“Love it or hate it, Marmite could stop the spread of MRSA”, reports The Daily Telegraph.
The news is based on the results of a laboratory study which found that vitamin B3, which is found in a number of food products such as Marmite, can increase the ‘germ-killing’ activity of a certain type of white blood cell known as neutrophils. This in turn could help prevent or treat infection with so-called superbugs such as MRSA (meticillin-resistant staphylococcus aureus).
However, the claims that Marmite can treat these types of infection is ‘spreading it on a bit thick’. The concentrations of vitamin B3 used by the researchers were far higher than is found in both Marmite and vitamin B3 supplements.
It is also important to point out that the majority of the research was carried out in mice, so the results may not necessarily be replicated in humans.
At the current time there is no evidence that eating Marmite, other dietary sources of vitamin B3, or vitamin B3 supplements, could treat or prevent bacterial infections in humans.
Further clinical trials will be required to confirm whether vitamin B3 is safe and effective in humans.
Also, people should not start taking high doses of vitamin B3 unless they have been recommended to do so by a doctor, as it is not safe or suitable for everyone.
How health journalism works
The fact that most of the news sources that reported this story used Marmite in their headline appears to be the result of several papers using news copy syndicated from the Press Association (PA) summarising the research.
In the published research paper, no mention of Marmite, or similar products, is made.
It is unclear whether this is a canny piece of journalism by PA trying to add some flavour to a rather dry piece of research, or a public relations exercise for the journal that published it – or even by Marmite manufacturer Unilever.
The Independent (online edition) is explicit in its use of PA copy, while some other papers do not state this, despite having uncannily similar copy and word-for-word quotes.
Where did the story come from?
The study was carried out by researchers from Cedars-Sinai Medical Centre, UCLA and Oregon State University in the US, the National Cancer Institute of Singapore and the University of Muenster in Germany. It was funded by a Burroughs-Wellcome Career Award, the US National Institutes of Health, an A*STAR Investigator grant and Deutsche Forschungsgemeinschaft.
The study was published in the peer-reviewed Journal of Clinical Investigation.
The results of the study were generally accurately reported in much of the media. However, all of the UK news sources had misleading headlines about Marmite. Although Marmite is a good source of vitamin B3, the papers go on to state that much higher B3 concentrations were used in the study than could be obtained from Marmite. It seems odd that the papers reported this fact, yet stuck with the Marmite headlines. Claims by The Sun that Marmite can also ‘boost brainpower’, ‘heal the heart’, and ‘prevents hair loss’, should also be taken with a pinch of salt.
The BBC News made the best job of reporting this story – by avoiding any mention of Marmite.
What kind of research was this?
This was laboratory based research, which used blood samples from humans, and a mouse model, to investigate ways of altering the immune system so that infections could be prevented and cleared.
The researchers state that a particular protein (known as C/EBP ε) is required for the production of white blood cells. They say that people with a particular genetic mutation do not produce the correct protein, so they are particularly susceptible to infection from Staphylococcus aureus bacteria.
They wanted to test whether this protein – produced in greater amounts or made more active – might help fight and prevent infection.
Vitamin B3 (also known as nicotinamide) has been demonstrated to stimulate the production of similar proteins to C/EBP ε. So the researchers tested the effects of vitamin B3 treatment upon blood samples from humans and mice and live mice that were infected before or after with Staphylococcus aureus.
What did the research involve?
The researchers took blood samples from 12 healthy volunteers, as well as white blood cells that were extracted from the bone marrow of mice. These samples were pre-treated in the laboratory with vitamin B3 before being cultured (grown) with Staphylococcus aureus.
Two groups of mice were used in the study:
- normal (wild type) mice
- genetically engineered mice, which were deficient of the C/EBP ε protein
The researchers then looked at the following scenarios:
- whether mice pre-treated with vitamin B3 would be more resistant to infection from Staphylococcus aureus
- whether treating mice with vitamin B3 who were already infected by the bacteria would help clear out the infection
- whether vitamin B3 would help treat human blood samples that had been contaminated by Staphylococcus aureus
Two strains of Staphylococcus aureus were used:
- ‘normal’ Staphylococcus aureus
- methicillin-resistant Staphylococcus aureus (MRSA) – a strain that has evolved resistance to one or more antibiotics
What were the basic results?
The researchers found that vitamin B3 treatment could increase the immune response to Staphylococcus aureus by up to 1,000 times, mainly by increasing the ability of a type of white blood cell (neutrophils) to kill the bacteria. Vitamin B3 was also effective in treating infected human blood samples, and at both preventing, and treating, infection in normal mice.
Further laboratory analysis demonstrated that vitamin B3 increased the activity of C/EBP ε in the white blood cells of normal mice, suggesting that this was the way in which vitamin B3 was achieving its infection-fighting effects. vitamin B3 was found to be effective against both ‘normal’ Staphylococcus aureus and MRSA in these circumstances.
Conversely, in the mice who were genetically engineered to be deficient of the C/EBP ε protein, vitamin B3 was not effective in treating, or preventing, Staphylococcus aureus infection. This suggests that vitamin B3 would not be effective in treating humans who had a similar mutation.
This concentration of vitamin B3 used to treat human blood has been previously been used in other clinical trials, suggesting that this dosage would be safe for use in humans.
How did the researchers interpret the results?
The researchers concluded that they have demonstrated that nicotinamide (vitamin B3) “can improve host defense and thereby promote bacterial clearance”.
This study has found that vitamin B3 can increase the killing activity of a certain type of white blood cell (neutrophils), leading to the prevention and treatment of Staphylococcus aureus infection. It appears to have this effect by enhancing the activity of a particular protein that is essential for white cell development. Vitamin B3 was demonstrated to be effective in human blood samples that were infected with Staphylococcus aureus, and in the prevention and treatment of infection in a live mouse model. The treatment was also effective against a particular strain of MRSA that was tested.
Vitamin B3 (nicotinamide) is already used in the treatment of B vitamin deficiencies, and this study used concentrations of vitamin B3 that have been tested in clinical trials, suggesting that it would be safe for human use. However, this concentration is much higher than could be obtained by eating Marmite. In fact, the study does not mention Marmite at all. Further clinical trials will be required to confirm whether vitamin B3 is effective for the prevention and treatment of infections in humans, and to determine its safety and optimum dosing strategy.
Overall, this study provides no evidence that eating Marmite or other sources of vitamin B3, will stop the spread of the super-bug MRSA in humans.