If you live in Georgia, you're more likely to have a healthy brain than if you live in Minnesota. That's according to an annual state-by-state ranking released this week by a national health education campaign called Beautiful Minds.
While Georgians could use more "mental stimulation through reading and game playing," their high level of religious activity elevated them to a No. 10 ranking. And while Minnesotans read more and are active in their communities, their low level of religious activities contributed to their No. 31 ranking.
Why the emphasis on religion? Research has linked religious activity with everything from reduced stress to better memory retention.
One recent study, published in December of 2013 in JAMA Psychiatry, found that people at risk of depression were much less vulnerable if they identified as religious: Brain MRIs revealed that religious participants had thicker brain cortices than those who weren't as religious (those with a family history of depression often have a thinning of the cortices).
Harold G. Koenig, director of the Center for Spirituality, Theology, and Health at Duke University and a professor of psychiatry, said the depression research will likely be hailed as a landmark study -- but he wasn't surprised by the findings. He's written books, including "The Healing Power of Faith," "Faith and Mental Health," about the health benefits of religion. Those benefits include lowered stress through prayer and meditation.
"One of the worst killers of brain cells is stress," said Dr. Majid Fotuhi, founder and chief medical officer of NeurExpand and a lecturer at Harvard Medical School, as well as a consultant to the Beautiful Minds project. "Stress causes high levels of cortisol, and cortisol is toxic to the hippocampus. One way to reduce stress is through prayer. When you're praying and in the zone you feel a peace of mind and tranquility."
The social element of attending religious services has also been linked to healthy brains.
"There's something magical about socializing," Fotuhi said. "It releases endorphins in the brain. It's hard to know whether it's through religion or a gathering of friends, but it improves brain health in the long term. And it's also been shown that people who are introverted and don't participate are more likely to get Alzheimer's."
Listening to sermons and reading religious works like the Bible may also invoke a cognitive benefit, Koenig said.
"You're exercising your higher cortical function, thinking about complex concepts that require some imagination."
And while a 2011 study found a shrinking of the hippocampus among people of certain religions, Koenig, a co-author of the study, points out that no one has replicated that work yet.
So where does that leave non-believers?
"Out of luck, I guess," Koenig joked. "Actually, I would suspect that people doing the types of things like religious people do -- socializing, doing similarly complex cognitive tasks, would have similar benefits. But it is interesting that religion provides that whole package of things that people can adopt and pursue over time."
While a January study published in the journal Brain Connectivity identified specific networks of the brain used to contemplate religious beliefs, suggesting that some people may be "hard-wired" to be religious, the opposite -- that religious belief begets a healthier brain -- has not been shown. Research has instead focused on long-term religious activity, not belief.
"My personal belief is that having a strong belief is key to getting the benefits," Fotuhi said. "It's hard to study these things; it's why research has stayed away from them. But there does seem to be a strong link between spirituality and better brain health."