- By Rita Rubin
Grandmothering, but not too much grandmothering, may be good for your brain, new research suggests.
Older adults with large social networks and those who report high levels of participation in social activities, such as volunteer work and visiting friends, have sharper brains and keep them that way longer than their peers who are less engaged and less active, Australian scientists wrote recently in the journal Menopause. But, they said, researchers have overlooked caring for grandchildren as a social activity that could help stave off a decline in thinking ability and memory.
The scientists focused on 186 women age 57 to 68 who completed a questionnaire about whether they had grandchildren and, if so, whether they currently took care of them and for how many days each week. The questionnaire also asked if the women felt their children had been particularly demanding of them in the previous year.
Study participants also took four tests that assessed how well they could recall words read to them and their executive function, a set of mental skills that includes managing time and planning and organization.
(MORE: Avoid the Grandparent Trap)
Of the 186 women, 55 did not have grandchildren. On average, those without grandchildren were about a year younger and had completed about a year more education than the grandmothers. The women without grandchildren were also more likely to be employed.
The women who said they cared for their grandchildren one day a week had the best memory test scores of all. The women’s scores on the executive function tests were similar, except for those who said they cared for grandchildren at least five days a week — those women had lower scores.
The Role of Mood, Fatigue
A third of the participants reported feeling that their children were demanding, but because that question asked only for a simple "yes" or "no" answer, the researchers didn't know the nature of the demands. However, their findings suggest that the demands involved a heavy load of babysitting. The more time the women spent caring for their grandchildren, the more likely they were to feel that their children were demanding. That association indicates mood might be a factor in the relationship between spending a lot of time with grandchildren and a decline in mental acuity, the researchers write.
The study raises several questions, acknowledges co-author Cassandra Szoeke, a neurologist who directs the Women’s Healthy Aging Project at the University of Melbourne. Among them:
- Could fatigue help explain why the women who cared for their grandchildren five days a week or more didn’t perform as well on the processing and planning tests? “We will be looking at this in our next study,” Szoeke told Next Avenue. “We do know that people who are sleep-deprived or fatigued do perform worse on the planning and processing speed tasks.”
- Would the grandchildren’s ages — infants vs. toddlers vs. school-age children — make a difference? “This is an important point,” Szoeke said. “We are now asking the women this question to determine if there is a relationship with the age of children.”
- Some of the youngest women in the study are mothers of teens or even tweens, not grandmothers. Do women who become mothers at a relatively late age stay sharper than those who become empty-nesters sooner? “This is an excellent question, but one we haven’t answered in this research,” Szoeke said. “The question is not straightforward,” she added, because older mothers not only are older but also tend to have more education, both of which impact memory and learning.
- Would the results be similar in a study of U.S. women? “We have no reason to believe the finding would be different in other countries,” Szoeke said. “However, this is just one study, and I hope to see many more both nationally and internationally.”
Unique Human Grandmothers
One reason scientists might have overlooked the impact of grandmothering on brain sharpness is that they have no animal models to study.
Females in no other primate species live long, healthy lives after menopause. Chimpanzee females, for example, continue to ovulate until they nearly reach the maximum age for their species and most die before they go through menopause.
A popular explanation for women’s long postmenopausal life is called the “grandmother hypothesis.”
“The hypothesis contends that, in past epochs, women who remained vigorous beyond their fertile years may have enhanced their reproductive success by providing care for their grandchildren,” according to an article on “the grandmother effect” by James Herndon, who retired last year as a researcher at the Yerkes National Primate Research Center at Emory University in Atlanta. “This care would have enabled their daughters to resume reproduction sooner.”
Physical strength and resistance to age-related decline in mental sharpness play a role in in this “peculiarly human” individual known as grandma, Herndon wrote.
Rita Rubin is a former USA Today medical writer who now writes about health and science for publications including Next Avenue, WebMD and NBCNews.com.