Cod Liver Oil's Incredible Immune Boosting Powers
There is abundant evidence that cod liver oil may be one of the best immune boosters that exists. Find out why it works better than lab-made vitamin supplements.
Note: much of the info for this post came from various articles in Dr. Chris Masterjohn’s Substack Harnessing the Power of Nutrients. He did his postdoctoral research on the interactions of vitamins A, D, and K so refer to his Substack for additional in-depth research.
In today’s article:
The History of cod liver oil (CLO)
The evidence in favor of cod liver oil’s immune-boosting potential
The mechanism by which cod liver oil boosts the immune system
Is taking a vitamin A supplement just as effective as CLO?
How to take CLO
Are some CLOs rancid?
What about vitamin toxicity?
History of cod liver oil:
Hippocrates mentions the use of fish oils as medicine.
In 1771, the British physician Thomas Percival showed that cod liver oil was more effective than a placebo at treating rheumatism.
Around 1799, physicians began using it to effectively treat rickets (a disease caused by vitamin D deficiency).
By the 1800s, cod liver oil was used to effectively treat eye infections and tuberculosis, the leading cause of infectious death.
In 1848, the Royal Brompton Hospital in London published the results of the first five years of using cod liver oil (CLO) to treat tuberculosis. The British Medical Journal revisited these results in a 2011 article Cod liver oil and tuberculosis. Results showed that patients treated with CLO were over three times as likely to recover from tuberculosis.
(Note: during the 1800s, physicians also began promoting the use of animal fats related to reproduction such as butter, egg yolks, and whole milk—my, how times have changed! These are also good sources vitamins A and D.)
Between 1920 and 1940, interest in vitamin A as an immune booster grew as two researchers, Sir Edward Mellanby (who discovered vitamin D) and Harry Norman Green showed through research that vitamin A protected against infections of the eyes, lungs, tongue, throat, and GI tract. Here’s one of their papers titled Vitamin A as an anti-infective agent.
Researcher Richard Semba revisited Mellanby’s work and published an article in 1999 called Vitamin A as “Anti-Infective” Therapy, 1920–1940. He concludes:
After a pause of almost 50 yr, the value of vitamin A as “anti-infective” therapy was addressed again in controlled clinical trials, and these studies provided compelling new scientific evidence for the use of vitamin A as an important public health intervention.
(For anyone wanting to do a deep dive into vitamin A, Semba expanded this research into a book: The Vitamin A Story: Lifting the Shadow of Death.)
The Evidence in Favor of Cod Liver Oil’s Immune Boosting Potential: Building up the Host Instead of Only Attacking the Pathogen
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