Dietary sources of vitamin D are especially important. If you cannot go outside into the sun, or during the winter months in the UK, you are unable to get enough sun exposure to make vitamin D. At this point, your only options are dietary vitamin D or taking supplements.
Most foods containing significant amounts of vitamin D are of animal origin. 5 egg yolks will give you half your recommended daily vitamin D (around 5 micrograms or 200 IU), and 100g of oil-rich fish such as salmon contains between 50-100% of your daily recommended (5-10 micrograms or 200-400 IU).
Yes! One of the only plant-based options are wild mushrooms, and a large handful (100g in weight) would contain more than your daily recommended vitamin D (10-30 microgram or 400-1200 IU). We should also add that some supermarket mushrooms won’t contain barely any vitamin D as they are actually grown in the dark! Milks usually have vitamin D added, so most soy, almond and rice milk will contain around a quarter of your recommended daily vitamin D per cup (2.5 micrograms or 100 IU). Orange juice is commonly fortified with vitamin D so it has a similar amount per cup to the milks. Cereals also usually have small amounts of vitamin D added to them.
Adding vitamin D to food has been done for a long time and is considered safe. America has added it to its milk since the 1930s, and here in the UK we add it to cereals, margarine and more. Public health teams have thought that adding vitamin D to certain foods is the answer to targeting populations that tend to be lower in vitamin D. Adding it to wheat flour, used in creating chapati, parathas and pooris, could help increase the typically lower levels of vitamin D found in the South Asian heritage UK population.
You are pretty much correct! Chapati’s (although delicious) have been linked to contributing to Asian populations reduced vitamin D levels. It is thought that one of the contents of the chapati flour may play a part in causing trouble with the vitamin D absorption pathway.