In the Christmas issue published on bmj.com today, Professor Sir Malcolm Green explains: "a review of a historical study from 1848 reveals that cod liver oil was an effective treatment for tuberculosis."

1,077 individuals with consumption (tuberculosis) were enrolled to participate in the study conducted by physicians at the Hospital for Consumption, Chelsea (now the Royal Brompton Hospital). 542 participants received standard treatment with cod liver oil, while 535 (controls) participants received standard treatment without cod liver oil.

Results from the study revealed that between the two groups, improvement rates were similar, the disease was stabilized in 18% of participants who received cod liver oil, in comparison with only 6% of participants in the control group. In the control group deterioration or death occurred in 33% of patients compared with 19% of patients given cod liver oil.

According to Prof. Green, some children are still given cod liver oil today. This may be because cod liver oil was prevalently used to treat and prevent tuberculosis in the late 19th and early 20th centuries.

The decrease in tuberculosis mortality is generally attributed to enhanced living conditions. Reduction in transmission might be due to less overcrowded living. According to Green, nutrition was probably as vital. He explains:

"It could well be that the widespread use of cod liver oil encouraged by doctors played a significant part.

Cod liver oil is a rich source of Vitamin D, which we now know is important in fighting infections, as well as preventing conditions such as rickets.

A role for Vitamin D in combating tuberculosis gives a rational basis for sunshine therapy, which was widely practiced for patients in sanatoriums before chemotherapy became available, as vitamin D is synthesized in the skin when exposed to the sun. Patients were put out on their beds to lie in the sun in summer and winter, and many were sent to Switzerland and other sunny countries for treatment."

Today several individuals who develop tuberculosis in the UK are lacking vitamin D.

Green concludes that because tuberculosis is still a prevalent infection, killing millions of individuals each year around the world, there might be a role for vitamin D supplements in fighting this awful disease.

Written by Grace Rattue