Lack of sunlight = B12 deficiency?

[Korn]

Hi,

in an article by dr. Gina Shaw, I read that "Vitamin B12 deficiency is usually symptomatic of a larger problem i.e. poor intestinal flora, poor absorption and also lack of sunlight." Even though lack of sunlight can lead to vitamin D deficiency, which again can cause the body to absorb less calcium, and calcium is needed for proper B12 absorption, I haven't seen any direct link between sunlight and B12 documented anywhere. Who has?

[Korn]

From http://www.mercola.com/2002/jan/30/vitamin_b12_a.htm:
'Sanders86 (1988, UK) studied the growth and development of 37 vegan children. All were breast-fed for their first 6 months and in most cases well into their second year.


The majority of children grew and developed normally but they tended to be smaller in stature and lighter in weight than the general population. Energy, calcium, and vitamin D intakes were usually below the recommended amounts. Their diets were generally adequate with a few children having low intakes of riboflavin and B12.

Most parents knew to supplement the diet with B12. Sanders concluded that provided sufficient care is taken, a vegan diet can support normal growth and development.'

B12 is needed for growth. And, again: Calcium is needed for B12 absorption, and lack of vitamin D is bad for your calcium intake. Most people spend too much time indoors (most of us work indoors at the time of the day when there is most sun), which will influence our calcium, and therefore our B12 intake. Most of these vegan kids were low in both calcium and vitamin D, and tended to be smaller in stature. This isn't necessarily a bad thing –*there is no reason to use the height of meat-eaters, who also consume a lot of dairy products, as a reference for how tall humans should be. Calfs have a much higher growth rate than humans, so consuming cows milk, even after the age when babies normally are not breast feed anymore, most likely can over-stimulate growth in humans. This kids were also lower in weight than average children which isn't at all a bad thing, since overweight is a growing problem among children.

It is interesting that they were low in calcium and vitamin D. It is not difficult to get enough calcium from a balanced vegan diet, but we need exposure to sunlight to get enough vitamin D. Some hundred years ago, most people were staying outdoor a lot, and lack of glass meant less windows, which made outdoor life much more attractive (more light), in addition to the fact the humans needed to go out to collect food, whether they were hunting, fishing or collecting/growing plants.

If you come across Gina Shaw (at the Summerfest?), please say hello from me and ask her about sources for the link between lack of sunlight and B12 deficiency. I find it likely to be correct, but would like to know more about this...

[eve]

I can't see how lack of sunlight is linked with B12 deficiency. Where I live it is sunny every day all year round, yet a few of my friends, who incidentally are meat eaters, have a B12 deficiency. Their doctors give them injections, plus they are told to eat more meat!

[snaffler]

Not sure about the B12 thing I seem ok there, but I think I suffer in the winter when we have very little sun light in the UK and I am serioulsy getting to the stage in my life and cosidering a move to sunny places.

It hit me hard this winter, but funnily it only takes one sunny day to lift me and my spirits. Although a good regular exercise pattern I have taken on the last 12 months has made a huge change, I still need my sunlight to keep me on top of things.

[Korn]

I can't see how lack of sunlight is linked with B12 deficiency. Where I live it is sunny every day all year round, yet a few of my friends, who incidentally are meat eaters, have a B12 deficiency.

I don't know if sun is linked with B12 deficiency, but even if it is, people who get enough sun might be exposed to lots of other things that reduce their B12 intake or disturb the absorption...