“There are more people on the planet over the age of 65 than ever before in human history (1).” As we learn more about normal age changes to physiological function and how exercise and nutrition support activity in older adults, there is a unique opportunity for health professionals to provide sound nutrition strategies to support active aging.
The population of those over the age of 65 increased from 36.6 million in 2005 to 47.8 million in 2015, a 30% increase that is projected to double to 98 million by 2060. The number of older adults 85 years and older is expected to triple from 6.3 million to 14.6 million by 2040. And, approximately one in every seven persons in the population is an older adult. As we learn more about normal age changes to physiological function and how exercise and nutrition support activity in older adults, health professionals are provided a unique opportunity to deliver sound nutrition strategies to support active aging (1,2).
Learning from masters athletes (those who remain or become competitive as older adults) and applying what we know to active, older adults could help increase the years of healthy life expectancy. For those who reach the age of 65, the average life expectancy is an additional 19.4 years (20.6 years for women and 18 years for men). Older adults spent approximately 13% of their income on health care, as compared with 7.5% among all consumers (2). Encouraging an active lifestyle with sound nutrition strategies could help older adults maintain functional fitness that would reap big rewards to not only the individual, but to society.
This article will review normal physiological age changes in healthy adults and discuss how these changes might impact exercise and alter nutrition needs. Keep in mind it is difficult to untangle usual aging from disuse and chronic disease. But, in studying masters athletes or those who are very active into older ages, we get confirmation that chronological age is not a good indicator of functional age. Indeed, masters athletes counterbalance the negative stereotypes of aging by showing a picture of good health, physical independence, and robust cognitive skills into advanced age (3).
There are no statistics on how many older adults compete in athletic events designed for masters athletes or senior games, but data for the New York City Marathon show that older age groups have the largest relative increase in participation and improved their performance times at rates greater than that for younger athletes (4). In 2017, approximately 10,674 athletes from 34 countries competed in the Huntsman World Senior Games, held yearly in St. George, Utah, for those aged older than 50. That number is a significant increase from the 500 participants in the 1987 inaugural games. As gyms and fitness facilities attract older adults, the need to provide sound nutrition and exercise strategies will grow.
NORMAL AGE CHANGES
With aging, every system declines, even in active older adults. Despite the claims for superfoods, supplements, or special exercises to reverse or halt the aging process, aging cannot be stopped, but we can halt the decline of muscle loss, poor balance, decreased aerobic fitness, and accumulation of excess body fat. Despite the challenges of understanding normal aging from disuse associated with sedentary behaviors, researchers have identified the following as normal age changes.
Normal age changes in the cardiovascular system have been identified as (1):
- Modest left ventricular hypertrophy
- Left ventricular stiffening
- Left atrium thickening and dilation
- Calcification of aortic valve
- Declines in maximal exercise heart rate
- Declines in aerobic exercise capacity
Maximal oxygen consumption or V˙О2max decreases about 10% per decade beginning at approximately 30 years (most physiological changes begin in early adulthood, between 30 to 40 years). Masters athletes have greater V˙О2max compared with their inactive peers and much less arterial stiffness, considered by some clinicians to be a biomarker for increased risk for cardiovascular disease (3). The stress of exercise training leads to positive cardiovascular adaptations and improved functional health in older adults who continue to maintain a high level of fitness.
Body Composition Changes
With aging comes changes to body composition, including (5):
- Increase in abdominal fat
- Increase in deposition of fat in skeletal muscle, heart, liver, and bone marrow
- Increase in body weight until approximately 70 years
- Redistribution of fat including an increase in visceral fat and a decrease in peripheral fat
However, these changes may be related to lifestyle behaviors, including a decrease in physical activity and an unbalanced energy intake. Exercise training can prevent some of the changes in body composition with aging, but a slight increase in body fat is likely to occur even in fit older adults.
Changes to the skeletal system due to aging are hard to quantify because approximately half of peak bone mass is achieved in adolescence, so osteoporosis is truly a disease that begins in childhood (1). Bone loss begins in the fourth decade, and in women, rapidly declines during the 5 years after menopause; then the decline slows, but never fully recovers. With aging, bone thins and the circumference widens to “make up” for thinning bones but isn’t enough to protect bone from osteoporosis and fractures. There is no cure for osteoporosis, but exercise, especially weight-bearing exercise throughout life, helps to preserve bone in both older men and women. Consuming sufficient calcium and vitamin D throughout the lifespan also can support bone health. Although food is the preferred vehicle for nutrients, consuming fortified foods or taking supplements may be necessary to augment food intake.
Although highly variable, both muscle mass and strength decline with age. Small declines are seen between 30 and 50 years, with more steep declines occurring after 50 years. After menopause, women have a more rapid decline in skeletal muscle mass and strength than men do (6). Emerging research suggests that the current recommendations for dietary protein are insufficient to support muscle protein synthesis in older adults, especially active older adults. An international study group (The PROT-AGE Study Group) recommends increasing protein for older adults to 1.0 to1.2 g protein per kilogram of body weight per day (7). In addition, although research is limited on masters athletes and protein needs, it seems there is a slower muscle recovery rate from hard exercise compared with younger athletes who are similarly trained (8). This phenomenon has been called “age-related anabolic resistance,” thought to be caused by less sensitive signaling pathways leading to slower rates of muscle protein synthesis. Nutrition strategies may be the answer to offset these changes.
Unfortunately, only limited research examines what masters athletes eat. Most of the research is focused on physiological measures. Because of insufficient research to make definitive nutrition recommendations for all older active adults, we can use current guidelines on macronutrients for athletes to make practical recommendations for healthy, active older adults. The word healthy is stressed because older adults with chronic illnesses who take multiple medications need nutrition advice from a registered dietitian nutritionist who can provide medical nutrition therapy. For example, the simple advice to consume more fruits and vegetables may be harmful to an older active adult who has kidney disease with the need to restrict potassium intake.
Table 1 provides guidelines for carbohydrate and protein intake for older, active adults. These guidelines are adapted from what is known about physiological changes in aging, recommendations for athletes by professional organizations, and practical considerations. Keep in mind that specific recommendations should be individualized depending on the person’s medical condition, current fitness level, and fitness and body composition goals.
Carbohydrate recommendations have shifted from static guidelines (i.e., endurance athletes need 5 to 10 g/kg/bw/day) to carbohydrate availability (i.e., having sufficient carbohydrate available to meet the demands of training and competition), so that carbohydrate needs will vary depending on activity duration and intensity.
Older active adults can restore muscle glycogen at rates similar to younger athletes if sufficient carbohydrate and energy are ingested. Among masters athletes, the rate of muscle repair is slower, so it is likely that glycogen restoration also is slower (8). Because of this, older athletes should consider adding 30 to 40 g of high-quality protein along with carbohydrate postexercise to both restore glycogen and stimulate muscle protein synthesis.
There is much interest in protein intake in older adults and when layered with exercise, protein needs seem to be higher because of the anabolic resistance of older muscle. Older adults need a higher protein-per-meal dose to achieve maximal muscle protein synthesis and, currently, the best advice is to aim for about 30 g/protein spread throughout the day in 3 meals with 2.5 to 2.6 g of leucine (7). Leucine, the amino acid called the anabolic trigger, is found in dairy foods (cow’s milk, cottage cheese, cheese, yogurt), beef, chicken, turkey, and fish. Soy protein provides leucine in smaller concentrations than animal foods but is a good protein food for vegetarian athletes. Table 2 shows sample meals and snacks containing 30 g of protein.
There is much interest in protein intake in older adults and when layered with exercise, protein needs seem to be higher because of the anabolic resistance of older muscle. Older adults need a higher protein-per-meal dose to achieve maximal muscle protein synthesis, and currently, the best advice is to aim for approximately 30 g/protein spread throughout the day in 3 meals with 2.5 to 2.6 g of leucine.
Recommendations for carbohydrate and protein intakes for athletes can be incorporated into a healthy eating pattern, but there is no one best plan for older adults. When thinking about nutrition advice for older, active adults, four guiding principles are suggested:
- Include all energy-containing nutrients (carbohydrate, protein, and fat)
- Focus on nutrient-rich foods
- Consider disease risk
- Enjoy eating and mealtime (11)
Dietary patterns that fit those criteria include the Mediterranean Diet, Dietary Approaches to Stop Hypertension (DASH) plan, a Flexitarian Plan, and the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet.
Changes with aging also can affect hydration status in active, older adults. Some of those changes include:
- Less body water
- Decreased thirst sensation and blunting of thirst sensation when dehydrated
- Decreased ability to concentrate urine
- Less sweat produced per sweat gland
In addition, some medications and dietary supplements can alter body water status. Thiazide diuretics, ginseng, saw palmetto, and St. John's Wort can increase urine production (12).
Hydration guidelines for older active adults are not that different than for younger athletes. The key difference is attending to hydration and making a plan to drink sufficient amounts of fluids during exercise, especially under hot and humid environmental conditions, and replacing fluids after a bout of exercise.
Motivating older adults to enjoy eating and mealtime may be easy, but how can health professionals encourage healthy eating and physical activity to improve health and functional fitness? Reviewing what motivates masters athletes to continue to maintain a high level of fitness might help to encourage older adults to get and stay active. The factors cited as motivators for masters athletes include (3):
- Enjoyment and fun
- Competition and winning
- Maintenance of fitness and health
- Social support and sociability
And, older adults should be reminded that it is never too late to eat well and move well. Highlighting inspiring older athletes could help. Consider these feats:
- In 2016, Ida Keeling, at 100 years, broke the 80-years-and-older world record for the 100-yard dash at the Penn Relays, and she didn’t start exercising until she was 67.
- Julie “Hurricane” Hawkins, at 101 years, was the oldest female athlete to compete at the USA Track & Field Masters Championship, running the 100 meters in 40.2 seconds.
- Sister Madonna Buder (known as the “Iron Nun”) is the oldest person to finish an ironman triathlon in less than the 17-hour time limit at 77 years.
- Clarence Bass, who began lifting weights at 13 years, has never stopped his fitness routine. At 80 years, he maintains a single-digit level of body fat and his fitness, as evaluated by the Cooper Clinic, is rated as that of a 40-year-old (For an amazing pictorial of Mr. Bass, see his Web site at www.cbass.com).
BRIDGING THE GAP
It is difficult to separate normal aging from a lifetime of sedentary behavior and poor nutrition, but it is never too late to encourage older adults to eat well and move well. Drawing on research from masters athletes, many of the physiological changes experienced by older adults could be minimized to improve function and health.
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Keywords:© 2018 American College of Sports Medicine.
Healthy Aging; Nutrition for Older Adults