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Junk study on Vitamin D shows nothing much but how bad science reporting is

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UPDATED! Mea Culpa from me. The post has been corrected*.  Thanks to Rob.

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More junk reporting from the Australian government broadcaster the ABC which just copies the junk science press release. Is this what we pay $1b a year for?

The Journalists missed the key factor which was blood levels of participants.

The headline says Clinical trial finds vitamin D does not ward off colds and flu  but all it really shows is that in a group that already have *normal, non-deficient levels* of Vitamin D, taking big doses of Vitamin D once a month won’t will raise your blood levels — but won’t make a big difference to your risk of respiratory infections. And it only applies to people aged 60 -74.

Most participants in the study had a normal but sub-optimal Vit D levels and after five years of sporadic high doses, were raised to optimal levels at the end.

After taking 60,000 IU each month, supplementers apparently went from having 77.5  nmol/L up to 114.8 nmol/L,. To put this in perspective, normal levels of Vitamin D start at “50” and above, and there are professors who point out that there are many reasons to aim for Vitamin D levels of “100 – 150”.  Toxicity starts from 220nmol/L.

UPDATE: As we saw in the Brenner et al study of 10,000 Germans, when people are quite deficient (below 30 nmol/L) they are twice as likely to die of respiratory diseases as people whose blood levels are normal — defined as being above 50 nmol/L. The people who are most at risk of dying are those who are clinically deficient at below 20 nmol/L. Their risk was 3 times greater.  That study showed that a shocking 40% of all respiratory deaths might possibly be due to being deficient in Vitamin D. This new study in Queensland only shows that raising Vitamin D levels in people who are not deficient won’t make much difference.

If so-called science journalists only bothered spend five minutes reading the short summary (not even the whole paper) they could report something useful. See  The Lancet Diabetes and Endocrinology. The journalists made a big deal of how the “researchers analysed self-reported health data from 16,000 Australians aged between 60 and 84”. But the study ruled out most participants, and ended up with only 2,598 people.

I rate the study: barely worth noticing.

The shoddy work by “science communicators” is just another example of how science writing becomes de facto mere repetition of press releases which are usually dependent on government funding. No hard questions asked.

If you don’t know or care much about Vitamin D3 you may want to find out how it’s linked to all cause mortality (unlike nearly every other vitamin) : Let’s solve the other pandemic: Vitamin D deficiency — to help beat Coronavirus?

In essence 2,500 people were given 60,000 IU of Vitamin D3 or a placebo once a month and followed for five years. They kept diaries for two months each year to track colds and flu like symptoms.

Diagnostic Vitamin D levels according to the conservative Royal College of Pathologists of Australia:

Mild vitamin D deficiency: 30–49 nmol/L

Moderate vitamin deficiency: 12.5–29 nmol/L

Severe vitamin D deficiency: < 12.5 nmol/L

Some professors suggest the optimal target might be more like 100 – 150 nmol/L 

Professor Robert Heaney, says that Vitamin D “enables the body to absorb calcium” and that the level should be set at 100 nmol/L

Professor Bruce Hollis, who is a world expert in Vitamin D for pregnant women and their babies, says that the baby takes nutrients from the mother and that pregnant women should have 125 nmol/L

Recent evidence reveals beneficial effects of vitamin D at serum levels around 50 ng/mL (125 nmol/L)[6],[7],[8] or higher – effects not seen at levels below 40 ng/mL (120 nmol/L), indicating a need for upward revision of the deficiency reference threshold.

Based on the data, it is reasonable to assume that, should the threshold for vitamin D deficiency be raised to a level of 50 ng/mL (125 nmol/L), the percentage of the population determined to be deficient would most-likely be closer to 90% or greater

Another group of approximately 40 experts in vitamin D have requested through their call to action that blood levels should aim to be between 100-150 nmol/L.[9]

Even with that tiny 5nmol/L improvement in their Vitamin D3 levels, participants had slightly fewer symptoms, they didn’t get quite as sick, or for quite as long. It’s not much, but imagine what they might have achieved if they raised their D levels even to “normal”?

Lead researcher and head of QIMR Berghofer’s Cancer Aetiology and Prevention group, Professor Rachel Neale, said participants who received vitamin D supplements reported they had cold and flu symptoms for slightly less time than participants who did not take the vitamin. They also had severe symptoms for less time and needed less medication to manage their symptoms.

“Our clinical trial showed that people who took vitamin D supplements were infected with colds and flus at the same rate as those who were given placebos. Those who got the supplements did, however on average, report a small reduction in the number of days they experienced symptoms (on average about half a day),” Professor Neale said.

It worth knowing that people who take Vit D3 may want to consider adding Vitamin K as well.

h.t David of Cooyal

Posts on Vitamin D3

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*Mea Culpa!

I misread the units, and on a post criticizing bad science writing. :-(. Ouch.  The central conclusion did not change — that their reporting of the study didn’t shed much light on what the study meant, and journalists missed the most important numbers in the study (the blood levels). But it does matter, and I apologize. Most people were not deficient to start with in this study. Instead of a moderate deficiency barely being resolved to a mild deficiency, the study shows that a sub-optimal but normal level was shifted up to an optimal level. So sporadic bolus doses did raise D levels, but most people in this study were not deficient at all, so they were not at high risk of respiratory disease mortality to begin with and the study was unlikely to improve outcomes in respiratory diseases.

REFERENCES:

Brenner, Holleczek, and Schoettker, B. (2020)  Vitamin D insufficiency and deficiency and mortality from respiratory diseases in a cohort of older adults: potential for limiting the death toll during and beyond the COVID-19 pandemic, https://www.medrxiv.org/content/10.1101/2020.06.22.20137299v1

Pham et al (2021)  The effect of vitamin D supplementation on acute respiratory tract infection in older Australian adults: an analysis of data from the D-Health Trial, The Lancet, Diabetes and Endocrinology, https://doi.org/10.1016/S2213-8587(20)30380-6

 

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