Turmeric: a powerful weapon against disease or just a tasty spice?

It is news that should warm any curry lover’s heart: eating spicy food may be good for your health — that is, if it contains turmeric, the bright yellow spice used in many Asian dishes.

You may think you’ve heard this before — after all, aren’t half the herbs and spices in your cupboard meant to offer magical health benefits? What makes turmeric different is the increasing body of laboratory research that demonstrates its potential to affect a wide range of disease including cancer, dementia and arthritis.

So what is it?
The powdered turmeric you find you in your curry comes from the ground root of Curcuma longa, a plant from the ginger family. There are several different components of turmeric, but most research has focused on a compound called curcumin which shows the greatest biological activity. Turmeric also contains oils which are thought to be active too, but these are less well studied.

Alzheimer’s disease
Although there have been a number of studies that show curcumin can prevent and break down amyloid-beta plaques, a hallmark of Alzheimer’s disease, there have been limited trials in humans.

One such trial carried out by researchers at Edith Cowan University in Perth was published earlier this year. They gave 96 volunteers either a curcumin supplement or a placebo three times daily for a year. The results were promising, but the study was small and only lasted a year, so the long-term effects could not be assessed.

It seems, as with other turmeric research, there is still a great deal of work to do and the Alzheimer’s Society says that turmeric is unlikely to prevent or relieve Alzheimer’s disease.

Joint arthritis
Osteoarthritis is the most common type of arthritis and is commonly treated with analgesics, steroids, and other anti-inflammatory drugs.

Traditional Chinese and Ayurvedic medicines use turmeric as an anti-inflammatory to treat arthritis in patients. There are thousands of studies on osteoarthritis and turmeric but only a limited number of human clinical trials.

A recently published meta-analysis in the Journal of Medicinal Food found only eight randomised controlled trials using turmeric or curcumin that met their criteria. The researchers did find that the evidence suggests that curcumin helped treat arthritis but they also concluded that, because of the small number and quality of the trials published, they could not definitively conclude that curcumin really does treat arthritis.

Cancer
There have been a number of studies looking at turmeric as a treatment and so far the best results have been observed in breast, bowel, stomach and skin cancer cells in laboratory studies.

Like Alzheimer’s research, the challenge is moving from the laboratory to human subjects and Cancer Research UK says there needs to be more clinical trials before curcumin can be used to treat cancer in patients.

Research is also being carried out to see whether turmeric can be used to prevent cancer.

Dr Lynne Howells, a research fellow at Leicester University’s Experimental Cancer Medicine Centre, uses curcumin in her work in translational research, which in practice means getting a drug or a compound out of the laboratory and into patients.

She said: ‘Curcumin was chosen for a number of reasons. Epidemiological research reveals that bowel cancer is up to eight times less common in India than it is in the UK. There are obviously many different contributing factors that affect disease incidence, but it has been known for a very long time that turmeric derivatives have anti-inflammatory and anti-septic properties.’

Her team are interested in curcumin and turmeric derivatives for their potential cancer chemoprevention properties — that is, the ability of a drug to prevent or delay growth of cancers. This is of particular interest in populations that may be at high risk for certain types of cancer.

She explained: ‘Food–derived chemicals have potential in this setting, because you need to give a drug to someone every day over a long period of time to prevent or delay disease occurrence, and so these chemicals must be proven to be safe and tolerable for anyone taking them – turmeric has been consumed for centuries, so there is plenty of evidence for this.’

Dr Howells and her colleagues are particularly interested in cancer stem cells, thought to be the cells that make the cancer resistant to chemotherapy drugs and drive tumour growth. They have also done a number of clinical studies in healthy volunteers and cancer patients that investigate levels of curcumin in the blood stream.

One of the challenges facing research into turmeric-derived products is funding clinical trials. These trials are expensive and pharmaceutical companies that fund or sponsor a trial usually own a patent on the drug tested, so there is some prospect of recovering the cost.

Dr Howells explained: ‘This is not the case for turmeric derivatives, so at the moment it is unfortunately very difficult to undertake clinical trials large enough to give us definitive answers to the curcumin question.’

So should you add a daily dose of turmeric to your diet for your health? The answer seems to be no, not unless you fancy a good curry to cheer yourself up.

Despite the number of studies, research into turmeric in the human body is still in its infancy and, although there are some promising early results, those all-important clinical trials need to be carried out before we can be sure that turmeric works as well in the human body as it does in the laboratory.