Oct 22, 2008

Rhodiola rosea

Posted in Chemspy, Geek, Science, spectroscopy at 1:00 pm by David Bradley -- 108 Comments; add your comment

UPDATED: 2010-04-22

The marketing hype surrounding Rhodiola rosea would suggest that anyone taking it would be cured of almost any ailment and have renewed vitality. It may have some benefits, as yet unproven, but the idea that it could allow you to live long and prosper? Well, there are no peer-reviewed scientific research papers to support such claims, as far as I know.

R rosea (aka golden root, roseroot, hóng jǐng tiān in TCM) is a member of the Crassulaceae family and grows across the Arctic, the mountains of Central Asia, the Rockies, the Alps, the Pyrenees, the Carpathian Mountains, Scandinavia, Iceland, Great Britain and Ireland. According to some herbalists it could be an elixir for life.

The Wikipedia entry for R rosea says it may be effective for improving mood and alleviating depression and early stage studies on people have shown some efficacy in improving physical and mental performance, alleviating fatigue, and reducing high-altitude sickness. A possible mode of action involves what the entry describes as, “optimizing serotonin and dopamine levels”. This apparently happens by inhibition of the enzyme monoamine oxidase, which supposedly ties in with an effect on endorphins, the body’s natural opiates.

A recent massively hyped press release I received about R rosea highlights a previously published article that claims that, “the roots appear to aid the brain by alertness and energy, without any trace of stimulants such as caffeine.” Isn’t that a contradiction in terms? If the root stimulates the brain, then surely by definition it is a stimulant?

I asked the author of the press release, Linda Todten of publicity company TMC Communications, to explain exactly what the description was intended to convey, this is what she had to say:

As you know, the trend is for “energy drinks” that combine large amounts of caffeine, or caffeine containing plants such as Guarana, along with high amounts of carbs for a big “energy boost.” The studies that the Swedes and Russians have done over the years have shown how this category of plant, the Adaptogen, can actually bring the body back to its full energy level without being over stimulated as happens with caffeine. Plus, the extract SHR-5 has been shown to have a very solid mental acuity boost via double-blind, placebo controlled studies in students or night shift physicians and others.

But, any product with a physiological effect cannot work without some side-effects; no herbal extract could be that specific at the molecular level.

Indeed, the plant root contains a variety of chemical natural products including rosavin, rosarin, rosin and salidroside (and sometimes p-tyrosol, rhodioniside, rhodiolin and rosiridin), which are all described as active ingredients of R rosea. These compounds are polyphenols, they may have some antioxidant activity but good evidence for positive health effects in people remains elusive, indeed that is the case for most antioxidants.

R rosea products are marketed in the USA and elsewhere. Todten had this suggestion: “Think about the fact that this one product (Arctic Root brand) has sold over 400 million doses. Not many dietary supplements can claim that. That says, to me, that people must like the way it works to reduce stress or energize,” she told me. “People are not sheep, and they wouldn’t make a product a best seller in Europe over ten years with hundreds of millions taken if it didn’t do something that they liked!”

Well, couldn’t that simply be the power of marketing? What we need are references in the medical literature that provide results from large-scale, randomised, double-blind, placebo-controlled clinical trials of R rosea. I don’t think there are any such studies published in the peer-reviewed journals yet, despite the apparent 2000 entries on R rosea in Google Scholar and meta-analyses with their inherent limitations and penchant for cherry-picking in some cases.

Fundamentally, there is no difference between a “natural” chemical and a “synthetic” one and equally no difference between the active component in a herbal remedy and that present in a pharmaceutical product. Indeed, some 40% of prescription drugs are based on natural products or derivatives of the active components of herbal medicines.

Of course, that doesn’t mean that just because there is some equivalence that all herbal medicines are active. Many are stufff and nonsense and the claims of some marketers for any given product, whether ginseng, hoodia, St John’s Wort, R rosea etc are often entirely full of hyperbole. Moreover, a herbal remedy may contain a range of other components that are not beneficial and may even be detrimental.

One website describes R rosea thus: “Extracts of the roots have a reputation for stimulating the nervous system, relieving depression, enhancing work performance, improving cognition and memory function, eliminating fatigue and preventing high altitude sickness. The extract has been classified as an adaptogen. In simple terms, an adaptogen helps produce adjustments in the body to resist stress (e.g. chemical, biological, and physical). In addition, Rhodiola rosea also contains a range of antioxidant compounds.”

It’s that phrase “have a reputation for” that is most intriguing. Lots of things have a reputation but reputations are not scientific proof of a behaviour.