MONDAY, Sept. 1, 2014 (HealthDay News) -- The quality of Americans' diets has improved somewhat but remains poor overall, and dietary disparity between the rich and poor is growing, a new study shows.
"The study provides the most direct evidence to date that the extensive efforts by many groups and individuals to improve U.S. dietary quality are having some payoff, but it also indicates that these efforts need to be expanded," study author Dong Wang, a doctoral student in the department of nutrition at the Harvard School of Public Health (HSPH), said in a Harvard news release.
"The overall improvement in diet quality is encouraging, but the widening gap related to income and education presents a serious challenge to our society as a whole," study senior author Walter Willett, chair of the department of nutrition at HSPH, said in the news release.
The new information came from data on more than 29,000 adults -- aged 20 to 85 -- who took part in the 1999 to 2010 National Health and Nutrition Examination Surveys. The quality of their diets was rated from 0 to 110, with a higher score indicating a healthier diet.
The participants' average dietary score rose from nearly 40 in 1999 to 2000 to almost 47 in 2009 to 2010. More than half of that improvement was due to people consuming fewer trans fats, according to the HSPH researchers.
Other beneficial changes in Americans' eating habits included increased consumption of whole fruit, whole grains, nuts, legumes and polyunsaturated fats, and reduced intake of sugar-sweetened beverages.
However, people are not eating more vegetables and haven't reduced their consumption of red and/or processed meat. Also, their salt intake has increased, a finding the researchers called "disconcerting."
The study also found that richer people have healthier diets than poorer people, and that this disparity increased between 1999 and 2010. Healthy foods generally cost more and poor people often lack access to stores that sell healthy foods, the researchers noted.
Education also played a role in dietary quality, which was lowest and improved more slowly among people who had 12 years or less of school, according to the study published online Sept. 1 in the journal JAMA Internal Medicine.
Mexican Americans had the best dietary quality, while blacks had the lowest. Mexican Americans' healthier eating habits may be due to dietary traditions or culture, while blacks' poorer eating habits may be due to lower income and education levels, the researchers said.
The study also found that women tend to have better quality diets than men.
The U.S. National Library of Medicine has more about nutrition.