If you've had more than enough of dark winter months, you're not alone. This year has been one of the toughest winters on record, especially gruelling for those who suffer with SAD (seasonal affected disorder).

The lack of sunlight not only lowers our mood, it also means many of us are lacking in vitamin D. (It's estimated that by the end of winter half the population of England is low in the vitamin, compared to two-thirds in Scotland.)

Professor Sue Penckofer, of Loyola University, Chicago, explains: "Vitamin D deficiency continues to be a problem despite the nutrient's widely reported health benefits. Winters compound this issue when more people spend time away from sunlight, which is a natural source of the vitamin."

If you're concerned that you're not getting enough vitamin D, you can help improve your mood by eating oily fish, eggs, liver and fortified foods such as margarine, breakfast cereals and powdered milk.

Studies show that increasing your levels of the vitamin can help to lift mood, in some cases proving better than light boxes. However, the best way to ward off the winter blues is to eat vitamin D rich foods while getting more exposure to sunlight.

Recent studies also show that vitamin D (which is produced by the body in reaction to sunlight) helps boost the immune system, playing a key role in activating white blood cells that protect the body from flu, food poisoning and even cancer.

Feeling unwell? Check your symptoms with the NHS
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