Great Food for Your Body, Heart and Brain



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Power Makers: Meat and Milk
Once nutrients make their way into a neuron, small furnaces within the cells turn them into energy by combusting glucose and oxygen. The cellular furnaces, known as mitochondria, create energy less efficiently as you age. As mitochondria sputter, cells have less energy to power critical activities like the repair of everyday damage and replication of DNA. The downslide in cell metabolism likely contributes to the cognitive decline seen with age.

What's more, mitochondria spew cell-damaging free radicals of oxygen into their environment, and the more they age, the more renegade-free radicals they generate. "It's like an old car engine that's spitting out black smoke," explains Bruce Ames, professor of biochemistry and molecular biology at the University of California at Berkeley.

Give mitochondria a tune-up, reasons Ames, and they'll turn out more energy and fewer free radicals. He focuses on two food-based mitochondrial boosters: acetyl-L-carnitine and lipoic acid. Acetyl-L-carnitine, a version of an amino acid found in meat, milk and avocado, helps shuttle fatty acids into mitochondria. Lipoic acid, found in beef, spinach and broccoli, quenches free radicals. In cahoots, these compounds in high concentrations combat memory loss in lab rats, Ames reports. He's testing a combination pill for people.

Another dietary factor -- or, more precisely, lack thereof -- may beef up mitochondrial function. Low caloric intake, shown to prolong the life span of rats, also seems to revive mitochondrial function, perhaps because mitochondria with fewer nutrients to burn emit fewer free radicals.

It may also do more: promote the growth of entirely new neurons. Mark P. Mattson, chief of the neurosciences lab at the National Institute on Aging and flag bearer for low-cal research, advises people who are overweight to cut back on calories. The benefits are less clear for people who are already of normal weight.

Youth Keepers: The Berry Elixir
Along with an increase in free radicals, aging can bring a decrease in the body's ability to deal with these errant molecules, which have a particular affinity for attacking cell membranes. And in a vicious cycle, the damage caused by unchecked free radicals -- aka, oxidative stress -- ends up compounding the aging process.

"Every major disease that kills people in this country has an oxidative stress component," says Joseph of Tufts University. For him and other researchers interested in preserving the brain's ability to function, oxidative stress seems like a natural enemy. The scientists also have natural allies: fruits and vegetables. They contain a whole circus troupe of antioxidants, colorful substances that arrest free radicals by nullifying their rogue electrons.

Some antioxidants are already familiar faces in nutrition. Vitamins C and E, for instance, are the main antioxidants in the brain. But they're getting new respect as potential keepers of brain health, since they appear to guard aging neuronal membranes from free radicals.

Other antioxidants have only recently stepped into the limelight. Many are natural chemicals that plants have evolved to protect themselves from disease. The major antioxidants in plants, known as flavonoids, come in two main flavors: anthocyanins, in brightly colored fruits, and their colorless cousins, anthoxanthins, found notably in green tea (epigallocatechins) and soybeans (isoflavones).

With a rich load of anthocyanins, the most colorful produce also tends to be the most potent. Blueberries, blackberries and cranberries offer more antioxidant protection than the legendarily nutritious brussels sprout. Their antioxidants also have anti-inflammatory actions, soothing overagitated immune cells that may hamper brain activity.

In practice, the petite blueberry reverses some of the effects of aging on the brain, boosting short-term memory and spatial learning -- reviving the ability of doddery lab rats to move through mazes. People who eat a cup of blueberries a day perform well on tests of motor skills. Purple grape juice, similarly rich in flavonoids, similarly boosts performance. Grape juice and red wine also promise to stave off heart disease, in part because of the activity of another powerful antioxidant, resveratrol.