Contents
What it is
Turmeric is the rhizome of a perennial in the ginger family. It is a close relative of ginger and looks much like it, but the flesh inside is a vivid orange. It is native to India and Southeast Asia. That colour comes from curcumin, and it accounts for most of the yellow in curry. Curcumin barely dissolves in water and is poorly absorbed on its own, which is why the traditional practice of cooking it with fat and pepper is so often explained in terms of absorption. The pigment is strong enough to stain hands and dishes.
Scientific name Curcuma longa
Only about 2–5% of turmeric powder is curcumin. When trials report improvements in joint pain or inflammatory markers, they typically use 500–1,500 mg of curcumin a day, which would mean tens of grams of the powder. A bowl of curry does not get you there.
On top of that, curcumin barely dissolves in water and is metabolised quickly by the liver. So any honest discussion of turmeric's benefits has to start with absorption.
Key benefits
- Moderate evidence
It reduces joint pain
A meta-analysis of 16 randomised trials in 1,810 people with knee osteoarthritis found turmeric extract improved pain (standardised mean difference -0.82) and physical function over placebo, and matched NSAIDs for effect while causing 12% fewer adverse events. It is the most consistent finding in the turmeric literature. The trials disagree substantially, though (I² 86%), and carry moderate risk of bias, so the true effect remains uncertain.[1]
- Moderate evidence
It lowers inflammatory markers
Multiple studies report drops in markers such as CRP and IL-6 after curcumin supplementation. The effect was clearest in metabolic syndrome and other chronically inflamed states, and modest in healthy people.[2]
- Early research
It eases indigestion
In functional dyspepsia, turmeric has beaten placebo on symptom scores. The effect is thought to relate to its stimulation of bile flow.[3]
- Moderate evidence
It supports antioxidant defences
Curcumin neutralises free radicals directly, but it also raises the activity of the body's own antioxidant enzymes — and that second route is probably the more important one. A meta-analysis of 66 randomised trials found higher total antioxidant capacity and SOD activity alongside lower MDA. These are blood markers, not disease outcomes.[2]
How to eat it well
- Add black pepper. Piperine substantially raises curcumin's bioavailability. A pinch per teaspoon of turmeric is enough.
- Pair it with fat. Curcumin is fat-soluble; coconut oil, olive oil or a milk-based golden latte all work on this principle.
- Keep the heat brief. A quick bloom in oil is ideal; long boiling causes losses.
- For cooking, 1–2 teaspoons (3–6 g) a day is a realistic range. Beyond that you are in supplement territory, where dose and purity need checking.
- Fresh turmeric root can be grated like ginger. It stains hands and boards, so be warned.
How to read the grades
Each benefit carries a label showing how far research on people supports it. Grades differ between items even within the same ingredient.
- Nutrition data
- A fact verifiable from food composition databases or health authorities. This is a different kind of statement from a clinical effect.
- Strong evidence
- Consistently confirmed across randomised controlled trials or meta-analyses.
- Moderate evidence
- Human studies exist, but effect sizes are small or results are mixed.
- Early research
- Cell or animal work, or small preliminary studies.
- Not established
- Commonly claimed, but not confirmed in studies on people.
What to watch out for
- Avoid it with gallstones or bile duct obstruction, since it stimulates bile flow.
- Combined with anticoagulants, it may raise bleeding risk.
- Rare cases of raised liver enzymes have been reported with high-dose supplements. Check with a clinician if you have liver disease.
- Curcumin can interfere with iron absorption, which matters if you have iron-deficiency anaemia.
- Culinary amounts are fine in pregnancy; therapeutic-dose supplements are not recommended.
Nutrition
Approximate values per 100 g edible portion.
- Calories
- 312 kcal16%
- Carbohydrates
- 67.1 g24%
- Fiber
- 22.7 g81%
- Protein
- 9.7 g19%
- Fat
- 3.3 g4%
- Potassium
- 2,080 mg44%
- Iron
- 55 mg306%
- Manganese
- 19.8 mg861%
Percentages are of the US FDA Daily Value for adults and children 4 and over. National reference intakes differ by sex and age.
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Sources
The databases and health authorities this article's nutrition figures and health statements draw on.
- 1Efficacy and Safety of Turmeric Extracts for the Treatment of Knee Osteoarthritis: a Systematic Review and Meta-analysis of Randomised Controlled TrialsMeta-analysisWang Z, et al. Curr Rheumatol Rep 2021PMID 33511486
- 2Antioxidant and anti-inflammatory effects of curcumin/turmeric supplementation in adults: A GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trialsMeta-analysisDehzad MJ, et al. Cytokine 2023PMID 36804260
- 3Curcuma longa Linn versus omeprazole in treatment of functional dyspepsia: A randomized, double-blind, placebo-controlled trialClinical trialYongwatana K, et al. J Gastroenterol Hepatol 2022PMID 34652861
- 4USDA FoodData CentralFood composition database
- 5NIH Office of Dietary SupplementsHealth authority
- 6PubMedResearch literature
