**5. Other Possible Beneficial Association of Nuts**

As the population of the world is getting older, a global priority for the aging population should be the maintenance of independence and freedom of movement. One of the hallmarks of aging and a major public health concern is the loss of mobility due to sarcopenia and dynapenia, or progressive loss of skeletal muscle mass and muscle strength, respectively. Another gerontological condition, described by physical inactivity, slow walking speed, fatigue, and weakness, is frailty [136].

In the elderly, both conditions, sarcopenia and frailty, are characterized by increased levels of pro-inflammatory cytokines, including TNF-α, IL-6, and CRP. Therefore, knowing its antioxidant and anti-inflammatory potential, dietary intake of food rich in monounsaturated fatty acids (MUFAs) and PUFAs is of particular interest for this age group [137]. One recent study mentioned that quantities of 2 to 5 g per day of marine *n*-3 PUFA, corresponding to approximately 20 to 50 g walnuts, is shown to reduce muscle wasting and augment the intracellular anabolic signaling, thus having beneficial effects for the prevention and treatment of sarcopenia in mature adults [138]. Also in this age group, malnutrition and sarcopenia frequently overlap. In order to overcome the loss of lean mass and meet the increased energy requirements, the recommended protein intake is higher (1.2–1.4 g/kg/day) than that of healthy adults [139]. Because the protein level is between 15 to 21% in most tree nuts and around 26% in peanuts, nuts should be included in healthy diets as plant food sources of protein [140].

Nutrition is a factor that could influence osteoarthritis (OA), the most dominant form of arthritis with limited treatment, mainly through symptom management [141]. As food impacts systemic lipid levels, high consumption of saturated fat is linked with higher levels of pro-inflammatory fatty acids, while diets rich in less-inflammatory MUFAs and PUFAs, lipids also found in tree nuts and peanuts (Table 7) may reduce cartilage degradation and OA progression [142].


**Table 7.** Average fat composition of nuts [3,139].

MUFA—monounsaturated fatty acids; PUFA—polyunsaturated fatty acids; SFA—saturated fatty acids.

In a group of postmenopausal women, MD enhanced with up to 20 g/day nuts was significantly associated with bone mineral density (*p* = 0.045), indicating that nuts may be beneficial in osteoporosis prevention [143].

Two biomarkers of aging, advanced glycation end products (AGEs) and length of telomeres, can be influenced by nut diets. AGEs, a complex class of compounds, can be formed in vivo, as part of normal metabolism, or acquired exogenously from unhealthy diets or environment. They can accumulate in tissues during aging. Data suggests that AGEs can have damaging effects in CVD, neurodegenerative diseases, T2DM, cancer, or sarcopenia [144–146]. It was shown that nut-enhanced MD may constitute a good instrument towards the inhibition of AGEs formation and absorption [145]. Telomeres, protecting DNA sequences at the end of the chromosomes, present a defensive mechanism against risk factors for a number of age-related diseases, including osteoporosis, CVD, CHD, T2DM, pulmonary fibrosis, AD, and cancer [147–149]. Several studies demonstrated that reactive oxygen species (ROS) can accelerate telomere attrition, induce DNA damage response, and senescence [150]. Sirtuins or the action of telomerase can counter telomere shortening. Among the environmental factors lessening telomere attrition are polyphenols, *n*-3 PUFA, or vitamin E, active antioxidant molecules [150]. A recent study linked regular nut consumption with telomere length and a significant reduction in cellular aging and biologic senescence [151]. Fiber, another valuable compound in nuts, can mediate longer telomeres and reduce biologic aging [152]. A two year trial conducted by Freitas-Simoes et al. [153] in an elderly population confirmed that supplying the diet with walnuts at 15% of daily energy (30 to 60 g/day) postponed leukocyte telomere attrition, potentially influencing the aging process.

Together with physical exercises, long-term daily intake of tree nuts and/or peanuts may contribute to maintaining the health of the skeletal system, muscle mass and strength, as well as the well-being of middle-aged and elderly population.
