The Biology of Belief

Science and religion argue all the time, but they increasingly agree on one thing: a little spirituality may be very good for your health

  • Illustration by Christian Northeast for TIME

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    Pray and meditate enough and some changes in the brain become permanent. Long-term meditators — those with 15 years of practice or more — appear to have thicker frontal lobes than nonmeditators. People who describe themselves as highly spiritual tend to exhibit an asymmetry in the thalamus — a feature that other people can develop after just eight weeks of training in meditation skills. "It may be that some people have fundamental asymmetry [in the thalamus] to begin with," Newberg says, "and that leads them down this path, which changes the brain further."

    No matter what explains the shape of the brain, it can pay dividends. Better-functioning frontal lobes help boost memory. In one study, Newberg scanned the brains of people who complained of poor recall before they underwent meditation training, then scanned them again after. As the lobes bulked up, memory improved.

    Faith and health overlap in other ways too. Take fasting. One of the staples of both traditional wellness protocols and traditional religious rituals is the cleansing fast, which is said to purge toxins in the first case and purge sins or serve other pious ends in the second. There are secular water fasts, tea fasts and grapefruit fasts, to say nothing of the lemon, maple-syrup and cayenne-pepper fast. Jews fast on Yom Kippur; Muslims observe Ramadan; Catholics have Lent; Hindus give up food on 18 major holidays. Done right, these fasts may lead to a state of clarity and even euphoria. This, in turn, can give practitioners the blissful sense that whether the goal of the food restriction is health or spiritual insight, it's being achieved. Maybe it is, but there's also chemical legerdemain at work. ( See pictures of Pope Benedict XVI visiting America. )

    The brain is a very energy-intensive organ, one that requires a lot of calories to keep running. When food intake is cut, the liver steps into the breach, producing glucose and sending it throughout the body — always making sure the brain gets a particularly generous helping. The liver's reserve lasts only about 24 hours, after which, cells begin breaking down the body's fats and proteins — essentially living off the land. As this happens, the composition of the blood — including hormones, neurotransmitters and metabolic by-products — changes. Throw this much loopy chemistry at a sensitive machine like the brain and it's likely to go on the blink. "There are very real changes that occur in the body very rapidly that might explain the clarity during fasting," says Dr. Catherine Gordon, an endocrinologist at Children's Hospital in Boston. "The brain is in a different state even during a short-term fast." Biologically, that's not good, but the light-headed sense of peace, albeit brief, that comes with it reinforces the fast and rewards you for engaging in it all the same. ( See pictures of the end of Ramadan. )

    How Powerful Is Prayer?
    For most believers, the element of religious life that intersects most naturally with health is prayer. Very serious theologians believe in the power of so-called intercessory prayer to heal the sick, and some very serious scientists have looked at it too, with more than 6,000 published studies on the topic just since 2000. Some of them have been funded by groups like the John Templeton Foundation — part of whose mission is to search for overlaps of religion and science — but others have come from more dispassionate investigators.

    As long ago as 1872, Francis Galton, the man behind eugenics and fingerprinting, reckoned that monarchs should live longer than the rest of us, since millions of people pray for the health of their King or Queen every day. His research showed just the opposite — no surprise, perhaps, given the rich diet and extensive leisure that royal families enjoy. An oft discussed 1988 study by cardiologist Randolph Byrd of San Francisco General Hospital found that heart patients who were prayed for fared better than those who were not. But a larger study in 2005 by cardiologist Herbert Benson at Harvard University challenged that finding, reporting that complications occurred in 52% of heart-bypass patients who received intercessory prayer and 51% of those who didn't. Sloan says even attempting to find a scientific basis for a link between prayer and healing is a "fool's errand" — and for the most basic methodological reason. "It's impossible to know how much prayer is received," he says, "and since you don't know that, you can't determine dose."

    Such exactitude does not dissuade believers — not surprising, given the centrality of prayer to faith. But there is one thing on which both camps agree: when you're setting up your study, it matters a great deal whether subjects know they're being prayed for. Give them even a hint as to whether they're in the prayer group or a control group and the famed placebo effect can blow your data to bits.

    First described in the medical literature in the 1780s, the placebo effect can work all manner of curative magic against all manner of ills. Give a patient a sugar pill but call it an analgesic, and pain may actually go away. Parkinson's disease patients who underwent a sham surgery that they were told would boost the low dopamine levels responsible for their symptoms actually experienced a dopamine bump. Newberg describes a cancer patient whose tumors shrank when he was given an experimental drug, grew back when he learned that the drug was ineffective in other patients and shrank again when his doctor administered sterile water but said it was a more powerful version of the medication. The U.S. Food and Drug Administration ultimately declared the drug ineffective, and the patient died. All that may be necessary for the placebo effect to kick in is for one part of the brain to take in data from the world and hand that information off to another part that controls a particular bodily function. "The brain appears to be able to target the placebo effect in a variety of ways," says Newberg. There's no science proving that the intercessions of others will make you well. But it surely does no harm — and probably helps — to know that people are praying for you.

    See pictures of spiritual healing around the world.

    See pictures of a drive-in church.

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