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C H A P T E R 1 3 Nutrition for Older Adults 335

Peak Bone Mass: density are accrued. Around the age of 30 years, peak bone mass is attained (USDHHS,
the most bone mass a 2012). Thereafter, more bone is lost than is gained. During the first 5 years or so after onset
person will ever have. of menopause, women experience rapid bone loss related to estrogen deficiency. After that,
bone loss continues at a slower rate.

Osteoporosis is a disease characterized by a decrease in total bone mass and deteriora-
tion of bone tissue, which leads to increased bone fragility and risk of fracture. An estimated
10 million Americans have osteoporosis, and another 34 million have low bone mass, which
puts them at risk for osteoporosis (National Osteoporosis Foundation [NOF], 2012). It is
predicted that one in two women and up to one in four men over the age of 50 years will
break a bone due to osteoporosis (NOF, 2012). Older adults, white women, postmeno-
pausal women, people with low body weight, and those with a low calcium intake are most
at risk for osteoporosis. Cigarette smoking, heavy alcohol intake, physical inactivity, and
certain medications also reduce bone mass.

Osteoporosis prevention begins early in life with an adequate intake of calcium and
vitamin D combined with daily weight-bearing physical activity to promote peak bone
mass: the greater the peak bone mass attained, the less damaging the inevitable loss of bone
mass. Adequate calcium and vitamin D and daily weight-bearing physical activity are vitally
important throughout life for strengthening and protecting bones (USDHHS, 2012).

Once bone mass has deteriorated to the point where osteoporosis is diagnosed, medica-
tions are necessary to stop bone loss and increase bone density. Nutrition plays a supportive role,
with adequate calcium and vitamin D being the most prominent concerns. People who cannot
or will not consume the equivalent of 3 cups of milk daily should obtain the remaining calcium
they need from calcium supplements. Calcium from supplements is absorbed best in doses of
500 mg or less, so if multiple doses are required, they should be spread out over the day. Other
nutrients that are important for bone health include vitamin A, vitamin K, magnesium, and
vitamin C—nutrients that can be obtained through a healthy diet that contains at least five serv-
ings of fruits and vegetables daily (Nieves, 2005). High-protein diets are often cited as a risk
for osteoporosis because they may increase calcium excretion. However, cross-sectional studies
indicate that high-protein diets do not adversely affect calcium retention (Roughead, Johnston,
Lykken, and Hunt, 2003) and that protein undernutrition is associated with low bone mineral
density and greater risk of fracture (Heaney, 2002). Excess sodium should be avoided; high
sodium intakes have been shown to increase urinary calcium losses. Limited evidence suggests
that a low-sodium diet may positively impact bone density (Carbone et al., 2005).

Sarcopenia

Sarcopenia: the loss Age-related loss of lean body mass is a normal part of aging; sarcopenia occurs when
of muscle mass with age-related loss of skeletal muscle mass is accompanied by loss of muscle strength and
aging. function. Advanced sarcopenia is characterized by physical frailty, increased likelihood of
falls, impaired ability to perform ADL, and diminished quality of life (Paddon-Jones et al.,
2008). Sarcopenia is estimated to affect 8% to 40% of adults over the age of 60 years
and approximately 50% of those over the age of 75 years (Berger and Doherty, 2010).
Sarcopenia should be considered in all older adults with observed declines in physical
function, strength, or overall health and especially in older adults who are bedridden, who
cannot rise independently from a chair, or who have a slow gait (Evans, 2010).

At around 50 years of age, loss of muscle mass averages 1% to 2% per year, but because
of the large reserve of muscle, function is not impaired. In the early 60s, a person’s loss of
muscle becomes evident as muscle strength declines an average of 3% per year. An estimated
20% to 40% of muscle strength may be lost by the time a person reaches the 70s. Loss of
muscle strength, rather than mass, is associated with mortality risk (Newman et al., 2006).