Vitamin D – Why we need it and when to take it? – Barefoot Nutrition

Vitamin D – Why we need it and when to take it?

Vitamin D is where sunshine meets well-being, however, unfortunately modern life dictates a limited exposure to sunlight.  Most of us have to work indoors, wear clothes and wear sunscreen to avoid skin cancer - which all add up to a vitamin D deficiency epidemic!

Vitamin D plays a pivotal role in your health and is essential for various bodily functions, including the absorption of calcium and phosphorus, maintaining bone health, and supporting the immune system.

The body can produce vitamin D when the skin is exposed to sunlight, however the ability to synthesise vitamin D depends on various factors such as geographical location, skin pigmentation, time of day, and season!

Yes, vitamin D is also found in a small number of foods and sources include oily fish such as salmon and mackerel, red meat, liver, egg yolks and fortified foods such as fat spreads and breakfast cereals. However, whilst vitamin D-rich foods contribute to daily intake, it is difficult to for us to get enough from food alone, and so it is important to look to supplements to ensure consistent and adequate levels. 

The above is why we at Barefoot Nutrition chose vitamin D as our first product - we feel it’s the most important to supplement, for everyone.


The official guidelines state that children from the age of 1 and adults need 400iu (10mg) per day through the winter months (October – April).  However, it’s been suggested that the adult body uses 3000-5000iu of vitamin D per day (Heaney et al 2003) and that current dose recommendations are way too low.

A dose of 4000iu a day through the months of September to May (in the UK) should be enough to maintain your blood levels at around 100nmol/l (Moyad, 2009).

If you don’t regularly go out in the sun in the summer, and if you cover up in the sun or have dark skin then year-round supplementation is recommended (Scientific Advisory Committee on Nutrition, 2016) alongside all children aged 1-4 and all babies (unless they’re having more than 500ml of infant formula a day).

At Barefoot Nutrition we try to look at our hunter-gatherer ancestry for the baseline for our recommendations.

Looking at vitamin D from an ancestral perspective, hunter-gatherers from the stone age were likely to have been outside a lot and so getting a good dose of daily vitamin D. Considering our DNA has hardly changed since then, one could assume we need similar amounts to fulfil our health requirements. Comparing modern day hunter-gatherers in sunny countries, these guys had an average blood level of 115 nmol/l of vitamin D. (Luxwolda et al 2012). Now compare that to government guidelines of 25nmol/l. (SACN 2016).

25nmol/l will stop you getting rickets, but what about the hundreds of chemical processes that vitamin D is needed to keep you healthy?

Are you aiming to prevent disease or promote health? Being health promoters, we know that 4000iu will let you achieve around 100nmol/l in your blood (Moyad M, 2009) which is a decent level without any risk of toxicity. In fact, it is important to note that no one has ever shown any signs of vitamin D toxicity of any dose under 10,000iu a day (EFSA, 2012).

Visit our ‘Products’ page for more information on our Vitamin D3 Complete supplement!

EFSA (2012). EFSA panel on dietetic products, nutrition and allergies (NDA) Scientific Opinion on the Tolerable Upper Intake Level of Vitamin D. EFSA Journal;2012; 10 (7): 2813.

Heaney, R P, 2003. Human serum 25-hydroxycholecalciferol response to extended oral dosing with cholecalciferol. The American Journal of Clinical Nutrition, 77 (1), 204-210

Moyad, M A, 2009. Vitamin D: A Rapid Review. Dermatology Nursing. (1), 21 Scientific Advisory Committee on Nutrition, 2016. Vitamin D and Health.

Luxwolda et al 2012. Vitamin D Status indicators in indigenous population in East Africa 2012

The Scientific Advisory Committee on Nutrition (SACN) recommendations on vitamin D. 2016


Leave a comment

Please note, comments must be approved before they are published