Friday, March 12, 2010

Proven: Viamin D Prevents the Flu -- Throw Out Your Tamiflu

by Chris Masterjohn

Well, technically we only "prove" things in math and logic, when we assume our premises. But the most recent study on vitamin D and the flu, published in the American Journal of Clinical Nutrition, gets as close to proving anything as we can get in nutritional and medical science.

Researchers from Japan conducted a double-blind, randomized, placebo-controlled trial involving over 300 school children aged 6 to 15 years old. Eight physicians were involved in diagnosing the flu among these children, spread across 12 hospitals. They randomly allocated half the chilren to take 1200 IU per day of vitamin D and the other half to take a placebo. The children took the supplements from the beginning of December, 2008 to the end of March, 2009.

Barely over ten percent of children in the vitamin D group developed Influenza A, whereas almost twenty percent developed the illness among the placebo group. This suggests that vitamin D cut the risk of developing the flu almost in half. Many of the children in both groups began taking additional vitamin D supplements after the trial was underway, however. Excluding these children from the analysis showed that vitamin D cut the risk of flu by 64 percent, or just under 2/3.

In a remarkable secondary finding, vitamin D appeared to nearly obliterate the risk of asthma attacks. Children who were previously diagnosed with asthma were six time more likely to have an asthma attack during the course of the study if they were in the placebo group. This suggests that vitamin D supplementation reduced the risk of getting an asthma attack by 83 percent.

The authors cited previous work showing that the drugs marketed as Relenza and Tamiflu only reduce the incidence of flu by eight percent. While comparing across studies is never as reliable as a study designed to compare two treatments, we can tentatively consider from this comparison that vitamin D is eight times more effective than Relenza or Tamiflu.

Vitamin D directly interacts with our DNA and tells our genes to start making more flu-killing "antimicrobial peptides." One of these, named "defensin," stops the flu virus from invading cell membranes.

The authors of the paper also cited other studies showing that probiotics (good bacteria) and a preparation of echinacea, propolis, and vitamin C helped reduce the risk of flu.

Why take shots and drugs when good nutrition gives us the immunity to illness we're supposed to have?

Read more about the author, Chris Masterjohn, PhD, here.


  1. We also use elderberry in our household during flu season, I think it's helped.

  2. Chris-

    My thoughts exactly having read about that Japanese study this week. Our 4- and 6-year-old haven't been ill (knock on wood) since we started them on 1000IU Vitamin D drops in their food. I'm not big on supplementation in general, but Vitamin D needs to be on even the shortest list of dietary adjuncts, it seems. Thanks for all of your good work.

  3. Interesting timing. My cat has had asthma off and on for a few years. The treatment of choice is prednisone/prednisolone. I was giving her 5mg/day and it was not alleviating her symptoms.

    I decided to give her a large dose of D based on human weight recommendations per the Vitamin D council, knowing well that felines do not produce cholecalciferol on their own and must get it from their diet. To my astonishment, the attacks diminished by the third day and disappeared by the fourth. She's been asthma free for a couple of weeks and slowly weening off prednisole (1.5 mg/day and soon off).

    Thanks for the report!

  4. mtflight,

    I was under the impression vit d is produced in their fur as it is in our skin, and they ingest it when they groom. Am I wrong here? That would still leave indoor cats (and all cats during vit d winter) reliant on diet. I wonder if they get barely enough to prevent overt deficiency, like most people.

  5. Hi Justin,

    I was under the same impression as yourself, and after all it would make sense being that they like sunbathing. Later I saw "Vitamin D a D-lightful Story," presented by Dr. Michael Holick at the UV Foundation website. He clearly states that felines cannot make D3.

    I would think this is quite a novel question and possibly hasn't been studied in depth, but please let me know if you come across anything contradictory to that effect as I'd like to know!

    P.S. Great presentation if you haven't seen it.

  6. Vitamin D also lowers the risk of cardiovascular disease for people who follow a weight loss program. I have read on Project Weight Loss that we should stay in the sun for 15-30 minutes to take our vitamin D. I like to have my intake of Vitamin D while I ride the bike in a sunny day. :P

  7. Hadn't seen it so thanks for the link, I enjoyed it.

  8. Vitamin D deficiency also greatly increases the susceptability of the mucosal barrier to damage and increased risk of inflammatory bowel disease (IBD).

    IBD results in decreased absorption of many vital vitamins and minerals which causes other deficiencies. For example, a study found that those with IBD had lower vitain K than controls in spite of the fact that their intake of vitamin K was the same as controls.

    IBD caused by vitamin D deficiency can cause excessive weight loss, but in my experience this fact has yet to reach main stream medical practice.

  9. Jack C, I think you meant to say decreases.

  10. Justin, I did not mean to say "decreases" for the subject is vitamin D deficiency which increases the incidence of inflammatory bowel disease, poor mineral and vitamin absorption, and can result in excessive weight loss.

  11. Ah, sorry... guess I miss the word deficiency there. Shouldn't hop on Google Reader the second I wake up, I'll be more careful next time!

  12. bariatric surgery memphis

    Vitamin D also lowers the risk of cardiovascular disease for people who follow a weight loss program. I would think this is quite a novel question and possibly hasn't been studied in depth, but please let me know if you come across anything contradictory to that effect as I'd like to know!


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