A study from Tufts University researchers found taking vitamin D supplements along with a meal containing fat significantly increased the absorption of vitamin D. Published in the Journal of the Academy of Nutrition and Dietetics, the study divided 50 healthy older men and women into three groups; one group took vitamin D while consuming a fat-free breakfast, while the second and third groups took vitamin D while consuming a breakfast that was 30% fat by calories. The ratio of monounsaturated to polyunsaturated fats was 1:4 in the meal consumed by the second group, whereas that ratio of dietary fat was reversed in the meal consumed by the third group (4:1). All the participants took a single, 50,000 IU dose of powdered vitamin D3 with their breakfast for this one-day study. Here’s what the researchers discovered:

• Twelve hours after taking the vitamin D supplement, participants who ate a fat-containing breakfast experienced a 32% increase in vitamin D absorption compared to those in the fat-free group.
• Participants who ate a fat-containing breakfast experienced a 40% increase in vitamin D absorption after 10 hours and a 25% increase after 14 hours, compared to those in the fat-free group.
• The absorption rates of the two groups who consumed a fat-containing breakfast did not differ significantly at any point. Hence, the ratio of monounsaturated to polyunsaturated fats did not affect vitamin D absorption.

Source: Journal of the Academy of Nutrition and Dietetics