It is well known that our metabolism slows down as we get older and that means that older people need to eat fewer daily calories. However, a new study has found that healthy older people need to consume as much protein as young people to avoid the possible effects of inadequate protein intake such as: loss of muscle mass and strength and weakened immune function.
In this study, 18 elderly people between 66 and 79 years old and 23 young adults between 22 and 38 years old participated, all of them healthy. They followed 3 different periods of 18 days in which they followed 3 diets: low protein diet (63% of the NRV, 0.5g of protein per kg of body weight and day), medium protein diet (94% of the NRV, 0.75g of protein per kg of weight and day) and high-protein diet (125% of NRV, 1g of protein per kg of body weight and day). For the duration of the study, for each participant, the amount of nitrogen from both the food ingested and from their feces and urine was quantified to calculate the nitrogen balance (the amount ingested minus the amount eliminated).
All people increased their nitrogen balance by increasing the amount of protein ingested. It was calculated that the amount of protein necessary for adequate body function was 0.85g per kg of body weight and day, both in young and old.
When aging, the decrease in caloric needs reduces appetite and certain social circumstances such as loneliness, few financial resources and even the inability to prepare food can cause, in some cases, the diet of the elderly is poor in protein. Therefore, because protein needs are maintained, it is necessary to ensure that the elderly consume an adequate amount of high quality protein in their diet to avoid problems such as excessive loss of muscle mass and strength or an excessively weakened immune system. In these cases, the use of a high quality protein concentrate can be a comfortable and effective measure to ensure daily protein intake.
Reference: Am J Clin Nutr 2008;88:1322–9