"Will You Live Longer if You Take Vitamin D Supplements?"
In 1822, a Polish physician was the first to publish
that sunlight could cure the vitamin D deficiency disease: rickets.
His work was ignored by mainstream medicine for a century,
not coming into widespread use until the 20th century, when wire cages were
affixed to tenement buildings so babies could benefit from the sun.
Are we in a similar situation now,
where the medical profession has just not caught up with the science?
Researchers have documented correlations
between all sorts of good things to higher vitamin D levels,
even to the point of seeing whether vitamin D supplementation
might reduce the adverse effects of earthquakes.
Seems to help with everything else, so why not?
It's actually not as silly as it sounds.
Traumatic events like natural disasters can have a significant psychological impact,
which may be affected by vitamin D status.
But when researchers put supplements to the test,
the purported links often didn't pan out.
This lack of effect may exist in part because low vitamin D levels
may just be a marker for things like aging, obesity, smoking, and inactivity.
Or maybe low vitamin D didn't lead to disease, but maybe disease
led to low vitamin D --- inflammation can drop D levels within the body.
So just because low D levels and disease seem to be correlated
doesn't mean that vitamin D deficiency is the cause.
While the majority of observational studies may show a link,
where you just measure D levels and disease rates, in only a handful
of conditions have interventional studies proven vitamin D to be effective,
where you give people D supplements or placebos and see what happens.
But one of those conditions for which vitamin D supplements
appear to genuinely work is helping to prevent mortality.
56 randomized clinical trials, involving nearly 100,000 people
between the ages of 18 and 107, mostly women,
randomized to four years of vitamin D supplements or sugar pills.
Put all the studies together and those given vitamin D supplements lived longer,
also specifically lowering the risk of dying from cancer.
Note this effect appeared limited to vitamin D3 though,
the type derived from plants and animals,
not vitamin D2, the type derived from yeast and mushrooms.
How large an effect was it?
It would take 150 people taking vitamin D supplements for 5 years to save one life,
and so if we were talking about a drug,
you'd have to weigh that against the cost and
side effects of dosing so many people.
But when we're talking about something as safe and cheap
as vitamin D supplements it seems like a bargain to me.
A similar analysis pegged the benefit at 11% in terms of
reduction of total mortality, which is pretty substantial,
potentially offering a life extension benefit on par with exercise.
Though no, it does not seem to reduce the adverse effects of earthquakes.
The only concern that was raised is that it may give people license
to like order an extra doughnut or something.
We still have to eat healthy.
Any longevity benefit from vitamin D would just be a small adjunct to a healthy lifestyle.
But for those of us who want all the help they can get,
the question then becomes OK, how much should we take?
The question I'll address next . . .