Another study has been published finding that higher consumption of fruits and vegetables (5 servings a day) is associated with a longer life.
Researchers from the Harvard T. H. Chan School of Public Health looked at the data from several large studies. They found that about 5 servings per day of fruit and vegetables was associated with the lowest mortality (death from any cause), and from deaths that can be attributed to cancer, heart disease, and respiratory disease. Specifically 3 servings of vegetables and 2 servings of fruits.
Eating fruits and vegetables above that level (5 servings per day) didn't seem to make a difference. Another finding: eating starchy vegetables (corn, peas, potatoes) and fruit juices were not associated with a lower risk of mortality.
However, keep in mind that the results were based on answers to Food Frequency Questionnaires (FFQ), where people answered questions about foods that they ate in the past year. Can you remember how frequently (daily, weekly, or monthly) you ate specific foods? Would you admit, in writing, that you eat lots of junk food or foods that you know are not so good for you?
As you can imagine, there is debate over how valid and reliable these questionnaires are. For example: Is It Time to Abandon the Food Frequency Questionnaire? in 2005, in 2015, and in 2018. FFQs are used because they are the cheapest option.
Some criticisms of FFQs: People don't accurately remember, and they may lie (they want to look better) by underreporting or overreporting foods. Also, the lists are premade - so if the foods you eat aren't on the lists, then it's not counted. Frequent omissions: onions, cucumbers, celery, quinoa, garlic, herbs.
Food dishes that contain many ingredients (such as many Asian dishes) can not be dealt with in FFQs that look at individual foods only. Canned foods are considered equivalent to fresh vegetables and fruits - yet they are not in many ways. No mention of organic vs non-organic foods (studies find nutritional differences, and a cancer link). Eh...
While filling out a sample online FFQ (from the National Cancer Institute) I realized that if I were part of a study - I would definitely answer so that my eating habits look better (!!), plus after answering for a while there was an urge to just get it over with (it took too long). Mutter to myself: "that sounds good, eh, who can remember..". Also, there was no way I would have admitted to any junk food binges.
From Science Daily:The right '5-a-day' mix is 2 fruit and 3 vegetable servings for longer life
Studies representing nearly 2 million adults worldwide show that eating about five daily servings of fruits and vegetables, in which 2 are fruits and 3 are vegetables, is likely the optimal amount for a longer life, according to new research published today in the American Heart Association's flagship journal Circulation. ...continue reading "Eat At Least 5 Servings A Day of Fruits and Vegetables"