Can you absorb Vitamin D without a fat source?

What we know from the following study is that “the amount of fat with which vitamin D is ingested does not seem to significantly modify the bioavailability of vitamin D3”

A systematic Review on the topic showed “Vitamin D was better absorbed when it was consumed with fat-containing meals, but absorption also occurred without fat or oily vehicles.”

Silva, M. C., & Furlanetto, T. W. (2018). Intestinal absorption of vitamin D: a systematic review. Nutrition Reviews, 76(1), 60–76. 

An interesting study by Dawson in 2013, looked at whether a meal and its fat content influence D3 absorption and 25(OH)D levels. They looked at men and women between 50-59 years of age, and randomly assigned to one of three meal groups: no meal, high‐fat meal, or low‐fat meal; each was given a monthly 50,000 IU vitamin D3 supplement with the test breakfast meal (or after a fast for the no‐meal group) and followed for 90 days.

What they found 12 hours after the test dose was an increase in the plasma 25(OH)D in the low fat group in comparison to the high fat or no fat group.

However, at 30 and 90 days, although all groups had increased plasma concentration, there was no significant difference between the 3 groups.

Dawson-Hughes B, Harris SS, Palermo NJet al. Meal conditions affect the absorption of supplemental vitamin D3 but not the plasma 25-hydroxyvitamin D response to supplementation. J Bone Miner Res. 2013;28:1778–1783. doi: 10.1002/jbmr.1896.

In summary, Vitamin D absorption is complex. Although the traditional thinking has been that Vitamin D absorption is better with fatty meals, we now have data to say that is likely not the case. Although further studies are needed, we know that Vitamin D can be absorbed without fat or oily vehicles, and that the amount of fat with which vitamin D is ingested does not seem to significantly modify the bioavailability of vitamin D3 in the body.