Tuesday, January 28, 2014

Vitamin D: Science vs the Media

In early December, 2013, the Lancet published a paper measuring the effects of Vitamin D supplements on illness. On January 24th, 2014, seven weeks later, the media woke up and published many 'reports' on the unstudied effects of Vitamin D supplements on health (not on illness).  Should you trust the science? or the media?

The Science:

On Dec 6, 2013, the Lancet journal of Diabetes and Endocrinology (the study of hormones) published a paper titled: "Vitamin D status and ill health: a systematic review". You can click the link to see the conclusion yourself. They reported that:

"Investigators of most prospective studies reported moderate to strong inverse associations between 25(OH)D concentrations and cardiovascular diseases, serum lipid concentrations, inflammation, glucose metabolism disorders, weight gain, infectious diseases, multiple sclerosis, mood disorders, declining cognitive function, impaired physical functioning, and all-cause mortality. High 25(OH)D concentrations were not associated with a lower risk of cancer, except colorectal cancer. "

English translation: In most prospective studies, where Vitamin D concentrations are measured in patients, low Vitamin D is correlated with increases in cardiovascular disease, serum lipid concentrations, inflammation, glucose metabolism disorders, weight gain, infectious diseases, multiple sclerosis, mood disorders, declining cognitive function, impaired physical functioning, and all-cause mortality. High Vitamin D levels were associated with a lower risk of colorectal cancer, but not other cancers.

"Results from intervention studies did not show an effect of vitamin D supplementation on disease occurrence."

English: when Vitamin D was supplemented, in scientific studies, no disease effect was shown - positive or negative.

and "Supplementation in elderly people (mainly women) with 20 μg vitamin D per day seemed to slightly reduce all-cause mortality."

English: Vitamin D supplements help elderly people to live longer, but more details are not available.

and "The discrepancy between observational and intervention studies suggests that low 25(OH)D is a marker of ill health."

English: It seems (but we're not sure) that low Vitamin D is a result of ill health, but not necessarily a cause.

Important Distinction:

None of the studies measured "health".  The studies measured Vitamin D concentrations, and Vitamin D supplementation, and illness, and mortality.  There were no studies that measured health.

The News:

Note; For some reason, all of the news reports came on the same day, January 24th, more than 6 weeks after the study was published.

WebMD: "Vitamin D Supplements Don't Help Your Health: Review", by By Robert Preidt, Health Reporter. Jan 24, 2014.
- health was not measured, only illness.

International Business Times: "Is Vitamin D The ‘Sunshine’ Supplement? Study Finds Healthy People Are 'Unlikely' To Benefit ", by Zoe Mintz, Jan 24, 2014.
 - for some reason, the International Business Times chooses to put the words 'sunshine' and 'unlikely' in quotes, although these words did not appear in the actual scientific study's conclusion.
 - headline says 'healthy people unlikely to benefit'? Does that mean that the elderly people in the study who clearly benefited from longer lives - were not 'healthy' according to the International Business Times?

The Guardian Liberty Voice: "Vitamin D Supplements Do Not Improve Health", by Jean-Paul Gauthier. Jan 24, 2014.
 - health was not measured, only illness.

The Daily Mail: "Why taking Vitamin D Supplements is 'pointless'", by Jenny Hope, Medical Correspondent.
 - The Daily Mail decides to put the word 'pointless' in quotes, although it did not appear in the scientific study's conclusion.
 - Jenny ignores the evidence and goes on to reach conclusions that are not supported by the research study.

CBS News: "Vitamin D supplements won't protect against disease in healthy adults", by Ryan Jaslow, CBSNews.com Health Editor.
 - most of the studies were not of healthy adults, they were studies of disease, and supplementation effects on disease.
 - there was no attempt to determine which study subjects were 'healthy', so this conclusion has no scientific basis.

I am not a fan of conspiracy theories, but the fact that the news was reported by many organizations on the same date is difficult to explain.

How is it that the news reporters can make such simple mistakes?

Maybe the simplest answer is that scientists, and news reporters, consistently confuse 'health' with illness.  Scientific studies study illness, and the effects of specific actions (in this case, supplementation with Vitamin D) on illness.  There is no attempt made to measure health, or healthiness.  But news reporters want to report on 'health', so the attempt to translate 'illness studies' into 'health studies', and the result, frankly, is nonsense.

to your health, tracy

Tracy is the author of two book about healthicine: