In centuries past, Scottish people obtained much of the Vitamin D they needed, by exposing their skin to outdoor daylight, but today most of us live and work indoors.
The relatively scarce sunlight compared to southern countries used to be unknowingly compensated for by eating a lot of oil rich fish. The combination of outdoor life and fish, gave healthy protection to people living in northern countries. Darker skin types block more sunlight than light skin types, representing a protective mechanism appropriate to a person’s native climate. It seems that the further north humans emigrated, the more pigment they lost, obviously to make the maximum use of the scarce sunlight.
How Much Vitamin D Is Enough?
During the last 10 – 20 years, it has become clear that our health is better when higher Vitamin D blood levels are reached, than previously thought sufficient. Here is the modern understanding:
Severe deficiency: <25 nmol/l
Deficiency: 25-50 nmol/l
Insufficiency: 50-75 nmol/l
Sufficiency: 75-150 nmol/l
Toxicity: >400 nmol/l
How much Vitamin D your body contains will depend on how much sunshine you get, fish you consume and the level of supplements you are taking, as all three contribute to Vitamin D levels.
Your doctor can test your Vitamin D level, or you can obtain a mail-in kit for around £25. There are also other websites and shops that sell test kits.
If you decide to make a change to your lifestyle, such as by taking a supplement, it will take around three months until your blood level stabilises, and you can again reliably test to see if you’ve hit the golden figure of 75-150 nmol/l. It is then important to continue with those supplements to maintain that level.
So how do we increase Vitamin D intake?
Get More Sunlight
Sufficient sunshine to produce good Vitamin D levels is estimated to be around half an hour a day, in mid day summer, arms, legs and face exposed without sunscreen. As a rule of thumb the sun has to be high enough in the sky to make a shadow which is shorter than your body length. That is only possible in Scotland from the end of April to September, between approximately 11am to 3pm. So for six to seven months of the year Scotland’s sun simply isn’t strong enough to produce Vitamin D in the skin.
If you think you receive enough sunshine outdoors on arms and legs in those summer months, you might choose to take supplements only during the winter. However, most of us in Scotland do not get outdoors sufficiently at lunchtime and should consider supplements all year round.
If you have a dark skin type, the time you would need to spend in the summer sun to make sufficient Vitamin D is much longer and you should most certainly consider taking a supplement all year round.
Eat More Oily Fish
Today we eat less fish than many years ago. We estimate that people living in Scotland would have to eat several portions of oil-rich fish daily to obtain sufficient Vitamin D. In fact, here is a beautiful study on the evolutionary history of the north-faring populations, who could only survive by loosing skin pigment and eating fish in their regular diet.
Take Vitamin D Supplements
Vitamin D Supplements are the easiest way for most of us to get the Vitamin D that we need and for most people there are no side effects. Taking Vitamin D in form of a fish meal could also be considered as taking a supplement. It doesn’t seem therefore so unnatural to replace the traditional fish provision with a supplement. We agree with the US Endocrine Society Guidelines and recommend as a minimum daily dose:
Pregnant women: 50 mcg or 2,000 IU
Age 12+: 50 mcg or 2,000 IU
Age 5 – 12: 25 mcg or 1,000 IU
Birth to Age 4: 10 mcg or 400 IU
Quite a few people, especially here in Scotland will need higher supplement levels to reach the optimal blood levels of between 75 – 150 nmol/l.
You can get Vitamin D Supplements from various health food shops, most pharmacies or from the internet. Here are some trusted sources:
There are generally no side effects to taking Vitamin D supplements, though if you or a relative has had a calcium related disorder, you should contact your doctor before starting. In a few exceptional circumstances Vitamin D can lead to excessive calcium in the blood, including Sarcoidosis. If you or any relative has had these conditions, then you should discuss Vitamin D with your doctor. Naturally, if you develop abdominal pains, undue thirst, vomiting, weakness or feel unwell in any way after starting supplementation then you should see your doctor urgently and suggest your blood is checked for calcium.
Here are some other good Vitamin D information sources, and please join our forum to take part in further discussion: