ONCE LIMITED to hospitals and crime labs, DNA testing is now available to the masses, thanks to a handful of companies such as the Great Smokies Diagnostic Lab, in Asheville, North Carolina (see "Code Breakers"); Global DNA Solutions, in Malibu, California; and Sciona, which dominates the direct-to-consumer market thanks to a take-home test first sold at the end of 2002.

Despite its sci-fi nature, plugging nutrigenomics into your training plan is fairly simple. The Sciona test is available online or through distributors like Seattle-based Genelex, which charges $495 for processing the kit. You just swab the inside of your cheek and mail the swabs to the lab for a chemical analysis of genes that relate to heart health, antioxidation and detoxification, inflammation, bone health, and insulin sensitivity. After you receive the analysis, you can get in touch with one of Genelex's 60 nutritionists, like Los Angeles–based Carolyn Katzin, who's assisted dozens of marathoners and triathletes with their diets. Over the course of a 30-minute phone consultation, Katzin will go over your genetic profile and create a meal plan to help you get the most out of your training. "My job," says Katzin, "is to pack you with energy and antioxidants."

Last fall, recreational athlete Alesandra Rain, 48, experienced nutrigenomics firsthand. An avid cyclist, she was forced to give up her 100-mile-a-week riding schedule because of a weakening spine. A DNA test from Global DNA Solutions pointed out that she couldn't metabolize vitamin B or calcium in pill form, conditions that resulted in a loss of bone density. Her dietary consultant told her to add pine nuts, broccoli, cauliflower (for vitamin B-6), and onions (a key source of quercetin, which helps bones retain calcium) to her salads. A month after her dietary shift, "my spine healed," says Rain, who also enjoyed giant gains in her workouts— lifting three times the weight she had previously.

The list of amateurs and pros jumping on the nutrigenomics train continues to grow. Currently, the NFL Players Association is considering ordering tests for all their athletes to help them boost their performance naturally and safely. But they may want to wait a couple of years. That's when Sciona plans to release a $200 jock-specific test that analyzes ten additional genes not found in the current 19-gene nutrition test.

"We'll look for genetic variations involved in lung capacity and heart rate that can reduce or increase the amount of oxygen in the blood, a factor that affects performance and endurance," says Grimaldi. The test will also indicate whether you're predisposed to anaerobic sports, like climbing or boxing, or endurance activities, like cycling or running—or if you're somewhere in between.