Contribution of different vitamin D forms and fortified foods to vitamin D intake in Europe: A narrative review

In the current narrative review, the bioavailability of the main vitamin D forms is evaluated. The mean intakes and main contributing forms of vitamin D in the European diet are estimated, as well as the major contributing dietary sources. The literature is reviewed for studies reporting on the proportion of users and non-users of fortified food with vitamin D intakes below reference intakes. In addition, the availability of vitamin D-fortified prepackaged retail products and fortification levels in the European market is assessed. Previously, vitamins D2 and D3 forms were considered the primary forms in the diet. Recent analytical methods suggest that dietary 25(OH)D3, when adjusted for higher bioequivalence, significantly contributes to total vitamin D intakes. When also considering 25(OH)D3 from foods, the estimated vitamin D intake from an average European diet was 3.8 µg/d of total Vitamin D Equivalents: vitamin D3, vitamin D2 and 25(OH)D3, contributing about 71 %, 2 %, and 27 %, respectively. Animal foods, fortified fats and spreads contributed most to total intakes. Literature suggests that 94–100 % of Europeans aged ≥ 13 y fail to meet the vitamin D reference intake of 10 µg/d. About 98–100 % of vitamin D-fortified food users and 99–100 % of non-users in the UK and Netherlands consumed less than 10 µg/d of vitamin D. About 1.2 % of prepackaged foods and drinks were voluntary fortified with vitamin D, margarine and plant-based drinks providing most of the daily vitamin D. Encouraging fortification and other strategies may support closing the gap between current and recommended vitamin D intakes. • This study highlights the emerging role of dietary 25(OH)D3 as a significant contributor to total vitamin D intake, adjusting for its higher bioequivalence, a shift from the traditional focus on vitamin D2 and D3 forms. • The study reveals that 25(OH)D3 contributes about 27 % to the total vitamin D intake in an average European diet, with animal foods, fortified fats, and spreads being the primary contributors to overall vitamin D consumption. • The findings emphasize that up to 100 % of Europeans fail to meet 10 µg/d of vitamin D, suggesting that fortification and other strategies are needed to close the intake gap. • The study highlights the limited availability of vitamin D-fortified products in the market, suggesting that fortification currently contributes negligibly to the general population.