October 2018 Issue

Herbs and Spices: Herbal Anxiolytics for Anxiety and Depression — Do They Work?
By Densie Webb, PhD, RD
Today's Dietitian
Vol. 20, No. 10, P. 14

An estimated 44 million Americans suffer from anxiety disorders ranging from generalized anxiety disorder to panic attacks, making it the most common mental disorder in the country. Anxiety is defined as a mood of fear, worry, and uneasiness resulting from the apprehension of something bad happening.1

Anxiety disorders are characterized by persistent, uncontrollable, and overwhelming anxiety. Only about one-third of those who experience severe anxiety receive treatment.2 Any drug or herb used to treat anxiety is referred to as an anxiolytic.

Diet and Anxiety
The role of food in anxiety is complex and, to date, not fully understood. Animal research indicates that both dietary composition and dietary habits can influence anxiety. Whether food affects anxiety levels likely depends not only on the diet's composition but also on previous dietary experiences, including one's mother's diet during pregnancy.3

In rats, a high-sugar diet increased anxious behavior, while a high-fat diet decreased anxious behavior. In addition, taking away a high-fat, high-sugar diet in animals prone to obesity has been shown to increase anxiety. Irregular eating (to mimic the eating habits of dieters) can impact behavior through its effect on circulating hormones.3

Natural Remedies
While dietary remedies are unproven and conventional drug treatments for anxiety can be expensive, difficult to obtain, and have serious negative side effects, several natural herbal remedies, including kava kava, valerian, St. John's wort, and lemon balm, have been a part of traditional medicine for centuries, in some cases dating back to Hippocrates' time.

But has research that applies modern scientific methods and standards proven the efficacy of herbal anxiolytics? Yes and no. Much of the research showing benefits has been performed in animals, and many of the findings in humans either are from small, poorly controlled studies or are anecdotal. That doesn't mean they aren't effective—it just means there's no proof positive that they work and work safely.

Recommended dosages and forms (eg, tinctures, extracts, roots) vary greatly. Be sure patients and clients know there's no oversight for standardization, safety, or efficacy of herbal preparations in the United States. Here's some of what we know about four of the most common anxiolytic herbals.

Kava Kava
Kava kava is a preparation from the plant Piper methysticum, which contains six psychoactive compounds called kavalactones that act as muscle relaxers. As the most studied of all the herbal anxiolytics, it has demonstrated the most effectiveness against mild anxiety and anxiety disorders in humans.

Benjamin Weeks, PhD, a professor of biology at Adelphi University in Garden City, New York, says, "Kava kava can provide a 'rational euphoria.'" Most clinical studies have shown that kava kava can be an effective treatment for both anxiety and premenstrual syndrome.1

While a dose of 3 to 5 mL kava kava tincture is considered safe for most people, it isn't considered safe for use in pregnancy, in patients with liver disease, or in those who frequently consume alcohol.4 Liver function tests may be indicated for regular users, though liver toxicity is a rare side effect.5,6

Valerian
This root has been shown to induce sleep and improve sleep quality without side effects.7 (Insomnia or poor-quality sleep is known to contribute to anxiety.8) Tinctures of Valeriana officinalis (3 mL 30 minutes before bedtime) have been suggested for sleep.9

Studies have found that 400 to 900 mg a day of valerian root in capsule form may be as effective as diazepam (Valium) for reducing anxiety.1 The active root extract, valernic acid, acts by increasing production of the calming neurotransmitter GABA (gamma aminobutyric acid).

St. John's Wort
St. John's wort (Hypericum perforatum) is a perennial plant native to Europe and parts of Asia, North America, and South America. The flowering tops are the source of the botanical preparations. Several different compounds can be extracted, with hypericin being the most studied.6 However, it's now believed that hyperforin and related compounds are mostly responsible for St. John's wort's effect on mood. While it's been mostly studied for the treatment of depression, it also has been found in some, but not all, studies to be effective for anxiety as well, which is helpful because depression and anxiety frequently co-occur.6 St. John's wort is believed to work by increasing brain levels of the neurotransmitter serotonin and by reducing inflammatory and oxidative stress.1

Most side effects, such as gastrointestinal upset, dizziness, sleep disturbances, and headaches, are mild to moderate. However, it's not considered safe for use during pregnancy or lactation, and photosensitization reactions (eg, inflammation, redness, itching) with exposure to sunlight, while rare, can occur.

Suggested doses are 2 to 5 mL tincture three times per day or one to two 300- to 450-mg tablets per day.4,10 A 2017 meta-analysis of studies lasting four to 12 weeks found St. John's wort to be effective in treating mild to moderate depression.11 Because St. John's wort carries the potential to interact with several medications, counsel patients to check with their health care providers before using it in combination with any prescription drug.

Lemon Balm
Lemon balm, or Melissa officinalis L, is recognized by the German Commission E, a government body that develops recommendations for herbal medicines, as a treatment for nervous insomnia.12 "It contains molecules that can help with anxiety," according to Weeks.

Taking 2 to 5 mL tincture three times a day4 or 300 mg leaf extract twice per day can improve sleep and possibly relieve symptoms of anxiety.12,13 Aromatherapy with lemon balm essential oil also has been found in a double-blind, placebo-controlled trial to have a calming effect in Alzheimer's patients.14 The herb is generally considered safe for use.

Because there's no oversight of the supplement industry, inconsistencies are common among brands containing the same labeled dosages of herbal remedies. In addition, recommendations for dosing and effectiveness vary greatly. ConsumerLab.com is a good source of information, both for background on herbals and results of analyses of specific brands.

— Densie Webb, PhD, RD, is a freelance writer, editor, and industry consultant based in Austin, Texas.

References
1. Alramadhan E, Hanna MS, Hanna MS, Goldstein TA, Avila SM, Weeks BS. Dietary and botanical anxiolytics. Med Sci Monit. 2012;18(4):RA40-RA48.

2. Understand the facts. Anxiety and Depression Association of America website. https://adaa.org/understanding-anxiety. Accessed July 31, 2018.

3. Murphy M, Mercer JG. Diet-regulated anxiety. Int J Endocrinol. 2013;2013:701967.

4. Abascal K, Yarnell E. Nervine herbs for treating anxiety. Altern Complement Ther. 2004;10(6):309-315.

5. Sarris J, Stough C, Bousman CA, et al. Kava in the treatment of generalized anxiety disorder: a double-blind, randomized, placebo-controlled study. J Clin Psychopharmacol. 2013;33(5):643-648.

6. Lakhan SE, Vieira KF. Nutritional and herbal supplements for anxiety and anxiety-related disorders: systematic review. Nutr J. 2010;9:42.

7. Bent S, Padula A, Moore D, Patterson M, Mehling W. Valerian for sleep: a systematic review and meta-analysis. Am J Med. 2006;119(12):1005-1012.

8. Freeman D, Sheaves B, Goodwin GM, et al. The effects of improving sleep on mental health (OASIS): a randomised controlled trial with mediation analysis. Lancet Psychiatry. 2017;4(10):749-758.

9. European Medicines Agency, Committee on Herbal Medicinal Products. Assessment report on Valeriana officinalis L., radix and Valeriana officinalis L., aetheroleum: final. http://www.ema.europa.eu/docs/en_GB/document_library/Herbal_-_HMPC_assessment_report/2016/04/WC500205373.pdf. Published February 2, 2016.

10. European Medicines Agency, Committee on Herbal Medicinal Products. Assessment report on Hypericum perforatum L., herba: draft. http://www.ema.europa.eu/docs/en_GB/document_library/Herbal_-_HMPC_assessment_report/2018/03/WC500245212.pdf. Published January 30, 2018.

11. Ng QX, Venkatanarayanan N, Ho CY. Clinical use of Hypericum perforatum (St John's wort) in depression: a meta-analysis. J Affect Disord. 2017;210:211-221.

12. Cases J, Ibarra A, Feuillère N, Roller M, Sukkar SG. Pilot trial of Melissa officinalis L. leaf extract in the treatment of volunteers suffering from mild-to-moderate anxiety disorders and sleep disturbances. Med J Nutrition Metab. 2011;4(3):211-218.

13. Kennedy DO, Little W, Scholey AB. Attenuation of laboratory-induced stress in humans after acute administration of Melissa officinalis (lemon balm). Psychosom Med. 2004;66(4):607-613.

14. Ballard CG, O'Brien JT, Reichelt K, Perry EK. Aromatherapy as a safe and effective treatment for the management of agitation in severe dementia: the results of a double-blind, placebo-controlled trial with Melissa. J Clin Psychiatry. 2002;63(7):553-558.

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