Vitamin D content in fortified low fat milk in Saudi Arabia.

BACKGROUND

Vitamin D deficiency is common in many countries, including Saudi Arabia. Various population-level preventive measures have been implemented, including milk fortification with vitamin D.

OBJECTIVES

The main objective of the study was to determine vitamin D levels in fortified low fat cow milk on the Saudi Arabian market and to compare it with the label claims.

DESIGN

Cross-sectional study.

SETTING

Academic research center.

MATERIALS AND METHODS

Five milk batches from five major producers were purchased in five replicates from five major retail stores in Riyadh, Saudi Arabia. We used a validated liquid chromatography assay to measure vitamin D levels. All samples were producer labeled to contain 400 IU/L (10 ng/mL) vitamin D and were analyzed within the first 40% of their validity period. Intra-batch, inter-batch, and inter-producer variations were determined as a coefficient of variation.

MAIN OUTCOME MEASURES

Intra-batch, inter-batch and inter-producer variations in vitamin D level.

RESULTS

Overall, mean (SD) measured vitamin D level was 10.2 (1.6) with a range of 7.1-13.9 ng/mL. In 25 of 125 samples (20%), the vitamin D level was outside +/- 20% of the label claim (10.4% under-fortified, 9.6% over fortified). Intra-batch, inter-batch, and intra-producer variations were 1.6 -20.8%, 8.2-20.8%, and 16.1%, respectively.

CONCLUSIONS

Vitamin D content in fortified low fat cow milk on the Riyadh market matches label claim in 85% of the samples of major retailers. Variations from label claim in 15% of the samples are small and may not be clinically important.

LIMITATIONS

This study was limited to five major retailers in the Riyadh area and did not examine full-fat or non-fat milk samples.