HLTH 4320 Week 9 Older Adult Nutrition Brief Example

Nutrition After 70: Protein, Vitamin B12 and Vitamin D, What the Reference Values Say, What Expert Groups Add and Where the Evidence Stops

Student Name

Walden University

HLTH 4320: Nutrition Across the Lifespan

Instructor Name

Month Day, Year

Nutrition After 70: Protein, Vitamin B12 and Vitamin D, What the Reference Values Say, What Expert Groups Add and Where the Evidence Stops

Summary

The Dietary Reference Intakes treat everyone 71 and older as one group, though a healthy 72-year-old and a frail 90-year-old differ in muscle mass, absorption and illness. For three nutrients of particular concern in later life, this brief sets out the reference values, what expert groups recommend beyond them and the evidence behind each. Protein needs may be higher than the reference value suggests, vitamin B12 absorption from food often declines and vitamin D values were raised for the oldest group, though a large trial found that extra vitamin D did not prevent fractures in healthy older adults. A final section states where the evidence stops.

Protein

For all adults, those over 70 included, the protein RDA is 0.8 g for each kilogram of body weight daily (Institute of Medicine, 2005). An international expert group, PROT-AGE, reviewed protein needs with aging and recommended an average of at least 1.0 to 1.2 g per kilogram daily for people over 65 to maintain and regain lean body mass and function, more for active older adults and 1.2 to 1.5 g for most older adults with acute or chronic disease, with an exception for those with severe kidney disease not on dialysis (Bauer et al., 2013).

The two figures do not strictly conflict. The RDA is set to prevent deficiency in healthy people, while PROT-AGE aimed at preserving muscle and function. But they lead to different advice: a 70-kilogram older adult would need 56 grams a day by the RDA and 70 to 84 grams by PROT-AGE. The group itself noted that evidence was not yet sufficient for recommendations on protein quality or timing.

Vitamin B12

The RDA for vitamin B12 is 2.4 micrograms a day for adults of all ages (Institute of Medicine, 2006). What changes with age is absorption. In large American and British surveys, about 6% of people aged 60 and older were deficient in vitamin B12, and closer to 20% had marginal status, with deficiency becoming more common with age (Allen, 2009). In older people, the main cause is malabsorption of the vitamin bound to food, partly due to gastric atrophy, rather than low intake. Most older adults can still absorb the crystalline form used in fortified foods and supplements, which is why reference guidance advises adults over 50 to obtain much of their B12 from those sources (Institute of Medicine, 2006).

Vitamin D

The RDA for vitamin D is 800 IU a day for adults 71 and older, higher than the 600 IU for younger adults, set for bone health assuming little sunlight (Ross et al., 2011). Older adults make less vitamin D in their skin and often spend less time outdoors.

Whether more is better is a different question. The VITAL trial gave 25,871 generally healthy midlife and older adults (men from 50, women from 55) either a daily 2,000 IU dose of vitamin D3 or a placebo. Over about five years, the supplement did not reduce total, nonvertebral or hip fractures (LeBoff et al., 2022). The participants were not selected for low vitamin D levels or for osteoporosis, so the result speaks to supplementation of the general older population, not to treatment of deficiency.

Where the Evidence Stops

The evidence for older adults has gaps that a brief should state rather than fill.

The reference values group everyone 71 and older together. There are no separate values for the very old, though people in their late 80s and 90s differ substantially from those in their early 70s.

Trials often underrepresent the oldest and frailest adults. The vitamin D fracture trial enrolled generally healthy adults living in the community; it cannot tell us whether supplementation helps nursing home residents or people with very low vitamin D levels.

For protein, the higher recommendations rest largely on studies of muscle and function over months, not on long-term trials showing fewer disabilities or deaths. PROT-AGE called for future studies that measure physical function directly (Bauer et al., 2013).

For vitamin B12, the benefit of correcting marginal status, as opposed to clear deficiency, is uncertain; Allen (2009) noted that intervention studies were still needed to assess functional benefits.

Older adults also take more medications, some of which affect nutrient absorption, and have more chronic diseases, but reference values are set for healthy people. Much of what matters most for an individual older adult therefore falls outside the reference tables.

Implications

For practitioners writing for older adults, three points follow. Protein advice should state which standard is being used, the RDA or a function-based recommendation. Vitamin B12 advice should focus on fortified foods or supplements rather than total food intake. And vitamin D advice should distinguish meeting the 800 IU RDA from taking higher doses in the hope of preventing fractures, which a large trial did not support for healthy older adults.

References

Allen, L. H. (2009). How common is vitamin B-12 deficiency? The American Journal of Clinical Nutrition, 89(2), 693S-696S. https://doi.org/10.3945/ajcn.2008.26947A

Bauer, J., Biolo, G., Cederholm, T., Cesari, M., Cruz-Jentoft, A. J., Morley, J. E., Phillips, S., Sieber, C., Stehle, P., Teta, D., Visvanathan, R., Volpi, E., & Boirie, Y. (2013). Evidence-based recommendations for optimal dietary protein intake in older people: A position paper from the PROT-AGE Study Group. Journal of the American Medical Directors Association, 14(8), 542-559. https://doi.org/10.1016/j.jamda.2013.05.021

Institute of Medicine. (2005). Dietary Reference Intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids. The National Academies Press. https://doi.org/10.17226/10490

Institute of Medicine. (2006). Dietary Reference Intakes: The essential guide to nutrient requirements (J. J. Otten, J. P. Hellwig, & L. D. Meyers, Eds.). The National Academies Press. https://doi.org/10.17226/11537

LeBoff, M. S., Chou, S. H., Ratliff, K. A., Cook, N. R., Khurana, B., Kim, E., Cawthon, P. M., Bauer, D. C., Black, D., Gallagher, J. C., Lee, I.-M., Buring, J. E., & Manson, J. E. (2022). Supplemental vitamin D and incident fractures in midlife and older adults. New England Journal of Medicine, 387(4), 299-309. https://doi.org/10.1056/NEJMoa2202106

Ross, A. C., Manson, J. E., Abrams, S. A., Aloia, J. F., Brannon, P. M., Clinton, S. K., Durazo-Arvizu, R. A., Gallagher, J. C., Gallo, R. L., Jones, G., Kovacs, C. S., Mayne, S. T., Rosen, C. J., & Shapses, S. A. (2011). The 2011 report on dietary reference intakes for calcium and vitamin D from the Institute of Medicine: What clinicians need to know. The Journal of Clinical Endocrinology & Metabolism, 96(1), 53-58. https://doi.org/10.1210/jc.2010-2704