September 2, 2014

US Diet Improves, But Is Still Rated Poor

Eric Hopton for redOrbit.com – Your Universe Online

The quality of the US diet is showing signs of slow and steady improvement, but there are clear indications that overall the diet is still “poor.” Much of the improvement in US dietary intake is due to reductions in the consumption of trans fats. The difference between higher and lower socioeconomic and racial/ethnic groups is widening. These are the conclusions of a new study by the Harvard School of Public Health (HSPH), highlighting a mixed message for those concerned with long-term dietary trends and their impact on US health standards.

The results of the Harvard research have been published in the journal JAMA Internal Medicine and the base period for this work was between 1999 and 2010, which the report’s authors chose as they wanted to study the effects of major changes in the economy, in government policy, and in food processing in the first decade of the 21st century.

Dong Wang, who is the lead author of the report and a doctoral student at HSPH, is hoping that the findings will help inform public policy on health and diet and improve strategies for tackling the problems of nutrition-related diseases. Those policies and strategies already in place are showing signs of positive impact, but need to be expanded.

The links between dietary quality and the incidence of major chronic diseases such as cancer, coronary heart disease and diabetes have been clearly demonstrated in previous studies. The burden of these conditions is markedly different across different sub-groups of society and diet is closely linked to socioeconomic status (SES).

The research took a sample of over 29,000 adults from the National Health and Nutrition Examination Survey (NHANES) and then used the Alternate Health Eating Index 2010 (AHEI-2010) to evaluate data from the sample. The AHEI-2010 index score indicates the relative health of an individual. Higher AHEI-2010 scores represent healthier diets. The index scores the intake of certain foods on a scale of 0-10. Where consumption of a particular food is thought to be beneficial -- foods like vegetables and fruit, whole grains, nuts, long-chain omega-3 fats, and polyunstaurates -- higher scores represent a higher intake. Conversely, higher scores for the consumption of trans fats, sugary drinks, fruit juices, red or processed meat, and sodium represented lower intake.

Average AHEI scores improved from 39.9 in 1999 to 46.8 in 2010 and the authors attribute over half of that improvement to reductions in trans fat consumption. Intake of sugar-sweetened drinks and fruit juice was down while consumption of whole grains, nuts, whole fruit, legumes, and polyunsaturates had risen. However, sodium intake was up, which resulted in a lower score.

SES indicators based on income and education were used to assess differences in dietary health between groups. Higher SES groups scored higher than lower groups across the board, but the trend is not encouraging. The gap between the higher and lower groups increased from 3.9 in 1999-2000 to 7.8 in 2009-2010. Price and availability of healthier option foods were major factors in the SES group difference. Education was another key component and those individuals with 12 or less years at school had notably less healthy diets.

When looking at racial/ethnic factors, Mexican-Americans scored highest. Non-Hispanic blacks fared the worst and again the researchers identified income and education as key factors. Across all groupings, women scored higher than men for the quality of their diet.

This work shows that awareness and government intervention can have positive outcomes in improving diet, but that much more is needed and greater emphasis needs to be given to the higher risk SES groups.