There have been loads of pseudo-science posts and infograms on facebook lately all about the wonders of turmeric so I thought I’d take a little look at some of the claims and see if there was actually any scientific evidence for them.
Turmeric is a spice used in Asian cooking and gives curry dishes that yellow colour. It’s been used as a medicinal herb in India for hundreds of years and recent studies are starting to back up some of the claims that it contains medicinal compounds. These compounds are called curcuminoids, and the most important is curcumin, which is the main active ingredient in turmeric. Curcumin has powerful anti-inflammatory effects and is a very strong antioxidant, however the turmeric only contains about 3% curcumin. Most of the studies actually use an extract which lifts the dosage of curcumin to 1g at a time.
It would be almost impossible to reach these levels just by using turmeric in your food. So IF you decide you want to reap the benefits of this spice you are probably better off taking an extract which contains curcumin, in high levels. To further complicate matters curcumin isn’t easily absorbed into the bloodstream so even taking the supplement may not give you the benefits. Studies have shown though that consuming the substance piperine (found in black pepper) can increase absorption by up to 2000 % (Planta Medica Journal), so taking it together with whole peppercorns may help.
Inflammation is an important response of the body that helps it fight infection and repair damage, and short-term inflammation is beneficial, however chronic (or long-term) inflammation can be a problem and can result in the body attacking it’s own tissues. Studies have demonstrated that chronic, low-level inflammation plays a role in many diseases e.g. heart disease, cancer, Alzheimer’s, metabolic syndrome (Journal of Clinical Investigation, Nature). So it’s certainly important to consider ways to combat this.
Curcumin is strongly anti-inflammatory, and in fact matches some commercially produced anti-inflammatory drugs (Alternative Medicine Review). In–vitro (i.e. test tube) studies have shown that curcumin acts on a molecular level and blocks a transcription factor (NF-κB) which “turns on” genes which cause inflammation in many chronic diseases (Journal of Biological Chemistry, Journal of Melanoma Research). Human trials have taken place and suggest that doses of 1 – 8g of curcumin per day may have an anti-inflammatory effect so it seems promising (Journal of Alternative and Complementary Medicine). Other studies have shown that curcumin regulates numerous transcription factors, cytokines, protein kinases, adhesion molecules, redox status and enzymes that have been linked to inflammation at low cost with few side effects (International Journal of Biochemistry and Cell Biology).
We’ve all heard about how good anti-oxidants are for us, they protect our bodies from free radicals which are highly reactive molecules with unpaired electrons that can interact with DNA, fatty acids and proteins in the body causing ageing, damage and disease. Curcumin has been shown to neutralise free radicals (Advances in Experimental Medicine and Biology) but it also boosts the activity of the body’s own antioxidant enzymes (Journal of Applied Toxicology) so it’s offering a double whammy.
Neurons are capable of forming new connections, and in some parts of the brain even multiplying and increasing in number. One of the main drivers of this process is a type of growth hormone, called Brain-Derived Neurotrophic Factor (BDNF) and many brain disorders such as Alzheimer’s and depression have been linked to reduced levels of this hormone (Journal of Biological Psychiatry, Neuron Journal). Studies in rats have indicated that curcumin can increase brain levels of BDNF (Journal Brain Research, and Journal of Behavioural Brain Research). Recent Epidemiologic data has shown that regular curcumin intake may be related to better cognitive function in healthy elderly people too. This suggests it may be effective at delaying or reversing age-related decreases in brain function and brain diseases (PLOS one Journal). In rat studies it has even been shown to increase brain function and improve memory (Journal of Biogerontology) so there may be a whole lot of potential out there.
Curcumin has beneficial effects on several factors known to play a role in heart disease (International Journal of Cardiology). But the main benefit is that it improves the function of the endothelium (the inner lining of blood vessels). Heart disease often involves the inability of the endothelium to regulate blood pressure and blood clotting etc (Basic Research in Cardiology). A study of postmenopausal women showed the consumption of curcumin combined with aerobic exercise significantly improved endothelial function (Journal of Nutrition Research) and another study showed it to be as effective as the drug Atorvastatin (Drugs Journal). Other studies have shown it can help coronary artery bypass surgery patients by reducing the risk of experiencing a heart attack by up to 65% (American Journal of Cardiology).
This is probably the one you’ve all read about. There is some evidence that curcumin can suppress proliferation of a wide variety of tumour cells – but the doses tested were up to 10g a day (Journal of Anticancer Research). On the molecular level curcumin has been shown to inhibit cancer cell growth, development and spread (Cancer Letters Journal). Studies have shown that it can reduce angiogenesis (growth of new blood vessels in tumours), metastasis (spread of cancer), as well as contributing to the death of cancerous cells (the AAPS Journal).
It’s not fully understood why it has this effect on cancer cells and not normal cells but it may be due to the fact that cellular uptake of curcumin is higher in tumour cells than in normal cells, also glutathione levels are lower in tumour cells making them more sensitive to curcumin. In addition most tumour cells produce a growth factor (NF-κB) that normal cells don’t and curcumin suppresses this.
Most studies are all in the lab or involve animals but there are a few limited human clinical trials which show some promise for cancer treatment and prevention in humans (Journal of cancer research and Current Medicinal Chemistry Journal). One study of 44 men displaying lesions in the colon (which sometimes are the precursors to colon cancer) showed that consumption of 4g of curcumin daily for 30 days reduced the number of lesions by 40% (Journal of Cancer Prevention Research). So this should all be viewed with caution at this stage, and it’s certainly not a miracle cure but it does look promising and is being tested in many other clinical trials already so watch this space!
Alzheimer’s is the most common neurodegenerative disease in the world and as there is no really effective treatment at present prevention is key. Curcumin can cross the blood-brain barrier, which means it may be useful in brain-related conditions (Annals of Indian Academy of Neurology). We know that inflammation and oxidative damage play a role in Alzheimer’s and as I mentioned before curcumin can reduce both (Journal of CNS Neuroscience & Therapeutics). One key factor in Alzheimer’s is the buildup of proteins called amyloid plaques – and curcumin has been shown to help reduce these buildups (Journal of Alzheimer’s disease). Human trials are limited though so much more study needs to take place.
As curcumin is a great anti-inflammatory it’s not surprising that it may also help with arthritis. One small study of 45 patients showed that in patients with rheumatoid arthritis, 500mg of curcumin a day was more effective than traditional anti-inflammatory drugs (Journal of Phytotherapy Research). Another study over 3 months found that supplementation of 200mg curcumin per day helped to improve walking distance and inflammation in osteoarthritis patients (Panminerva Medica Journal). Given the safety of curcumin and lack of side effects it’s certainly something worth trying if you do suffer from arthritis.
A really interesting study of 60 patients diagnosed with depression over 6 weeks showed that taking 1g of curcumin per day was as effective as taking Prozac. Although this is a small study it once again shows the potential of curcumin. Depression can be linked to reduced levels of brain-derived neurotrophic factor (BNDF) and the reduction in the size of the hippocampus (a part of the brain which is involved in memory and learning) Curcumin boosts BNDF levels, and the brain neurotransmitters serotonin and dopamine (Journal of Psychopharmacology and European Journal of Pharmacology) all of which act to reduce depressive thoughts and feelings.
Take home message
So the take home message? Is turmeric a wonder food that’s going to cure chronic illness, prevent cancer and treat depression… not really… Is there a compound found in turmeric that may do some of this – yes! All in all curcumin seems to have a lot of potential and it doesn’t seem to have any significant side effects which makes it a great supplement to consider taking. Throwing a tsp of turmeric in your smoothie etc isn’t going to do any of this though – so if you’re looking for the health benefits then get yourself a high strength supplement (ideally one that also contains piperine or bioperine to allow absorption by the body). If however you love the taste and colour turmeric brings to your food then sprinkle that sh*t all over it!
So all in all curcumin sounds like a pretty good thing to be taking!