Food Health

The Golden Spice: Understanding the Health Benefits and Risks of Turmeric

12 min read

Turmeric is a richly hued and strong-tasting spice that’s venerated on the Indian subcontinent for its spiritual significance, culinary uses, and medicinal power. And lately, it’s been marketed as a superfood supplement promising protection from disease and increased longevity. So what does scientific research say about turmeric? Does it live up to its hype? Does it have any side effects in high doses? Is it dangerously high in lead? And what’s the best way to consume it?

The International Olympic Committee sometimes adds new events to the Olympics. Recent sports being considered for inclusion are kickboxing, karate, squash, flag football, and breakdancing.

Those are all well and good, but what would seriously make my day is an Olympic event highlighting the foods that do the most to support health and longevity.

If I were a betting man, I’d put my money on the benefits of turmeric to win the gold. And that would be fitting since turmeric is known in India as “haldi,” the Golden Spice. It earned its nickname not just from its bold yellow-gold color but its associations with prosperity, purity, and good fortune.

In India, powdered turmeric features prominently in a traditional pre-wedding ceremony. Turned into a yellow paste, it’s applied liberally to the bride and groom’s bodies to bring them good fortune and ward off the evil eye. Unmarried friends and family members may also benefit, as whoever gets touched by the paste will supposedly find an attractive partner soon.

In addition to its ritual uses, turmeric has been revered in India for its powerful medicinal properties for over 4,000 years. A mainstay of Ayurveda, the Indian healing tradition, as well as Traditional Chinese Medicine, turmeric is now being extensively studied by modern science for its potential health benefits.

In fact, it’s thought that turmeric may be one of the most potent anti-inflammatory compounds ever examined. And preliminary evidence suggests it may reduce the risk of just about every major chronic condition.

As a result, turmeric has achieved virtual superfood status in the industrialized world, bottled into a variety of supplements. But is it effective in supplemental form? And if you get it through food, how much is enough? Can you get too much? And should you be concerned about lead exposure?

Let’s dive into the world of turmeric and explore the evidence about the health benefits and risks of the Golden Spice.

What Is Turmeric?

Fresh turmeric holding by hand, Food ingredients in Asian food and used in beauty spa and herbal medicine

Turmeric, or Curcuma longa to botanists, is a plant in the ginger family (called Zingiberaceaea, which would get me knocked out of a spelling bee if I didn’t have it written out in front of me). Other members of that family include galangal and cardamom.

Turmeric is native to Southeast Asia, where it’s now grown commercially (primarily in India) and used as a cooking spice.

There are over 50 different cultivars of turmeric, with the most common being the Madras and Alleppey varieties.

The culinary part of the plant is its rhizome (underground stem). Think gingerroot, just a bit skinnier and a whole lot yellower. As a spice, turmeric has a slightly bitter, pungent, and nutty taste. And its intense hue can range from yellow to gold to orange. It’s the main spice in many curry powders and the one that gives them their distinctive color.

Turmeric has both culinary and medicinal uses. Around the world, almost one billion people use it daily as a cooking spice. You can eat the rhizomes whole, either cooked or raw. And you can also use them dried and ground into a spice powder. In addition to its culinary uses, turmeric is also used as a preservative for food and as a coloring agent for mustards.

Turmeric and extracts made from it are also consumed as a supplement, orally in capsule or liquid form, or even as a paste.

Turmeric Nutrition

Like a lot of other spices, turmeric is a rich source of many essential minerals. These include iron (the nonheme variety that doesn’t build up in blood), copper, manganese, zinc, magnesium, and potassium. Fresh turmeric also delivers a small amount of fiber.

Turmeric’s big claim to fame, though, is its curcuminoids — the compounds that give the root not just its yellow color but also many of its health benefits. The main curcuminoid is curcumin, which, despite its name, doesn’t come from cumin. Curcumin is a polyphenol, a plant compound that acts as an antioxidant in our diets and has disease-fighting properties.

For more on polyphenols, check out our full article here.

The Benefits of Turmeric

At the top of this article, I said that turmeric could win a gold medal at the Nutrition Olympics. Let’s look at the evidence that leads me to give the spice a 10 out of 10.

Turmeric Anti-Inflammatory Benefits

Woman holding.

Curcumin is often used as an anti-inflammatory agent in Ayurveda and Traditional Chinese Medicine. And many studies have put this application to the test.

A 2019 article reviewed test-tube and animal studies where curcumin showed protective effects against several gastrointestinal problems that were caused or worsened by inflammation (our view on the use of animals in medical research is here). These included acid reflux, Barrett’s esophagus (where the esophageal lining experiences damage from acid reflux), and H. pylori infection of the stomach.

Curcumin has also shown promise in reducing the effects of inflammatory bowel disease (IBD). It seems to work by helping to calm cells that are involved in inflammation. As a result, it’s theorized that curcumin could be a treatment option for reducing IBD flare-ups.

A 2021 meta-analysis also found curcumin to be effective in lessening the pains of rheumatoid arthritis (RA) by reducing inflammation, swelling, and pain. Included among the results was a 1980 study out of Iran that found curcumin supplementation helped reduce morning stiffness and joint swelling in human patients with RA.

Turmeric and Blood Sugar

Curcumin also shows great promise in treating and perhaps even preventing type 2 diabetes. A 2021 meta-analysis provided evidence that the compound may achieve these results by reducing inflammation and blood sugar levels.

And a 2023 meta-analysis of human trials found that turmeric can help lower blood sugar and hemoglobin A1c levels in people with type 2 diabetes. Unlike many diabetes drugs, however, the side effects of turmeric were positive. They included lowering total and LDL cholesterol, triglycerides, blood pressure, insulin resistance, and markers of inflammation. The results appeared to be dose-dependent — that is, the more turmeric people consumed, the greater the effects.

Turmeric and Brain Health

Depressed senior Asian man lying in bed cannot sleep from insomnia

Because of curcumin’s anti-inflammatory and other beneficial properties, it’s being studied as a potential treatment for Alzheimer’s and other neurodegenerative diseases. The challenge is to deliver the curcumin in a way that enables it to easily cross the blood-brain barrier. Researchers are trying to make the compound more bioavailable by binding it to “carrier molecules.”

A 2022 review article reports that curcumin may also help people with early-onset Alzheimer’s lessen the sleep disturbances that often accompany the disease. This is important because your body requires quality sleep to “do maintenance” on the brain and clean out harmful substances — so Alzheimer’s and poor sleep make for a vicious cycle of increasing brain damage.

Turmeric and Cancer

Research shows that curcumin can help prevent the initiation of cancers and slow their development once they’ve occurred. How does it do this? Researchers believe that its anticancer mechanisms include inhibiting cellular growth, reducing the invasion and migration capabilities of cancer cells, enhancing programmed cell death, reducing inflammation, and favorably altering the intestinal microbiome.

Based on studies of which molecules curcumin targets in cancer cells, it may be that curcumin could be particularly effective in combating prostate cancer, colorectal cancer, and head and neck squamous cell cancer.

And according to a 2020 review article, several studies suggest that adding curcumin to chemotherapy treatment regimens enhances the efficacy of both chemotherapy and radiotherapy. This combination may extend the survival times of patients, boost the levels of proteins that prevent the spread of cancerous tumors, and alleviate adverse effects.

Turmeric and Heart Health

Medical heart cardiology

A 2017 meta-analysis found that the curcumin in turmeric might help lower LDL (“bad”) cholesterol and triglycerides in the blood. It seems particularly effective in reducing cholesterol levels in people with metabolic syndrome — a cluster of conditions that increase the risk of heart disease. While much research has focused on curcumin, some studies also suggest that whole turmeric may be even more effective at lowering cholesterol than supplemental curcumin alone.

There are several conditions that increase the risk of cardiovascular disease. And these conditions all share several underlying factors: oxidative stress, impaired mitochondrial function, metabolic irregularities such as changes in lipid levels and glucose processing, as well as inflammatory responses. Curcumin demonstrates a wide range of effects that target these particular factors, suggesting that it could reduce the risk of heart disease in some of the most vulnerable populations, including elderly people as well as those who are obese and/or have type 2 diabetes.

Curcumin Bioavailability

To recap, science has recognized what many cultures have known for centuries: Turmeric has powerful medicinal properties that can help treat a wide variety of diseases and conditions. But much of the data and recorded health benefits of turmeric have been based on studies that used supplements and extracts of curcumin rather than whole turmeric root or turmeric powder.

This creates a challenge because we know that human bodies aren’t great at absorbing curcumin, either from food or in supplemental form. That’s because curcumin is what’s known as hydrophobic, which doesn’t mean it’s afraid of swimming pools. Rather, it’s very poorly absorbed in water, which makes it hard for your body to get the compound into your cells where it can do good. That means the underlying science is unavoidably muddy since it’s hard to know what dose of curcumin a patient has absorbed. You can only tell the amount given.

Fortunately, researchers have begun finding proven ways to increase curcumin’s bioavailability.

1. Turmeric and Black Pepper

Turmeric and Pepper in bowls. Rizzuto

When you eat dishes that contain turmeric, you can absorb more curcumin if you add black pepper. This gives you the synergistic compound piperine, which significantly enhances the serum concentration, absorption, and bioavailability of curcumin. One study found that people who ate piperine along with curcumin absorbed 20 times more of the curcumin than people who didn’t receive black pepper. (If you’re looking to make this sound impressive, you can also say that black pepper increases curcumin bioavailability by 2,000% — which is just a fancy way of adding two zeros and a percent sign.)

You can take advantage of this finding by following Dr. Greger’s advice: Every day, consume a quarter teaspoon of dried turmeric with a pinch of black pepper.

Editor’s Note: Our top choice for dried turmeric is Burlap & Barrel’s New Harvest Turmeric. Grown in southern India using sustainable agriculture techniques, this organic turmeric stands out for its exceptional quality. It boasts a high curcumin content of 4%, which contributes to its potent health benefits and vibrant flavor. It’s also rigorously tested in an internationally accredited food safety lab to ensure it’s free of contaminants like lead. Click here to learn more.

2. Eat Turmeric with a Healthy Fat

Another way to increase the bioavailability of curcumin is to eat a healthy fat along with your turmeric. That’s because, while curcumin isn’t very soluble in water, it gets along really well with fat. Traditional Indian cuisine reflects this insight, as Indian dishes that include turmeric are often cooked with coconut milk, vegetable oil, or ghee.

If you want to stick to whole plant foods, remember that nuts, seeds, and avocados are generally good sources of healthy fat that can increase curcumin bioavailability as well.

Here are some of our favorite turmeric-containing recipes to help you get more of the Golden Spice into the cells of your body.

3. Curcumin Supplements

Closed up dry organic turmeric powder in capsule on wooden spoon on white background Promtha

Researchers have also found ways to increase the bioavailability of supplemental curcumin.

Nanoparticle Curcumin

One is by encapsulating the curcumin in nanoparticles, which are just like regular particles, but a lot more nano.

Okay, okay. I’ll look it up for you: Nanoparticles are very (very, very) small particles measured in nanometers, and a nanometer is one-millionth of a millimeter. The thing about nanoparticles is that at that size, they behave differently than larger particles, both on a physical and chemical level. And one of those differences is in the way they can dissolve in water while protecting the curcumin they’re surrounding.

Micellar Curcumin

A second technique for increasing the bioavailability of supplemental curcumin is to chemically change it to a micellar form. Micelles are very small lipid molecules that act as a carrier for fat-soluble curcumin and make it water-soluble, which allows the curcumin to sneak in, so to speak.

But does that actually work? Well, to put it to the test, researchers conducted a study, published in Molecular Nutrition & Food Research in 2014. They gave participants a 500-mg dose of curcuminoids in either a native curcumin powder, micronized powder, or liquid micelles, and then measured blood levels of curcuminoids in the 24 hours that followed. The researchers found that, compared to the native curcumin, the micronized powder conferred a 9-fold increase in absorption. That sounds pretty impressive until you hear about the winner — the liquid micelle format, which led to a 185-fold increase.

In their discussion, the researchers also compared their bioavailability results with those found in other studies on bioavailable curcumin forms, including the use of the piperine found in black pepper (which led to a 20-fold increase in bioavailability), turmeric essential oils (which had a 7-fold higher bioavailability), and curcumin incorporated into lecithin (which conferred a 4-fold better absorption). They called micellar curcumin’s 185-fold result “unrivaled.”

Liposomal Curcumin

A third method of increasing bioavailability is to create liposomal conjugated curcumin. Liposomes are tiny spherical structures made up of lipid bilayers that can carry therapeutic agents like drugs or natural compounds. Like micellar curcumin, liposomal curcumin has an outer membrane that bonds with water, which allows the fat-loving curcumin inside to enter human cells more readily.

Downsides & Risks of Turmeric

The way curcumin is vying for that nutritional gold medal, you might think that the more of it you get, the better. But there are several reasons to be cautious about overconsumption of the Golden Spice.

Human studies on the effects of turmeric as a food have looked at doses ranging from less than 1/16th of a teaspoon a day up to about 2 tablespoons a day. And participants have taken these amounts sometimes for more than a month.

And while traditional Indian diets may include as much as a teaspoon of turmeric per day (or about an inch of fresh turmeric root), supplemental forms of curcumin with enhanced bioavailability could deliver the equivalent to cups of turmeric — definitely not a dose that you could achieve by eating real food.

According to the European Food Safety Authority and the World Health Organization, the acceptable daily intake value of curcumin is 0–3 milligrams per kilogram of body weight. So someone weighing 150 pounds (68 kilograms) is advised to limit their consumption to 204 milligrams of curcumin per day, or approximately 1 tablespoon. Although curcumin has been found to be safe at doses of 8 grams per day in both phase I and phase II clinical trials, there is some concern that very high doses, perhaps especially when combined with enhanced bioavailability, could lead to some side effects.

Turmeric Side Effects

Back pain, kidney inflammation, man suffering from backache at home

Too much turmeric might possibly be able to cause DNA damage — at least, that’s what researchers have found in test-tube studies. So people who are pregnant, in particular, may want to moderate their turmeric consumption. High-dose curcumin also appears to thin the endometrial lining, which can interfere with in vitro fertilization.

Turmeric helps the gallbladder pump more vigorously, which is one way it can protect the liver and even prevent gallstones. But if there’s already an obstruction in the bile duct, those additional gallbladder contractions can cause a lot of pain.

Moderating turmeric consumption may also be a good idea for people with a predisposition to forming kidney stones. That’s because turmeric is high in oxalates, which can bind to calcium to form calcium oxalate, the key ingredient in about 75% of all kidney stones. (Some curcumin products, however, contain little to no oxalate.)

And in some people, high doses of turmeric may also cause gastrointestinal problems, including diarrhea, constipation, flatulence, and nausea.

Turmeric can also act as a blood thinner, which means it may interact with several classes of medications, including blood thinners, aspirin, and diabetes drugs.

Lead in Turmeric

There’s one more issue with turmeric that isn’t about the plant itself, but its preparation.

Turmeric powder from Bangladesh and India sometimes contains lead chromate, which enhances the spice’s appearance by making it a brighter shade of yellow. Which is to say, some turmeric powder is contaminated with lead.

There’s no safe level of lead; it can seriously damage reproductive, neurological, and cardiovascular systems — especially in children. If you want to protect yourself and your family from possible lead contamination, the best option is to buy fresh turmeric root or to buy organic turmeric and curcumin products.

To be extra safe, you can contact manufacturers to ask if they test for lead and other metals. California’s Proposition 65 seeks to protect, or at least inform, consumers by providing warnings about lead in foods like ground turmeric.

Use Turmeric in Good Health — Thoughtfully

Vegan curry with cauliflower, chickpeas and butternut squash topped with peanuts, served with rice and cilantro

Turmeric, the Golden Spice, has long been venerated in India and other Asian countries for its vibrant hue, culinary appeal, and medicinal qualities. Rich in curcuminoids, turmeric boasts antioxidants and disease-fighting polyphenols, making it a superfood of immense value. And modern scientific studies are confirming and highlighting its anti-inflammatory properties, brain-boosting effects, and potential for managing conditions like diabetes, cardiovascular disease, and cancer.

Despite all those beneficial properties, turmeric comes with some concerns. While supplements promise convenience, their proper usage and dosage require consideration. And potential lead contamination concerns may lead some people to make sure their turmeric is grown organically or comes in a tested supplement, rather than dried and powdered. As with many medicinal spices, moderation and informed sourcing is key.

Editor’s note: Purality Health has developed a unique micelle liposomal product they call Curcumin Gold. The liposomes are a healthy lipid (fat) bilayer that surrounds the curcumin and protects it from stomach acids, bile, and digestive juices that could destroy it. Once it reaches the intestinal wall, the micelles release, and they are absorbed into the bloodstream and thus the cells. Curcumin Gold also contains ginger oil and vegan DHA fatty acids from algae for added anti-inflammatory effects. The product is 100% vegan, organic, soy-free, and non-GMO.We asked Purality Health about their products and lead, and they told us they run ICP MS (the highest standard for heavy metal testing) on every batch of Curcumin Gold. They test internally and also hire a third party for independent verification, and the test results find no lead in any of their products.If you use our link, you’ll get a discount, and they’ll contribute a portion of the proceeds to the work of Food Revolution Network. Click here to find out more.

Tell us in the comments:

  • Do you cook with turmeric? What are your favorite ways to use it?
  • Have you ever seen fresh turmeric root at a market or grocery store?
  • Do you take curcumin supplements?

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