Turmeric, a spice widely used in South Asian cooking, contains curcumin, a compound researchers are studying for its potential effects on inflammation, blood sugar, cholesterol and other aspects of health. However, evidence remains insufficient to establish that turmeric supplements can prevent or treat most diseases for which they are promoted.
The spice comes from the underground stem of Curcuma longa, a plant in the ginger family. Curcumin gives turmeric its characteristic yellow-orange colour and is responsible for much of the scientific interest in its potential medicinal properties.
Research has examined whether turmeric and curcumin could help people with conditions including osteoarthritis, diabetes, cardiovascular disease, depression and Alzheimer’s disease. Findings vary by condition, and promising results from laboratory experiments do not necessarily translate into proven benefits in people.
The US National Center for Complementary and Integrative Health (NCCIH) says there is not enough evidence to draw definitive conclusions about turmeric or curcumin for most health conditions.
What research says about turmeric’s potential benefits
Joint pain and inflammation
Turmeric and curcumin have been studied for their potential to reduce inflammation and ease joint pain, particularly in people with osteoarthritis, a condition that causes pain and stiffness when the protective tissue in joints deteriorates.
Some clinical studies have reported improvements in knee pain, stiffness and physical function among people taking turmeric or curcumin preparations. However, researchers say larger, higher-quality studies are needed to establish how effective these products are, which formulations may work and whether their benefits persist over time.
The findings do not establish turmeric as a replacement for prescribed arthritis treatment.
Blood sugar and diabetes
Studies have investigated whether curcumin supplementation can improve blood sugar regulation and insulin resistance, a condition in which the body’s cells respond less effectively to insulin, the hormone that helps control blood glucose.
A 2023 systematic review and meta-analysis examined 59 randomised controlled trials involving turmeric or curcumin supplementation. The researchers reported improvements in several measures of blood sugar regulation, including fasting blood glucose and glycated haemoglobin, a measure of average blood sugar levels over roughly two to three months.
However, the studies used different formulations and doses, making the results difficult to translate into a standard treatment recommendation. Evidence that a supplement improves some blood sugar measurements does not establish that it prevents diabetes complications or controls the disease reliably.
People with diabetes should not replace prescribed medication with turmeric supplements.
Heart health and cholesterol
Researchers have also examined curcumin’s potential effects on blood fats and other cardiovascular risk factors.
Some studies suggest that supplementation may influence cholesterol levels and markers of inflammation. But changes in individual measurements do not necessarily mean that a person faces a lower risk of heart attack, stroke or other cardiovascular events.
There is not enough evidence to conclude that turmeric prevents heart disease.
Depression and anxiety
Curcumin has been studied as a possible complementary treatment for depression and anxiety, partly because of its potential effects on inflammation and other biological processes.
Some small clinical studies have reported improvements in depressive symptoms among people taking curcumin. The evidence remains limited, however, and does not establish turmeric as an effective stand-alone treatment for depression or anxiety.
People experiencing persistent mental health symptoms should seek advice from a qualified health professional rather than relying on supplements alone.
Alzheimer’s disease and cognitive decline
Laboratory and animal studies have examined whether curcumin could affect processes associated with Alzheimer’s disease, including the accumulation of abnormal proteins in the brain.
These findings have prompted interest in whether the compound might help protect cognitive function. However, the results have not established that turmeric prevents Alzheimer’s disease or slows its progression in people.
The NCCIH says clinical evidence supporting curcumin supplements for preventing dementia or Alzheimer’s disease remains insufficient.
Cancer research
Curcumin has attracted scientific interest because laboratory experiments suggest it may affect inflammation, cell signalling and other processes involved in cancer development.
Researchers have investigated its potential role in cancer treatment, including whether it could help reduce certain treatment-related side effects. However, studies in people have generally been limited by small participant numbers, short follow-up periods and differences in the products and doses used.
There is currently insufficient evidence to recommend turmeric or curcumin supplements as a treatment for cancer. They should not replace cancer treatment prescribed by an oncology team.
How turmeric is used
Turmeric is commonly added to curries, soups, sauces and other dishes. It can also be consumed in drinks, including turmeric milk, or taken as a dietary supplement.
The amount of curcumin in food varies, and turmeric supplements may contain substantially different concentrations of the compound. Researchers also face a challenge because curcumin is poorly absorbed by the body when taken orally.
Some products contain additional ingredients, such as piperine from black pepper, to increase absorption. Greater absorption does not automatically mean greater health benefits, and it may also increase the risk of adverse effects.
There is no universally established dose of turmeric or curcumin for treating the range of conditions for which the supplements are marketed.
Safety concerns and possible side effects
Turmeric used in ordinary food quantities is different from concentrated supplements. Conventional oral turmeric or curcumin products are generally considered likely to be safe for most people when taken in recommended amounts for up to two or three months, according to the NCCIH.
Possible side effects include nausea, vomiting, acid reflux, stomach discomfort, diarrhoea and constipation.
Some formulations designed to increase curcumin absorption have been associated with liver injury. The risk is particularly relevant to concentrated products promoted for their enhanced bioavailability.
People taking medication or managing an existing health condition should consult a qualified health professional before starting turmeric supplements because herbal products can interact with medicines. People who are pregnant should avoid medicinal-dose turmeric supplements unless advised by a health professional, as their safety in pregnancy is uncertain.
Although turmeric has a long history of culinary and traditional medicinal use, that history does not establish that it can prevent or cure disease.
The evidence so far supports continued research into curcumin, particularly its possible effects on inflammation and metabolic health. For most other proposed uses, larger and better-designed clinical trials are needed before firm conclusions can be drawn.
