USA: Living a longer life: whose advice helps?

. LOS ANGELES, California / Los Angeles Times / Fitness & Nutrition / July 13, 2009 For decades, longevity gurus have touted their plans. But have they delivered? Aging experts weigh in. By Marnell Jameson Live a life without frailty and disease, and enjoy lasting youth, both physical and mental. Purveyors of longevity have been cashing in on that promise for centuries -- never mind that not one of the people prescribing a life-extension plan has ever delivered one that worked. "Longevity gurus share one characteristic," says Jay Olshansky, author of "The Quest for Immortality: Science at the Frontiers of Aging" and a professor of epidemiology at the University of Illinois at Chicago School of Public Health. "Most are dead. And they all died at about the same age and of the same causes as the rest of the population." Here's a look back at some of the folks who have influenced American views of longevity and related behavior over the last 100 years. Click here to view what our aging experts have to say about their approaches. Adelle Davis 1904-74 Jack LaLanne 1914- Nathan Pritikin 1915-85 Robert Atkins 1930-2003 Roy Walford 1924-2004 Jim Fixx 1932-84 Durk Pearson 1943 - Sandy Shaw 1943 - Alan Mintz 1938-2007 Mehmet Oz 1960 - Television personality and medical doctor Dr. Mehmet Oz talks at the Venetian Hotel-Casino in Las Vegas, Nevada during the Consumer Electronics Show (CES) on January 8, 2009. David McNew / Getty Images The longevity guru du jour, Mehmet Oz is a cardiac surgeon . and the director of the Cardiovascular Institute at Columbia University Medical Center in New York. He's also the power behind RealAge.com, a website that invites visitors to learn how their birth age stacks up against their "real age." He's also the author of several books with Dr. Michael Roizen, including "YOU: The Owner's Manual: An Insider's Guide to the Body That Will Make You Healthier and Younger." A telegenic media personality, Oz often appears on "The Oprah Winfrey Show" wearing scrubs and touting ways to achieve optimal health and "extreme longevity." He declares that people living today can reach age 125, "without any question." The verdict: Though the public loves his optimistic views on longevity, scientists in the field are less charitable. "Oz mistakenly assumes we all have the potential to live as long as the longest-lived person, and that's not true. He doesn't understand the difference between preventing disease and aging," Olshansky says. However, researchers do give Oz points for his RealAge Test, an online questionnaire that has visitors enter information about their genes, health issues and lifestyles, to determine their age score. "I'm all for any education tool that provides an interesting way to get the public thinking about healthier behaviors," Perls says. "Most of what's on his site is backed by good science." The site has received criticism, most notably from the New York Times, for sharing visitors' medical profiles with pharmaceutical companies for marketing purposes. [rc] health@latimes.com Copyright 2009 Los Angeles Times