NUTRITION AND THE OLDER ADULT

Aging is a process that occurs throughout life.  Its impact, however, is often ignored until adulthood.  Progressive changes in body composition, sensory perception, functional status and physiologic functioning occur at all ages.  The rate of change is strongly influenced by the genetic background and life experiences of the individual(1-3).

    Older adults display wide individual variations in aging processes and thus in nutritional needs and concerns.  Maximizing and maintaining adult potential becomes the major health care objective.  The nutritional care goal is to provide education and support to achieve this objective as decreases in metabolic needs, declining activity levels, illness, infirmity, economic hardship, loss of social support systems, and other variables mandate adjustments in food intake.

    Each older adult should be viewed as a unique individual.  Chronological age and functional capacity do not directly correlate.  Diversity increases with age (4).  Provision of quality nutritional care requires the regular, systematic, longitudinal assessment of each older individual as well as a nutritional care plan based on specific needs identified.  The least restrictive regimen possible should be implemented.

Dietary Considerations for the Older Adult
When planning the diet for older adults, the Dietary Reference Intakes (DRIs) and Dietary Guidelines for Americans  (5-8) provide population specific guidelines.  The DRIs divide the adult population older than 50 years into 2 life-stage groups: 51 through 70 years and older than 70 years (5-7).  Overall nutrient requirements are similar between these age groups with the exception of vitamin D, which increases with age.  To ensure adequate consumption of vitamin B12 and vitamin D, the Dietary Guidelines for Americans recommends consuming vitamin B12 in its crystalline form, e.g., fortified foods or supplements, and consuming extra vitamin D from vitamin-D-fortified foods and/or supplements (8).  

    In addition, taste and smell dysfunction tends to begin at around 60 years of age and becomes more severe in persons over 70 which can effect nutritional intake (5,9).  Two thirds of persons over 75 years of age are edentulous.  Therefore, more sweet flavorings or salty foods may be required to satisfy the appetite of elderly individuals and improve nutritional intake.  When planning nutrient restrictions to accompany medical care in this population, moderate to mild restrictions, of such nutrients as sodium, are recommend to ensure overall adequate nutrition intake (10) .  

Energy and Nutrient Considerations
Basal metabolic rate (BMR) decreases 2% with each decade of life; lean body mass declines 6% with each decade and is usually replaced with fat.  As BMR decreases with advancing age and physical activity is reduced, energy needs decrease.  The current DRIs suggest an average gradual reduction of kilocalories after the age of 19 years by deducting 10 kcal/day for males, and 7 kcal/day for females for each year of age above 19 years.  For a 51 year old male, this would equate to a 320 kilocalorie reduction from the baseline DRI (11).  Refer to Dietary Reference Intake Values for Energy by Active Individuals (11).   Meeting the nutritional needs of the older adult is challenging because although caloric needs decrease, protein, vitamins and minerals remain the same or increase.  The average daily calorie intake for persons over 51 years of age is 2400 calories for men and 2000 calories for women (11).  With decrease in calorie intake there is a decline in micronutrient intakes, especially calcium, zinc, iron and vitamins (5).  Health problems arise when the caloric intake is less than 1500 kcal per day (12). 

    The 2002 DRIs recommend that the RDA for protein should be 0.8 g/kg daily for adults of all ages (10).  However, other studies recommend protein be increased to 1.0 to 1.25 g/kg daily (11-14) or 12% to 14% of total energy intake for the elderly.

    Metabolic and physical changes that affect the status of vitamin B6, B12, and folic acid may alter behavior and general health, whereas adequate intake of these nutrients prevents some decline in cognitive function associated with aging (5,15).  Deficiencies of these nutrients, along with inadequate intake of vitamin C and riboflavin, may result in poor memory (5,15).  Immune function affected by nutritional status may be improved by an increased intake or supplementation of protein, vitamins B6 and E, and zinc (5,15).  It is recommended that persons 51 years of age and older consume foods fortified with vitamin B12 or take a supplement containing crystalline form of vitamin B12, as 10% to 30% of older adults have protein-bound vitamin B12 malabsorption (5, 8,15-16).  In addition, inadequate intake of folate and vitamins B-6 and B-12 status may result in hyperhomocysteinemia, a significant risk factor for atherosclerotic vascular disease (5).

    Vitamin D levels may be reduced in the elderly even with adequate exposure to the sunlight, and deficiency may be exacerbated by homebound status, use of sun block, poor dietary intake, decreased capabilities to synthesize cholecalciferol in the skin, and decreased number of gastrointestinal receptors (12,18-20).  Decreased capacity to absorb calcium is also observed because of reduced estrogen levels, low circulating 25 (OH)D, partial intestinal resistance to 1,25(OH)D, and impaired renal conversion of 25(OH)D to 1,25(OH)2D (5).  Supplementation of 1.0 to 1.7 g calcium along with vitamin D (400 IU) is shown to reduce the incidence of age-related hip fractures and decrease the rate of age-related bone loss (5).  The Dietary Guidelines suggest that individuals who are considered high-risk for vitamin D deficiency may need to consume higher intakes of vitamin D (e.g., 25 micrograms or 1,000 IU) to reach and maintain 25-hydroxyvitamin D values at 80 nmol/L (8).  Other nutrients, including vitamin A and K, magnesium, and phytoestrogens are also involved in maintaining bone health and should also be evaluated for adequate intake (5).   

    Dehydration is a major problem for the elderly.  Water intake needs are the same for the young and the old, but the elderly are prone to inadequate water intake.  Frequently, diseases will reduce the ability to recognize thirst, create an inability to express thirst, or decrease access to water (5,21).  Even healthy elderly persons appear to have reduced thirst in response to fluid deprivation.  Fear of incontinence and difficulty making trips to the toilet, due to arthritic pain or other immobility, may also interfere with adequate fluid consumption (5).  The elderly should be encouraged to ingest about 2 L of fluid per day or 30 ml/kg body weight.

Contributors to Poor Nutritional Status in the Elderly
A variety of factors may contribute to poor nutritional status as individuals age (22-26). Table A-4 lists some of the factors frequently identified as potential causes of malnutrition.  These must be kept in mind when evaluating nutritional status and when developing a care plan to prevent, delay, or correct problems identified.  For some conditions, cure is not possible but ameliorative or palliative nutritional interventions are often indicated (25, 26).  Improvement in the quality of life will frequently ensue.

Other Dietary Considerations (5)

• Minimize dietary restrictions to encourage better food intake.  Maintaining the desire to eat and the enjoyment of food minimizes the risks of weight loss and undernutrition, especially in elders in long-term care.  For these people, a more liberalized nutrition intervention, rather than a therapeutic diet, may be warranted to maintain quality of life (5, 10).  Refer to Medical Nutrition Therapy for Diabetes Mellitus for specific recommendations for older adults with diabetes mellitus. 
• Encourage adequate intake of foods high in fiber.  The 2002 DRI for Adequate Intake (AI) of total fiber is 30 g/day for men, and 21 g/day for women for adults over 50 years (10).  Include foods that can be easily chewed and not cause gastrointestinal discomfort. 
• Hyponatremia is often seen in the hospitalized patient.  Sodium-restricted diets should be used with caution in the elderly.
• The hospitalized elderly patient frequently has a low level of albumin.  Response to medical nutrition therapy to improve the albumin level is longer in the older individual.
• Failure to thrive is a growing problem in the aging population.  Depression, use of many medications, underlying medical illnesses, and other factors should be addressed to correct this condition.  

 References

1. Dwyer J. Screening Older American’s Nutritional Health: Current Practices and Future Possibilities. Washington, DC: Nutrition Screening Initiative; 1991.
2. White JV. Risk factors for poor nutritional status.  Primary Care. 1994;21:19-32.
3. Gopalan C. Dietetics and nutrition: impact of scientific advances and development. J Am Diet Assoc. 1997;97:737-741.
4. National Research Council.  Recommended Dietary Allowances. 10th ed. Washington, DC: National Academy Press; 1989.
5. Position of The American Dietetic Association: nutrition across the spectrum of aging. J Am Diet Assoc. 2005;105: 616-633.
6. Institute of Medicine, Food and Nutrition Board.  Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluroide.  Washington, DC:  National Academy Press; 1997.
7. Institute of Medicine, Food and Nutrition Board.  Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate Vitamin B12, Panthothenic Acid, Biotin and Choline.  Washington, DC:  National Academy Press; 1998.
8. Dietary Guidelines for Americans 2005.  Available at: www.healthierus.gov/dietaryguidelines. Accessed January 31, 2005.
9. Schiffman SS. Changes in taste and smell: drug interactions and food preferences. Nutr Rev. 1994;52:S11
10. Position of The American Dietetic Association: liberalized diets for older adults in long-term care.  J Am Diet Assoc.  2002;102:1316.
11. Institute of Medicine’s Food and Nutrition Board.  Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Choles- terol, Protein, and Amino Acids.  National Academy of Sciences, 2002: 265-334; preprint at http://www.nap.edu.books/0309085373/html/index.html. Accessed September 16, 2002.
12. Campbell WW, Crim MC, Dallal GE, et al. Increased protein requirements in elderly people: new data and retrospective reassessments.  Am J Clin Nutr. 1994;60:501-509.
13. Harris NG. Nutrition in Aging. In: Mahan LK, Escott-Stump S. Krause’s Food, Nutrition, and Diet Therapy. 10th ed. Philadelphia, Pa: WB Saunders Co; 2000:294.
14. Evans WJ, Cyr-Campbell D. Nutrition, exercise, and healthy aging.  J Am Diet Assoc. 1997;97:632-638.
15. Tripp F. The use of dietary supplements in the elderly: current issues and recommendations. J Am Diet Assoc. 1997;97: S181-S183.
16. Rosenberg IH, Miller JW. Nutritional factors in physical and cognitive functions of elderly people.  Am J Clin Nutr. 1995;55(suppl):1237S-1243S.
17. Ho C, Kauwell GPA, Bailey LB.  Practitioners’ guide to meeting the vitamin B-12 Recommended Dietary Allowance for people aged 51 years and older. J Am Diet Assoc.  1999;99:725-727.
18. Bogden JD, Bendrich A, Kemp FW, et al. Daily micronutrient supplements enhance delayed hyposensitivity skin test responses in older people. Am J Clin Nutr. 1994;60:437-447.
19. Morley JE, Soloman DH. Major issues in geriatrics over the last five years. J Am Geriatr Soc. 1994;42:218-225.
20. Chapuy MC, Arlot ME, Deboeuf F. Vitamin D-3 and calcium to prevent hip fractures in elderly women. N Engl J Med. 1992;327:1637-1642.
21. Gloth MF, Gundberg CM, Hollis BW, et al. Vitamin D deficiency in homebound elderly persons. JAMA. 1995;327:1637-1642.
22. Weinburg AD, Menaker KL. Dehydration: evaluation and management in older adults. Council on Scientific Affairs, American Medical Association. JAMA. 1995;274:1552-1556.
23. White JV. Risk factors associated with poor nutritional status. Niedert K, ed. Nutrition Care of the Older Adult. Chicago, Ill: American Dietetic Association; 1998.
24. White J. Risk factors associated with poor nutritional status in older Americans. In: Nutrition Screening 1: Toward a Common View. Washington, DC: Nutrition Screening Initiative; 1991.
25. White J, Ham R, Lipschitz D, Dwyer J, Wellman N. Consensus of the Nutrition Screening Initiative: risk factors and indicators of poor nutritional status in older Americans. J Am Diet Assoc. 1991;91:783-787.
26. Goodwin J. Social, psychological and physical factors affecting the nutritional status of elderly subjects: separating cause and effect. Am J Clin Nutr. 1989;50:1201-1209.

Manual of Clinical Nutrition Management                                                     
Copyright © 2008 Morrison Management Specialists, Inc.
All rights reserved.