1. All subjects had normal vitamin D levels, not so for the average person
2. Monthly dose is exactly the opposite of how an average person would take vitamin D
3. As mentioned, it doesn’t rule out benefits, seen in other studies, by not even attempting to follow previously used successful protocols

I was similarly immune when I used to travel internationally for work about once a month, to diverse places around the world. I did this continuously for about 4 years. After an initial breaking in period, I found I was broadly resistant to colds. My guess is that my immune systems was being exposed to a wider variety of bugs and so was better primed. The hell of permanent jet lag is not worth it though.

What this tells me, is New Zealanders are not very healthy people, and must have very compromised immune systems. Or, do I just hang around a healthier bunch of people?

This study proves nothing, one way or the other, to me. I’ll keep taking my Vit D every morning. I use the Carlson’s drops – might try putting it on my skin, in the crook of my elbow, instead of orally. Heard this might be more beneficial. I need to think about how to test this before I start though.

Cheers

“In conclusion, we report that monthly administration of 100 000-IU doses of vitamin D3 did not reduce the incidence or severity of URTIs in healthy, predominantly European adults with near-normal vitamin D levels. Further research is required to clarify whether there is benefit from supplementation in other populations and with other dosing regimens.”

The authors acknowledge that in another recent randomized controlled trial, Mongolian schoolchildren lowered their RTI incidence by 50% with only a 300 IU daily supplement. In that case, the D3 was added to milk served in school – whether that was first thing in the morning or later in the school day, I don’t know.

I think I could walk down the street and randomly select 322 people who, over the next 9 months, would not have 1,204 incidents of UTI. That is just a crazy number.

I think there were some not so healthy individuals in the trial who skewed the numbers in both groups. I wonder if the incident of UTI per individual participant is in the report? Not just the average per all participants. Did everyone contract 3 UTIs? Or, half contract 6, and the the other half none? Or, a third 9?

I would also like to see the serum Vit D levels of each individual participant, so you could compare those who contracted a UTI versus those who didn’t, those who contracted more than the average versus those who contracted less than the average. Averaging everything out skews the effect, one direction or the other.

Think of all the people you know and work with, are they really sick more than 3 times a year? From any cause, let alone UTI? I’m not buying it. I can’t remember the last time I had a UTI, let alone 3 or more in 9 months. I’ve been taking Vid D regularly for over 4 years, and haven’t had a single cold, or the flu.

This calls for Raspberries, instead of Cheers

Seth: My criticism is reasonable whether or not my idea that time of day matters is true or supported by evidence. It surprises me that a serious scientist would take one null result as seriously as Linder does, not recognizing that there are dozens of possible explanations of that result that do not assume Vitamin D is worthless.

Bio-hacking, self experimentation, what ever you want to call it, may have some of the same biases (placebo effect), but not as likely (you may think something worked, but not long after discover maybe not, and try something else). After all, it’s your health you’re tinkering with, not some abstract population.

Cheers

So the initial idea behind taking Vitamin D was that if people who spend all day indoors and a lot of their time under artificial light get depressed or have trouble sleeping especially in the winter, they might be missing that daily pulse of sunlight. if you give them back a big pulse of Vitamin D *as if* they were getting lots of morning/midafternoon sun, they might get back on track. Like a pacemaker. Feel more awake in the morning, feel more tired around bedtime, sleep better through the night.

Lots of anecdotal evidence (and a few studies) suggest this actually works – that people who take a daily dose of D early in the day sleep better and feel better and get fewer colds. But if it works, the expected mechanism is that the *timing* of the D improves your sleep quality and quantity, and we know that people who sleep well have a stronger immune system and get fewer colds or recover faster from the ones they get.

One massive *monthly* dose of D does NOT simulate what the sun does to us, so it doesn’t fit the pattern that is thought to improve sleep/mood/immune system response. Nor does D taken in the evening, or taken at random times.

Seth: I believe this because (a) I never noticed any effect of Vitamin D until I started taking it early in the morning and got the dose right (a weaker dose had no clear effect), (b) cases where people changed the time of day they took Vitamin D and noticed a big change in sleep (Tara Grant’s original observation), (c) cases where people started taking Vitamin D in the evening and their sleep suddenly got worse, (d) cases where people started to take Vitamin D in the morning and their sleep suddenly got better, and (e) persistent failure of big Vitamin D studies that do not control time of day to find effects of Vitamin D. Five sorts of findings.