Wellness products such as kombucha, CBD oil, and even "activated charcoal," have grown in popularity in recent years, thanks to their purported health benefits, but do these products actually do what they claim to do? The New York Times' Dawn MacKeen and Amitha Kalaichandran investigated five popular wellness products to find out.

Kombucha

Kombucha is a fermented drink that is typically carbonated and is made by brewing sugar, black or green tea, liquid from a previous batch, and symbiotic culture of bacteria and yeast, sometimes called the scoby.

Proponents of kombucha say it improves digestion, boosts the immune system, reduces blood pressure, and can be beneficial to diabetics.

However, few studies have looked at how effective kombucha really is. Only one study has looked at its health benefits in humans, according a literature review, and it found that the 24 adults with non-insulin dependent diabetes who consumed kombucha for three months saw their mean blood sugar levels stabilize. However, the study was neither controlled nor randomized, and its authors noted that many of the claims about kombucha are based on anecdotal and unverified evidence.

Other research on cells and animals has found that kombucha may have anti-inflammatory and antimicrobial properties, but according to Franck Carbonero, a microbiome scientist at Washington State University-Spokane, "We don't know if it does anything."

Celery juice

Celery juice is purported to help alleviate digestive problems and treat autoimmune disorders, psoriasis, acne, and a whole host of other health problems.

However, according to Rachel Scherr, an assistant research scientist in nutrition at the University of California, Davis, "There's no scientific evidence to support any of the claims being made."

But that doesn't mean you need to avoid it, as it's "overall … a healthy juice," according to Elizabeth Bradley, medical director of Cleveland Clinic's Center for Functional Medicine. According to MacKeen, celery juice has greater amounts of potassium and vitamin K than tomato and carrot juices.

Activated charcoal

Activated charcoal refers to charcoal that has had gases such as oxygen added to it at high temperatures, creating pores in the charcoal that allow it to bind to other substances.

Proponents of charcoal say it works as a detoxifier that can remove teeth stains and even help stop aging, MacKeen reports.

But does the substance live up to the hype? Not quite.

A study in January 2019 found that activated charcoal in toothpaste was not as effective as other whitening agents at whitening cow, goat, and sheep teeth, and another review from 2017 of 118 studies did not find enough evidence to support the safety or efficacy of charcoal-based toothpastes or powders.

CBD

Cannabidol (CBD) comes from the cannabis sativa plant, perhaps best known for also containing tetrahydrocannabinol (THC), which is the high-inducing chemical found in marijuana. Proponents of CBD say it can relieve anxiety, depression, and post-traumatic stress disorder (PTSD).

CBD has been shown to potentially help reduce nervousness and cognitive impairment in patients with social anxiety. However, another, double-blind study, found healthy participants who took CBD saw small or non-existent changes in their emotional reactions to unpleasant images or words.

Harriet de Wit, co-author of the study and a professor at the University of Chicago's department of psychiatry and behavioral neuroscience, said, "If it's a calming drug, it should change their responses to the stimuli. But it didn't."

Mallory Loflin, an assistant adjunct professor at the University of California, San Diego, said she believes CBD could help treat PTSD, but more research is needed on the subject. "Our top therapies attempt to break the association between reminders of the trauma and the fear response," she said. "We think that CBD, at least in animal models, can help that process happen a lot faster."

Overall, CBD is "pretty safe" as long as you take "pure CBD," according to Marcel Bonn-Miller, an adjunct assistant professor at the University of Pennsylvania's Perelman School of Medicine.

Turmeric

Turmeric for thousands of years has been used in Ayurvedic medicine, which refers to a holistic healing system that originated in India more than 3,000 years ago. The spice is believed to work as an antiviral, antibacterial, and antiparasitic in Ayurvedic medicine. It's also purported to help with a variety of conditions, including high cholesterol, hay fever, depression, and hangovers.

However, a 2017 paper published in the Journal of Medicinal Chemistry concluded that turmeric doesn't have the health benefits it's purported to have. In fact, according to the National Center for Complementary and Integrative Health, there isn't enough reliable evidence for turmeric to be recommended for any condition.

Moreover, if a patient is taking turmeric, experts recommend patients inform their doctors, as high doses of turmeric and its constituents could have some unpleasant side effects like diarrhea and nausea (MacKeen, New York Times, 10/16 [1]; MacKeen, New York Times, 10/16 [2]; Kalaichandran, New York Times, 10/16; MacKeen, New York Times, 10/17 [3]; MacKeen, New York Times, 10/17 [4]; WebMD.com, accessed 10/17).