Our supply of vitamin D comes, for the most part, from sun exposure. That’s why we might notice the effects of low vitamin D are more pronounced in the winter months as this is when “the sun is too low in the sky for vitamin D metabolism to occur in the skin,” Carson explains.

As we’re stuck inside more than usual, Carson recommends upping your intake of vitamin D-rich foods instead. She lists “oily fish such as salmon, mackerel and sardines besides dairy, eggs and mushrooms” as good sources. After that, you can start to consider a vitamin D3 supplement, such as Viridian Nutrition D3 capsules, £34.45 for 150 or Solgar’s Vitamin D3 tablets, £9.25 for 90.

Does sunscreen block vitamin D? A doctor sets the record straight