Vitamin D, in context.

Vitamin D is the one nutrient the body can make from sunlight. In a British winter it cannot, which is why food sources and daily formulas come up every autumn.

Vitamin D is a fat-soluble vitamin. Unlike most nutrients, the body can make it when skin is exposed to summer sunlight. In the UK, between October and early March, that sunlight is not strong enough, which is why UK guidance discusses dietary sources and supplements for the winter months.

This page explains what vitamin D does in the body, which foods contain it, and how it sits within the Immufix formula.

What Vitamin D does in the body.

Vitamin D contributes to the normal function of the immune system, to the maintenance of normal bones and to normal muscle function.

Vitamin D contributes to the normal absorption and utilisation of calcium and phosphorus, and to normal blood calcium levels. It contributes to the maintenance of normal bones, normal teeth and normal muscle function, and it has a role in the process of cell division.

These are the functions the authorised list allows a food business to describe. Nothing on this page goes beyond that list, and each claim is credited to vitamin D itself.

How much counts as a source.

The Nutrient Reference Value for vitamin D on UK labels is 0.005 mg a day. A food counts as a source of vitamin D at 15 % of that per 100 g (0.00075 mg) and as high in vitamin D at 30 % (0.0015 mg); drinks use half those percentages per 100 ml. Those are the thresholds every food page here applies, and the only basis on which a food page says “source of” or “high in”.

Foods with the most vitamin D, per 100 g.

Per 100 g, these are the foods in the database with the most vitamin D. Dishes and recipes are left out so the list shows single foods.

Where Vitamin D comes from in food.

bloater (0.025 mg), herring (0.019 mg), herring pickled (0.016 mg), salmon pink (0.0136 mg), jackfish (0.013 mg), sprats (0.013 mg), chicken eggs (0.0128 mg), salmon red (0.0118 mg)

Vitamin D in the Immufix formula.

Vitamin D is one of the vitamins in the formula's micronutrient core, delivered in the same measured 25g serving as the fibre, amino acids and supporting carbohydrate.

The declared amount per serving, and the share of the Nutrient Reference Value it represents, are printed on the label and listed on The Science page.

Questions people ask.

Where the numbers come from.

Food figures from the UK Composition of Foods Integrated Dataset (CoFID, 2021), per 100 g; reference values from Regulation (EU) 1169/2011 Annex XIII as retained in GB law; claim wording from Wording already published on the site's Science page. Contains public sector information licensed under the Open Government Licence v3.0. All foods A to Z.