Can Essential Oils Enhance Memory and Brain Function?

everydayhealth.com

Essential oils are clear liquids that can be found in every part of a plant, including the flowers, leaves, stems, and seeds. These substances, which evaporate easily when exposed to the air, are primarily responsible for a plant's scent. Essential oils can be extracted from a raw plant with a number of techniques, including distilling and cold-pressing, and bottled for use at home.

Essential oils are most commonly used in aromatherapy, an ancient practice in which fragrant plant extracts are used to improve physical, mental, or spiritual well-being. When inhaled, scent molecules interact with receptors on the olfactory bulb, which connects directly to the brain, stimulating responses that could address a variety of health conditions.
Essential oils have been studied as a remedy for various conditions, such as depression, insomnia, and nausea, but results have been mixed. One focus of study is the effect of essential oils and aromatherapy on brain health.

Essential Oils for Memory: The Science
The sense of smell may be linked to brain health. Declines in cognition, whether due to aging or disease, often parallel declines in the sense of smell, suggesting a dynamic neural connection between smell and cognition. Older adults who take part in olfactory training — regular exposure to specific odors, which is used to train or retrain the sense of smell — benefit with improved cognitive performance and subjective well-being.
A number of studies have suggested that the use of essential oils or aromatherapy can improve memory and cognitive functioning.

One recent study, for example, found that nightly aromatherapy significantly improved the memory of older adults. This experiment asked healthy men and women between the ages of 60 and 85 to use an aromatherapy diffuser for two hours every night, rotating through seven different essential oils: rose, orange, eucalyptus, lemon, peppermint, rosemary, and lavender. After six months, those who had been exposed to the essential oils overnight scored 226 percent higher on a word list recall than those in a control group.

"The olfactory sense is the only sense that has direct access to the memory centers of the brain, and olfactory enrichment is a good way to stimulate those centers with little effort," says Michael Leon, PhD, lead author on the study and professor emeritus of neurobiology and behavior at the University of California in Irvine.

Essential Oils That May Help With Memory

Other studies have tried to isolate the benefits of specific fragrances.

Peppermint oil may enhance performance on memory and attention tests, while also improving feelings of alertness. The minty, cooling scent may also improve reaction time and mental quickness. Animal studies suggest that peppermint oil may protect neurons in the brain and improve the body's balance of free radicals and antioxidants.

Rosemary oil may increase the brain's supply of the neurotransmitter acetylcholine, enhancing the chemical connections between neurons, which mimics the way that some medications for dementia work. Studies in both adults and children have found that rosemary oil can boost short-term memory and a review of animal studies found that rosemary significantly improved cognition in lab animals, including those with memory deficits.

Lavender oil, which is often recommended to improve sleep quality, has mixed results for memory enhancement. One study found that lavender aroma actually decreased memory and reaction time. But a review of multiple studies found that lavender enhanced or improved several aspects of cognition, especially sustained attention. A small study that measured electrical activity in the brain found that lavender oil caused volunteers to experience significant increases in brain waves associated with relaxation, leading to improved concentration and cognitive flexibility.

Rose oil, in a small study of students in Kazakhstan, was found to improve the ability to recall information, but did not improve the ability to learn new information.
Despite these study results, there is no consensus that essential oils truly improve memory or cognitive performance. 

In a systematic review of essential oil experiments, researchers could not find "any convincing evidence that aromatherapy (or exposure to fragrant plant oils) is beneficial for people with dementia." The quality of evidence, they wrote, is poor: "Most studies were very small so that there was a lot of uncertainty about their results. Results of different studies did not agree with one another." And a review of odor, memory, and mood said that claims for aromatherapy as a therapy generally rely on "a lack of scientific rigor and confusion regarding the mechanisms involved."
The American Lung Association states, "Be cautious about broad health claims about essential oils. Scientific research on the efficacy and safety of essential oils for specific health conditions is limited and more evidence is needed."

How to Use Essential Oils for Cognitive Health

There are a several different ways of using essential oil aromatherapy:

Indirect Inhalation A spray bottle or electric diffuser disperses tiny aromatic airborne particles through the room
Direct Inhalation Smelling fragrance directly from an open bottle, from a tissue or cotton ball, or rubbed onto the palms of your hands and inhaled
Steam Inhalation Mixing essential oil into boiling water and inhaling the scented steam
Aromatherapy Massage Essentials oils can be diluted into a massage or body oil and rubbed into to the body
Essential oils can also be applied directly to the skin when mixed into a carrier oil, and are also available as creams and lotions. 

Essential oils are generally considered safe, but they are not necessarily harmless. These compounds can cause side effects, such as asthma and headache, and can irritate the skin. Some essential oils are dangerous if swallowed, and some may interfere with prescription medications. Consult a healthcare professional before starting a new essential oil treatment.

How to Keep Your Brain Sharp
If you're concerned that your memory is declining, essential oils should only be one part of a strategy to keep your brain sharp:

Healthy lifestyle habits, like eating a healthy diet and getting exercise, may dramatically reduce the risk of Alzheimer's disease.
Mentally stimulating work — jobs that regularly require you to analyze new information or solve new problems — can help slow cognitive decline and ward off dementia. Teaching, computer programming, and repairing cars are examples of cognitively stimulating jobs.

Brain exercises, like memory games, learning a new language, or playing a musical instrument, can help your brain stay sharper for longer.
Nicotine and alcohol have distinct negative effects on brain health; quit smoking and drink only in moderation (or not at all) to improve your odds of staying mentally fit in old age.

The Takeaway
Essential oils like peppermint, rosemary, and lavender might enhance memory and cognitive function. These fragrant plant compounds are generally safe, smell pleasant, and may help you feel more alert. More evidence is needed, however, to know if aromatherapy really can boost your memory.

Sandi Hewins