Improvements in the U.S. diet between 1999 and 2012 prevented an estimated 1.1 million premature deaths, primarily from cardiovascular disease and diabetes, according to a recent Harvard study in Health Affairs.
About half of the benefit came from a big reduction in trans fats, thanks to the removal of partially hydrogenated oils from many packaged and fast foods. Smaller improvements came from modest increases in fruits, whole grains, nuts, legumes, and polyunsaturated fats, along with reductions in red and processed meat and, especially, sugary beverages. These findings came from the Alternate Healthy Eating Index (AHEI), a tool that the researchers used to evaluate dietary information collected from a cross section of nearly 34,000 adults.
Still, the average American diet “remains poor,” the study concluded. While a perfect score on the Index is 110, the average American diet increased from a terrible 39.9 to a merely lousy 48.2 during the period studied. Holding down the overall score was slightly higher sodium intake and no increase in consumption of vegetables and omega-3 fats from fish, compared to 1999. Another drag on the overall score was the lower scores for poorer, less educated, and obese people.
To compute the impact of these dietary changes on health and mortality rates, the researchers correlated the AHEI findings with a database about diet, risk factors, and diseases in 173,000 nurses and other health professionals. Based on the 8.3point in crease between 1999 and 2012, they estimated that the diet improvements reduced new cases of diabetes by nearly 13 percent, coronary artery disease by 10 percent, stroke by 5 percent, and cancer by 1 percent.
Bottom Line: Even small but steady improvements in overall diet quality can produce big benefits across the population, the researchers said. Pointing to the role the government played in reducing trans fat as a precedent, they concluded that “Policy initiatives are urgently needed to address other healthy eating components to maintain and accelerate improvements in diet — in particular, to reduce the large and growing disparities between socioeconomic groups that translate directly into greater differences in morbidity and mortality.”
Also see 14 Keys to a Healthy Diet.