Despite vitamin D deficiency being common in the Middle East, few studies have attempted to pinpoint its health effects and determine what can be done to combat it.
Therefore, researchers from the University of the United Arab Emirates conducted an RCT to assess whether vitamin D3 and calcium, alone or in combination, have significant health benefits in adults with vitamin D deficiency.
Healthy but low on D?
The researchers recruited 545 “apparently healthy community free-living”adults 18 years of age and older in Al Ain, UAE for the RCT and randomly assigned them to receive tablets containing either 2000 IU oral vitamin D3, 600 mg calcium, a combination of both, or a placebo per day for six months.
The study, conducted over a three-year period, focused on self-rated health and bone turnover markers as primary outcomes and measured the participants’ 25(OH)D levels using their blood and urine samples.
Outcome measures were biochemical variables of metabolic risk factors, bone turnover (biochemical measures of bone metabolism), and muscle and general health. Of the 545 subjects, 277 completed a six-month follow-up after the trial was completed.
The researchers found that 25(OH)D levels “marginally increased” in the two groups that received vitamin D3 alone or in combination with calcium, while a decrease in 25(OH)D levels was seen in those who received vitamin D3 alone. had received the calcium supplement or a placebo.
According to subgroup analysis, parathyroid hormone (PTH) concentration decreased and the calcium-creatinine ratio increased significantly in those who took a combination of vitamin D and calcium, compared to those who took vitamin D or calcium alone, while an increase in both was seen in the placebo group.
However, at the six-month follow-up, there were “no statistically significant differences between the supplement and placebo groups” in body weight, BMI, blood pressure, body aches and general health.
Shortage of benefits: why?
There were several possible reasons for the lack of potential benefits of the supplements in the RCT, including the large number of randomized subjects who did not attend the six-month follow-up. However, the researchers noted that Baseline demographic and clinical characteristics were well balanced between the groups that had follow-up data compared to those who did not come for follow-up.
In addition, 25(OH)D levels did not show the expected increase in relation to dose and duration of supplementation, although this was slightly better in those who reported more than “120 (50th Quartile) Prescribed Trial Medication”.
In addition, 198 (70%) of subjects in the study were overweight or obese, which: “reported to significantly reduce response to vitamin D supplementation”, possibly by “greater volume of distribution and tightly bound vitamin D in adipose tissue”.According to recent research and the recommendations of some health professionals, obese individuals should get two to three times more vitamin D than normal-weight individuals.
Even so, adjustments for BMI, physical activity, sun exposure, and a vitamin D and calcium-rich diet showed no effect “Significant association with baseline vitamin D levels or response to supplements”.
The researchers wrote that there was an urgent need to study the impact of a higher dose, frequency and duration of vitamin D supplementation to “Achieve and sustain higher levels of 25(OH)D” and determine whether vitamin D supplementation would have clinical benefits for a high-risk population.
They further acknowledged that research was needed to test emerging evidence about how increased dietary intake or oral supplementation with calcium may reduce the harmful health effects of low vitamin D concentrations.
Finally, they stated that it was important to study the effects of higher dose, frequency and duration of vitamin D supplementation, including more testing and adherence to achieve and maintain higher levels of 25(OH)D, especially in high concentrations. at-risk populations.
Source: BMC Musculoskeletal Disorders
†A randomized, double-blind, placebo-controlled trial of vitamin D supplementation with or without calcium in community-dwelling vitamin D-deficient subjects“
Authors:Salah Garibala, et al.