Nutritional status in a healthy elderly population: vitamin D

Area of Science:

• Nutritional Science
• Gerontology
• Biochemistry

Background:

• Vitamin D is crucial for bone health and overall well-being.
• Aging is associated with changes in vitamin D metabolism and status.
• Limited sunlight exposure and dietary intake can lead to vitamin D deficiency.

Purpose of the Study:

• To assess the vitamin D status in healthy, free-living elderly individuals.
• To investigate factors influencing vitamin D levels, including diet, supplementation, season, and sex.
• To examine the relationship between vitamin D status and bone metabolism markers.

Main Methods:

• Measurement of dietary and supplemental vitamin D intake.
• Quantification of plasma 25-hydroxyvitamin D (25-OHD) concentrations.
• Comparison of elderly participants with a younger control group.
• Analysis of seasonal variations and sex differences in 25-OHD levels.
• Assessment of plasma alkaline phosphatase as an indicator of bone turnover.

Main Results:

• Elderly participants exhibited significantly lower plasma 25-OHD levels (15.5 ng/ml) compared to younger controls (29.1 ng/ml).
• Plasma 25-OHD showed seasonal variation in the elderly, with lowest levels in January and highest in September.
• Men had higher plasma 25-OHD concentrations than women.
• Vitamin D supplementation was associated with higher plasma 25-OHD levels, irrespective of season.
• Plasma alkaline phosphatase was inversely correlated with plasma 25-OHD, suggesting a link to bone health.

Conclusions:

• Inadequate dietary vitamin D intake and insufficient sunlight exposure contribute to low vitamin D status in the elderly.
• Moderate vitamin D supplementation and increased sunlight exposure are recommended for American elderly to enhance vitamin D nutriture.
• Addressing vitamin D deficiency is important for maintaining bone health in aging populations.