Nutrients, Nutrition

Vitamin D

This is probably one of my favourite vitamins and one I struggle with personally the most. Having tanned skin, spending most of my time working from home and having two genetic SNPs (polymorphisms) in my vit. D receptors means that often my levels are sub-optimal – even with supplementation!

In fact, the moment I stop supplementing my vitamin D levels drop to deficiency or even “severe deficiency” levels (yup, just did my blood test a couple of weeks ago after taking a break from supplements and, surprise-surprise, my levels were so low my doc told me to get a D injection asap).

But more than just being classified as “deficient”, when my levels are low I begin to feel really fatigued, my mood is low, I struggle to focus and my muscles feel achy with minimal exertion. Why does this sun vitamin have such wide-reaching effects? Simply because it is essential for so many bodily functions, including:

  • Calcium & phosphorus balance 
  • Bone health
  • Hormone health
  • Immune function
  • Cardiovascular function
  • Nervous system function
  • Cell differentiation (& cancer prevention)
  • Insulin production & glucose tolerance
  • Blood pressure regulation
  • Gene transcription & regulation of hundreds of genes*

*As you’ll find out in the Younger You book, vitamin D is a powerful DNA methylation adaptogen and an active demethylating nutrient, ensuring the right genes get turned on.

This fat-soluble vitamin is made in our skin and can be found in small amounts in:

  • Salmon
  • Mackerel
  • Sardines
  • Egg yolk

It’s best to assess vit. D status through a simple blood test and be aware that deficiency can produce profound signs & symptoms such as muscle & back pain, muscle weakness, high blood pressure, muscle cramps, achy bones & decreased bone density, insulin resistance & blood sugar imbalances, poor cognitive function, increased risk of infection (including viral infections), dysregulated & overactive immune function (autoimmunity) and the list can go on and on.

So do make sure you spend enough time out in the sun (15-30 mins will do) – it’s the quickest way to boost your vit. D levels!


  1. Lord R, Bralley J. Laboratory Evaluations For Integrative And Functional Medicine. Duluth, Ga: Genova Diagnostics; 2012.
  2. Higdon J. Vitamin A. Linus Pauling Institute. Published 2022. Accessed January 26, 2022.