Written By: Molly Wong Vega, MS, RDN, CSSD, CSP, LD - Sports Dietitian with Memorial Hermann IRONMAN Sports Medicine Institute.
This article will discuss:
Muscle and physical function have a crucial role in healthy aging. Skeletal muscle loss and loss of function are intrinsically tied to one another and can occur as early as the 4th decade of life. This loss also increases the risk for cardiovascular disease, fractures, and insulin resistance. In fact, walking speed has been tied to health outcomes, whereby, the slower one walks the worse health they may possess. Lifestyle factors such as resistance training and nutrition interventions are significant components of ongoing research investigating how to prevent this loss of muscle and function so that we may age healthfully.
In particular, many dietary components have been touted as a panacea to healthy aging. But what does the research say? The most common dietary components discussed and researched include: protein (including specific amino acids – or basic building blocks of proteins), Vitamin D, Omega-3 (specifically EPA and DHA), creatine and antioxidants.
Protein
Protein is, arguably, the most widely studied and important dietary component with regards to healthy musculoskeletal aging. Protein intake can stimulate muscle maintenance and building. However, with aging, muscle’s sensitivity to protein intake declines and thus its ability to maintain or build muscle declines without appropriate increases in protein intake. Not only do older individuals experience higher rates of muscle accrual with more optimal levels of protein intake, but they also tend to have better physical functioning and mobility.
In addition to daily protein intake, protein dose per meal and the even distribution of protein throughout the day in 3-4 meals has the capability to improve muscle maintenance. However, the typical western diet and meal pattern does not usually align with these recommendations. In a typical western diet pattern, protein intake gradually increases by meal from breakfast to dinner, with the highest intakes at the last meal of the day. A simple change such as maintaining the same amount of protein intake at breakfast, lunch and dinner can improve muscle maintenance.
Supplementation of individual amino acids (the building blocks to proteins) that have largely been studied, center around leucine or its metabolites. Research supports the fact that leucine has been found to be a primary driver in muscle maintenance and accrual. Much of the research on the dose dependent manner of protein intake and the distribution effect on muscle was built upon the identification of leucine’s dosing stimulus on muscle growth. However, individual amino acid supplementation containing leucine have not been shown to be more efficacious nor necessary when compared to whole protein sources; especially when individuals are consuming adequate amounts of protein.
Protein quality and digestibility have not fully been studied but do point to the fact that lower amounts of animal protein are needed to attain the same stimulatory effect on muscle accrual when compared to plant based protein sources. However, this does not preclude the ability of individuals following a vegan diet to reap the same benefits of protein intake on muscle. Simply, those focusing on more plant-based sources of protein may require higher amounts of protein intake and more specialized planning of nutrient intake to optimize maintenance of muscle with aging.
Many barriers exist to achieving adequate and appropriate protein intakes. Declines in protein intake can be related to changes in appetite hormones, early satiety or changes in taste or sense of smell. Scheduling conflicts and busy lifestyles can also contribute to the inability to follow through with these most recent evidenced based recommendations. Protein supplements can play a role in overcoming many of these barriers if individuals are unable to achieve these goals with whole foods. However, nutritional supplements are largely unregulated and thus ingredients and purity are rarely verified. Third party tested (NSF or Informed Sport Certified) supplements should always be utilized when selecting a protein supplement to incorporate into your regular dietary habits.
Vitamin D
Vitamin D, a fat-soluble vitamin made through skin’s exposure to sunlight, is an essential nutrient supporting bone and immune health. Vitamin D deficiency has been reported as a widespread health concern, with older adults at higher risk for deficiency. Increasing research has been performed on the effects of vitamin D on muscle maintenance and accrual. To date, the evidence does not support maintenance of high dose vitamin D supplementation above sufficient levels (30-50 nmol/L) would promote additional benefits to muscle health. Only in the case of vitamin D deficiency has it been found to prevent loss of muscle and function.
Omega-3 (eicosapentaenoic acid - EPA & docosahexaenoic acid - DHA)
The research on the effect of omega-3 supplementation (specifically EPA and DHA) on muscle growth is in its infancy. What we currently know is that EPA and DHA supplementation may improve the declines in muscle’s sensitivity to the stimulatory effects of resistance training with aging and limit the effects of muscle loss with disuse. However, some findings have been contradictory. Key items that have not been adequately explained to date in the research are the potential differences in the response of men versus women, the confounding effects of inadequate protein intake or the presence of baseline omega-3 deficiency. EPA and DHA remain extremely important nutrients to overall health and have been shown to promote decreased cardiovascular risk and cognitive decline with age. In general, most Americans are lacking in EPA and DHA intake. These can be most easily attained through adequate protein intake of mackerel, herring, salmon or tuna in 2 meals per week. If this is not attainable by an individual either through dislike of these fish or inability to consume it in this frequency, one may consider the addition of an NSF or Informed Sport Certified omega-3 supplement focusing on EPA and DHA consumption.
Creatine
Creatine is primarily found in skeletal muscle and is extremely important for energy production. It is made in the body or obtained through dietary intake. Creatine is a well-studied ergogenic aide and has been shown to improve athletic performance in a variety of exercise tasks (physically and cognitively). For these reasons, it can be a viable nutritional strategy to aide in skeletal muscle growth with resistance training. Additionally, creatine muscle content has been found to be lower in that of individuals consuming mostly plant-based proteins, thus they tend to experience greater benefits with creatine use. Adverse effects of creatine supplementation are limited to case reports of high intakes or unknown intake amounts most reflective of poorly controlled manufacturing (non-3rd party tested or lack of knowledge on appropriate dosing). Additional caution should be used in individuals with pre-existing kidney dysfunction.
Antioxidants
Increasing research shows the adverse effects of chronic low-grade inflammation on poor health outcomes and chronic disease. The use of supplements or pharmaceutical agents to decrease inflammation are currently being studied. However, limited and contradictory evidence supports the use of antioxidant type nutritional supplements or pharmaceutical agents to limit loss of muscle and loss of muscle function. In fact, intake of high dose nutritionally based antioxidants such as Vitamin E and Vitamin C may counteract the necessary pro-inflammatory properties of acute exercise that are needed to create the beneficial long term anti-inflammatory effects that physical activity has on the body. These have the potential to negate an individual’s efforts on lifestyle changes centered around exercise and physical activity. At this time, antioxidant supplementation above what one would find naturally occurring in food and through food consumption is not recommended.
In summary, it is important to continue to work towards ways to promote healthy muscle with advancing age that negates adverse health effects. Ideally, diet can be optimized through food sources to support this end. However, many barriers exist to adequate intake of protein, vitamin D or omega-3s that would naturally lead to suboptimal levels or deficiencies. With this in mind, the use of an NSF or Informed Sport Certified tested supplements to prevent or overcome deficiencies and suboptimal intakes may be an avenue to support muscle health for older adults.
Take Home Message
Have questions or want to set up a consultation? Please contact Memorial Hermann IRONMAN Sports Medicine Institute Sports Dietitian Brett Singer at brett.singer@memorialhermann.org. or by phone at (713) 526-6143.
You can also follow him on twitter @bsinger10 or on Instagram @bsinger_sportsrd.