Researchers measured how much the participants’ gums were attached to their teeth. (Separated gums are a sign of periodontal disease, which can lead to tooth loss.) Among people aged more than 50 or older, those with lower levels of vitamin D in their blood lost 27 per cent (male) and 23 per cent (women) more gum attachment than those with higher levels.

The researchers suggest that vitamin D works by curbing inflammation in the gums rather than by strengthening bone density, because gum attachment was not linked to the density of the participants’ bones.

Best source of vitamin D is sunshine. Older people whose skin becomes inefficient at synthesising the vitamin from sunlight, will probably need a multivitamin, calcium+vitamin D supplement as well.