(RxWiki News) The medicinal effects of many herbs are often exaggerated. But sometimes science supports these claims.
In the past, lavender has been used as a calming agent, as well as to reduce anxiety.
A recent review of research on lavender showed evidence to support these assertions, even though the studies were not well done.
With better designed studies and stronger evidence, lavender may prove to be a powerful, yet safe, alternative to standard treatments.
"Ask your doctor about lavender capsules or liquid extracts."
Rachel Perry, MPhil, MA, of the Peninsula Medical School of the University of Exeter, authored this review along with several other members of the Complementary Medicine research team at Exeter.
After initial data mining, Perry and her team found 14 studies that met their standard for including them in the review. Seven studies found that lavender had at least some anti-anxiety effects, and one study found lavender was just as effective as the benzodiazepine lorazepam (also known as Ativan) at mitigating anxiety.
Perry makes a point about the research quality of those studies, or rather, the lack of quality. There is a procedure known as the Jadad scale or Oxford quality scoring system that is used throughout the world to assess the quality of research methodology.
Basically, the Jadad score (0-5) quantifies how closely a scientific study follows a set of standard rules. These rules involve methods of randomizing and blinding of treatments from participants and doctors, as well as also documentation of dropouts and withdrawals from the study.
The way blinding works in a scientific study is that the researchers hide certain information from the participants or themselves in order to prevent subconscious bias. Randomization is a process by which researchers attempt to divide study participants into either treatment or placebo groups.
Higher scores mean better documentation from researchers regarding randomization, study blinding and participant withdrawal in the text of their study.
Of the 14 trials in this review, two studies received a Jadad score of four, while the other thirteen studies scored one or less. The studies that scored low earned their rating because of sloppy or negligent documentation regarding the randomization and blinding of their treatments.
Some studies were also rated low because withdrawals of participants led them to not have enough people in the study to show statistically significant results.
The two studies that scored the highest on the Jadad scale provided the most evidence in favor of lavender as a treatment for anxiety. These two studies both used lavender in pill form, which allowed them to have more effective participant blinding.
With plants like lavender, blinding is difficult because plants often have a distinctive taste or smell. Orally administered pills allow researchers to circumvent this sensory problem.
Of the 14 studies reviewed by Perry and her team, seven showed anti-anxiety results for lavender to at least some degree and one study found that lavender was equal to lorazepam, a common benzodiazepine with the brand name Ativan.
Several hurdles can hold up effective botanical medicine research. Regularly getting a standard product with the same level and potency of active ingredients can be a problem because growing conditions and weather play a role in what chemicals the plant produces. There is also the difficulty with blinding that plants have due to strong smells and tastes.
In addition, there is relatively little funding for plants compared to funding for standard drugs. According to Perry, this is likely the true reason for the low volume of research available regarding lavender and other alternative medicines.
Perry and her team suggest that future studies pay careful attention to study design to avoid the common pitfalls they observed in many of the studies they reviewed.
This review of clinical research was published in the March 29 volume of the journal Phytomedicine. There were no reported conflicts of interest or funding declarations.
