SGU Episode 377

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SGU Episode 377
8th Oct 2012
(brief caption for the episode icon)
SGU 376                      SGU 378
Skeptical Rogues
S: Steven Novella
B: Bob Novella
R: Rebecca Watson
J: Jay Novella
E: Evan Bernstein
Quote of the Week
For my part, whatever anguish of spirit it may cost, I am willing to know the whole truth; to know the worst and provide for it.
Patrick Henry
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Forum Discussion

Introduction

You're listening to the Skeptics' Guide to the Universe, your escape to reality.

This Day in Skepticism (1:20)

• October 5 1945: Curse of the billy goat placed on Chicago Cubs

News Items

The Physics of Roulette (4:22)

• MSNBC: Scientists explain how physics can tilt the odds in roulette

Vitamin D and the Common Cold (14:28)

• BBC News: 'No proof' Vitamin D Stops Colds

S: All right, well, the next news item is about another vitamin that doesn't help with common colds.

J: Is this – is this vitamin D we're talking about?

B: Yeah, vitamin D, oh man.

E: Delta.

S: Yeah, so I guess D is after C in the alphabet, right? So –

E: Last time I checked.

S: Yeah,vitamin C doesn't work for common colds and now we're on to vitamin D doesn't work for common colds either.

E: Guess what's next?

S: (chuckles)

J: Washing your hands, that's – there's a vitamin wash. There you go.

S: There are actually very good reasons to suspect that vitamin D supplements may be helpful for a number of respiratory conditions: chronic obstructive pulmonary disease, COPD; or asthma, or even upper respiratory infections. Vitamin D classically is important for bone homeostatis and bone health, calcium regulation, but it's been found that it also is an important cofactor in certain aspects of the immune system for certain proteins in the immune system and vitamin D deficiency could impair immune system function. So therefore, it stands to reason that supplementing may be beneficial. The existing research was, however, recently reviewed, and it showed that there is no current evidence that just routinely taking vitamin D decreases the risk of getting a cold or the duration of getting and there was the largest study conducted to date. So this was 161 people in the vitamin D group; 161 in the control group; it was double-blind, placebo-controlled, and they followed subjects for 18 months, over an 18-month period. The vitamin D group had no advantage over the placebo group; both groups got about 3.7 colds per person over that period of time. 3.7 in the vitamin D group; 3.8 in the placebo group, so no statistically significant difference.

E: Steve, what do you think of these numbers: 161 people, 18 months. Are we talking a large enough sample size?

S: That's reasonable; I mean, the rule of thumb is 50 people in each arm is a reasonably powered study for most ef– it depends on the effect size you're looking for, but for a clinically relevant moderate effect size – rule of thumb, 50 people in each group is – is good. So this is 161 in each group; it's not a massive study, but it's perfectly reasonable; large enough, certainly, to have detected a clinically relevant effect. Obviously, you can't rule out a tiny effect; that would be too small to measure with that many people, but that's probably not clinically relevant either. This is probably not the last word on vitamin D and all respiratory effect because there is some reasonable plausibility here. There is some preliminary evidence to suggest that maybe it is helpful with COPD, for example. One big question in all of this research is: Does supplementing vitamin D only with those who are vitamin D deficient or insufficient, or will it also help with people who have a normal level of vitamin D to begin with? Probably, it seems that, if there is a beneficial effect, it's probably limited to those people who are low in vitamin D. Many people, their vitamin D levels do dip in the winter because we have less sunlight exposure and that's also when the flu's going around and kids are in school and passing germs around and people get more colds. Taking a vitamin D supplement to prevent the dip in your vitamin D levels over the winter is not unreasonable. But certainly this study shows that it's not – obviously a panacea; it's not helpful taking – taken routinely. One criticism of this study was that this was conducted in New Zealand and New Zealand gets more sunlight during their winter than maybe other parts of the world, and so the question is: do the results of this study extrapolate to–

E: To the Northern Hemisphere?

S: Yeah, parts of the world, or just farther away from the equator in either direction so that you have less sunlight exposure during the winter. That's, I think, a pretty minor criticism; you know, holding out for an effect. I think if there were any effect they still would've seen something with this size study. If people want to repeat it in higher latitudes, then that would be reasonable, it would seem. Vitamin D's been very interesting in the last ten years; we've discovered a lot more about it, above and beyond the classical view of it. Taking vitamin D supplements does seem to help reduce the incidence and severity of autoimmune diseases like Multiple Sclerosis. We've been paying a lot closer – I know we've talked about it before on the show^{[link needed]}; we've been paying a lot closer attention to vitamin D, adjusting the levels that we think are the minimum normal levels and increasing the recommendation for supplementation. I definitely find that – that physicians, primary care doctors, and others who are checking vitamin D levels a lot more often now, it's almost become routine, and then recommending supplements for those whose levels are very low. So that's been a pretty significant change just over the last four or five years, which is interesting, but doesn't prevent the common colds. If you're concerned about it, what I would recommend is just having your levels checked and if it's low, supplement it; if it's not low, don't worry about it. That seems to be the bottom-line recommendation at this point.

Harpooning Satellites (19:42)

• BBC News: UK Design to 'Harpoon' Old Satellites

Bee Brains (30:50)

• Bee Brains Help to Make Robots Smarter

Science or Fiction (50:44)

Item #1: Recent research supports the claim that the rise in allergies in recent decades is due excessive cleanliness and hygiene Item #2: Theoretical physicists claim that quantum mechanics supports the notion that an event can be both a cause and an effect of another event Item #3: Recent study shows that commonly prescribed Beta Blockers do not protect against heart attack and stroke

Skeptical Quote of the Week (1:06:34)

For my part, whatever anguish of spirit it may cost, I am willing to know the whole truth; to know the worst and provide for it.

Patrick Henry

References