- A new analysis used data from 209 clinical trials examining 64 OTC products to see if they helped with depression.
- Omega-3s, St John’s Wort, probiotics, vitamin D, and saffron have been studied a lot for treating depression.
- Among the most promising were folic acid, lavender, zinc, tryptophan, and rhodiola, but based on limited studies.
Depression is a much-discussed topic and the incidence has increased in much of the world over time, with symptoms that range from depressed mood and lack of pleasure to appetite loss, sleep disturbance and fatigue.
Besides prescription medications, there are now dozens of over-the-counter (OTC) natural remedies and supplements taken in the belief they can relieve symptoms of depression.
Do they work?
That’s the question an international team set out to study, the analysis based on findings from more than 209 clinical trials that included 64 different OTC products sometimes used to treat depression symptoms in adults ages 18 to 60. The findings were published in the journal Frontiers in Pharmacology.
Only looking at depression
The only thing the products were evaluated on were findings regarding depression symptoms. So they might or might not provide other, unrelated health or well-being benefits. And the researchers didn’t try to sort out dosage differences.
The group, which included researchers affiliated with institutions in the UK, Peru and Taiwan, found different levels of evidence for each type of remedy, after narrowing a list of nearly 24,000 studies and 1,367 papers down to the 209 clinical trials where a product was taken for at least a week. They are also planning papers on what they learned about OTC products for anxiety and insomnia.
Lead author Rachael Frost, an herbal medicine expert who is a senior lecturer at Liverpool John Moores University, wrote separately for the Frontiers journal that researchers grouped findings into products with substantive evidence either way (at least 10 clinical trials), emerging evidence (between two and 10 trials) and single trials.
“The products with substantive evidence are those that are well known – omega-3s (39 trials), St. John’s Wort (38), probiotics (18) and vitamin D (14) – as well as saffron (18), which is important in the Middle East and parts of Asia," she wrote.
St. John’s Wort and saffron more often showed effects against depression compared to placebo, with results similar to prescription antidepressants. Probiotics and vitamin D were more likely to reduce depressive symptoms than placebo, as well.
Omega-3s didn’t hold up consistently as better than placebo. Frost reported that fewer trials found effects for depression than trials that did not find such effects.
More studies needed
Of the 18 products examined by between two and 10 clinical trials, she wrote that “folic acid, lavender, zinc, tryptophan, rhodiola and lemon balm were the most promising. Bitter orange, Persian lavender, and chamomile tea also showed positive effects in two trials each.
Some products that are gaining in popularity, such as melatonin, magnesium and curcumin, showed mixed effects upon depression across multiple clinical trials. Mixed results were also found for cinnamon, echium, vitamin C and a combination of vitamin D plus calcium. Prebiotics, which support the good bacteria in our gut, and a supplement called SAMe did not seem to be better than placebo.”
She noted that 41 products had only a single trial available. “This is helpful as a starting point, but does not give us conclusive evidence.”
The researchers found good news in a lack of reported safety concerns, but say to always consult a health care professional to see if there are worrisome interactions with something else you take. They also noted that the safety concern reporting in the clinical studies was not as good as it should be and called for a higher standard of safety reporting.
The team found that some products people take for depressive symptoms have not been evaluated in clinical studies, including ginseng, ginkgo, lime flowers, orange blossom and peppermint.
The analysis is designed to be a starting point to help people figure out what might and might not work. And Frost wrote that the analysis “has pioneered an exploration into what research is needed to further assess such widely used health care products.”