Findings from a new observational study show that eating 2 fruit and 3 vegetable servings per day is associated with a lower risk of death related to cancer, cardiovascular disease, or respiratory disease. Starchy vegetables and fruit juices, however, did not appear to contribute to the reduction in risk.
Nutritionists have long recommended a balanced diet that can provide one's body with the proper nutrients to stay healthy. The traditional core components of the prescribed diet include vegetables, fruits, grains, proteins, and dairy. Now a new study by researchers at the Harvard T. H. Chan School of Public Health in Boston, MA, provides even more evidence that current dietary guidelines are effective, and in fact, it expands on them, finding that consuming at least "2 fruit and 3 vegetable servings on a daily basis may lower the risk of both disease-related death and death from all causes." The study appears in Circulation, a scientific journal of the American Heart Association (AHA).
What We Should Eat
“Groups like the American Heart Association recommend 4–5 servings each of fruits and vegetables daily. Our research corroborates that,” says Dr. Dong D. Wang, M.D., Sc.D., an epidemiologist and nutritionist at Harvard Medical School and lead author of the study.
The Department of Health and Human Services published their recommendations in the 2020–2025 Dietary Guidelines for Americans. According to this set of guidelines, half of the plate for every meal should contain fruits and vegetables.
Study Subjects Dietary Information
The researchers collected self-reported dietary information from two large studies - the Nurses’ Health Study (NHS) and the Health Professionals Follow-up Study (HPFS). The NHS study included registered female nurses between the ages of 30 and 55 years. The HPFS included males aged 40–75 years. These studies included follow-ups adding dietary data every 2–4 years, which went on for about 30 years. Participants with baseline heart disease, cancer, or diabetes were excluded, which left data from 66,719 females and 42,016 males. They also incorporated data from an additional 26 studies involving a total of 1.9 million participants, which examined the relationship between fruit and vegetable intake and death rates.
Higher Nutritional Values Are Best - Fresh, Not Canned
This study expands beyond current guidelines by differentiating among specific groups of fruits and vegetables. Researchers observed trends with a lowered risk of death for leafy greens and foods rich in vitamin C and beta carotene. Fruits and vegetables that fall into these categories include spinach, kale, carrots, and citrus fruits. Conversely, they didn't identify any trends for fruit juices or starchy vegetables, such as potatoes and peas. One possible reason for the latter is the prominence of canned foods. The canning process may deprive starchy vegetables of their antioxidant properties.
Compared with whole fruits, the fluid form of juices may cause a more rapid elevation of blood glucose and insulin levels, which can increase the risk of disease. In contrast to the existing guidelines, which include canned foods and juices among the recommended foods and drinks, this study calls for further research on the effects of these items on health.
------------------------------------------------ Study: https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.120.048996 Fruit and Vegetable Intake and Mortality: Results From 2 Prospective Cohort Studies of US Men and Women and a Meta-Analysis of 26 Cohort Studies Dong D. Wang, Yanping Li, Shilpa N. Bhupathiraju, Bernard A. Rosner, Qi Sun, Edward L. Giovannucci, Eric B. Rimm, JoAnn E. Manson, Walter C. Willett, Meir J. Stampfer, and Frank B. Hu Originally published 1 Mar 2021 https://doi.org/10.1161/CIRCULATIONAHA.120.048996Circulation. ;0