Hormone Health Hub: Expert Insights on Testing, Balance & Better Living — vitamin D and functional medicine

Did you know that low vitamin D could be disrupting your sleep? Research shows that vitamin D plays a key role in serotonin and melatonin production — the hormones that regulate your sleep-wake cycle. Dr. Kate Placzek explores the science behind the vitamin D–sleep connection, what else low vitamin D affects, and how to find out if deficiency is at the root of your sleep problems.

Had your vitamin D tested and left confused by the result? You are not alone. Different agencies have different opinions on what counts as deficient, sufficient or optimal — and the gap between “normal” and “optimal” matters more than most people realise. Dr. Jillian Harrington breaks down the reference ranges, explains what your result actually means, and outlines how to work towards the level that is right for your health.

Vitamin D has one of the most remarkable stories in nutritional science — from its discovery as the cure for rickets in the early 20th century to its emerging role in cancer prevention, heart disease, diabetes and depression. Yet a century after its identification, our understanding of vitamin D’s wider role in human health is still evolving. This article traces that history and explains why testing your vitamin D levels remains as relevant as ever.