There’s good news on the nutrition front — Americans are eating better, and their improved dietary choices have reduced disease burden and saved lives, researchers said.
Improvements in the American diet since 1999 have prevented an estimated 1.1 million premature deaths, including deaths from diabetes, cardiovascular disease, and cancer, reported a research team led by Dong Wang, a doctoral candidate at the Harvard T.H. Chan School of Public Health in Boston.
The FDA’s efforts to get trans fats out of the U.S. diet accounted for about half the improvement, Wang and colleagues indicated in the journalHealth Affairs. However, Americans are also eating less red meat and drinking fewer sugary beverages, and they have increased their intake of fruits, whole grains, and polyunsaturated fatty acids, the researchers reported.
But despite this recent progress, the U.S. diet is still poor overall and there is plenty of room for improvement, the investigators said.
Wang and colleagues used the Alternate Healthy Eating Index 2010 to evaluate 24-hour dietary recall data collected from 33,885 U.S. adults in the National Health and Nutrition Examination Survey (NHANES). A perfect score on the index would be 110.
From 1999 to 2012, Americans’ mean score increased from 39.9 to 48.2.
During that time period, index scores rose for specific healthy choices, including significant increases of 0.6 for fruit, 0.7 for whole grains, 0.5 for nuts and legumes, and 1.0 for polyunsaturated fatty acids, indicating Americans were eating more of these.
For nonhealthy choices, an increased index score reflected reduced consumption. Scores improved by 1.4 points for sugar-sweetened beverages and 0.4 points for red meat, indicating Americans were consuming less of these.
However, sodium intake increased slightly, and consumption of vegetables, long-chain omega-3 fatty acids, and alcohol did not change significantly during the study period, Wang and colleagues noted.
In addition, “the overall mean [index] never even achieved 50 points on a 0-110 scale, which indicates that the quality of the U.S. diet remains far from optimal,” Wang and colleagues wrote. “We also observed persistent or widening gaps in dietary quality across different socioeconomic subgroups. The quality of diet in non-Hispanic black participants, although significantly improved over time, was still lower than other racial/ethnic groups.”
To determine the reduced burden of disease attributed to better eating habits, the investigators analyzed other data, gathered in two ongoing prospective cohort studies evaluating diet, disease risk factors, and disease status: the Nurses’ Health Study (including 121,700 women) and the Health Professionals Follow-Up Study (51, 529 men).
Americans’ better eating habits from 1999-2012 prevented an estimated 1,064,840 all-cause premature deaths, Wang and colleagues concluded. Improved diet reduced new cases of diabetes by 12.6%, coronary heart disease by 10%, cardiovascular disease by 8.6%, stroke by 5.1%, and cancer by 1.3%, the investigators said.
“We observed a steady improvement in the dietary quality of U.S. adults, which has contributed to a substantial reduction in disease burden,” Wang and colleagues wrote. “To our knowledge, our study is the first documentation of the disease burden attributed to temporal changes in dietary quality.”
The findings “provide further justification for promoting healthful diets as a national priority for chronic disease prevention,” Wang told MedPage Today via email.
“For healthcare professionals’ everyday practice, the most important takeaway is that even small improvement in dietary quality can lead to substantial reduction in disease risk and disease burden,” Wang said. “For example, our data showed that an 8.3-point increase in the Alternate Healthy Eating Index could potentially prevent 1.1 million premature deaths. This 8.3-point increase can be easily translated into clinicians’ advice, e.g., increasing fresh vegetable consumption by 2 cups per day.”
Lauri Wright, PhD, of the University of South Florida in Tampa, agreed. “An important take home message is that even small improvements in diet can have an impact on developing diseases such as diabetes and cardiovascular disease,” said Wright, who is also a spokesperson for the Academy of Nutrition and Dietetics, via email.
“In this study for example, the fruit and vegetable intake increased by less than 1 serving per group,” Wright said. Still, she added, “the combination of improvements in diet helped decrease risk of the leading causes of death in Americans.”
Because the study found that the American diet is still suboptimal, “continued public health efforts need to focus on educating Americans on the importance of diet in disease prevention,” Wright said.
She also pointed to the role of trans fat reduction in the study findings, which, she said, “argues for consideration of further regulations to improve diet quality such as sodium content of foods,” Wright said.
This study was funded by the National Institutes of Health. The authors disclosed no relationships with industry.