What is Vitamin D? Everything You Need to Know.

What is Vitamin D? Everything You Need to Know.

In the pursuit of optimal health, certain nutrients stand out for their vital roles, and vitamin D is undoubtedly one of them. Often referred to as the "sunshine vitamin," vitamin D plays a crucial role in many physiological processes in the body including bone, teeth and muscular health, immune system function, gut health, cardiovascular health, and mood regulation.

What is Vitamin D?

Vitamin D is an essential nutrient, which we can consume from food and the body can produce in response to sunlight exposure. It exists in two main forms: vitamin D2 (ergocalciferol) found in fungi and plant sources, and vitamin D3 (cholecalciferol), which is thought to be the more potent and bioavailable form, mainly derived from animal-based sources and sunlight exposure. Vitamin D is a fat-soluble nutrient, which means that we can store it in the body.

Foods Rich in Vitamin D

The primary natural source of vitamin D is that which is produced in the skin from exposure to sunlight. However living in the northern hemisphere can make getting adequate exposure, particularly in the winter months, something of a challenge. For this reason vitamin D-rich foods in the daily diet are crucial for maintaining optimal levels, that said this can be easier said than done as there are only a few foods that naturally contain this vital nutrient. Fatty fish such as salmon, mackerel, and tuna are excellent sources, and fortified foods like some dairy products, orange juice, and cereals can provide a dietary boost. For those following a plant-based diet, mushrooms exposed to sunlight or UV light can be a valuable source of vitamin D2.

What is vitamin D deficiency?

It is estimated that 1 in 6 adults has low levels of vitamin D in their blood, resulting from inadequate sunlight exposure and low dietary intake. The symptoms of vitamin D deficiency can vary between individuals and in some cases, there are no noticeable symptoms. A blood test is the best way to detect vitamin D deficiency, could provide valuable early detection and allows for supplemental intervention. People at greater risk of deficiency include those with limited sun exposure, darker skin, over 65s, certain medical conditions, or specific dietary restrictions. Vitamin D deficiency can:

Impact Bone Health:

  • Vitamin D maintains bone health by helping the gut to absorb calcium and regulating blood levels of calcium and phosphorus.
  • Severe vitamin D deficiency in children can lead to rickets, a condition characterised by soft and weak bones. This is particularly relevant in growing children, as vitamin D is essential for the proper absorption of calcium and phosphorus, crucial for bone development.
  • In adults, vitamin D deficiency can contribute to osteomalacia, a condition where bones become soft and prone to fractures.
Impair Immune System Function:
  • Vitamin D is known to modulate immune function. Deficiency may compromise the immune system, potentially leading to an increased susceptibility to infections and a reduced ability to fight off illnesses.
Increase Risk of Chronic Diseases:
  • There is growing evidence linking vitamin D deficiency to an increased risk of various chronic diseases, including cardiovascular diseases, diabetes, certain cancers, and autoimmune disorders. While more research is needed to establish causation, maintaining adequate vitamin D levels appears to play a protective role against these conditions.

Cause Muscle Weakness and Pain:

  • Vitamin D deficiency has been associated with muscle weakness and pain. It is essential for muscle function, and insufficient levels may contribute to conditions like myalgia and muscle aches.

Affect Gut Health:

  • Recent studies have shown significant links between vitamin D levels and gut bacteria, with higher reported vitamin D intake improving the quantity and diversity of gut bacteria.

Contribute to Mood Disorders:

  • Some studies suggest a potential link between vitamin D deficiency and mood disorders, including depression. While the exact nature of this relationship is complex and not fully understood, maintaining adequate vitamin D levels may contribute to mental well-being.
Cognitive Decline:
  • Research has explored the association between vitamin D deficiency and cognitive decline in the elderly. While the exact mechanisms are not clear, there is ongoing investigation into the potential role of vitamin D in maintaining cognitive function.

What is the difference between vitamin D, D2 and D3?

Whilst vitamin D is fat-soluble nutrient used to regulate calcium and phosphorus levels, as well as performing many other functions, in the body, vitamin D3 is the natural form produced by the body when exposed to sunlight.

Vitamins D2 and D3 play the same roles in the body and both raise blood levels, however they differ in molecular structure and how they are metabolised in the liver. It is thought that vitamin D3 is more effective than vitamin D2 at raising blood levels of the precursor to active vitamin D, calcifediol.

What about vitamin D supplementation?

Supplementation is widely recommended between October and April for much of the population, and throughout the year for those with limited sun exposure or at greater risk of vitamin D deficiency.

Vitamin D3 is usually sourced from lanolin (sheep's wool) or fish oil, and now can be found in vegan form, sourced from lichen. Whichever vitamin D supplement you choose the most important factor is selecting a high-quality one as this is essential for efficacy.

Top tip for taking vitamin D

As a fat loving nutrient, the best time to take your vitamin D supplement is after eating a snack or meal with a good healthy fat content, such as flax seeds, avocado, nuts and seeds, good quality greek yoghurt, coconut yoghurt or olive oil.

Vitamin D is a cornerstone of overall well-being, and while sunlight remains the best natural source, incorporating vitamin D-rich foods and choosing the right supplement form are essential for maintaining optimal levels and ensuring your body gets enough of this crucial nutrient, particularly in the winter months each year.

Back to blog