Vitamin D pills show no common cold benefits for people with sufficient vitamin levels

By Stephen Daniells

- Last updated on GMT

Related tags: Vitamin d

Vitamin D pills show no common cold benefits for people with sufficient vitamin levels
Mega-doses of vitamin D once per month did not reduce the number of upper respiratory tract infections (URTIs), compared to placebo, but would differences have been observed in people with lower levels?

New data published in the Journal of the American Medical Association​ (JAMA​) indicated that a monthly dose of 100,000 IUs of vitamin D3 for 18 months was associated with the same number of URTIs per participant, the duration of symptoms, and the number of days of missed work as the placebo group.

In an accompanying editorial, Jeffrey Linder, MD, from Brigham and Women’s Hospital and Harvard Medical School, Boston, said the results of the VIDARISstudy “suggest that vitamin D should join the therapies listed in the Cochrane reviews as being ineffective for preventing or treating upper respiratory tract infections in healthy adults.”


However, such conclusions were challenged by renowned vitamin D researcher Michael Holick PhD, MD, from Boston University Medical Center. Dr Holick told NutraIngredients-USA: “This trial showed that people who were already vitamin D sufficient did not receive an additional benefit from vitamin D supplements.”

The average blood levels of vitamin D of the study participants at the start of the study – measured by 25-hydroxyvitamin D (25-OHD) levels - was 29 ng/mL. Sufficient levels are 30 ng/mL or above.

The new study should not mean that people stop taking vitamin D supplements, said Dr Holick. “What we still do not know is whether supplements of vitamin D would alter the rate of upper respiratory tract infections in people with deficient or insufficient levels of the vitamin.”

Dr Holick added that the evidence suggested it would since it is well-known that children with rickets had significantly higher incidences of upper respiratory tract infections.

This point was noted by the authors of the VIDARIS study - David Murdoch, MD, et al. from the University of Otago in New Zealand: “It is possible that an effect may be observed in a population with a higher prevalence of vitamin D deficiency, as occurred in a recent trial of vitamin D supplementation to reduce exacerbations of chronic obstructive pulmonary disease.

“In that trial, vitamin D supplementation significantly reduced exacerbations only in patients with baseline 25-OHD levels less than 10 ng/mL.”

Continue supplementation

Cara Welch, PhD, Sr VP, scientific & regulatory affairs for the Natural Products Association (NPA) told this website: “We’ve seen vitamin D supplementation have a beneficial effect on those who are truly deficient and this study is not set up to change this understanding.

“The investigation of vitamin D will continue and I would expect to see follow-up studies looking at daily intakes as opposed to monthly administrations or looking at populations who are truly vitamin D deficient.

“In the meantime, consumers should not be dissuaded from taking vitamin D supplements.”
Study details

Dr Murdoch and his co-workers followed 322 healthy people in New Zealand from February 2010 until November 2011. Participants were randomly assigned to receive an initial dose of 200,000 IU oral vitamin D3, then 200,000 IU one month later, then 100,000 IU or placebo every month for 18 months.

Results showed that average 25(OH)D levels increased from an initial level of 29 ng/mL to 48 ng/mL in the vitamin D group.

During the course of the study, 593 URTI episodes were documented in the vitamin D group and 611 in the placebo group.

Statistically, there were no significant differences in the average number of URTIs per participant (3.7 per person in the vitamin D group and 3.8 in the placebo group), the average duration of symptoms per episode (12 days in each group), and the average number of days of missed work as a result of URTIs.

Real world

In his editorial, Dr Linder added: “The VIDARIS trial, which assessed upper respiratory tract infections as they actually occur in the real world, demonstrated that vitamin D supplementation does not reduce the incidence of respiratory tract infections in adults who have sufficient levels of 25-OHD.

“In developed countries, for bone health, most persons should already have daily vitamin D intake sufficient to achieve adequate 25-OHD levels. Those seeking preventive interventions for the common cold are likely to be similar to the participants in the VIDARIS trial.”

Source: JAMA
2012, Volume 308, Number 13, Pages 1333-1339, doi:10.1001/jama.2012.12505
“Effect of Vitamin D Supplementation on Upper Respiratory Tract Infections in Healthy Adults: The VIDARIS Randomized Controlled Trial”
Authors: D.R. Murdoch, S. Slow, S.T. Chambers, et al.

Editorial: JAMA
2012, Volume 308, Number 13, Pages 1375-1376, doi: 10.1001/jama.2012.13130
“Vitamin D and the Cure for the Common Cold”
Authors: J.A. Linder 

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vit d and colds

Posted by marie lopckie,

The Otago study:
As in other studies of nutrients,doses of Vit D achieved levels of vit D hardly likely to boost immune system much.
75 to !00ng/ml level has already been suggested as a desirable level for NZ-- to be advised years hence, much more than the (average) 50ng/ml achieved at the end of survey.
This is not significantly up from the start of (average)29ng/ml, when compared with the over 300ng/ml found in lifeguards in Queensland considered to be healthy. It takes a long time to build up levels.
M H Lockie
107 Wilton St

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Health Food Manufacturers' Association (HFMA) response

Posted by Health Food Manufacturers' Association (HFMA),

"A study published this week in JAMA found that the monthly administration of 100,000 IU of vitamin D (2.5mg) did not reduce the incidence or severity of upper respiratory tract infections in healthy adults. However the study participants already had a good vitamin D status and a beneficial effect cannot be ruled out in those with poor vitamin D status. Vitamin D is known to have a role in immune response and it is therefore important to maintain a healthy vitamin D level in the body." said Graham Keen, HFMA Executive Director.

"This is further emphasised by a study published in the American Journal of Clinical Nutrition, reported in April 2011, which showed that nearly 90 per cent of white Britons, aged 45, have vitamin D deficiency during winter and spring[1]. There had also been a sharp rise in childhood cases of the bone disease rickets due to low vitamin D levels[2]. To help remedy this situation, the NHS advised that the use of Vitamin D supplements and specific foods can help to maintain sufficient levels, particularly in people at risk of deficiency[3]."

“The findings of this latest study should not detract from this NHS advice. Vitamins and minerals are essential for good health and wellbeing and, in an ideal world, our diet would provide us with all the vitamins and minerals that our body needs for good health. But evidence from the National Diet and Nutrition Survey shows that a significant proportion of the UK population simply doesn’t achieve nutritional sufficiency through diet alone. As such, daily supplements provide important nutritional insurance for millions of users looking to safeguard their nutritional intake.”


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pysiological production vit D

Posted by Danielle Cook,

I agree with Randy re the body only produces approximately 10,000 IU vit D daily. The dosage given (and was it D3 or D2) should have been lower, and given on a more consistent basis.
Danielle Cook MS, RD, CDE

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