The increased need for protein is partly due to the fact that as we age, we begin to lose muscle mass. In addition, it is more difficult to put on new muscle mass due to the body working against this muscle building process, naturally losing around 0.5-2% of muscle mass each year after the age of 50 (1). The good news is that we can fight against this process with proper protein intake and physical activity. Research shows that regular resistance exercises like weight lifting or body-weight exercises at least two times per week, in conjunction with adequate protein consumption, can help to preserve muscle mass in the aging population (1).
Part of the reason older adults need more protein is due to the fact that they lose the ability to synthesize leucine, an essential amino acid for muscle building. This phenomenon is known as “leucine resistance.” Because the body is not synthesizing as much leucine, it is helpful to intake protein sources that are high in leucine such as: chicken, beef, pork, tuna, firm tofu, navy beans, dairy products (milk, yogurt, cheese), and pumpkin seeds. Leucine is essential as it “turns on” the muscle building on the cellular level. Without adequate leucine, the body doesn’t optimize muscle building even with protein consumption. Because the body becomes resistant to leucine, more protein is required to achieve the same maximal muscle-building and recovery benefits derived from a serving of protein; thus, you need to eat more protein to elicit the same benefits.
For an average-sized person between the ages of 18 – 40 years old, 20 – 25 grams of protein has been proven to be adequate to elicit maximal benefit from a serving of protein. However, for individuals over 50, 40 grams of protein has been shown to be necessary to stimulate a similar response (or 1.0 gram per kilogram of body weight) (2). Some research indicates that a dietary protein intake of at least 1.2 grams per kilogram of body weight is even more protective against sarcopenia and overall strength decline (3).
Don’t know how much you should be eating? Use Strength.com’s protein calculator.
It is notable that protein is not just used for muscle synthesis but has several other roles in the body. As we age, decreased protein stores contribute to increased skin fragility, lower immunity, poorer healing and longer recuperation time when one gets sick (2).
Because appetite may also decrease with age, it is important to ensure that a high-quality protein source is consumed with each meal. While animal-based proteins are the most bioavailable, combined plant-based sources of protein can also be used to intake a complete amino acid profile. For example, eggs are a complete protein whereas rice and beans combined make up a complete protein.
In conclusion, protein is important for all ages but becomes critical as we age in order to protect against muscle and overall strength loss. The good news is that it is never too late to make dietary and lifestyle changes, we can always make the effort to intake enough protein to feed our muscles and increase strength. So, grab a friend, hit the gym and fuel up (with some protein) afterwards!