Micronutrient Status, Health Implications, and Assessment Aproaches in Older Adults: A Narrative Review of Recent Studies

As populations age, micronutrient deficiencies increase and are linked to frailty, functional decline, cognitive impairment, anemia, and a higher healthcare burden. This review synthesizes evidence from the past five years on adults ≥65 years, comparing residents of nursing homes/assisted-living facilities with community-dwelling peers. Community-dwelling older adults show high prevalence of deficiencies—particularly vitamin D, calcium, magnesium, folate, and zinc—while vitamin B12 deficiency is less common overall but increases with age due to malabsorption. Institutionalized adults face higher risk, driven by limited dietary variety, reduced sunlight exposure, greater multimorbidity, and polypharmacy. Reported rates include vitamin D deficiency in 70–94% of institutionalized adults (≈6.3-fold higher odds), zinc deficiency in 50–66% (vs. 31–49% in the community), iodine deficiency in 67–78% (vs. 22% in the community), and a Mini Nutritional Assessment classification of severe malnutrition/at risk in 67.9% (vs. 28% in the community). Consequences encompass frailty, falls, infections, higher costs, and increased institutionalization. Recommended actions include routine biomarker screening, improving access to vitamin D (supplementation/fortification), individualized care for micronutrient deficiencies—including vitamin B12 when relevant—multidisciplinary nutrition support, and long-term targeted research to guide best practices for healthy aging and equity.