On November 15, 2010, the American Heart Association Scientific Sessions 2010 featured presentations of the results of two studies which indicate that lifestyle has a greater impact on whether one will develop cardiovascular disease than being genetically predisposed to acquire the disease.

Diet, physical activity, alcohol intake, smoking status, weight, and blood pressure and glucose levels were assessed at the beginning of the study and at the seventh and twentieth years of follow-up.

Among participants who maintained five healthy lifestyle factors (having a healthy body mass index, limiting alcohol consumption, consuming healthy amounts of potassium, calcium and fibre and a low intake of saturated fat; participating in regular exercise, and never smoking) 60 percent had a low risk profile for cardiovascular disease after 20 years. That percentage dropped to 37 percent for those who had four factors, 30 percent for three factors, 17 percent for two and 6 percent for one or none. Separate analyses for men, women, Caucasians and African-Americans turned up similar findings.

This clearly shows what we intuitively have known for years. Lifestyle and dietary habits have significant impact on our gene expression. It is what we do and how we live that determines our cardiovascular risk.

Two years ago, researchers at UCLA found that specific regions in the brains of long-term meditators were larger and had more gray matter than the brains of individuals in a control group. This suggested that meditation may indeed be good for all of us since, alas, our brains shrink naturally with age.

Now, a follow-up study suggests that people who meditate also have stronger connections between brain regions and show less age-related brain atrophy. Having stronger connections influences the ability to rapidly relay electrical signals in the brain. And significantly, these effects are evident throughout the entire brain, not just in specific areas.

Eileen Luders, a visiting assistant professor at the UCLA Laboratory of Neuro Imaging, and colleagues used a type of brain imaging known as diffusion tensor imaging, or DTI, a relatively new imaging mode that provides insights into the structural connectivity of the brain. They found that the differences between meditators and controls are not confined to a particular core region of the brain but involve large-scale networks that include the frontal, temporal, parietal and occipital lobes and the anterior corpus callosum, as well as limbic structures and the brain stem.

The study appears in the current online edition of the journal NeuroImage.

“Our results suggest that long-term meditators have white-matter fibers that are either more numerous, more dense or more insulated throughout the brain,” Luders said. “We also found that the normal age-related decline of white-matter tissue is considerably reduced in active meditation practitioners.”

But there is a “but.” While it is tempting to assume that the differences between the two groups constitute actual meditation-induced effects, there is still the unanswered question of nature versus nurture.

“It’s possible that meditators might have brains that are fundamentally different to begin with,” Luders said. “For example, a particular brain anatomy may have drawn an individual to meditation or helped maintain an ongoing practice – meaning that the enhanced fiber connectivity in meditators constitutes a predisposition towards meditation, rather than being the consequence of the practice.”

Still, she said, “Meditation appears to be a powerful mental exercise with the potential to change the physical structure of the brain at large. Collecting evidence that active, frequent and regular meditation practices cause alterations of white-matter fiber tracts that are profound and sustainable may become relevant for patient populations suffering from axonal demyelination and white-matter atrophy.”