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The hobbit — an unexpected deficiency


A striking feature of fantasy literature has been the consistent victory of good characters over bad. While the consensus has been to attribute this to narrative conventions about morality and the necessary happiness of endings, we hypothesised that a major contribution to the defeat of evildoers in this context is their aversion to sunlight and their poor diet, which may lead to vitamin D deficiency and hence reduced martial prowess.

Vitamin D is a fat-soluble, secosteroid hormone, which in humans is largely synthesised in the skin when exposed to ultraviolet light, and is sometimes called “the sunshine vitamin”.1 Vitamin D is also found in some foods, particularly oily fish and, in small amounts, in egg yolks, cheese, beef, liver and some mushrooms. It has a well described role in calcium metabolism, with deficiency resulting in rickets and osteomalacia. Vitamin D also has immune-modulating roles with potential effects on susceptibility to conditions ranging from multiple sclerosis to tuberculosis and accelerated lung function decline.2,3 Skeletal muscle weakness is known to be a feature of vitamin D deficiency although it has not been found to contribute to muscle dysfunction in chronic obstructive pulmonary disease…