Vitamin D is a hormone designed to support the immune system by regulating its reaction to infection throughout the body.
Available in sunlight, supplements are often recommended in winter when the sun’s rays are not strong enough in the northern and southern hemispheres. Vitamin D is found in oily fish, red meat, liver and egg yolks. Vegans rely on mushrooms and fortified foods to maintain good nutritional levels.
Graphics credit: Liz Gould
Graphics credit: Liz Gould