Dietary calcium and vitamin D intake in an adult Middle Eastern population: food sources and relation to lifestyle and PTH.
Little is known about calcium and vitamin D intakes in Middle Eastern countries, where the prevalence of hypovitaminosis D is high. This study identifies major sources of calcium and vitamin D in the Lebanese diet, examines lifestyle factors that may influence intake of these nutrients and investigates the relationship between nutritional or lifestyle factors and parathyroid hormone (PTH). Three hundred sixteen young healthy volunteers aged 30 to 50 (men, non-veiled and veiled women) were recruited from different rural and urban Lebanese community centers. Food frequency questionnaire was used to evaluate the consumption of vitamin D and calcium-rich foods. We also measured serum PTH levels. Mean daily calcium and vitamin D intake were respectively 683.8 +/- 281.2 mg and 100.6 +/- 71.0 IU. Daily vitamin D sources were divided as follows: 30.4 +/- 46.4 IU from milk and dairy products, 28.2 +/- 26.3 IU from meat and poultry, 25.8 +/- 25 IU from fish, 8.5 +/- 8.6 IU from eggs, and 7.8 +/- 14.3 IU from sweets (respectively 30.2%, 28%, 25.6%, 8.4% and 7.7% of the total vitamin D intake). Mean daily calcium from animal and vegetable sources were respectively 376.3 +/- 233.6 mg and 307.9 +/- 118.5 mg. Animal/total calcium intake ratio was 52% and was only statistically significantly higher in urban people compared to rural ones. Multivariate analysis showed that male sex and urban residence were independent predictors of both vitamin D and calcium intakes (p < 0.01 and p < 0.01 respectively). In addition, veiling was an independent predictor of low vitamin D intake (p < 0.05) and a high body mass index (BMI) was an independent predictor of low calcium intake (p < 0.05). Finally, PTH was inversely correlated with vitamin D intake and the animal/total calcium intake ratio (r = -0.18 and r = -0.22, p < 0.01), while no significant results were achieved for the vegetable calcium. In a multivariate model, urban living, female gender, low vitamin D and calcium intakes, low animal/total calcium intake ratio, and high BMI, are independent predictors of hyperparathyroidism. The deficient nutritional status of vitamin D and calcium in Lebanon justify the implementation of dietary public health measures. People at most risk for secondary hyperparathyroidism should be advised to increase their dietary calcium (mostly animal calcium) and vitamin D, to take supplements, or to increase their sun exposure.