The One Test We Recommend for Everyone?

Can a simple, inexpensive test save your health?

Having optimal vitamin D levels is a key factor in gaining and maintaining outstanding health.

Optimal vitamin D is also absolutely crucial in preventative medicine and avoiding a wide variety of degenerative diseases.

We advise ALL of the clients in our Functional Medicine and Nutritional Therapy practice, to get their levels tested quickly, easily and cheaply.

Here’s why.

Vitamin D: The One Test We Recommend For Everyone

If there’s one test everyone, and I mean absolutely every person living in the UK and around the world (1), should take, it’s this test. 

A, fast, cheap, pin-prick vitamin D test. 

And everyone should get tested – we find that even people living modern lives in the tropics don’t have optimal vitamin D levels.

Why is vitamin D such a big deal?

We’re designed to walk around outside half naked most of the time, naturally making about 10,000IU of vitamin D per day.

But our modern lives mean we only get a fraction of the direct sunlight exposure we need in order to maintain optimal vitamin D levels.

When we do get sunlight, we’ve been educated by cancer specialists and general media hysteria to apply factor 50 sunscreen all over ourselves (not to say that excessive sun exposure and getting sunburnt isn’t a real concern – it is and can cause DNA damage increasing the risk of cancer). 

But we seem to have taken to completely blocking sunlight exposure to skin, meaning that vitamin D synthesis is blocked.

And unfortunately, a vitamin D deficiency caused by not getting enough sunlight actually contributes to an increased risk of cancer (3).

Back to the real story...

It’s estimated that 90% of us in the UK are in a state of vitamin D deficiency.

That includes the young, the old and everyone in between.

Up to 20% of us are not just deficient, but severely deficient.

And we’ve all read about the return of rickets in children born in the UK over the past 15 years. Whilst this in an overt sign of vitamin D deficiency, we are also seeing more subtle consequences of a vitamin D deficiency, such as low mood, hormonal imbalances, fatigue and aches and pains. 

‘Yeah but I spend loads of time outdoors and I’ve just had two weeks in Spain’ we hear clients say.

Unfortunately, that rarely gets close to giving you what your body needs.

48 weeks of minimal sun exposure is seldom rectified in just 4 weeks of vacationing in sunnier climates, as the test results we see week in and week out prove.

We're at a critical point

There has been no sign of significant improvement in Vitamin D status in over a decade.

Ironically, many Clinical Commissioning Groups in the UK have now banned testing in all but the most severe of cases.

So a lot of people want to supplement with vitamin D, but what dose of vitamin D is safe and effective?

How much vitamin D should you take?

First it is essential to get your levels tested, because too much vitamin D can be toxic.

Where a deficiency exists, doses of 10,000IU a day have been taken for 5 months with no adverse effects (this study was performed in men) (4).

However, at a dose of 10,000IU a day, we recommend getting your levels re-tested regularly.

50,000IU of vitamin D once a week for 8 weeks has been successfully used in a number of studies, too.

This is enough to double levels in most people (5)

A daily dose of 2000IU is recommended to correct a deficiency in children (6), and getting levels re-tested regularly is wise.

The optimal range for serum vitamin D (D2 + D3) is generally considered to be around 30-50ng/ml or 75-125nmol/L. The optimal ranges can differ (usually it is higher) in particular chronic conditions.

How can a vitamin D deficiency affect you?

As vitamin D is important in so many different functions in your body, a vitamin D deficiency can cause widespread problems (to understand more about the root cause, systems approach to health, read this article):

Specific populations at risk of vitamin D deficiency

Some people are at greater risk of a vitamin D deficiency, or may have lower levels, than others.

Our advice is that everyone should monitor their vitamin D levels regularly.

Having said that, people in the following groups should pay especially close attention to their levels:

The wrap

It’s simple. 

Get your vitamin D levels tested (accurate home testing kits can currently be bought for £29.00 here in the UK).

Take a high quality supplement that delivers exactly what it says on the tin, to bring levels to within the optimal range(2) and maintain levels consistently throughout the year.

This is subject to specific health conditions and any medications you are taking – always seek the advice of an appropriately trained practitioner if you have a medical diagnosis or are taking medications, for example those with the autoimmune condition, sarcoidosis, should not supplement with vitamin D (unless advised).

To your optimised, healthy future,

Dee & the Coho Health team

How can we help you? Send us a message below and we’ll come right back to you…




Even in countries with high amounts of sunlight and close to the equator, vitamin d deficiency prevalence is very high.



Seek advise from a suitably qualified healthcare practitioner, if your test result is below 80 nmol/L (30 ng/ml) and your told your levels are normal, you need to find a different practitioner.




Holick MF (2012). Evidence-based D-bate on health benefits of vitamin D revisited. Dermatoendocrinol 4(2): 183–190. Available at; (Accessed on 18 October 2012).



Vieth R, Chan PC, MacFarlane GD (2001). Efficacy and safety of vitamin D3 intake exceeding the lowest observed adverse effect level. Am J Clin Nutr 73:288–294.



Malabanan A, Veronikis IE, Holick MF (1998). Redefining vitamin D insufficiency. Lancet 351:805–806.



Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, Hanley DA, Heaney RP, Murad MH, Weaver CM (2011). Evaluation, treatment, and prevention of vitamin d
deficiency: an endocrine society clinical practice guideline. J Clin Endocrinol Metab 96(7):1911-30

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