A new study finds that though most U.S. adults fail to meet recommended daily levels of 10 key nutrients, those with disabilities do substantially worse.

At least 10 percent of U.S. adults fit into one or more category of disability, from those who have difficulties with activities of daily living, such as dressing, bathing and eating, to those who cannot use their legs or struggle to accomplish routine tasks, such as money management or household chores.

To determine how these physical or mental difficulties can affect nutrition, University of Illinois researchers analyzed two waves of self-reported food and supplement consumption data from 11,811 adults, more than 4,200 of whom qualified as disabled. The team drew the data from the 2007-2008 and 2009-2010 National Health and Nutrition Examination Surveys, which are conducted by the National Center for Health Statistics.

"We conducted statistical analyses to compare people with and without disabilities in terms of nutrient intake," said University of Illinois kinesiology and community health professor Ruopeng An and colleagues, who reported their findings in the Journal of Human Nutrition and Dietetics.

"We found that American people consume much lower amounts of nutrients than are recommended," An said. "For example, only 11.3 percent of people meet the daily recommended intake of fiber. Only 4.7 percent of adults consume recommended amounts of potassium."

A large majority of U.S. adults also fall short of recommended intakes of vitamin A, vitamin C , vitamin D, calcium and iron, An said. They also eat more saturated fat, cholesterol and sodium than recommended, he said.

The picture for those who are disabled is even bleaker. Disabled American adults were even less likely than those without a disability to meet recommended dietary levels of saturated fat, fiber, vitamin A, vitamin C, calcium and potassium, the researchers report. The only exceptions (for intake of vitamin A, vitamin C and fiber) were among people with the lowest level of disability, whose intakes were comparable to non-disabled adults, An said.

"In general, people with disabilities are also disadvantaged nutritionally compared with people without disabilities, even though the bar is already so low," he said.

Those with the most severe physical and mental challenges were also the least likely to eat well, An said. This makes sense if one considers the challenges they must overcome to obtain, prepare and eat a healthy diet, he said.

"Physically, financially and mentally, they have different barriers to accessing healthy food," he said.

A trip to the grocery store can be a challenge for anyone who uses a cane, walker or wheelchair to get around. Some cannot grasp small items, open cans or jars, or stand at a countertop to prepare foods. Some have difficulty chewing or digesting certain foods, or may be restricted to a liquid diet. Or they use medications that affect their appetite or ability to taste foods, An said.

"Dietary supplement use moderately improved vitamin C, vitamin D and calcium intakes," the researchers reported.

"Policymakers and activists for the disabled traditionally have focused primarily on improving transportation options and the physical accessibility of buildings, roads, paths and parking lots," An said. "Now it's time for them to turn their attention to the nutritional challenges that confront people with disabilities."