Measuring healthy eating habits
The study included 7,319 adults from 39 to 63 years old who answered food and health questionnaires and had periodic medical exams over a span of 18 years. Using a dietary assessment tool called the Alternative Healthy Eating Index (AHEI), each participant was given a score based on nine characteristics of a healthy diet:
- High in vegetables
- High in fruits
- High in nuts and soy
- High ratio of white (seafood and poultry) to red meat
- High in grain fiber
- High ratio of polyunsaturated to saturated fats
- Low in trans fats
- Regular multivitamin use
- Moderate alcohol consumption
The AHEI was developed as an alternative to tools that measure how closely people adhere to a Mediterranean style diet, and is believed to better reflect the healthy eating habits of Americans and the English.
A better diet prolongs life
This study found the following:
- Most of the deaths during the study period were due to cancer (49%) or cardiovascular disease (27%).
- People with the highest AHEI scores, indicating healthier eating habits, were 25% less likely to die from any cause and 40% less likely to die from heart disease than people with the lowest scores.
- When considered separately, only four of the nine healthy eating habits were associated with lower risk of death for any reason: nuts and soy, fiber, moderate alcohol, and, to a lesser extent, ratio of white to red meat.
- Only two of the healthy eating habits, when they were all considered separately, were associated with lower risk of cardiovascular death: nuts and soy, and moderate alcohol.
Of all the healthy dietary habits, moderate alcohol consumption was the most strongly associated with lower risks of both cardiovascular and all-cause deaths. Commenting on their findings, the study's authors noted that the relationships between AHEI scores and cardiovascular deaths and deaths from all causes had more to do with moderate alcohol intake and high nut and soy consumption than the other eating habits that were part of the index. Their findings especially highlight the important role of nuts and soy foods in a healthy diet.
How to make a good diet better
Fruits, vegetables, and trans fats did not seem to contribute to mortality risk in this study, but many prior studies confirm that they play important roles in cardiovascular and general health. The study's authors noted that fruit and vegetable intakes were high and trans fat intake was very low in general among the people in the study, limiting their ability to compare the protective effects of these basic healthy eating habits with poor eating habits.
So, what is the take home message from this study? Even if you already eat lots of fruits and vegetables and avoid trans fats, you might still be able to improve your diet:
- Have some nuts. Think about having almonds on your breakfast, walnuts on a salad, or a handful of pecans for a snack.
- Use soy foods. Try tofu in a stir-fry, or tempeh marinated and baked with broccoli florets and garlic, in place of meat or chicken.
- Enjoy a glass of wine. Alcohol isn't for everyone, but if it makes sense for you, feel free to enjoy up to one 12-ounce beer, 5-ounce glass of wine, or 1.5-ounce glass of spirits per day if you're a woman, two if you're a man.
(Am J Clin Nutr 2011;94:247-53)