In the study, researchers at the University of California, Irvine recruited 43 participants, aged 60-85 years who were randomly assigned to two groups. In the experimental group, participants were exposed to an essential oil diffuser nightly. They were instructed to rotate through one of seven different scents, one for each day of the week: rose, orange, eucalyptus, lemon, peppermint, rosemary, and lavender. Meanwhile, the control group was exposed to trace amounts of these essential oils.

All participants underwent a set of assessments at baseline and after the six-month intervention. The study found that, compared to the control group, participants in the olfactory-enrichment group displayed a 226 percent improvement in their performance on the Rey Auditory Verbal Learning Test—a word list recall test used to assess verbal learning and memory.

Authors highlighted that the sense of smell is the only sense that has direct access to the memory centers of the brain and that nightly aromatherapy use is a good way to stimulate those centers with very low effort and at very low cost.

Quercetin Supplementation Helps with Pollen Allergy Struggles

A 2022 randomized, double-blind, placebo-controlled study published in the European Review for Medical and Pharmacological Sciences² found that a phytosomal formulation of quercetin significantly improved several seasonal allergy symptoms during pollen season in Tokyo. Researchers followed allergy sufferers who took a quercetin phytosome supplement for four weeks during pollen season. A phytosome is a delivery system made of phospholipids (a type of fat) that makes a supplement more bioavailable.

Subjects assigned to the experimental group received 50mg of quercetin phytosome four times daily, for a total of 200 mg of quercetin phytosome each day over a period of four weeks. Researchers assessed a multitude of allergy-related quality of life parameters. After comparing baseline to the end of the four weeks, participants in the quercetin group showed significantly improved results in sneezing, mental focus, ability to participate in outdoor activities, better sleep, reduction in fatigue, and facial swelling.

Authors concluded that four weeks of continuous quercetin phytosome ingestion improved both subjective measurements (like sleep) and objective measurements (like severity of allergic rhinitis), which significantly alleviated the effect of allergic rhinitis on quality of life.

References

1. Woo, C. C., Miranda, B., Sathishkumar, M., Dehkordi-Vakil, F., Yassa, M. A., & Leon, M. (2023). Overnight olfactory enrichment using an odorant diffuser improves memory and modifies the uncinate fasciculus in older adults. Frontiers in neuroscience, 17, 1200448. https://doi.org/10.3389/fnins.2023.1200448
2. Yamada S, Shirai M, Inaba Y, Takara T. Effects of repeated oral intake of a quercetin-containing supplement on allergic reaction: a randomized, placebo-controlled, double-blind parallel group study. Eur Rev Med Pharmacol Sci. 2022:26(12):4331-4345.