The vitamin of the year – and probably of the decade – is D. Doctors have long known that vitamin D promotes healthy bone growth and severe deficiency causes rickets but researchers have only recently become aware of the far-reaching health effects of inadequate vitamin D levels.

Studies published over the past six months have linked vitamin D deficiency to a wide range of problems, including obesity, Alzheimer’s disease, cancer, infections, multiple sclerosis, diabetes, inflammation and heart trouble.