino acids that cannot be synthesized naturally in the body and must therefore be obtained from food are called essential amino acids. These include BCAAs. Various studies have shown that consuming essential amino acids is effective in preventing sarcopenia.

The rate of muscle protein synthesis is known to decline with age. A study of older adults found that subjects who consumed a formula of nine essential amino acids containing a high percentage of leucine, in combination with exercise, experienced faster rates of muscle synthesis than subjects who consumed whey protein instead.

In addition, older adults who regularly consumed this leucine-rich essential amino acid formula in combination with light exercise enjoyed increased muscle mass and strength and improved exercise function, including higher walking speeds.

Of the three BCAAs, leucine is the most effective in promoting the building of muscle protein. This suggests that as we get older, we should regularly consume high-quality proteins rich in leucine, such as dairy products, meat, fish, and eggs.

As we get older, our immune system also weakens, making us more likely to catch colds and other illnesses. Older people tend not to consume enough protein, leaving their immune system further impaired, to the point where, even if they receive an influenza shot, they may not be able to produce enough antibodies to provide adequate protection against influenza.

The graphs below show the results of a study conducted to investigate the effects of the amino acids cystine and theanine on antibody production in nursing home residents who had received a flu shot. The study participants were divided into two groups. One group was given cystine and theanine; the other group was not. The two groups were then compared as to the percentage of study participants with antibody levels high enough to be effective against influenza viruses.¹

The group that did not take cystine and theanine after being vaccinated showed almost no improvement in antibody production, but the group that took cystine and theanine showed a significant improvement. These results indicate that loss of immunity due to aging can be restored by consuming amino acids.

Appropriate exercise and regular intake of essential amino acids are important in preventing sarcopenia (loss of muscle mass due to aging). Moreover, amino acids can help restore immunity in older people.

To learn more about how the amino acids cystine and theanine function in the human immune system, click the following link.