Nutrient absorption in older adults
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Age-Related Changes in Nutrient Absorption in Older Adults
As people age, their bodies undergo changes that can affect how nutrients are absorbed and utilized. While the digestion and absorption of macronutrients (proteins, fats, and carbohydrates) generally remain well-preserved, the absorption of certain micronutrients—especially vitamin B-12, vitamin D, and calcium—becomes less efficient in older adults. This means that older adults are at a higher risk for deficiencies in these nutrients, even if their overall diet does not change significantly with age 15.
Vitamin and Mineral Absorption Challenges in the Elderly
Older adults often experience impaired absorption of key vitamins and minerals. The absorption of vitamin B-12, vitamin D, and calcium is particularly affected, which can lead to deficiencies that impact bone health, immune function, and overall well-being 15. Studies show that even healthy older adults with normal gastric acid secretion can absorb vitamin B-12 efficiently from milk and fortified bread, suggesting that fortified foods can help address this deficiency . However, deficiencies in other micronutrients such as zinc, selenium, iron, iodine, and copper are also common, especially among those living in institutions 57.
Protein and Amino Acid Absorption in Older Adults
The absorption of protein and amino acids is also altered with age. Older adults digest and absorb protein from mixed meals more slowly than younger adults, leading to delayed peaks in essential and branched-chain amino acid concentrations after eating. This slower absorption may suppress or delay muscle protein synthesis, which is important for maintaining muscle mass and function . Additionally, distributing protein intake evenly across meals, rather than consuming most protein at dinner, can improve amino acid absorption and whole-body protein balance in older adults .
Impact of Oral Health and Appetite on Nutrient Intake
Beyond physiological changes in the gut, older adults often face challenges related to oral health, such as poor dental function, chewing and swallowing difficulties, and loss of taste and smell. These issues can lead to reduced appetite, lower food intake, and increased risk of malnutrition. Social factors like isolation, depression, and insomnia can further contribute to undernourishment in this population .
The Role of Supplementation and Dietary Strategies
Given the increased risk of nutrient deficiencies, targeted nutritional interventions and supplementation are important for older adults. Supplements for calcium, vitamin D, vitamin B-12, zinc, iron, and omega-3 fatty acids can help address common deficiencies and support bone health, immune function, cognitive abilities, and muscle maintenance 56. Dietitians play a key role in developing personalized dietary strategies to ensure adequate nutrient intake and absorption in the elderly .
Conclusion
Nutrient absorption in older adults is affected by both physiological and lifestyle factors. While macronutrient absorption is generally maintained, the absorption of several key vitamins and minerals declines with age, increasing the risk of deficiencies. Delayed protein and amino acid absorption, oral health issues, and reduced appetite further complicate nutritional status. Fortified foods, even protein distribution, and targeted supplementation are effective strategies to support optimal nutrient absorption and overall health in the aging population 12345678.
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