Fitness & Healthy Lifestyle

The Vitamin D Lowdown

Ah Vitamin D.

AKA the sunshine vitamin.

If I had to pick a favourite micronutrient maybe, just maybe, this would be my choice. And not just because the best way to top up your levels is to leap about on a summer's day in a bikini ...

Although that doesn't hurt of course.

No Vitamin D is truly integral for many elements of our health & wellbeing but working out how much we need, how we get this if we don't live at the Equator, & which supplements are superior to others can get a little on the confusing side. But never fear I've broken all of this down for you in the following simple sections.

OPTIMAL LEVELS - all following levels & advice on dosages are for adults, if you have questions with regards to infants/children please do be in touch

This will depend on the individual but I am always looking for a blood result in the region of 80-110mmol/l. Different labs & services will use different recording methods so my advice is to only compare results from the same service to ensure accuracy.

I will also note that those with autoimmune issues require higher amounts of Vitamin D as this has a therapeutic action in managing the overactive part of their immune system. Due to it's protective effects on the nervous system & brain higher levels of D would also be exceptionally beneficial where there are any neurodegenerative concerns (also being aware that the elderly tend not to be out uncovered in the sun as readily as their younger counterparts). And Vitamin D is also imperative for the integrity of the intestinal barrier so those with GI inflammatory issues, potential food intolerances & similar concerns should all have their levels checked & ensure they are towards the top end of the range I suggest above.

Additionally those with darker skin will have higher requirements but lower absorption levels of sunshine derived D so they will need to account for this when considering their necessity for a supplemental top up.


First & foremost we look to the sun. When it hits our skin those lovely rays kick off a conversion train that results in the active form of Vitamin D (D3) circulating in our body. And if you live in lovely sunny climes & can regularly expose areas of skin that wouldn't usually be in the sun (your torso & back for example rather than just face & arms) you very well may be able to achieve your requirements. As a fat soluble vitamin you can also store Vitamin D so should you be out for the summer months in bright sunshine you might be able to 'live on' your stores throughout the winter but this wouldn't apply to many people as we can't top up our levels sufficiently to get us through to our next sun drenched sojourn.

So then we dive into the world of supplements which is always a daunting sphere. As I mention Vitamin D is fat soluble which means its absorption will always be better if taken in a fat based form (an oil based capsule or oil drops/liquids). We also need to consider the different types of Vitamin D because that conversion train I touched on is basically a building of your precursor blocks into the active form of this micronutrient so if you take a 'halfway house' option (D2 being the most common as this is the non-animal based form) your body still has to then convert that to active Vitamin D3. So you could be taking a D2 supplement that states a pretty high dose but you aren't going to make use of all of that as enzymatic conversion in the body doesn't work to 100% efficacy. Similarly a tablet of D3 won't be fully utilised as it's not in that fat based form. Swings & roundabouts OR WHAT?!

My advice therefore is simple - look for active Vitamin D3 (known as cholecalciferol) as an oil based capsule like these or a liquid oil drop like these. If you are vegan or vegetarian you would need to either take a higher dose of D2 or look at something like an algae derived D3.

The only way to know where you fall in terms of the range I suggest above is to test (a simple blood test). If your levels are below 80mmol/l I would add in a high dose of 4000-5000IU per day for 1 month then retest your levels. If you are then entering the optimal range drop your supplemental dose by half for another month. If it is the depths of winter then continue here & retest your levels 8 weeks later, if it's peak summer time then halve your dose again after the first 4 weeks & retest after 8 weeks. There can be genetic issues with uptake of Vitamin D (faulty receptor sites) so should you supplement & find your levels don't increase you would need to consult someone who can advise on this for you.

If your levels are good when you test & you are out in the sun then you don't need to supplement whilst that is the case. At the onset of winter however I would suggest adding in a 1000IU dose to ensure you don't find yourself dipping out of the bottom at any point.


I wanted to conclude this post but touching on this as in the times we are currently living in there is a lot of talk about how we can maintain robust health & avoid falling ill. Unfortunately there is no miracle cure. Exposure to illness allows our immune system to respond & create antibodies which should be protective against re-infection in future. But this is not assured, viruses & bacteria mutate over time which means that even if you've had something once you can still get it again.

When we look at overall nutrient status & elements such as Vitamin D which play key roles in immune function however what we can say is that keeping your levels up in that optimal range enhances your immune abilities in that should you succumb to an infection or virus your symptom duration is likely to be less severe & your return to wellness is likely to be swifter. But 1 piece of the puzzle does not complete the full picture so an appraisal of your overall diet, lifestyle & environment would be needed too.

As always please do be in touch with any questions.

With healthy wishes,

Phoebe x