One of my favourite larder essentials, this deep yellow spice is a member of the ginger family, and native to India. It’s joyful boost of colour and curried perfume adds a touch of exotic, and I use it in many of my southern Asian recipes. Besides being used for thousands of years to flavour Middle Eastern and Indian dishes, turmeric was an integral part of traditional medicine with it’s supposed medicinal properties. From anti-inflammatory to anti-oxidant activity, recently this ‘healing spice’ has returned to the limelight, garnering a rejuvenated reputation as a ‘super food’.
The yellow pigment of turmeric is due to a compound called curcumin and is generally acknowledged to be turmeric’s principal active component. While historically turmeric has been used for medicinal purposes, over the past years there have been a number of studies that has brought it back into the spotlight, suggesting that it may have anti-inflammatory and anticancer activities. In addition to it’s direct antioxidant activity, curcumin may also inhibit inflammatory enzymes, as well as increasing the amount of glutathione, another important free-radical busting antioxidant. Current research is focussing on curcumin’s antioxidant activity on inflammation, thought to be associated with Alzheimer’s disease, cancer and auto-inflammatory diseases. These studies seem to provide concrete evidence of the virtues of turmeric, but unfortunately digging deeper gives slightly less substance to these accolades. The preliminary trials have been promising, but more human trials are still needed before we can fully justify the extent of turmeric’s current reputation in the media.
One big issue is the poor bioavailability of curcumin. When we consume it, it is absorbed into our bodies, but most of it is broken down into metabolites before getting to the bloodstream. This has meant many studies in vitro (in a lab dish) have had exciting results, but aren’t necessarily translated into the human and animal trials. Most of the studies available have been based on between 2g-7g of isolated curcumin, and as a consequence, 3.6g have been suggested to be a sufficient amount of curcumin to provide activity in vivo (animal testing and clinical human trials). Curcumin makes up about 3.1% of turmeric by weight, so to translate that into recipe ready turmeric, you would need to consume 110g of turmeric on a daily basis. That is one heck of a lot of turmeric. If you’re finding it hard to visualise, imagine two to three of those spice jars you would pick up at the supermarket.
You can however, optimise the bioavailability of curcumin in two ways. One is through the addition of black pepper, which has been shown to increase the bioavailability of curcumin by 2000%. There is a compound in black pepper called peperine, which inhibits the metabolism of curcumin in the liver and intestinal wall, allowing it to pass into the bloodstream. Even a small amount can cause the blood levels of curcumin to dramatically increase. Tumeric is also fat-soluble, which means when it is consumed with fat, it bypasses the liver and is absorbed directly into the bloodstream through the lymphatic system.
In this way, tumeric (with black pepper) can be one spice to add to a diverse diet along with other whole foods and spices, rather than just consuming on it’s own in excessive amounts. Try adding it to your smoothie with some avocado, or add some black pepper to your next Thai curry.
Please check with your doctor if you are planning on adding tumeric to your diet on a daily basis if you are taking medication, as both pepper and curcumin can block some drugs from being metabolised effectively.