Both Lavender and Bitter Orange Reduce Anxiety in Postmenopausal Women

Postmenopausal women frequently report feelings of anxiety. Uncontrolled anxiety can harm physical health, reduce the quality of life, and increase the intensity of menopause symptoms. While several conventional drugs are available to treat anxiety, many women avoid using them because of side effects such as drowsiness, dizziness, memory impairment, and difficulty concentrating. Lavender (Lavandula angustifolia, Lamiaceae) flowers contain several compounds with an antidepressant, sedative, and anti-anxiety effects. Lavender oil, administered orally or as aromatherapy, has been tested in people with various mood disorders. Bitter orange (Citrus × aurantium, Rutaceae) peel and fruit contain some of the same compounds as lavender flowers, and bitter orange flowers have sedative and hypnotic effects. The purpose of this randomized, triple-blind, placebo-controlled trial was to evaluate the effects of lavender and bitter orange in postmenopausal women with mild to moderate anxiety.

Postmenopausal women (n = 156, aged 45-60 years) with anxiety were recruited from gynecology clinics at Imam Reza Hospital and Fatemiyeh Hospital in Urmia, Iran during 2015. Included participants had scores ranging from 20 to 53 for both state and trait anxiety using the State-Trait Anxiety Inventory (STAI), had natural menopause, had their last menstrual period one to six years ago, did not smoke or drink alcohol, and had no history of asthma or allergies to lavender or citrus. Excluded participants were taking anti-anxiety drugs or traditional medicines had a history of severe physical illness that caused anxiety or experienced a recent traumatic life event.

Whole, dried lavender, and bitter orange flowers were obtained from the Yashil Sahand Drug Company in East Azerbaijan, Iran. The flowers were powdered in the author’s laboratory, and the resulting powders were filled into capsules at the Yashil Sahand Drug Company. Participants were randomly assigned to receive two 500 mg capsules/day of either lavender, bitter orange, or placebo (starch) for eight weeks. They were instructed to take one capsule in the morning after breakfast and one capsule in the evening after dinner.

At baseline, participants completed a demographic questionnaire and the STAI. During the study, participants completed daily checklists to record when they took the capsules and to report any adverse effects (AEs). At the end of the eight-week intervention, participants completed the STAI and a validated questionnaire regarding their response to and satisfaction with the intervention. The participants, data collectors, and personnel assessing the outcomes were blinded as to the group allocations.

A total of 156 participants (n = 52 in each group) completed the study. Some participants in the lavender group (n = 3), bitter orange group (n = 4), and placebo group (n = 4) stopped taking the capsules, but they were followed for eight weeks and included in the analysis. Participants in the placebo group had a significantly lower current age (P = 0.011) and age at menopause (P = 0.029) compared to the lavender and bitter orange groups. All other demographic characteristics and STAI scores were similar among the groups at baseline. All calculations were based on the intent-to-treat dataset. A general lineal model was used for the analyses, adjusted for baseline STAI scores and potential confounding factors (current age and age at menopause).

State-anxiety scores, which indicate current feelings of anxiety, were significantly lower in the lavender group (P = 0.004) and bitter orange group (P = 0.018) compared to the placebo group after eight weeks. Trait-anxiety scores, which indicate anxiety as a personal characteristic, were significantly lower in the lavender group (P = 0.019) and bitter orange group (P = 0.042) compared to the placebo group after eight weeks. No significant differences in the state- or trait-anxiety scores were found between the lavender group and the bitter orange group after eight weeks. Response to the intervention was rated as “very good” or “good” by 83.7% of participants in the lavender group, 83.4% of participants in the bitter orange group, and only 43.8% of participants in the placebo group. Most participants in the lavender group (73.5%) and bitter orange group (79.2%) reported satisfaction with the intervention, compared to less than one-third of the participants in the placebo group (31.3%). More than 50% of the participants in each group could not guess correctly the group to which they were assigned. AEs were mild and transient and included nausea, palpitations, and headache. The number of AEs reported appeared to be similar among the groups (n = 8 for lavender; n = 7 for bitter orange; n = 13 for placebo); however, no statistical analysis was performed. Compliance was not reported.

The authors conclude that “The positive effect of bitter orange and lavender on anxiety in postmenopausal women suggests that they can be used to decrease anxiety in such women.” Acknowledged limitations of this study include the use of only one subjective outcome measure (possible errors of self-reporting information), failure to measure other potentially confounding factors such as body mass index and stress, and the restriction of enrollment to women with mild or moderate anxiety (which may explain the relatively small treatment effect). The authors point out that further studies are required to determine if the present results are robust and to evaluate the effects of lavender and bitter orange in women with severe anxiety. They also recommend the assessment of other herbal medicines for the treatment of anxiety in postmenopausal women.

Editorial Comment

In sub-section 2.2 of the materials and methods, the authors state the capsules “did not have volatile oils and thus had no odor.” However, in sub-section 2.3 the authors report that the capsules contained powders prepared from whole, dried flowers and the most “active constituents in lavenders [sic] were characterized as the linalool (36.12%), linalyl acetate (26.32%) and caryophyllene (7.55%), and in bitter orange capsules as limonene (20%), linalool (32%), flavonoid (5%).”

Linalool, linalyl acetate, limonene, and caryophyllene are aromatic volatile oils, and the powdering process would not remove these constituents (although it may reduce their concentration). 

Resource:

Farshbaf-Khalili A, Kamalifard M, Namadian M. Comparison of the effect of lavender and bitter orange on anxiety in postmenopausal women: a triple-blind, randomized, controlled clinical trial. Complement Ther Clin Pract. May 2018;31:132-138. doi: 10.1016/j.ctcp.2018.02.004.

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