The influence of dietary intake and sunlight exposure on the vitamin D status in an elderly Spanish group

Traditional dietary habits and the living style in Spain should theoretically be enough to assure a healthy vitamin D status: a very high fish intake and one of the highest sun exposure rates of all countries in Europe. However, in spite of this, there is a high percentage in the elderly showing low vitamin D serum values. This paper is part of the Euronut-SENECA study, a major multicentre survey assessing the nutritional status in the elderly from 19 centres over 12 countries in Europe. In it, the vitamin D status in 55 healthy individuals from Spain has been studied and assessed by measuring dietary and supplemental vitamin D intakes; the influence of sunlight exposure such as physical activity, permanence in the sun, clothing, etc.; and 25-hydroxyvitamin D [25 (OH)D] serum concentration. The mean dietary intake was 1.3 +/- 1.5 micrograms/day, being fish, and specially fatty fish, the main source (62%). Of the total, 85% of the elderly did not reach the Spanish recommended dietary intake (2.5 micrograms/day). The mean 25(OH)D serum level was 25 +/- 14.7 nmol/l and there was a high percentage with deficit (13%) (8.4 +/- 1.9 nmol/l) and marginal (62%) (19.8 +/- 4.2 nmol/l) levels. People who usually walked 1.9 +/- 1.3 hours/day or stayed in the sun every day or as much as possible, had higher (p < 0.05) serum 25 (OH)D concentrations (27.7 +/- 2.4 nmol/l and 31.3 +/- 3.7 nmol/l, respectively) than people who did not (16.6 +/- 1.2 nmol/l and 21.3 +/- 2.1 nmol/l, respectively). There seems to be some relationship between the elderly group which wore no clothing cover or light clothing and a higher vitamin D serum level (34 +/- 27 nmol/l) and a lower vitamin D serum level for the elderly group which wore a jacket, coat, suit or sweater (20 +/- 16 nmol/l). In conclusion, neither does the effect of sunlight exposure on cutaneous vitamin D synthesis, although important for this elderly group, nor does the daily intake supply sufficient vitamin D to maintain adequate 25(OH)D levels. A possible remedy would be either to increase the time of sunlight exposure with no or little clothing cover or to take vitamin D supplements.