Hormone Health Hub: Expert Insights on Testing, Balance & Better Living — vitamin D and healthy immune response

A melanoma diagnosis changes everything — but it can also be the catalyst for a smarter, more proactive approach to skin health. In this personal account, Lissa Gienty of ZRT Laboratory shares her melanoma story and the evidence-based steps she now takes to protect herself, including optimising vitamin D and melatonin levels and monitoring her diurnal hormone rhythms.

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.