What is Vitamin D?
Vitamin D serves a dual role in our bodies: it acts as both a nutrient synthesised following sunlight exposure and through certain foods in our diet, and as a hormone that regulates various cellular and organ functions. After your body obtains vitamin D from food, supplements or sunlight, vitamin D is then converted into a hormone, known as calcitriol or activated vitamin D, which may provide numerous health benefits in the body. Before we dive into the ins and outs of vitamin D, it’s important to note that it exists in two primary forms: vitamin D3, sourced from animals, including humans, and vitamin D2, derived from plants.
What does Vitamin D do?
You may be aware of the importance of calcium for strong bones, but it’s worth keeping in mind that vitamin D is required for the absorption of vital nutrients such as calcium and phosphorus, and hence plays a key role in the maintenance of healthy bones, teeth, and muscles. Deficiency in vitamin D may lead to bone deformities known as rickets in children and bone pain known as osteomalacia in adults. Additionally, there is an emerging body of research suggesting a potential link between adequate vitamin D levels and improved heart health, cognitive function, immune regulation, and protection against gum disease, bacterial and viral infections. However, further research is needed to substantiate these claims.
Vitamin D Deficiency
Most of our vitamin D comes from sunlight, but in places like the UK where sunlight is scarce during autumn and winter, taking supplements is advised by government guidelines to prevent deficiencies. Specifically, 1 in 6 adults have low levels of vitamin D and aside from natural sunlight, insufficient vitamin D intake may be due to dietary limitations, poor absorption, or increased metabolic needs.
Without enough vitamin D, our bodies struggle to absorb calcium from food, leading to the body sourcing it from the bones instead. This may result in conditions like rickets, osteomalacia (softening of bones), osteoporosis, weakened immune function, menstrual irregularities, and musculoskeletal pain and fatigue.
Here are a couple more things to know about vitamin D and deficiencies: If you live in a city, you might have a higher likelihood of being deficient in vitamin D. Furthermore, sitting by a window won’t boost your vitamin D levels because you can’t generate vitamin D through glass. If you want to increase your vitamin D levels through sunlight exposure, make sure to go outside directly into the sun.
Vitamin D Testing
Testing for 25-hydroxyvitamin D, the form of vitamin D synthesised in the liver, is the most reliable way to determine if you have a deficiency. This test can be done through a simple blood test at your GP or healthcare provider, and it’s advised to schedule this test during winter, when you’re more likely to have lower levels of the vitamin.
Plant-Based Sources of Vitamin D
Dietary D2, the plant form of vitamin D, can be found in sunflower seeds, chlorella and mushrooms. In particular, mushrooms offer an excellent plant source of vitamin D since they produce this vitamin when exposed to UV light, similar to humans. Fortified tofu and vegan yoghurt are also good options for increasing vitamin D levels. If you prefer supplements, high-quality vitamin D supplements are commonly available in tablet or in liquid form. Excitingly, we’ve just introduced our new Mango Sunshine shot, offering approximately 100% of your recommended intake of vitamin D intake in a single tasty shot. Give them a try!
Author: Plenish Nutritionist, Katie Morley
DipNT, mBANT, mANP, CNHC
Email: katiemorley@holsome.uk
Website: www.holsome.uk