Title: Nutrition and sarcopenia
Key words: sarcopenia, muscle, ageing, creatinine, muscle fibres, cytokines, protein intake, skeletal mass, energy input, elderly, age, growth hormone, resistance training, strength, nutritional, genetic, vitamins, minerals, oxidative, antioxidants, superoxide transmutase, vitamin E,
Date: Oct 2006
Category:
Nutrimed Module:
Type: Article
Author: Morgan, G
Nutrition and sarcopenia
Nutritional deficiencies in the elderly have been well documented (Finch 1998). To what extent is sarcopenia, the age-related loss of muscle mass, strength and function in the elderly attributable to nutritional deficiency and to what extent to normal metabolic ageing processes? Review of the literature provides only an incomplete answer to this question but does help to increase our understanding of the ageing process in muscle.
Muscle ageing begins at an early age, when energy intake, nutritional adequacy and physical activity are at a high level. Markers of muscle mass and muscle function, such as creatinine excretion (Tzankoff 1977), oxidative capacity (Bunker 1987), grip (Giampaoli 1999), and leg strength (Evans 1993) show a gradual decline from the early 20’s. Anthropometric measures confirm that sarcopenia is directly correlated with age, levels of disability (Baumgartner 1998) and, in men, with osteoporosis (Baumgartner 1996). Studies have shown that the sarcopenia is characterised by a more selective loss of Type II muscle fibres (Larrson 1983, Lexell 1995), the composition of this fibre in muscle dropping from 60% to around 30% in those aged over 70 (Evans 1997). Histochemically, this has been shown to be associated with an increased turnover of this fibre type (Singh 1999). Associated metabolic changes in levels of IGF-1, cytokines such as IL-6 and growth hormone have been reported (Blumberg 1996, Ferrucci 2002, Pedersen 2003).
Both protein intake and skeletal mass decline with age (Gallagher 1997), along with energy input and basal metabolic rate (Tsankoff 1978). The appendicular skeletal mass has been reported to diminish by 1.2 Kg. per decade into old age (Starling 1999). Several surveys, however, have failed to show that prevalent protein intakes in the elderly are unable to meet demands. In free-living subjects, Munro (Munro 1987) failed to find any correlation between protein intake and sarcopenia over a range of intakes. Bunker (Bunker 1987), likewise, in healthy and disabled groups, found no correlation between their nitrogen balance and protein intake. Higher protein intakes in resistance training had no effect on muscle turnover and strength gains (Bunker 1987). These studies confirmed that the elderly’s protein requirements were covered by the WHO recommendation of 0.75 g/Kg per day (WHO 1985) and were met in all the elderly groups. More refined studies, using [13C]leucine, have subsequently shown that the metabolic demand of fat free muscle in the elderly is in fact some 30% lower than in younger individuals, and that protein requirements are somewhat lower in this age group, being only 0.66 g/Kg per day for men (Millward 1997, Fereday 1997). In the resistance training group, 0.8 g/Kg per day was found to be quite adequate, an intake exceeded in all groups, both housebound and fully mobile (Campbell 2002).
In sum, these studies have shown that muscle turnover is slowed down and that, in spite of adequate protein nutrition, muscle mass and strength slowly decline with age. Research on lifetime athletes shows that, even with regular aerobic and anaerobic training, these changes still occur, though the decline is muted (Wilmore 1999). The adaptability of muscle into old age to various training regimes has been well described (Frontera 1988, Campbell 1995). Two studies have addressed the question of whether the loss of muscle mass and function might have a nutritional as well as a genetic component. Both groups were given an additional one third of the RDA of a mixture of vitamins and minerals during the course of a programme of resistance training. Strength and muscle mass gains were augmented in one group (Singh 1999) and were unchanged in the other (Fiatarone 1994). Nevertheless there are many theoretical reasons for thinking that that the muscle ageing process may be partly modulated by nutritional, and specifically oxidative, factors.
Free radical damage to protein increases with age due to mitochondrial damage, poor regeneration of antioxidant enzymes such as superoxide dismutase, and diminishing vitamin and mineral intake (Weindruch 1995, Ji 2002). Muscle damage is augmented by an increased release of cytokines and other inflammatory markers, which is more marked in aged and poorly exercised muscle (Bales 2002, Ferrucci 2002, Pedersen 2003). Even though muscle retains remarkable recuperative power (Yarasheki 1993, McGuire 2001), the number of satellite cells that can regenerate muscle cells diminishes with age and cannot meet the challenge posed by oxidative stress on poorly conditioned muscle (Singh 1999).
The ability of antioxidants to protect elderly muscle from oxidative stress has been demonstrated in several studies of vitamin E (Reznick 1992, Meydani 1993). Given the synergistic nature of the antioxidant system, it is likely that combinations of vitamins and minerals would offer greater protection. That this is likely follows from the results of epidemiological and intervention trials carried out on other degenerative disorders, such as cardiovascular disease, Alzheimer’s disease and cancer. Prospective studies looking at the long-term effects of these factors, both dietary and in supplement form, on sarcopenia are obviously called for
References
1. Finch S, et al. (1998) National Diet and Nutrition Survey: People aged 65 and over. Vol 1. Report of the Diet and Nutritional Survey. London: H.M. Stationery Office
2. Tzankoff SP, Norris AH (1977) Effect of muscle mass decrease on age-related BMR changes. J Appl Physiol 43: 1001-1006
3. Bunker V, Lawson M, Stansfield M, Clayton B (1987) Nitrogen balance studies in apparently healthy elderly people and those who are house-bound. Br J Nutr 57: 211-221
4. Giampaoli S, et al. (1999) Hand-grip strength predicts disability in non- disabled older men. Age & Aging 28: 283-88
5. Evans WJ, Campbell WW (1993) Sarcopenia and age-related changes in body composition and functional capacity. J Nutr 123: 465-8
6. Baumgartner RN, et al. (1998) Epidemiology of sarcopenia among the elderly in New Mexico. Am J Epidemiol 147: 755-63
7. Baumgartner RN, Stuber PM, Kochler KM, Romero L, Garry PJ (1996) Associations of fat and muscle masses with bone mineral in elderly Men and women. Am J Clin Nutr 63: 365-72
8. Larrson L (1983) Histochemical characteristics of human skeletal muscle during aging. Acta Physiol Scand 117: 469-71
9. Lexell J (1995) Human aging, muscle mass, and fibre type composition. J Gerontol. Series A: Biol Sci Med Sci 50: 11-16
10. Evans WJ (1997) Functional and metabolic consequences of sarcopenia. J Nutr 998S-1003S
11. Singh F, et al. (1999) Insulin-like growth factor 1 in skeletal muscle after weight-lifting exercise in frail elders. Am J Physiol E135-E143
12. Blumberg JB (1996) Status and functional impact on nutrition in older adults. In: Handbook of the Biology of Aging. Schneider EL, Rowe JW, eds. Academic Press, San Diego, pp 393-430
13. Ferrucci L, et al (2002) Change in muscle strength explains accelerated decline of physical function in older women with high interleukin-6 serum levels. J Am Geriatr Soc 50: 1947-54
14. Pedersen BK, Bruunsgaard H (2003) Possible beneficial role of exercise in modulating low-grade inflammation in the elderly. Scand J Med Sci Sports 13: 56-62
15. Gallagher D, et al. (1997) Appendicular skeletal muscle mass: effects of age, gender, and ethnicity. J Appl Physiol 83: 229-39
16. Tzankoff SP, Norris AH (1978) Longitudinal changes in basal metabolic rate in man. J Appl Physiol 33: 536-9
17. Starling RD, Ades PA, Poehlman ET (1999) Physical acivity, protein intake , and appendicular skeletal muscle mass in older men. Am J Clin Nutr 70: 91-96
18. Munro HN, et al. (1987) Protein nutrition of a group of free-living elderly. Am J Clin Nutr 46: 586-92
19. FAO/WHO/UNU (1985) Energy and protein requirements. Report of a joint expert consultation. World Health Organ Tech Rep Ser, pp 724
20. Millward DJ, Fereday A, Gibson N, Pacey PJ (1997) Aging, protein requirements, and protein turnover. Am J Clin Nutr 66: 774-86
21. Fereday A, Gibson NR, Cox M, Pacey PJ, Millward DJ (1997) Protein requirements and ageing: metabolic demand and efficiency of utilisation. Br J Nutr 77: 885-707
22. Campbell WW, et al. (2002) Dietary protein adequacy and lower body versus whole body resistive training in older humans. J Physio 542: 631-42
23. Wilmore JH, Costill DL (1999) Physiology of Sport and Exercise, 2nd ed. Human Kinetics, Champaign, Illinois. Chapter 17: 545-568
24. Frontera WR, Meredith CN, O’Reilly KP, Knuttgen HG, Evans WJ (1988) Strength conditioning in older men: skeletal muscle hypertrophy and improved function. J Appl Physiol 64: 1038-44
25. Campbell WW, Crim MC, Young VR, Joseph LJ, Evans WJ (1995) Effects of resistance training and dietary protein intake on protein metabolism in older adults. Am J Physiol 268: E1143-E1153
26. Fiatarone MA, et al. (1994) Exercise training and nutritional supplementation for physical frailty in very elderly people. N Engl J Med 330: 1769-75
27. Weindruch R (1995) Interventions based on the possibility that oxidative stress contributes to sarcopenia. J Gerontol, Series A: Biol Sci Med Sci 50: 157-61
28. Ji LL (2001) Exercise at old age: does it increase or alleviate oxidative stress? Ann N York Acad Sci 928: 236-47
29. Bales CW, Ritchie CS (2002) Sarcopenia, weight loss, and nutritional frailty in the elderly. Annu Rev Nutr 22: 309-23
30. Yarasheki KE, Zashwieja JJ, Bier DM (1993) Acute effects of resistance exercise and muscle protein synthesis rate in young and elderly men and women. Am J Physiol 265: E210-E214
31. McGuire DK, et al. (2001) A 30-year follow-up of the Dallas bed rest and training study. II. Effect of age on cardiovascular adaptation to exercise training. Circulation 104: 1358-66
32. Reznick AZ, Witt E, Matsumoto M, Packer L (1992) Vitamin E inhibits protein oxidation in skeletal muscle of resting and exercised rats. Biochem Biophys Res Comm 189: 801-6
33. Meydani M, et al. (1993) Protective effect of vitamin E on exercised- induced oxidative damage in young and older adults. Am J Physiol 264: R992-R998