How much time did our ancestors spend in the sun? And does it matter for your health today?
A new study provides an interesting clue.
From sunny Africa to the dark north
Our human ancestors emigrated from eastern Africa and spread across the entire planet. That often meant that the sun became much weaker. Since vitamin D is produced by our skin when in strong sunlight their levels of vitamin D dropped rapidly when moving north, which may have led to severe health problems.
In an extremely short time, evolutionary speaking, the ancestors of northern people developed lighter skin. They rapidly shed their built-in sun protection, likely to catch all the sun and vitamin D that they could.
In not-so-sunny Sweden, where I live, a lot of people have severe shortage of vitamin D during the winter, despite having light skin. Statistically such deficiency is correlated with just about every disease there is. Such correlations doesn’t prove that the deficiency leads to all these diseases, but it’s possible that it contributes.
What is normal?
How much vitamin D is “normal” to have in your blood? That’s a common question. According to my lab between 75-250 nmol/L is normal, and below 75 is considered a deficiency.
- (Divide by 2.5 for values in ng/ml, i.e. 30-100 ng/ml would be considered normal)
This means that all the patients I’ve tested during the winter in Sweden are deficient, if they haven’t travelled south or taken a vitamin D supplement. Extreme deficiencies of 20 or less isn’t uncommon. The lowest I’ve seen is 14 nmol/L.
These extreme deficiencies have often been tired patients, sometimes with a history of winter depressions. Taking supplemental vitamin D has several times led to remarkable recoveries within a few weeks. Well done trials have also shown significant such effects.
The answer
A study of traditionally living people in sunny East Africa gives us a clue to what’s normal. These people all have dark skin, built in sun protection. They spend most of the day outdoors but avoid strong sun when they can. Perhaps their skin and sun habits are similiar to our ancestors (who lived in the same environment).
The average vitamin D level was 115 nmol/L (46 ng/ml). The lowest level found was 58 and the highest 171. Here is the study:
- Luxwolda MF, et al. Traditionally living populations in East Africa have a mean serum 25-hydroxyvitamin D concentration of 115 nmol/l. Br J Nutr. 2012 Jan 23:1-5. [Epub ahead of print]
How do we get vitamin D during the winter?
For those who don’t spend their days outdoors in a sunny climate there are three good options to get vitamin D:
- Strong sun (travelling south or using a tanning bed with the right wave lengths)
- Eating fatty fish (350 grams daily may give you 2 000 units)
- Supplements (the cheapest, easiest way)
Personally I’ve been taking 4 000 units daily (recently increased to 5 000). I skip it during sunny summer times. This fall my vitamin D level was 95 nmol/L.
Less than an average Maasai but not too bad.
Also, part of the problem is "strong" sun. Rule of thumb: if your shadow is longer than you are tall, you're not producing vitamin d.
I also take 4000 units daily.
What's the upper limit of a safe dosage?? My Vitamin D was 40 on 2000 units/day of Vitamin D, I upped it to 6000 units and now my husband is certain I'm going to die of an overdose (I'm not worried). My doctor only recommends 2000 units/day and I fall "within standard range" (25 to 79 ng/mL) according to the hospital's lab report, so the doctor doesn't think it's low at all.
Here's a really good interview about Vit D deficiency from an expert who got kicked out of a uni in the US because he didn't toe the line about staying out of the sun.
http://www.4bc.com.au/blogs/4bc-blog/vitamin-d-expert/20110727-1hzzy....
There is some interesting research suggesting a link between skin cancer and LACK of vitamin D, which might help to explain why there is more skin cancer in many parts of Scotland than in most sunny Mediterranean countries.
I don't use sunscreens, because of the nasty ingredients they have. I use lemon juice and macadamia oil instead.
MCT is also very stable so it's less likely to go rancid. It's also taste neutral, some of the others taste disgusting if you bite the capsule to check if the oil is not rancid.
I haven't time to find it now but there was a study on vitamin D requirements for African American women in relation to calcium absorption from diet and I'm sure they were able to manage a good calcium economy on a lower 25(OH)D than their paler skinned neighbours. So what may be a reasonable 25(OH)D for a dark skin may be inadequate for some others.
I try to stay around 60ng/ml ~ 150nmol/l as that gives me a stored reserve of D3.
If I had to go into hospital, Had an operation, met with some calamity I would be better able to respond to that crisis. We know having surgery drops vitamin D status 40% so having a safety margin stored about your person enables you to withstand that drop and not end up deficient.
The most vitamin D deficient people before surgery end up staying in hospital longer, have more complications and the long term survival is lower, so being prepared by always being on the higher end of the optimum range may be sensible.
Useful article here on how to protect your skin from the effects of UV radiation. Really works but takes 8 ~12 weeks so start now for better protection this summer.
Natural Sunscreen Options
Anyway I've heard that in Sweden pickled herring is traditionally served around Christmas, when the UV radiation is at its lowest. Is that correct? I'm thinking that particular holiday tradition is no accident. Just speculating.
So while I could get about a fifth of my daily amount from food, if I ate pickled herring daily I'm afraid the fish daily option isn't my choice.
It certainly was the way the INUIT survived the winter as they did consume fish, seal, game fermented in seal/fish oil in holes in the ground and did make 5000iu/daily/vit d3 from food sources, but I don't think picked fish 3 times daily is going to be readily adopted by most readers here.
I still think having an understanding of the process underlying DNA damage by UVA gives one the ability to do something to prevent that damage.
UVA radiation-induced oxidative damage It costs nothing for all men and post menopausal women to become blood donors
Iron sensitizes keratinocytes and fibroblasts to UVA-mediated matrix metalloproteinase-1
grassrootshealth.net has been promoting Vitamin D for some time. On the site is a study reporting that no one reached a toxic level (defined as 200 ng/ml) taking 10,000 IU per day. The authors state they believe you'd have to take 50,000 IU per day for a number of months to reach a toxic level. From reading various papers on that site, I concluded that the optimum level is probably around 100 ng/ml or so and there probably isn't much benefit from higher levels than that.
I think I first became aware of the possibility of a Vitamin D deficiency from the "Security Now" podcast (it's normally about computer security) by Steve Gibson and Leo Laporte. Steve is the inventor of the Gibson Light Pen for the Apple ][ and the author of SpinRite, a hard disk utility. His Vitamin D page is at http://www.grc.com/health/vitamin-d.htm . Steve (who was born in 1955) tried to increase his Vitamin D by sun exposure, but found, as is the case for most people over 50, that it didn't work for him, so he takes supplemental Vitamin D. I buy the same brand he mentioned (Now Foods) from iherb.com as they had the best price I could find. Costco also sells gel caps for about the same price per capsule, but they use soy oil whereas Now Foods uses olive oil as the solvent.
Is there not a risk of skin cancer with using sunbeds?
The winter sun is useless you live quite close to the equator, since the the sun is to low in the sky and the UV-B radiation is to low.
For those who want to believe that UK health professionals are practising evidence based medicine this paper may come a bit of a shock given that over the past 5 years there have been some 2500+ papers on the topic roughly 50 each week far too many for me to keep up with.
Background Current recommendations for the treatment of vitamin D deficiency vary from calciferol 800 IU per day to loading doses of vitamin D followed by maintenance therapy of up to 2000 IU per day.
Objective To assess the preparations and doses of vitamin D used to load and maintain patients with serum 25-hydroxyvitamin D (25OHD) <25 nmol/l.
Methods We examined all requests for serum 25OHD over a 12-month period, from September 2009 to 2010 in southwest Scotland. We wrote to all 33 general practices asking whether they usually started replacement therapy with a loading dose and/or recommended over-the-counter maintenance preparations. We accessed the Emergency Care Summary for all patients with serum 25OHD <25 nmol/l to determine whether they had been prescribed maintenance therapy.
Results Serum 25OHD was requested in 1162 patients. Levels were <25 nmol/l in 282 (24%) patients, only 173 (61%) of whom were receiving vitamin D replacement therapy 3–15 months after diagnosis. Only four (1.4%) were prescribed a loading dose. One hundred and fifty-three (54%) were treated with cholecalciferol or ergocalciferol and 19 (7%) with alfacalcidol or calcitriol. The median dose of chole/ergocalciferol was 800 IU per day, usually in combination with 1200 mg calcium per day.
Conclusions We have shown a divergence between clinical practice and even the most conservative expert advice for vitamin D replacement therapy.
Part of the problem is that UK drug companies won't/can't supply cholecalerol Vit D3 which is the effective human form (presumably the fact a years supply of 5000iu daily should cost no more than £15 is a bit of a disincentive. They have ergocalciferol available but as that works out around £2400 they are reluctant to put people on it.
The idea that any UK GP could order a bulk supply from reputable FDA approved manufacturers in the USA at cheaper prices than you and I can negotiate is not surprising given the tendency of UK health professionals to rip of the NHS whenever given the chance.
we all know, nature is the best supplier of all vitamins and minerals. but now a day destroy all the nature energy, read every one this article. i am waiting for articles like this.
£20 to UK addresses, £25 outside the UK.
I haven't yet used this service but I will do ASP and let you know the results but for UK readers I'm sure this is the CHEAPEST source of 25(OH)D testing and as they also offer this for overseas customers it may well be the cheapest option for other readers.
I had increased from a 1000 IU's tablet form to five NOW Foods 1000 IU's in olive oil for three months. I had spread the five 1000 IU softgels out between three meals. We can't get a 5000 IU in Canada or have it shipped from Amazon.
I also eat canned sockeye with the bones pretty much daily and sometimes fatty fish twice daily plus 200 IU's with my calcium citrate/magnesium supplement and 200 IU's in my multivitamin. All D3.
My doctor said it is okay for me to continue with this amount but once we have lots of sun should decrease to 2000-3000 IU's daily. I am being retested in six months. When winter returns I'll probably be taking 4000-5000 IU's to maintain a good level. Or at least that is the tentative plan.
I have had melanoma in 1999 (Clarks level 2 Breslow 0.25mm). She wants me to wear 35-45 SPF but then I won't get the D right? I also have celiac disease.
Any opinions/comments on my plan?
Thanks
I'm sure you are aware that New South Wales Australia is at latitude 33S and in the Southern Hemisphere for various reasons, the UVB is about 10% stronger than in the equivalent latitude in the northern hemisphere so somewhat more effective than in Los Angeles or Damascus. If 5000iu/d is more successful than less in NSW I would be interested in hearing your doctor's explanation of why less is required in Canada which is somewhat north of Los Angeles.
It would also be helpful if your Government stopped interfering in ways that disadvantaged their population and prevented or deterred them from taking advantage of cheap effective strength D3 from the US discount providers.
The calculator is a bit on the optimistic side.
For Northerly latitudes we have to remember this is a heat driven process and wind chill factor may make the process impracticable although theoretically possible.
Do remember also that to achieve the 125nmol/l (50ng/ml) level at which human milk is a complete vitamin d replete food for human babies and at which human DNA would keep vit d equilibrium if we lived naked outdoor lives takes more like 1000iu/vitamin d3 daily for each 25lbs you weigh.
It's not surprising human skin, given full body sun exposure and midday summer sun exposure creates 10,000~20,000iu in just a relatively short time.
Typically at latitude 50N an extra 5000~10,000iu/daily may be required in addition to vit d from food/and urban sunlight.
An easy rule of thumb guide to whether sunlight is likely to provide adequate UVB for vitamin D3 production is that providing your shadow is SHORTER than you are tall it's possible.
When shadow LENGTH is DOUBLE your standing height there is too little UVB and too much UVA so it's more likely to process any Vit d near skin surface into suprasterols the body doesn't use.
In the intervening period, when shadow length is greater than height but not twice your height then you are probably doing more good than harm.
I think it's also worth pointing out that city or urban atmospheres, living near busy roads or under airport runways may mean the amount of particulates in the atmosphere are blocking UVB to the extent that vitamin D production is reduced. I am not aware of any calculator that will help with this. There are Vitamin D lightmeter devices (at a price) that will tell you the UVB/UVA reaching ground level and this is the only way you can know for sure.
Also remember UVB acts on the 7 dehydroCHOLESTEROL molecule in your skin.
So if you take statins these act on the Mevalonate pathway and reduce the production of many other substances apart from just cholesterol.
If cholesterol production is lowered by statins it's inevitable that 7-Dehydrocholesterol ~ CoQ10 ~ testosterone ~ etc are also lowered. So the amount of 7-Dehydrocholesterol in your skin also comes into the equation.
Thanks so much for your excellent website. I've recently started lchf and believe this is the answer to many of my problems, chiefly obesity (50 lbs. overweight), high bp, aches and pains of age etc.--76 yrs. old). After only 5 days I've lost some weight, sleep better, feel better, and am VERY hopeful, and NEVER hungry.
But about vitamin D. For several years I had two dangerous bouts with bronchitis (which three times developed into pneumonia) and would mean sleeping in a chair for two or more weeks. I live in Georgia, USA and don't get much sun in winter. I had begun to think bronchitis/ pneumonia would someday kill me; I got sick so frequently that my dr. left a standing prescription of antibiotic and steroid. That was nearly two years ago. I began taking 5000 units of D3 and have had one case which I stopped immediately with the dr.'s prescriptions. Since then (one year and 1/2) I haven't had to use them. I take 5000 to 10000 a day, when I can remember. The reason I take so much is that I read that 20 minutes of full-skin exposure to summer sun creates 20,000 units; so I don't fear an overdose. Thanks again for you work.
Blessings, Richard
And it seems to be a reasonable explanation to this, becuse you get it mostly by grass.
I.E. for humans food that have eaten fresh grass.. now a days our food eats soy!
So to think about if one take D-3, eat grass feed meat, grass feed pigs, grass fedd hens/eggs!
Or take K2 to your D-3.. at least if you take high doses.