The available data for central regulation in humans are very limited. Whereas in animals there is a clear decrease in the orexigenic effect of the kappa opioid peptide, dynorphin , no effect on opioid antagonism of feeding could be demonstrated in humans . In contrast, the diminished role of opioids in thirst with aging could be demonstrated in humans .
The pathological causes of the anorexia of aging can be broadly divided into psychosocial and medical [24▪]. Recently, Ramic et al.[45▪] showed that loneliness played a role in producing anorexia and malnutrition. Depression is the most common cause of anorexia in older persons both in the community and in institutions [46–49]. The depression-related anorexia is most probably related to the increase in the potent anorectic neurotransmitter, corticotrophin-releasing hormone, which is increased in persons with depression . Late life paranoia results in a decrease of food intake because of the fear of being poisoned. Persons with dementia may increase their food intake early in the disease process but show dramatic increases at the end of the disease course. Anorexia tardive is similar to anorexia nervosa and occurs in older persons who have weight restricted all their life.
Based on the high prevalence of anorexia, all older persons should be screened for anorexia, utilizing a simple tool such as the Simplified Nutritional Assessment Questionnaire (SNAQ), which has been shown to have excellent predictive ability of future weight loss and protein energy malnutrition [53,54▪]. Supplementation with a high-quality essential amino acid mix appears to decrease weight loss and improve function even in persons with cachexia [55,56]. In all persons with anorexia, a careful clinical review should be done to try to detect treatable conditions. To date, orexigenic drugs, such as megestrol acetate  or dronabinol , have not proven to have major clinical benefits. Ghrelin agonists and other drugs are being developed to treat anorexia and associated weight loss but are not yet commercially available .
The anorexia of aging has been identified as a true geriatric syndrome. It has both physiological age-related causes and pathological causes. Anorexia in older persons should be identified and vigorously treated as it has a variety of deleterious effects in older persons.
Papers of particular interest, published within the annual period of review, have been highlighted as:
Additional references related to this topic can also be found in the Current World Literature section in this issue (p. 111).
1. Morley JE, Silver AJ. Anorexia of the elderly. Neurobiol Aging 1988; 9:9–16.
2. Morley JE. Anorexia, weight loss, and frailty. J Am Med Dir Assoc 2010; 11:225–228.
3▪. Donini LM, Dominguez LJ, Barbagallo M, et al. Senile anorexia in different geriatric settings in Italy. J Nutr Health Aging 2011; 15:775–781.
A study of 526 persons over the age of 65 years found anorexia was present in 21.2% with the highest prevalence in hospitalized and institutionalized patients.
4. Morley JE. Developing novel therapeutic approaches to frailty. Curr Pharm Des 2009; 15:3384–3395.
5. Abellan van Kan G, Rolland YM, Morley JE, Vellas B. Frailty: toward a clinical definition. J Am Med Dir Assoc 2008; 9:71–72.
6. Fielding RA, Vellas B, Evans WJ, et al. Sarcopenia: an undiagnosed condition in older adults. Current consensus definition: prevalence, etiology, and consequences. International working group on sarcopenia. J Am Med Dir Assoc 2011; 12:249–256.
7. Morley JE, Abbatecola AM, Argiles JM, et al. Society on Sarcopenia, Cachexia and Wasting Disorders Trialist WorkshopSarcopenia with limited mobility: an international consensus. J Am Med Dir Assoc 2011; 12:403–409.
8. Morley JE. Weight loss in older persons: new therapeutic approaches. Curr Pharm Design 2007; 13:3637–3647.
9. Landi F, Russo A, Liperoti R, et al. Anorexia, physical function, and incident disability among the frail elderly population: results from the ilSIRENTE study. J Am Med Dir Assoc 2010; 11:268–274.
10. Cornali C, Franzoni S, Frisoni GB, Trabucchi M. Anorexia as an independent predictor of mortality. J Am Geriatr Soc 2005; 53:354–355.
11. Bales CW, Buhr G. Is obesity bad for older persons? A systematic review of the pros and cons of weight reduction in later life. J Am Med Dir Assoc 2008; 9:302–312.
12. Kalantar-Zadeh K, Horwich TB, Oreopoulos A, et al. Risk factor paradox in wasting diseases. Curr Opin Clin Nutr Metab Care 2007; 10:433–442.
13. Schumm LP, McClintock M, Williams S, et al. Assessment of sensory function in the national social life, health, and aging project. J Gerontol Soc Sci 2009; 64 (S1):i76–i85.
14. Welge-Lüssen A. Ageing, neurodegeneration, and olfactory and gustatory loss. BENT 2009; 5 (Supp 13):129–132.
15. Schiffman SS. Effects of aging on the human taste system. Ann NY Acad Sci 2009; 1170:725–729.
16. Morley JE. Anorexia and weight loss in older persons. J Gerontol A Biol Sci Med Sci 2003; 58:131–137.
17. Essed NH, Oerlemans P, Hoek M, et al. Optimal preferred MSG concentration in potatoes, spinach and beef and their effect on intake in institutionalized elderly people. J Nutr Health Aging 2009; 13:769–775.
18. Nijs K, de Graaf C, van Staveren WA, de Groot LC. Malnutrition and mealtime ambiance in nursing homes. J Am Med Dir Assoc 2009; 10:226–229.
19. Koehler J, Leonhaeuser IU. Changes in food preferences during aging. Ann Nutr Metab 2008; 52 (Suppl 1):15–19.
20. Brogna A, Loreno M, Catalano F, et al. Radioisotopic assessment of gastric emptying of solids in elderly subjects. Aging Clin Exp Res 2006; 18:493–496.
21. Sturm K, Parker B, Wishart J, et al. Energy intake and appetite are related to antral area in healthy young and older subjects. Am J Clin Nutr 2004; 80:656–667.
22. Smits GJ, Lefebvre RA. Influence of age on the signal transduction pathway of nonadrenergic noncholinergic neurotransmitters in the rat gastric fundus. Br J Pharmacol 1995; 114:640–647.
23. Wilson MMG, Purushothaman R, Morley JE. Effect of liquid dietary supplements on energy intake in the elderly. Am J Clin Nutr 2002; 75:944–947.
24▪. Morley JE. Anorexia of aging: a true geriatric syndrome. J Nutr Health Aging 2012; 16:422–425.
This is a mini-review updating discussion of the role of the anorexia of aging as a true geriatric syndrome.
25. Tai K, Feinle-Bisset C, Horowitz M, et al. Effects of nutritional supplementation on the appetite and energy intake responses to IV cholecystokinin in older adults. Appetite 2010; 55:473–477.
26. Sturm K, MacIntosh CG, Parker BA, et al. Appetite, food intake, and plasma concentrations of cholecystokinin, ghrelin, and other gastrointestinal hormones in undernourished older women and well nourished young and older women. J Clin Endocrinol Metab 2003; 88:3747–3755.
27. Serra-Prat M, Palomera E, Clave P, Puig-Domingo M. Effect of age and frailty on ghrelin and cholecystokinin responses to a meal test. Am J Clin Nutr 2009; 89:1410–1417.
28. Landi F, Laviano A, Cruz-Jentoft AJ. The anorexia of aging: is it a geriatric syndrome? J Am Med Dir Assoc 2010; 11:153–156.
29. Lee A, Patrick P, Wishart J, et al. The effects of miglitol on glucagon-like peptide-1 secretion and appetite sensations in obese type 2 diabetics. Diabetes Obes Metab 2002; 4:329–335.
30. Di Francesco V, Barazzoni R, Bissoli L, et al. The quantity of meal fat influences the profile of postprandial hormones as well as hunger sensation in healthy elderly people. J Am Med Dir Assoc 2010; 11:188–193.
31. Gaskin FS, Farr SA, Banks WA, et al. Ghrelin-induced feeding is dependent on nitric oxide. Peptides 2003; 24:913–918.
32. Schneider SM, Al-Jaouni R, Caruba C, et al. Effects of age, malnutrition and refeeding on the expression and secretion of ghrelin. Clin Nutr 2008; 27:724–731.
33. Serra-Pratt M, Fernandez X, Burdoy E, et al. The role of ghrelin in the energy homeostasis of elderly people: a population-based study. J Endocrinol Invest 2007; 30:484–490.
34. Rigamonti AE, Pincelli AI, Corrà B, et al. Plasma ghrelin concentrations in elderly subjects: comparison with anorexic and obese patients. J Endocrinol 2002; 175:R1–5.
35▪. Moss C, Dhillo WS, Frost G, Hickson M. Gastrointestinal hormones: the regulation of appetite and the anorexia of ageing. J Hum Nutr Diet 2012; 25:3–15.
An in-depth review of the role of gastrointestinal hormones in the regulation of appetite. It concludes that an increase in CCK and a decrease in ghrelin play a key role in the anorexia of aging.
36. Donini LM, Savina C, Piredda M, et al. Senile anorexia in acute-ward and rehabilitations settings. J Nutr Health Aging 2008; 12:511–517.
37. Argiles JM, Anker SD, Evans WJ, et al. Consensus on cachexia syndrome. J Am Med Dir Assoc 2010; 11:229–230.
38▪. Capuron L, Schoecksnadel S, Feart C, et al. Chronic low-grade inflammation in elderly persons is associated with altered tryptophan and tyrosine metabolism: role in neuropsychiatric symptoms. Biol Psychiatry 2011; 70:175–182.
Aging is associated with an increase in interleukin-6 and C-reactive protein. This increase leads to an increase in tryptophan. The increase in tryptophan is associated with a reduction in motivation, tiredness, and anorexia.
39. Di Francesco V, Zamboni M, Zoico E, et al. Unbalanced serum leptin and ghrelin dynamics prolong postprandial satiety and inhibit hunger in healthy elderly: another reason for the ‘anorexia of aging’. Am J Clin Nutr 2006; 83:1149–1152.
40. Wang C, Nieschlag E, Swerdloff R, et al. Investigation, treatment and monitoring of late-onset hypogonadism in males: ISA, ISSAM, EAU, EAA and ASA recommendations. Eur J Endocrinol 2008; 159:507–514.
41. Smiechowska J, Utech A, Taffet G, et al. Adipokines in patients with cancer anorexia and cachexia. J Investig Med 2010; 58:554–559.
42. Banks WA, Coon AB, Robinson SM, et al. Triglycerides induce leptin resistance at the blood-brain barrier. Diabetes 2004; 53:1253–1260.
43. Kmeic Z. Central regulation of food intake in ageing. J Physiol Pharmacol 2006; 57 (Suppl 6):7–16.
44. Kmeic Z. Aging and peptide control of food intake. Curr Protein Pept Sci 2011; 12:271–279.
45▪. Ramic E, Pranjic N, Batic-Mujanovic O, et al. The effect of loneliness on malnutrition in elderly population. Med Arh 2011; 65:92–95.
Persons living alone are more likely to have a loss of appetite, lower body mass index, and be at increased risk of malnutrition.
46. White HK, McConnell ES, Bales CW, Kuchibhatla M. A 6-month observational study of the relationship between weight loss and behavioral symptoms in institutionalized Alzheimer's disease subjects. J Am Med Dir Assoc 2004; 5:89–97.
47. Lattanzio F, Laino I, Pedone C, et al. Geriatric conditions and adverse drug reactions in elderly hospitalized patients. J Am Med Dir Assoc 2012; 13:96–99.
48. Morley JE. Depression in nursing home residents. J Am Med Dir Assoc 2010; 11:301–303.
49. Thakur M, Blazer DG. Depression in long-term care. J Am Med Dir Assoc 2008; 9:82–87.
50. Visvanathan R, Chapman IM. Undernutrition and anorexia in the older person. Gastroenterol Clin North Am 2009; 38:393–409.
51. Fitzgerald SP, Bean NG. An analysis of the interactions between individual comorbidities and their treatments: implications for guidelines and polypharmacy. J Am Med Dir Assoc 2010; 11:475–484.
52. Morley JE. Undernutrition: a major problem in nursing homes. J Am Med Dir Assoc 2011; 12:243–246.
53. Wilson MM, Thomas Dr, Rubenstein LZ, et al. Appetite assessment: simple appetite questionnaire predicts weight loss in community-dwelling adults and nursing home residents. Am J Clin Nutr 2005; 82:1074–1081.
54▪. Rolland Y, Perrin A, Gardette V, et al.
Screening older people at risk of malnutrition or malnourished using the Simplified Nutritional Appetite Questionnaire (SNAQ): a comparison with the Mini-Nutritional Assessment (MNA) tool. J Am Med Dir Assoc 2012; 13:31–34.
SNAQ and the Mini-Nutritional Assessment (MNA) identify different populations. SNAQ can identify those at risk for weight loss earlier than MNA.
55. Morley JE, Argiles JM, Evans WJ, et al. Society for Sarcopenia, Cachexia and Wasting Disease. Nutritional recommendations for the management of sarcopenia. J Am Med Dir Assoc 2010; 11:391–396.
56. van Wetering CR, Hoogendoorn M, Broekhuizen R, et al. Efficacy and costs of nutritional rehabilitation in muscle-wasted patients with chronic obstructive pulmonary disease in a community-based setting: a prespecified subgroup analysis of the INTERCOM trial. J Am Med Dir Assoc 2010; 11:179–187.
57. Yeh SS, Lovitt S, Schuster MW. Pharmacological treatment of geriatric cachexia: evidence and safety in perspective. J Am Med Dir Assoc 2007; 8:363–377.
58. Wilson MM, Philpot C, Morley JE. Anorexia of aging in long term care: is dronabinol an effective appetite stimulant? – a pilot study. J Nutr Health Aging 2007; 11:195–198.