Sources of vitamin D for humans

Abstract

Abstract. Both vitamin D insufficiency and deficiency are now well-documented worldwide in relation to human health, and this has raised interest in vitamin D research. The aim of this article is therefore to review the literature on sources of vitamin D. It can be endogenously synthesised under ultraviolet B radiation in the skin, or ingested through dietary supplements and dietary sources, which include food of animal and plant origin, as well as fortified foods. Vitamin D is mainly found in two forms, D3 (cholecalciferol) and D2 (ergocalciferol). In addition to the D3 and D2 forms of vitamin D, 25-hydroxy vitamin D also contributes significantly to dietary vitamin D intake. It is found in many animal-derived products. Fortified food can contain D3 or D2 forms or vitamin D metabolite 25-hydroxy vitamin D. Not many foods are a rich source (> 4 μg/100 g) of vitamin D (D represents D3 and/or D2), e.g., many but not all fish (5–25 μg/100 g), mushrooms (21.1–58.7 μg/100 g), Reindeer lichen (87 μg/100 g) and fish liver oils (250 μg/100 g). Other dietary sources are cheese, beef liver and eggs (1.3–2.9 μg/100 g), dark chocolate (4 μg/100 g), as well as fortified foods (milk, yoghurt, fat spreads, orange juice, breakfast grains, plant-based beverages). Since an adequate intake of vitamin D (15 μg/day set by the European Food Safety Authority) is hard to achieve through diet alone, dietary supplements of vitamin D are usually recommended. This review summarizes current knowledge about different sources of vitamin D for humans.

The ultra-processed foods hypothesis: a product processed well beyond the basic ingredients in the package

“…Folate-fortified grain products are, purportedly, ultra-processed foods in the NOVA classification, yet avoiding their use in the year prior to conception has been associated with a 30% increased risk of spina bifida (29) and wheat flour is now fortified with folic acid, by law, in numerous countries worldwide. Notably, vitamin D intake from unfortified foods or as derived from sunlight exposure and the folate contents of/intakes from vegetables are almost always inadequate (30) to produce similar health effects to fortified foods (31)(32)(33) , meaning that national public health policies often focus on fortification and/or supplementation of diets (27,34) . Also worthy of mention are special foods for people who are lactose intolerant or living with coeliac disease or children with inborn genetic diseases, which are often lifesaving but require application of specialised food processing techniques (35) .…”

A systematic review of vitamin D status and dietary intake in various Slovenian populations

“…However, the usual daily dietary VitD intake in adults is below 10 μg in most European countries ( 13 ). This is because only a few foods (i.e., fatty fish) are naturally rich in VitD ( 14 ), and those are not common in the European diet. Some countries, therefore, have introduced the fortification of particular foods with VitD ( 15 ) or prescribed VitD supplementation to certain subpopulation groups.…”

Suboptimal Consumption of Relevant Immune System Micronutrients Is Associated with a Worse Impact of COVID-19 in Spanish Populations

“…In relation to the intake of vitamin D from natural sources, it is worth noting the difficulty in achieving an adequate intake of vitamin D just by diet, since very few foods suitable for human consumption are actually rich sources [ 38 ]. Specifically, only the intake of 100 g of three foods, fish liver oils (250 μg/100 g), certain types of mushrooms (21.1–58.7 μg/100 g) and some kinds of fish (5–25 μg/100 g), would cover the daily needs of vitamin D [ 38 ]. However, the sporadic (or low amount) consumption of these foods in Spain, especially fish liver oil, means there are difficulties in reaching the long-term achievement of significant quantities of dietary vitamin D intake.…”

“…However, the sporadic (or low amount) consumption of these foods in Spain, especially fish liver oil, means there are difficulties in reaching the long-term achievement of significant quantities of dietary vitamin D intake. On the other hand, there are some examples of foods with lower content than those aforementioned, but more commonly consumed, such as cheese and eggs (1.3–2.9 μg/100 g) and fortified foods (kinds of milk and dairy products of fruit juices), that could notably contribute to the intake of this vitamin [ 38 ]. In fact, less than 4% foods of the total nutritional items analyzed in our study fulfilled the theoretical requirement to be considered as a source of this vitamin.…”