A recent study published in the Nutrients Journal investigated the significant effects of desert olive tree pearls (DOTPs) on the cognitive function of Japanese older adults by alleviating complex attention, psychomotor speed, reaction time, cognitive flexibility, speed of thought, and executive function domains.

Study: Effects of Desert Olive Tree Pearls Containing High Hydroxytyrosol Concentrations on the Cognitive Functions of Middle-Aged and Older Adults. Image Credit: OrawanPattarawimonchai/Shutterstock.com

Background

Due to long life expectancy, Japan is experiencing a demographic shift towards a super-aging society. The Long-Term Care Insurance Law went into effect in 2000 to address issues that the elderly population faced, but it has since grown to be a significant source of distress.

Preserving and enhancing the cognitive abilities of elderly individuals presents challenges, with the rise in age-related dementia being a significant concern. The rapidly evolving costs and unpredictable effectiveness of pharmacological interventions for dementia pose challenges for older individuals implementing preventative strategies.

Non-pharmacological interventions for enhancing cognitive function in older individuals in Japan have been limited, and dietary modifications, natural supplements, and physical exercise are needed instead of relying solely on pharmaceutical interventions.

The Mediterranean diet (MedDiet) has been shown to decrease the likelihood of various ailments and offer therapeutic benefits.

Olive oil products, especially DOTPs, have hydroxytyrosol (HYD), a supplement with antioxidative, anti-inflammatory, anti-atherogenic, and anti-thrombotic health benefits.

The present study examined the impact of DOTPs enriched with HYD on cognitive abilities in middle-aged and older individuals over 12 weeks.

About the study

The investigation was carried out using a randomized, placebo-controlled, double-blind, parallel-group study in Tsukuba City, Japan, using regional information periodicals and telephone interviews to recruit middle-aged and elderly residents.

The study followed ethical guidelines and obtained consent from 72 participants. The research used methods that adhered to ethical norms between April 4 and June 26, 2022.

Atlas Olive Oils Company of Morocco produced DOTPs using olive leaves and fruits containing polyphenols like HYD, oleocanal, and oleacein. The DOTPs had the highest hydroxyl content (16.2 mg/g). Compared to a placebo group, participants consumed three grams of DOTPs combined with hydroxyl twice daily at breakfast and dinner.

After a 12-week intervention, cognitive function was evaluated to measure verbal, visual, and composite memory, processing and psychomotor speed, executive function, reaction time, attention, cognitive flexibility, and motor speed.

Data was analyzed using the SPSS software (version 26) with a significance level of p 0.05. The Shapiro-Wilk test was used to ascertain the normality of distribution for all data.

The mean baseline characteristics were compared to the standard deviation or frequency counts between groups.

Repeated measures were used to calculate differences in outcome measures between groups, with years of education as a covariate. When the interaction was significant, the primary outcomes of time and group were evaluated. The effect sizes have been calculated by removing the pre-test standard deviation from the average change.

Study outcomes

There was no difference between the outcomes of the DOTP and placebo groups in this study because all participants had the same physical condition, level of education, blood pressure, pulse rate, and drug use.

Over 12 weeks, participants in the DOTP group received 32.4 mg/day of HYD, 40.5–97.2 times greater than the placebo group (0.2–0.8 mg/day, totaling approximately 33.6–67.2 mg).

Cognitrax, a standardized method for assessing multiple cognitive domains using computerized tests, revealed a significant difference between the two groups. High concentrations of HYD in DOTPs substantially enhanced the cognitive function of older adults compared to middle-aged adults.

This suggests that DOTPs enhance cognitive function in older adults more effectively than middle-aged adults.

Due to dietary differences, Cognitive function improved in middle-aged Japanese individuals who consumed fewer olive-related foods than their Western counterparts.

Even after 12 weeks, the cognitive functions of complex attention, reaction time, cognitive flexibility, processing speed, and executive function demonstrated statistical significance (p 0.05).

Consuming DOTPs, which have high amounts of HYD, daily may have a positive effect on maintaining and enhancing cognitive function in elderly Japanese individuals who are unfamiliar with olive products.

Conclusions

To achieve the Japanese government's goals to better the lives of their aging population, they suggested healthy foods and supplements, such as the MedDiet, often associated with preventing various ailments.

Extra virgin olive oil (EVOO) is a beneficial active element in olives, part of the MedDiet. HYD is found in olives, which can help with Alzheimer's disease and prolong life expectancy.

The present study shows that MedDiet's DOTPs may be appropriate for middle-aged and older Japanese individuals. Results show temporary changes, but long-term intervention studies are needed to track cognitive function changes in this population.

In conclusion, DOTP consumption may be pivotal in extending healthy life expectancy and mitigating issues confronted by older Japanese adults.

Written by

Susha Cheriyedath

Susha has a Bachelor of Science (B.Sc.) degree in Chemistry and Master of Science (M.Sc) degree in Biochemistry from the University of Calicut, India. She always had a keen interest in medical and health science. As part of her masters degree, she specialized in Biochemistry, with an emphasis on Microbiology, Physiology, Biotechnology, and Nutrition. In her spare time, she loves to cook up a storm in the kitchen with her super-messy baking experiments.