In the past century, the leading causes of death have shifted from infectious diseases, such as pneumonia and tuberculosis, to chronic diseases such as cardiovascular disease and cancer – and research suggests that poor diet may a culprit.

The findings are particularly relevant for people with rheumatoid arthritis, or RA, who already have a higher risk of heart disease than the general population.

But researchers report that it's never too late to do something about it: Eating a healthy diet, even if you start at age 70, can add years to your life, according to a study in the January 2011 issue of the Journal of the American Dietetic Association.

The Deadliest Diets

Researchers at the University of Maryland in College Park asked more than 2,500 people, ages 70 to 79, detailed questions about their typical diet. Six major dietary categories were identified, based on participants' predominant food choices.

Those who ate a diet rich in high-fat dairy products like ice cream and cheese were 40 percent more likely to die over the study’s 10-year period than those who opted for a healthful diet filled with vegetables, low-fat dairy products and whole grains.

Those who favored sweets and deserts were 37 percent more likely to die than those who consumed a healthy diet, says lead author Amy Anderson, PhD, a postdoctoral fellow in the department of nutrition and food science at the University of Maryland in College Park.

The analyses took into account other factors that affect mortality including sex, age, race, education, physical activity, smoking and total caloric intake.

"Our study supports previous findings suggesting that eating a healthy diet is associated with better quality of life and longer survival – no matter what your age," Anderson says.