Impact of vitamin D3 dietary supplement matrix on clinical response

As a result of research suggesting increased health risk with low serum 25-hydroxycholecalciferol (25(OH)D), health care providers are measuring it frequently. Providers and patients are faced with treatment choices when low status is identified.

To compare the safety and efficacy of three vitamin D3 dietary supplements with different delivery matrices.

A 12-week, parallel group, single-masked, clinical trial was conducted in Seattle, Washington and Kailua Kona, Hawaii. Sixty-six healthy adults with (25(OH)D) <33 ng/mL were randomly assigned to take one of three D3 supplements, ie, a chewable tablet (TAB), an oil-emulsified drop (DROP), or an encapsulated powder (CAP) at a label-claimed dose of 10,000 IU/day. Actual D3 content was assessed by a third party and the results adjusted based on the actual D3 content administered. Mean change in 25(OH)D/mcg D3 administered; difference in the proportion of D3 insufficient participants (ie, 25(OH)D ≤30 ng/mL) reaching sufficiency (ie, 25(OH)D ≥30 ng/mL); and mean change in serum 1, 25-dihydroxycholecalciferol were measured.

In two of the three products tested, the measured vitamin D3 content varied considerably from the label-claimed dose. Differences in 25(OH)D/mcg D3 administered were significantly different between groups (P = .04; n = 55). Pairwise comparisons demonstrated DROP resulted in a greater increase than TAB (P < .05) but not than CAP. TAB was not different from CAP. The proportions reaching sufficiency were: 100% (TAB and CAP) and 80% (DROP) (P = .03 between groups; n = 55). 1, 25-Dihydroxycholecalciferol did not change significantly in any group.

Oil-emulsified vitamin D3 supplements resulted in a greater mean change in serum 25(OH)D concentration, but fewer patients reaching vitamin D sufficiency, than chewable or encapsulated supplements.