WEDNESDAY, Dec. 6, 2017 (HealthDay News) -- The old adage that "an apple a day keeps the doctor away" appears to be at least partly true for people living with multiple sclerosis (MS).
New research suggests that a healthy diet -- one that's chock-full of fruits, vegetables and whole grains but contains little added sugars and red or processed meats -- was associated with a reduced risk for disability.
The study also found that a healthy lifestyle was linked to less depression, fatigue and pain for people with MS. Living healthily means eating a healthy diet, exercising regularly, maintaining a normal weight and not smoking.
"This is an important topic that's very much on the minds of my patients," said Dr. Claire Riley, medical director of the Multiple Sclerosis Center at New York Presbyterian/Columbia University Medical Center in New York City.
"While it's not proven that attaining these lifestyle factors will improve MS or its progression, the associations are there," said Riley, who was not part of the study. "I recommend patients prioritize abstinence from smoking and getting to a healthy weight. After that, eat as healthy a diet as one can organize and afford and try to exercise regularly."
With MS, the body's immune system attacks the fatty substance that covers nerve cells -- called myelin -- as well as the nerve cells themselves, according to the National Multiple Sclerosis Society. This damage can cause symptoms such as fatigue, numbness, tingling, walking problems, dizziness and blurred vision.
The study included nearly 7,000 people with physician-diagnosed MS who had provided detailed dietary information for another study. More than 90 percent of the respondents were white, and the mean age was almost 60. On average, they'd had MS for 20 years.
"We developed a dietary quality score based on high intake of fruits and vegetables and whole grains and lower intakes of red and processed meats and added sugar from desserts and sugar-sweetened beverages," said study lead author Kathryn Fitzgerald. She's a postdoctoral research fellow at Johns Hopkins School of Medicine in Baltimore.
One limitation of the study is that no dietary information on lean meats or fish was provided, Fitzgerald said.
The study participants were placed into five groups, based on how healthy their diets were.
The group with the healthiest diets was about 20 percent less likely to have severe physical disability or severe depression, the study found. Severe disability was defined as needing some type of support -- a cane, wheelchair or scooter -- to walk 25 feet, Fitzgerald said.
People with the highest-quality diets consumed 1.7 servings of whole grains and 3.3 servings of fruits, vegetables or legumes daily. Diets of those on the lowest end contained 0.3 servings of whole grains and 1.7 servings of fruits.
Those with an overall healthy lifestyle were about half as likely to experience depression, 30 percent less likely to have severe fatigue, 40 percent less likely to have pain and one-third less likely to have thinking and memory troubles.
Fitzgerald said there are a number of theories as to how a healthy lifestyle, particularly a healthy diet, might help people with MS. "However, because of the design of the study, we can't say for certain how diet impacts MS disability," she said.
Samantha Heller, a registered dietitian with the NYU Langone Health System in New York City, said, "MS is a disease that creates inflammation, so if you eat a diet that decreases inflammation, it makes sense that disability and pain would improve."
The study also looked at the effect of a number of popular diet plans, such as the paleo diet, Wahl's diet, Swank, gluten-free and more. It generally found a slightly positive effect from these diets on the risk for disability.
Both Heller and Riley said this was likely due to weight loss from these diets.
"When you lose weight, you also decrease inflammation and give your joints a break," said Heller, who wasn't involved with the study. "For every pound lost, you lose 4 pounds of pressure on your joints."
The study didn't ask for specifics on how much people exercised, but for most people with MS, it's fine to exercise.
"Exercise, as tolerated, can help maintain muscle strength and quality of life," Heller said.
Riley added that she tells her patients to find an activity they enjoy doing. She also suggests getting aerobic exercise three to four times a week for at least 30 to 40 minutes and to work in some strength training, too.
"Exercise can put people in a better place," Riley said. "If they experience a relapse, they may be more able to recover quickly."
The study was published online Dec. 6 in Neurology.
The Multiple Sclerosis Society has more on MS.