Turmeric is the common name for the root-like underground stems, or rhizomes, of an Asian plant, Curcuma longa. Turmeric is best known as the yellow-orange spice – Indian gold – used to enhance Moroccan and Indian dishes, where it imparts a mild, aromatic, slightly bitter flavour and a vibrant, saffron colour.
Turmeric also has a long history of use as an effective Ayurvedic medicine. The active ingredients are polyphenols called curcuminoids, of which the majority (77%) is in the form of curcumin (diferuloylmethane). Medicinal turmeric can be concentrated to produce extracts that contain at least 95% pure curcumin.
Although curcumin was first isolated from turmeric in 1842, its chemical structure was not determined until 1910. Since then, it has become one of the most extensively studied herbal medicines, with over 9000 research papers listed on the National Institutes of Health PubMed database’
Turmeric and health
Turmeric has a long history of use as an Ayurvedic medicine to reduce inflammation, treat skin problems, boost general immunity, liver function and support weight loss.
These uses now have a firm scientific basis, with researchers identifying at least 20 ways in which curcumin interacts with cells to regulate their growth and survival, the self-programed recycling of worn out cells, and the self-destruction of abnormal cells which have the potential to form tumours.
Curcumin has a long list of potential therapeutic uses as it interacts with multiple cell signalling pathways either directly or indirectly. It can modulate the action of enzymes, hormone receptors, carrier proteins, inflammatory molecules, gene transcription factors, cell survival proteins, adhesion molecules, cell growth factors and drug resistance proteins.
It is also a broad-spectrum antibiotic.
Together, these actions make curcumin the equivalent of an ultra-smart drug; rather than targeting one particular health problem, as most drugs do, it has beneficial effects in many different conditions, including inflammatory conditions, diabetes, obesity, neurologic disorders and long-term problems affecting the eyes, liver, lungs, intestines, kidneys, heart and circulation.
Turmeric and weight loss
Turmeric is traditionally used to support weight loss. Curcumin boosts the metabolic rate of brown fat cells so they burn more fat as a fuel – this is one reason why you may find yourself sweating after eating a spicy curry.
In cell cultures, curcumin prevents the formation of new white fat cells (adipocytes) from pre-adipocytes. It also interacts with mature white fat cells to reduce the amount of fat they accumulate and suppresses their release of inflammatory chemicals.
The latest news is that curcumin also helps to regulate the production of hormones linked with obesity, such as resistin (which links obesity with insulin resistance and type 2 diabetes), leptin (the satiety hormone) and adiponectin (a hormone involved in fat breakdown).
In Ayurvedic medicine, turmeric is often combined with other herbal products such as guggul gum and coffee extracts for weight loss. In one study, a supplement that included turmeric, silymarin (from Milk thistle), guggul, coffee extracts and inulin (a prebiotic fibre found in artichokes) was added to the usual diet of 78 overweight patients with metabolic syndrome. After 4 months, this simple change helped volunteers lose around 2kg in weight, and their waist circumference reduced by 3cm.
Turmeric and inflammation
One of the main medicinal uses of turmeric is to reduce inflammation and pain. While inflammation is beneficial in the short-term, to let you know when something is wrong, in the long-term it causes persistent symptoms in conditions such as osteoarthritis, psoriasis and ulcerative colitis. Turmeric suppresses the production of TNF-alpha and other inflammatory chemicals to relieve joint pain, improve psoriasis (skin plaques and joint pain).
The fact that turmeric/curcumin can suppress TNF-alpha is astonishing, as this same molecule is the target of new TNF antibody drugs used to treat osteoarthritis, inflammatory bowel disease, psoriasis and ankylosing spondylitis. As well as being expensive these drugs must be given by injection. Curcumin is a natural alternative.
To read how curcumin is as efective as the non-steroidal drug, ibuprofen, click here.
Turmeric and psoriasis
Curcumin has beneficial effects against skin inflammation by quenching free radicals, reducing inflammation by inhibiting inflammatory chemicals (such as nuclear factor-kappa B) and regulating growth-related signalling pathways. In psoriasis, this helps to slow the over-production of cells that lead to plaque formation.
In a study involving 21 people with moderate to severe psoriasis, all received turmeric extracts for 17 days. Half also received visible light phototherapy for 14 days, while the remainder had simulated phototherapy. The combination of curcumin plus visible light phototherapy improved skin symptoms so much that none showed moderate or severe plaques after the treatment. At the end of the study period, 76% of all patients showed a response, with 81% those in the combination group showing a significant improvement compared to 30% taking curcumin alone.
The latest research shows that curcumin is especially effective in reducing psoriasis skin plaques when combined with LED blue light at a wavelength of 405nm plus red light at 630 nm or 660 nm.
Turmeric and irritable bowel syndrome
Eating spicy foods may worsen symptoms of irritable bowel syndrome, especially in women. However, turmeric is a traditional medicine used to relieve colic due to gallbladder spasm, and intestinal pain associated with irritable bowel syndrome (IBS).
A study involving 207 people with IBS assessed the effectiveness of taking turmeric extracts (72 mg or 144 mg) daily for 8 weeks. IBS symptoms decreased significantly in both groups by 53% and 60% after treatment. Abdominal pain/discomfort score reduced by 22% and 25% and around two-thirds of all subjects reported an improvement in symptoms after treatment. Although there was no placebo group, this study did show a dose-response effect despite the relatively low doses of turmeric used.
Turmeric and liver health
Within the liver, turmeric boosts the production of enzymes needed to process fat. It stimulates bile production and helps to improve fat digestion and relieve bloating. Turmeric is so effective at clearing fat from the liver, and preventing its accumulation, that curcumin is under investigation as a treatment for fatty liver disease which is often present in people who are overweight, especially in those who also have type 2 diabetes.
Turmeric and cholesterol
Turmeric reduces liver production of cholesterol and stimulates the uptake of ‘bad’ LDL-cholesterol by scavenger cells within the circulation. This effect is predicted to slow the progression of hardening and furring up of the arteries (atherosclerosis).
In a study involving 100 people with metabolic syndrome (a combination of any three of the following: high blood pressure, raised triglycerides, low ‘good’ HDL-cholesterol, high fasting blood glucose level and abdominal obesity) half had curcumin (1000 mg/day) added to their standard treatment, while the other half received an identical-looking placebo. To improve oral bioavailability, the curcumin capsules also included 10mg piperine. After 8 weeks, the curcumin group showed significantly reduced ‘bad’ LDL-cholesterol, total cholesterol and triglycerides plus raised ‘good’ HDL-cholesterol compared with placebo.
Turmeric and glucose control
Turmeric has beneficial effects on pancreatic cells to improve the release of insulin in healthy volunteers and is a promising functional food for preventing type 2 diabetes.
Turmeric and brain health
In parts of Asia where average consumption of turmeric is 1.5g per day, there is an unusually low prevalence of Alzheimer’s and other forms of dementia. Cell culture studies suggest that curcumin protects brain cells from a build-up of amyloid which is associated with some forms of dementia, although this is far from proven.
A study involving 60 people found that curcumin was as effective as the prescribed antidepressant drug, fluoxetine, for treating major depressive disorder. The response rate after six weeks treatment was 77.8% in the group receiving both fluoxetine (20mg) and curcumin (1g), 64.7% in the group receiving fluoxetine alone, and 62.5% in the group receiving curcumin alone, a result that was not statistically significant between the two interventions. Other studies also show that curcumin can improve the response to antidepressant medication.
Curcumin is believed to cross the blood-brain barrier to have an aspirin-like action against migraine, too. Some people find it helpful in preventing and relieving migraine, although this has not been studied in a clinical trial.
Turmeric and cancer
Numerous cell culture studies suggest curcumin may inhibit the development and progression of cancers by triggering the natural process in which abnormal cells are identified and programmed to self-destruct (apoptosis) without harming normal, healthy cells.
As well as targeting cancer cells, curcumin regulates cell signalling patients to help prevent tumour migration and invasion. Curcumin is currently under investigation as a potential treatment for bladder, lung, breast, prostate, liver, pancreatic, colon and ovarian cancers.
The curcumin absorption paradox
When turmeric is consumed, as little as 1% of the curcumin present in food or supplements is absorbed whole into the circulation. Of the rest, as much as 75% is excreted (you may notice an interesting discoloration on your toilet paper) and the rest is metabolised within the intestinal wall to form different metabolites such as glucuronides, sulfates, tetrahydrocurcumin and hexahydrocurcumin.
The small amount of pure curcumin that is absorbed, unchanged, travels directly to the liver where its metabolism is largely completed first time through. The end result is that very little intact curcumin is found within the circulation. Despite this, oral doses of turmeric do produce beneficial effects in other parts of the body, such as the skin and joints, even though little curcumin reaches tissues such as the skin or bladder.
This paradox lead researchers to suggest that, although the activity of curcumin metabolites is generally lower than that of curcumin, some may be equally or more active. Another possibility is that curcumin acts as a biological signal, which can prime immune cells within the intestinal wall to produce beneficial effect elsewhere in the body.
Immunity starts in the gut
One of the main ways in which foreign proteins and infections enter the body is via the stomach and intestinal tract. The gut is therefore lined with lymphoid tissue which is clustered in the walls of the small intestines in pale areas known as Peyer’s patches.
Peyer’s patches are teeming with T and B-lymphocytes which are the main white blood cells involved in regulating immune and inflammatory reactions. Each patch is capped with specialised, folded cells known as M (microfold) cells which dip their folds into the intestinal juices and take little sip-like samples of the contents. These samples of intestinal fluid are enclosed in pouch-like vesicles and presented to the waiting lymphocytes which are primed to react against potential infections and mount an immune response.
M cells are selective about the antigens they present to the waiting lymphocytes. They only present antigens that bind to molecules on their surface. This helps to avoid activating the immune system against innocuous food proteins. Curcumin interacts with numerous cell receptors and may well help to prime immune reactions in a beneficial way even if it remains unabsorbed, within the gut.
Scientists are currently investigating ways to improve the uptake of curcumin into the body, to maximise its benefits. One of these ways involves producing very small nano particles that can be absorbed intact via the M cells of Peyer’s patches.
This research has now led to the development of turmeric supplements with an enhanced formulation to boost curcumin absorption.
Improving curcumin absorption
One of the easiest ways to improve the absorption of curcumin is to combine it with something that stops it from being metabolised in the intestinal wall.
In the kitchen, for example, you simply need to combine turmeric with a pinch of black pepper. White, black and long peppercorns contain a unique alkaloid, called piperine, which blocks the glucuronidation of curcumin within the intestinal wall. This can boost its absorption into the circulation by 2000% (a forty-fold increase).
This effect was shown in 10 healthy males who took 2g curcumin powder (4x 500mg capsules) with or within the addition of 20mg piperine. Blood samples were taken over the following 5 hours to show the significantly improved absorption when the volunteers also took piperine.
I love black pepper and add lots to my curries, so it’s good to know I’m getting more than the flavour benefits.
Another way to boost curcumin absorption is to mimic advanced drug delivery systems in which turmeric is suspended in liquid capsules to produce tiny nanomicelles. These protect the turmeric from breakdown within the intestinal wall so it is absorbed 185 times better than powdered extracts – even those standardised to provide a high level of curcuminoids.
Another option is to combine turmeric with other herbal ingredients that have a complementary or synergistic action, such as green tea and pomegranate extracts designed to have beneficial effects on different organs, such as the breast, prostate, liver and pancreas, and which may even protect against certain cancers.
The form of turmeric supplement you need will, to some extent, depend on whether you are seeking an intestinal effect (for example to treat irritable bowel spasm), or want to improve its medicinal effects on other parts of the body such painful inflamed joints, or inflammatory skin patches associated with psoriasis.
Phase I clinical trials have shown that turmeric is safe even at very high doses (12 g/day).
How to add turmeric to your diet
Fresh turmeric is prepared by peeling the rhizomes, then slicing, grating, chopping or grinding the flesh to form a paste. Fresh roots can also be boiled, then dried and ground to produce an orange-yellow powder. Some products are concentrated and standardised to produce powders that contain at least 95% curcumin per dose.
If using turmeric powder, ensure it is as fresh as possible to obtain the most benefits. Ditch any old turmeric in your spice cupboard which has faded in colour or scent, and buy your spices in small quantities, little and often. Store in an airtight container in a cool, dry place out of direct sunlight.
In Ayurvedic medicine, turmeric is often prescribed at a dose of two level teaspoons of powder, stirred into coconut milk, to drink twice a day.
|Fresh turmeric roots are available on-line from Amazon.co.uk and Amazon.com if you want to use them fresh in cooking or prepare your own paste or powder.
To maximise absorption of curcumin, use turmeric in a dish that also contains white or black pepper – the piperine in the pepper makes it easier to absorb curcumin intact. As it is fat soluble, adding oil will also boost its absorption.Try mixing together 1 tablespoon freshly ground turmeric, 2 tablespoons extra virgin olive oil and 1 teaspoon freshly ground black pepper and add to soups, stews, casseroles, curries or other dishes.
Ensure your turmeric supplement is a well-known brand, made to pharmaceutical standards (GMP), to ensure it actually contains the level and purity of curcumin claimed on the label.
Supplements containing turmeric root provide a range of natural substances that evolved together within the rhizome which have complementary actions. These have a lower curcumin content and reflect the traditional Ayurvedic use of turmeric.
Products containing concentrated turmeric extracts provide a higher level of curcumins and may be more helpful for treating inflammatory conditions such as joint pains and psoriasis.
Have you tried turmeric or curcumin for general health, to boost immunity, or reduce any particular symptoms? How did you get on?
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