Vitamin D: Not Just Important for Bone Health
What Is Vitamin D, Exactly?
Vitamin D is a fat-soluble vitamin that plays a key role in keeping your body healthy. Unlike most vitamins, it also acts like a hormone, influencing many systems in the body—not just your bones.
Why Vitamin D Matters
Vitamin D does a lot more than most people realize:
Supports strong bones and teeth by helping your body absorb calcium. Low vitamin D can often be the cause of tooth decay.
Boosts immune function, helping your body fight infections. Low vitamin D level is linked to auto-immune disease like rheumatoid arthritis, Hashimoto’s thyroiditis and psoriasis.
Supports muscle strength, balance, and coordination
Plays a role in mood regulation, with low levels linked to low mood and seasonal depression
Contributes to overall long-term health, including heart and metabolic health
Signs You Might Be Low on Vitamin D
Vitamin D deficiency isn’t always obvious, but common signs can include:
Frequent colds or infections
Fatigue or low energy
Bone or back pain
Muscle weakness or aches
Low mood or “winter blues”
Get Tested
If these symptoms sound familiar, a simple blood test can confirm your levels. If you are unable to get a test through your GP, you can order one privately from an NHS laboratory via its website www.vitaminDtest.co.org. They cost around £30 (as of February 2026). This laboratory will provide a numerical result rather than just a ‘sufficient/deficient’ result. This is important because whilst NHS laboratories use a lower limit of 50nmol/L, research has shown that optimum levels, particularly for immune/autoimmune health need to be above 100nmol/L. Knowing your actual level will help to know what dose of supplement to take.
Supplements and Doses
It is difficult to get enough vitamin D from sunlight in the UK and food sources and the government recommend that everyone takes a supplement from around October to March. Many people need to take a supplement all year round, particularly if they work indoors, are unable to spend time outside or have darker skin types.
As vitamin D is a fat-soluble vitamin, it needs to be taken with food containing fats in order to be absorbed. However, formulations in sprays and drops allow for direct absorption into the blood vessels under tongue, which bypasses the stomach and so can be taken at any time. Supplements are available in different doses and the dose you take should be based on your current levels and whether you are trying to maintain or change your levels. We are all different however just for information, I take 4000IUs in winter and 2000IUs in summer to maintain my levels over 100nmol/L.
The Bottom Line
Vitamin D may be easy to overlook, but it plays a powerful role in your overall health. Making sure you get enough vitamin D is a small step that can have a big impact. Make sure you get tested every few years and supplement as appropriate to ensure you are keeping your levels optimised ☀️.