Vitamin D: Upping your intake in winter

Known as the sunshine vitamin, vitamin D is naturally made by the body when the skin is exposed to the sun. It is essential for the proper absorption of calcium, bone development, control of cell growth and immune functioning. Low levels of vitamin D have also been linked to depression.

Vitamin D is oil soluble, which means you need to eat fat to absorb it. Few foods naturally contain vitamin D (but some foods such as margarine and milk products may be supplemented with it). However, it is naturally found in fish oils and fatty fish and to a lesser extent in beef liver, cheese and egg yolks (an egg a day provides 10 per cent of your vitamin D needs). Mushrooms, especially sun-dried shiitakes, are very high in vitamin D. But leave any of your fresh mushrooms out in the sun for an hour or so and their vitamin D levels will soar! In fact, you need eat only three sun-exposed mushrooms to get your daily quota of the vitamin. Te Mata mushrooms in Hawkes Bay even sells D mushrooms that have been UV-exposed.

When it comes to fish, typically raw contains more vitamin D than cooked, and fatty varieties, such as salmon, tuna and sardines, contain more than leaner types. A small can of sardines will provide 70 per cent of your daily vitamin D needs. Fish canned in oil has more vitamin D than that canned in water.