Updated: Jul 21
You may have used turmeric in cooking, particularly South Asian and Middle Eastern dishes.
A relative of ginger, this staining bright yellow-orange spice has been used as medicine in places like India for centuries.
More recently, turmeric has been described as a super food.
There are plenty of health conditions whereby the benefits of turmeric are being explored as an anti-inflammatory, anti-oxidant, anti-microbial, anti-viral, anti-parasitic and even an anti-depressant.
We are going to focus only on the effects of turmeric on the gut and the microbiome in this article.
The Effects of Tumeric Upon the Gut
Curcumin is the main curcuminoid found in turmeric, and is a bright yellow phytochemical.
A Random-effects meta-analysis based on three studies and 326 patients found curcumin to have a beneficial effect upon IBS-type symptoms, although this was not statistically significant (1). Other studies have suggested that turmeric may help to reduce IBS symptoms, and is also being explored as a potential benefit in the management of inflammatory bowel disease
Tumeric is thought to activate bowel motility, and carbohydrate colonic fermentation. It is also suggested that curcumin may significantly affect and restore an imbalance of the gut microbiome.
To explore this theory further; a group of people were enrolled in a double blind, randomised, placebo controlled pilot study that involved taking either turmeric root, or curcumin preparations at 3000mg/day, twice daily for 8 weeks vs a placebo (5)
Using gut microbial DNA sequencing, it was found that both turmeric and curcumin changed the gut microbiota in a very similar way, with the study suggesting that curcumin was the main ingredient in both treatment groups driving this change.
Although the gut microbiota response to treatment was highly individual, most subjects taking curcumin found a 7% increase in observed bacterial species post treatment compared to -15% in their placebo group. “Responsive” subjects defined a signature involving uniform increases in species of both polysaccharide-degrading and hydrogen-consuming bacteria including Clostridium spp., Bacteroides spp., Citrobacter spp., Cronobacter spp., Enterobacter spp., Enterococcus spp., Klebsiella spp., Parabacteroides spp., and Pseudomonas spp.
There was also a theme of reduced abundance of several Blautia spp. and most Ruminococcus spp. species.
It is clear that more evidence is needed in regards to the effects of turmeric and curcumin upon the gut.
This could allow us to understand the complex interactions between gut microflora and curcumin, providing a better understanding of its therapeutic efficacy.
Bioavailability of Curcumin
Curcumin is considered to have a poor bioavailability; meaning that it passes through the body unmetabolised.
A study found that out of 72 Tumeric samples, including powders and commercial supplements there was a significant variation in the chemical composition of these products, especially for ones where ‘turmeric extract’ was advertised.
It was found that the manufacturing practices involved in the production of turmeric food supplements are critical stages to obtain high-quality final products. (6)
In light of the evidence that the small amounts of curcuminoids in turmeric powder are very poorly bioavailable, culinary quantities of turmeric powder added to foods for sensory purposes are unlikely to provide meaningful health benefits for the conditions reviewed and it is preferable to obtain a high quality supplement should you be considering turmeric supplementation.
Is it Safe?
Both Turmeric and curcumin are considered nonmutagenic and nongenotoxic.
Oral use of turmeric and curcumin did not have reproductive toxicity in animals at certain doses. Studies on humans have also not shown any toxic effects, and was found to be safe up to dosages of 6 g/day orally for 4–7 weeks.
Moreover, oral bioavailable formulations of curcumin were safe for human at the dose of 500 mg two times in a day for 30 days, but there are still few trials and more studies are needed regarding dosage of supplementation and this is likely to be quite individual to people and products . This is why following manafacturers recommendations for supplementation is currently the most appropriate suggestion.
To evaluate, curcumin is known as a generally safe substance although the higher the dose, the more that adverse effects such as gastrointestinal upsets have been reported.
Cautions to Consider
Turmeric is a natural blood thinner. You shouldn’t take turmeric if you take drugs that thin your blood or if you have an upcoming surgery.
Turmeric may also lower blood sugar, lower blood pressure, and is not recommended for gall bladder problems.
Taking turmeric for a long period of time or in high doses may increase your risk of indigestion, nausea, and diarrhoea. If so, this treatment may not be the best approach for you.
Turmeric has also caused liver damage in mice when taken long term. No liver damage has been reported in human studies.
If you’re on any medication, talk to your doctor before you begin any herbs or supplements, especially herbs such as turmeric that can interact with many different medications.
Women who are pregnant or breastfeeding shouldn’t use excessive amounts of turmeric. Anything more than what’s typically used when cooking is considered excessive for pregnant and breastfeeding women.
There’s a risk of allergic reaction with all natural remedies and health supplements. If you experience any symptoms if allergic reaction including hives, a fast heart rate, or difficulty breathing after using turmeric, you should discontinue use. If your symptoms are severe, you should seek medical attention.
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Gut love to you all
Cat & Rosie, Registered Dietitians
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