Could curry spice boost brain cell repair?
“Spicy diet can beat dementia,” is the unsupported claim in the Daily Express. Researchers found that the spice turmeric stimulated the growth of neural stem cells in rats, though this is a long way from an effective dementia treatment for humans.
This was laboratory and animal research investigating the effect of a turmeric extract (aromatic turmerone) on neural stem cells (NSCs). NSCs have some ability to regenerate brain cells after damage, but usually not the damage caused by degenerative brain diseases such as Alzheimer’s disease.
The study found that when the turmeric extracts were either directly cultured with NSCs in the laboratory (in vitro) or when they were directly injected into the brains of live rats (in vivo), the extracts increased the growth and development of the stem cells.
However, this research is in the very early stages. We don’t know whether this apparent increase in stem cells would have any effect on repairing brain damage in rats with degenerative brain diseases, let alone humans with these conditions. We certainly don’t know that eating turmeric, or other spices, would have any effect on the brain’s powers of regeneration.
Though the researchers hope these findings may pave the way towards new treatments for degenerative brain conditions, this is likely to be a long way off.
Where did the story come from?
The study was carried out by researchers from Institute of Neuroscience and Medicine, Research Centre Juelich, and University Hospital of Cologne, both in Germany. The study was supported by the Koeln Fortune Program/Faculty of Medicine, University of Cologne and the EU FP7 project “NeuroFGL.”
The study was published in the peer-reviewed Stem Cell Research and Therapy on an open access basis, so it is free to read online.
The quality of the Daily Express’s and the Mail Online’s reporting of the study is poor. Both sources claim that eating curries can "beat dementia". These claims are entirely unproven and are at best sensationalist, and at worst cruel for giving people false hope.
BBC News and ITV News’ coverage takes a more appropriate tone, pointing out that any potential human application at this stage is entirely hypothetical.
What kind of research was this?
This was an animal and laboratory study, which aimed to investigate the effect of Aromatic (ar-) turmerone on brain stem cells.
Ar-turmerone and curcumin are active compounds of the herb Curcuma longa, or turmeric as it is more commonly known. Many studies (such as a study we covered in 2012) have suggested that curcumin has anti-inflammatory effects and may have a protective effect on brain cells, though the effects of ar-turmerone are yet to be examined.
Neural stem cells (NSCs) have some ability to regenerate brain cells that have been destroyed or damaged, but usually are insufficient to repair the damage caused by degenerative brain diseases (such as Alzheimer’s) or stroke.
This research aimed to investigate the effects of ar-turmerone on NSCs in brain cells in the laboratory and in live rats.
What did the research involve?
In the first part of the research, NSCs were obtained from the brains of rat foetuses and cultured in the laboratory. Ar-turmerone was added to the cultures at various concentrations and studied for a number of days to look at the rate of stem cell proliferation.
In the second part of the research, a group of male rats were anaesthetised. Three then received an injection of ar-turmerone into the brain; six were injected with an equal volume of salt water. After recovery from the anaesthetic, the animals were put into cages and given free access to food and water as normal.
For five days following the surgical procedure, a tracer was injected into the animals (bromodeoxyuridine), which is taken up by replicating cells. Seven days after the surgery, the rats were scanned with a positron emission tomography (PET) scanner, which detects the tracer and produces 3-D images demonstrating the active cell division in the tissues.
After death, the brains of the rats were examined in the laboratory to look at how ar-turmerone had affected brain structure.
What were the basic results?
In the laboratory, the researchers found that ar-turmerone increased the number of neural stem cells. Higher concentrations of ar-turmerone caused greater increases in NSC proliferation.
In the rats, they also found that injection of ar-turmerone into the brain promoted the proliferation of NSCs and differentiation into different brain cell types. This was evident on both PET scanning and autopsy examination of the brain after death.
How did the researchers interpret the results?
The researchers conclude that both in the laboratory and in live animals, ar-turmerone causes the proliferation of nerve stem cells. They suggest that “ar-turmerone thus constitutes a promising candidate to support regeneration in neurologic disease”.
Conclusion
This laboratory and animal research has found that an extract from turmeric (aromatic turmerone) seems to increase the growth and differentiation of neural stem cells (NSCs).
However, this research is in the very early stages. So far, the extract has only been added to brain stem cells in the laboratory, or directly injected into the brains of only three rats. Though NSCs have some ability to regenerate brain cells after damage, this is usually not enough to have an effect in degenerative brain diseases such as Alzheimer’s.
The hope is that by boosting the number of NSCs, they could be more effective at repairing damage in these conditions. This study has not investigated whether the observed effects would make any meaningful functional differences in rats with degenerative brain diseases, never mind humans with these conditions.
As the researchers further caution, there are various issues to be considered when contemplating the possibility of any trials in humans. For example, it is recognised that causing the increased rate of growth and differentiation of NSCs carries some risk of cancerous change. Also, the route of administration used here in the rats – direct injection into the brain – would be likely to carry far too much risk and may not be possible in humans. We certainly don’t know whether taking turmeric extracts by mouth – or just by eating a spicy diet as the Express headline suggests – would have any effect on the brain’s powers of regeneration.
Though the researchers hope these findings may pave the way towards new treatments for degenerative brain conditions, this is likely to be a long way off.
