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Eat At Least 5 Servings A Day of Fruits and Vegetables

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. 

Diets rich in fruits and vegetables help reduce risk for numerous chronic health conditions that are leading causes of death, including cardiovascular disease and cancer. Yet, only about one in 10 adults eat enough fruits or vegetables, according to the U.S. Centers for Disease Control and Prevention.

Wang and colleagues analyzed data from the Nurses' Health Study and the Health Professionals Follow-Up Study, two studies including more than 100,000 adults who were followed for up to 30 years. Both datasets included detailed dietary information repeatedly collected every two to four years. For this analysis, researchers also pooled data on fruit and vegetable intake and death from 26 studies that included about 1.9 million participants from 29 countries and territories in North and South America, Europe, Asia, Africa and Australia.

Analysis of all studies, with a composite of more than 2 million participants, revealed:

  • Intake of about five servings of fruits and vegetables daily was associated with the lowest risk of death. Eating more than five servings was not associated with additional benefit.
  • Eating about two servings daily of fruits and three servings daily of vegetables was associated with the greatest longevity.
  • Compared to those who consumed two servings of fruit and vegetables per day, participants who consumed five servings a day of fruits and vegetable had a 13% lower risk of death from all causes; a 12% lower risk of death from cardiovascular disease, including heart disease and stroke; a 10% lower risk of death from cancer; and a 35% lower risk of death from respiratory disease, such as chronic obstructive pulmonary disease (COPD).
  • Not all foods that one might consider to be fruits and vegetables offered the same benefits. For example: Starchy vegetables, such as peas and corn, fruit juices and potatoes were not associated with reduced risk of death from all causes or specific chronic diseases.
  • On the other hand, green leafy vegetables, including spinach, lettuce and kale, and fruit and vegetables rich in beta carotene and vitamin C, such as citrus fruits, berries and carrots, showed benefits.

"Our analysis in the two cohorts of U.S. men and women yielded results similar to those from 26 cohorts around the world, which supports the biological plausibility of our findings and suggests these findings can be applied to broader populations," Wang said.

A limitation of the research is that it is observational, showing an association between fruit and vegetable consumption and risk of death; it does not confer a direct cause-and-effect relationship.

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