Turmeric was once nothing more than a spice in the cupboard you might add to the occasional curry. Yet it`s being hailed as the new supper food that will cure everything from heartburn to food poisoning.
I am not normally won over by such claims about specific foods, but there is something potentially persuasive about this humble spice.
In countries such as India, where they consume a lot of turmeric, they have lower rates of bowel cancer. It did make me wonder: could the two be linked?
Until now, most of the research into the effects of turmeric has been conducted on mice rather than humans, using doses far higher than you would find in an average diet.
But findings have been intriguing: for instance, one U.S. study involving mice found the active ingredient in turmeric, curcumin, can help slow down the progression of breast cancer in mice.
Other studies have found it may help destroy the plaques that form in the brain associated with Alzheimer`s disease.
As part of the BBC series Trust Me I`m A Doctor, we decided to see what effects — if any — turmeric had when used in the kind of quantities you might find in a normal diet.
Part of our curiosity stemmed from the large number of emails we receive asking if turmeric could be of benefit for various conditions.
Central to our experiment was a new test devised by scientists at University College London that looks not just at genes but at how hard they are working.
It`s well known that our genes influence our risk of disease, but we now know the way our genes work can be influenced by environmental factors, such as whether or not we smoke or drink.
We wanted to see if consuming turmeric had a measurable effect on our genes, which is where the new test came in.
This test looks at `the packaging` around the genes, explains Martin Widschwendter, a professor in women`s cancer, who helped develop it. The packaging is made of three components — a complex combination of chemicals that behaves like the genes` software programme, telling them what to do.
`This packaging regulates how much work a gene does or doesn`t do,` he says.
`The test looks at the changes in the packaging, known as methylation, that allows us to predict the risk of certain diseases, depending on which genes are affected and where the genes are affected.`
In other words, this packaging is like a dimmer switch that turns up or turns down the work of that gene and in so doing influences the risk of disease. So would turmeric make any difference to this?
To find out, we recruited just under 100 volunteers in the North-East — mostly people aged 40 to 50 for whom curry did not typically form a large part of their diet — to take part in a unique six-week experiment.
We split them into three groups: one third would be given a turmeric capsule containing 3.2mg (about 1 tsp) of the spice, one third a placebo capsule and the remainder would be asked to include 1 tsp of turmeric in their diet every day.
The volunteers had a blood test before the experiment and afterwards. As well as looking at the methylation of their genes, we used another new test developed by Newcastle University to look at how well their blood cells were resisting inflammation.
The hope was this would give us an idea of how well their immune systems were performing.
The results surprised us all. For after six weeks, all the volunteers had a slight reduction in the number of their immune cells.
This, our experts thought, could be due to something as simple as the fact the weather was getting hotter as this can put pressure on the immune system (sunburn, for example, puts stress on it).
By contrast, the test looking at what was going on with their genes produced very different results. Those taking the placebo had no change, but neither did those taking the turmeric supplement.
However, the volunteers who had been adding turmeric to their food did have significant changes.
`We could see changes to a gene associated with cancer, depression and allergies such as asthma,` says Professor Widschwendter.
He adds: `The changes we saw were just in the blood — we have to say that the changes in the tissue may be different.
`However, the results were fascinating. We showed turmeric is able to reset important components of our gene`s software.`
But why might turmeric have such benefits?
One suggestion is that it affects how the enzymes that regulate methylation behave.
And why did the supplements not affect our genes, when adding the spice to food did?
Our experts thought it could be that cooking with turmeric makes it more digestible — or it could be that it needs to be taken with other nutrients found in food to be properly utilised in the body.
The fact that the volunteers added it to a whole range of foods means we can be confident that it was the turmeric and not anything else they were eating that was causing the effect.