QUESTION: "I was wondering about how much protein older people need. I'm a 75-year-old man and do not foresee ever adding meat back into my diet, but I wondered if I need to start eating eggs and dairy products. (I've been vegan for many years.) I think that my muscle mass is disappearing because I do not exercise and probably do not get enough protein."
ANSWER: Age-related muscle loss is extremely common. After the age of 50, most people lose approximately 1 to 2 percent of their muscle per year1,2. Rates of muscle loss in aging are higher in men than in women3,4. The name given to the muscle loss that occurs with aging is sarcopenia. Sarcopenia can significantly impact your quality of life by decreasing mobility and increasing risk of falls. While there is much ongoing research regarding sarcopenia and what can be done to slow its progress, both the amount of exercise that you get and the foods that you eat are likely to play a role.
You're right to question the amount of protein that you need. Some research suggests that slightly higher protein intake, coupled with resistance training, can lead to improved muscle mass in older men5. The evidence suggests that an appropriate range of protein intake for older vegans is between 0.36 and 0.57 grams per pound of body weight per day. Using this range, a 65-year-old vegan man who weighs 180 pounds would need between 65 and 103 grams of protein per day. You can definitely achieve this range while following a vegan diet.
Since you probably don't need as many calories as you did when you were younger, it's important to make your calories count. Choose foods that are good protein sources, such as soybeans, quinoa, lentils, black beans, kidney beans, tempeh, seitan, and textured vegetable protein products like vegetable burgers and vegetable sausage. Limit empty sources of calories, such as soda and 'junk' foods like chips or sweets. Some research has also suggested that sarcopenia may be slowed by consuming protein with every meal (rather than, for example, carbohydrates at one meal and protein at another)6.
Lack of regular exercise is a significant factor contributing to age-related muscle loss. Men and women who are less physically active have less muscle mass and are more likely to experience falls than their counterparts who are more physically active. Resistance training has been clearly shown to increase both muscle strength and muscle mass. The term resistance training refers to exercises that work to increase muscle strength and endurance through repetition using weights, weight machines, or resistance bands. No other intervention has proven to be as effective at reversing age-related muscle loss as resistance training. The U.S. Department of Health & Human Services recommends that older adults perform muscle-strengthening activities at least two days each week. When resistance training is used, they recommend one set of 8 to 12 repetitions of each exercise.
For maximum effectiveness, exercises should involve all of the major muscle groups.
Other dietary factors that may play a role in age-related muscle loss include leucine and vitamin D.
Leucine, an essential amino acid, has a unique role. It is the most powerful amino acid in terms of its effects on promoting muscle protein synthesis and decreasing muscle protein breakdown6. While we don't know exactly how much leucine is needed to promote muscle protein synthesis, making sure that your diet contains good leucine sources seems like a reasonable strategy. Vegan foods that are rich in leucine include soybeans, lentils, black-eyed peas, peanuts, almonds, chickpeas, tahini, flaxseeds, and walnuts. The daily recommended intake of leucine for adults is approximately 19 milligrams per pound of body weight per day. For a 180-pound man, this is equivalent to 3,420 milligrams per day.
Vitamin D's role in combating sarcopenia is also under investigation. Vitamin D preserves muscle strength and reduces the risk of falls7. Vitamin D supplements, ranging from 800 to 1,000 International Units (IU) per day, may help to increase muscle strength in older people8,9. You can read more about vitamin D on VRG's website at <www.vrg.org/journal/vj2009issue2/2009_issue2_vitamin_d.php>.
- Hughes VA, Frontera WR, Roubenoff R, Evans WJ, Singh MA. 2002. Longitudinal changes in body composition in older men and women: role of body weight change and physical activity. Am J Clin Nutr 76(2):473-81.
- Sehl ME, Yates FE. 2001. Kinetics of human aging: I. Rates of senescence between ages 30 and 70 years in healthy people. J Gerontol A Biol Sci Med Sci 56(5):B198-208.
- Gallagher D, Ruts E, Visser M, Heshka S, Baumgartner RN, Wang J, Pierson RN, Pi-Sunyer FX, Heymsfield SB. 2000. Weight stability masks sarcopenia in elderly men and women. Am J Physiol-Endoc M 279(2):E366-E375.
- Roubenoff R. Sarcopenia: a major modifiable cause of frailty in the elderly. 2000. J Nutr Health Aging 4(3):140-42.
- Haub MD, Wells AM, Tarnopolsky MA, Campbell WW. 2002. Effect of protein source on resistive-training-induced changes in body composition and muscle size in older men. Am J Clin Nutr 76(3): 511-17.
- Paddon-Jones D, Rasmussen BB. 2009. Dietary protein recommendations and the prevention of sarcopenia. Curr Opin Clin Nutr Metab Care 12(1): 86-90.
- Montero-Odasso M, Duque G. 2005. Vitamin D in the aging musculoskeletal system: an authentic strength preserving hormone. Mol Aspects Med 26(3):203-19.
- Bischoff HA, Stahelin HB, Dick W, Akos R, Knecht M, Salis C, Nebiker M, Theiler R, Pfeifer M, Begerow B, Lew RA, Conzelmann M. 2003. Effects of vitamin D and calcium supplementation on falls: a randomized controlled trial. J Bone Miner Res 18(2):343-51.
- Dawson-Hughes B. 2008. Serum 25-hydroxyvitamin D and functional outcomes in the elderly. Am J Clin Nutr 88(2):S537-40.
Written by VRG Volunteer Christine Kasum Sexton, MPH.