'Jury still out' on Atkins Diet
Popularity soars, but long-term health effects remain unknown
Scott Craven, The Arizona Republic, Feb. 25, 2004 12:00 AM
http://www.azcentral.com/arizonarep...nshealth25.html
For more than 30 years, the Atkins Diet has been going against the grain, recommending high-protein foods that often are associated with various ills, from colon cancer to heart disease.
That hasn't stopped millions of Americans from bellying up to the Atkins bar, which was bolstered late last year when two short-term studies showed the diet to be healthier than expected.
But doctors, nutritionists and other experts are not certain of the long-term health effects. Nor do they all agree with findings that indicate Atkins may be as good for you as it is effective.
The uncertainty hasn't dissuaded people from joining the low-carb craze. Sales of low-carb products and services should exceed $28 billion this year, nearly doubling totals from 2003, according to figures released this month by Lowcarbiz, a new publication tracking the trend. It also found that 28 percent of Americans are curbing their carbohydrate intake and an additional 20 percent are planning to reduce carbs this year.
Retailers are reacting quickly with stores and product lines aimed at low-carb diets. About 10 low-carb stores are opening in the United States each week, said Laurie Kuntz, chief executive officer of Lowcarbiz. And merchandising giants ConAgra and Unilever-Best Foods are the latest to unveil extensive low-carb lines.
Answers years away
In terms of health and safety, the one thing health experts do agree on is that definitive answers are years away.
People should not interpret last year's studies as proof that Atkins is safe and healthful, although that is likely just what dieters are doing, said Dr. George Blackburn, director of the Center for the Study of Nutrition Medicine at Beth Israel Deaconess Medical Center at Harvard University.
Too often, people make decisions based on the earliest research results, even when those results aren't conclusive.
"That is the regret," Blackburn said. "It's a dilemma. We really don't have the data to allow us to say it (the Atkins Diet) is safe. Nor can we say it is not safe. We just don't know."
In a six-month study involving 132 severely obese men and women, researchers at the Philadelphia Veteran Affairs Medical Center last year found those on a restricted-carbohydrate diet not only lost more weight than those on a conventional diet, but also had reduced levels of triglycerides, which contribute to heart disease.
In a similar yearlong study finished last year by Dr. Gary Foster at the University of Pennsylvania, those on the Atkins Diet lost the same amount of weight as those on a reduced-fat diet, but experienced lower triglyceride levels as well as an increase in HDL, the "good" cholesterol.
"The study flew in the face of conventional knowledge," said Foster, clinical director of the Weight and Eating Disorders Program at the University of Pennsylvania.
Spurred by his findings, Foster is in the second year of a comprehensive five-year study expected to determine if Atkins is a safe, healthy and effective weight-loss diet. Numbers seen in the initial study show that the Atkins Diet is healthy in the short term, but Foster said more definitive results are needed before he would recommend the diet for more than six months to a year.
His new study, funded by the National Institutesof Health, looks not only at weight loss and blood chemistry, but Atkins' effect on arteries (low-carb diets can limit elasticity, increasing the risk of heart disease), blood pressure, bone loss and kidney function.
Problems with studies
Not all doctors and nutritionists have been swayed by Foster's earlier study, the results of which were published in November in the New England Journal of Medicine.
The Physicians Committee for Responsible Medicine, which promotes a vegetarian diet, issued a warning about Atkins and other high-protein, low-carb diets, saying risks of long-term use include colorectal cancer, heart disease, osteoporosis and impaired kidney function. Dr. Carol Johnston, a professor of nutrition at Arizona State University who has published two studies on the reduced-carb Zone Diet, said the Foster study was fatally flawed, invalidating its "questionable" results.
The biggest problem, Johnston said, was that participants were not rigorously monitored, allowing them to cheat on the diets. Her suspicion was borne out when Johnston, who analyzed Foster's study, found that 40 percent of the Atkins dieters were not in ketosis, a condition in which the body burns fat because there are no energy stores supplied by carbohydrates. Atkins depends on ketosis for weight loss.
"The fact so many people were not in ketosis shows me they weren't following Atkins to the letter," Johnston said.
The Foster study also ignored suspected ills such as bone loss and kidney disease, Johnston said.
In addition, people should be careful if maintaining the diet for more than a few months because of the plan's avoidance of foods with essential vitamins, including calcium in milk and vitamin C in citrus.
"Atkins is not based on sound dietary principles," Johnston said. "Over time, people on that diet can develop scurvy and other complications. It can affect bone density. We really need to know more about it."
Dieters also should remember that not all carbs are bad. Whole grains break down slowly and do not significantly raise blood-sugar levels the way processed food, such as white bread and doughnuts, can. And carb-rich fruits and vegetables, such as oranges and carrots, provide health benefits vital to everyone, Johnston said.
Foster admitted the shortcomings of his study.
"You need large numbers of people and much more comprehensive and thoughtful testing," he said. "It was just that patients and even other physicians were asking about the diet. I got tired of saying we didn't know, so we did this small study."
Dena Bravata, a senior scientist at Stanford University, last year analyzed more than 100 studies of high-protein, low-carb diets and found that research came up short in determining if those plans were safe for everyone. Bravata was puzzled by the lack of long-term studies given the popularity of Atkins and the fact the diet has been around more than 30 years.
The two biggest problems with the studies were length and the age of participants. Most were short term, lasting 90 days or fewer. And none involved subjects with a mean age in excess of 54, so there was very little evidence of how low-carb diets affected older people, Bravata said.
As a result, Atkins remains a mystery. "In terms of safety, no one has found harmful side effects," she said. "But we've only looked at short-term effects. There's little evidence of what happens long term."
'We just don't know'
Time will tell if Atkins causes any ill effects, Harvard's Blackburn said. For now, it's best to check with a physician before going on any diet, particularly Atkins.
"I know most people will go on Atkins without checking with their doctors," Blackburn said. "But we can't say it's safe any more than we can say it's not. We just don't know at this point."
At its worst, Atkins could be a ticking bomb for people who stay on it for years, said Dr. Penny Kris-Etherton, distinguished professor of nutrition at Penn State. The damage that can be related to high-protein, high-fat diets, including bone loss and heart disease, may not show up for 10 to 15 years, she said.
Even more alarming is the faith people are putting into Atkins based on success stories from their friends and the media, Kris-Etherton said. She likened it to the low-fat stampede of the 1990s when consumers took the "reduced fat" label on foods to mean they could eat more. Much of the weight lost on the low-fat diets was regained because calories were ignored.
"We're on track for the same train wreck with Atkins," she said. Elaine Manahan, a dietitian at the Carl P. Hayden Veterans Affairs Medical Center in Phoenix, said she would recommend Atkins to those clients who needed to jump-start a weight-loss program because Atkins is known to take off pounds quickly in the initial stages.
Still, she's not particularly worried about long-term effects. "They're very difficult diets to follow because they're so strict," Manahan said. "Nearly everyone I know who started Atkins quit after a few months. They didn't like giving up so many carbs."
[related article - gotbeer]
3 Experiences on Atkins
Feb. 25, 2004 12:00 AM
http://www.azcentral.com/news/artic...5vignettes.html
Doctors commonly urge people to see their physicians before starting a diet, but in the rush to join the Atkins express, few are making the brief stop necessary to ensure the program is the best for them. The results among people we spoke with were mixed.
Lisa Hilton (above), 42, of Gilbert, lost 8 pounds in a month and remained near 152 for the next four months. The food on the plan bored, so after 5 1/2 months, she quit, relying instead on a mix of healthier eating and portion control. She now weighs 125 pounds.
"It was a lot more limiting than I thought it would be," Hilton said. "I can't think of anybody I know who stayed on it for more than a few months. You have to deprive yourself of too many things."
Dave Rowland, 51, of Phoenix, started Atkins a year ago to support his wife, Nona, who wanted to lose weight to fit into a certain dress. He dropped 15 pounds the first month and remains on Atkins, hovering at around 165 pounds, about what he weighed in high school. He also exercises and eats more fish and chicken than beef.
"It took an adjustment to stay on Atkins at first, but now it's easy, especially with all the Atkins food in stores and at restaurants," Rowland said. "I may cheat every now and then, have a little rice, but I don't feel deprived at all."
Willis Daychild (above), 40, of Phoenix, became interested in Atkins when his sister, a medical resident in Hawaii, told him she had heard good things about it. He dropped 44 pounds in three months, getting as low as 270 pounds before taking a break for the holidays. Blood tests showed his LDL (the bad cholesterol) down to 148 from 182 the year before.
"I was concerned about the health risks I'd heard about (concerning Atkins)," Daychild said. After the weight loss, "I thought, 'Wow, this diet works.' It calmed some of my fears."
- Scott Craven
"'Jury still out' on Atkins Diet"
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