Food is our source of energy for life and building material for the cells of our body. Therefore, most of the diet should be foods that provide the body with nutrients, and these are vegetables, fruits, grains, proteins, and dairy products. Nutritionists agree that a balanced diet should be followed for good health and wellness.
A recent study by researchers from the Harvard School of Public Health confirms these recommendations, and also adds that consuming at least two servings of fruits and three servings of vegetables daily can reduce the risk of disease-related death and generally contribute to longevity. It is generally accepted that the size of one serving of vegetables, fruits, or berries is approximately equal to the volume of one palm.
"While groups like the American Heart Association recommend four to five servings each of fruits and vegetables daily, consumers likely get inconsistent messages about what defines optimal daily intake of fruits and vegetables such as the recommended amount, and which foods to include and avoid," - said Dong D. Wang, M.D., epidemiologist, nutritionist at Harvard Medical School and lead author of the study.
According to the 2020–2025 Nutritional Guidelines for Americans, fruits and vegetables should take up half a plate at every meal. The same document notes that at the moment the diet of more than 80% of Americans is far from the norms of recommendations.
The latest Harvard School of Public Health researchers drew on data from two previous studies: the Nursing Health Study and the Follow-up Study of Healthcare Professionals.
The first study group included registered nurses aged 30 to 55 years, and the second group consisted of 40-75 years old men working in the health care sector. Data on the participants' nutrition was collected for 30 years: every two to four years, scientists made observations and included the information obtained in the general work. The study involved nearly 77,000 women and 42,000 men who were free of diabetes, heart disease, and cancer.
Also, scientists additionally used data from 26 studies involving a total of almost two million people. These works were aimed at studying the relationship between the consumption of fruits and vegetables with the mortality rate. It is important to note that in the studies, all participants were selected according to two main criteria - they have a profession in one area and corresponding education. This selection assumes approximately the same socioeconomic status of the volunteers. However, it should be borne in mind that, perhaps, by occupation, these people are more inclined to adhere to a healthy diet than workers in other professions.
Findings from one of the largest studies from the Harvard School of Public Health show that a higher intake of fruits and vegetables reduces the risk of dying from cancer, heart disease, and respiratory disease. A diet rich in fruits and vegetables increases the amount of potassium in the body and antioxidant activity. This results in lower blood pressure and improved lung function.
The study authors note that it is the daily consumption of five to ten servings of vegetables and fruits that reduces the risk of death. Also, the results of the study, in contrast to existing recommendations, indicate which vegetables and fruits reduce the risk of death. Thus, leafy greens, foods rich in vitamin C and beta-carotene, such as spinach, cabbage, carrots, and citrus fruits, have a positive effect on the body. Whereas starchy vegetables and fruit juices - like potatoes and peas - do nothing to prolong life.
Juices cause spikes in blood glucose and insulin levels compared to whole fruits, which can be detrimental to health. And one of the possible reasons why starchy fruits and vegetables are not beneficial is the popularity of canning them, in the process of which foods are deprived of antioxidant properties. In contrast to existing guidelines, which include canned food and juices as recommended foods and beverages, the study suggests that further research is needed on the effects of these foods on human health.
Fruits and vegetables include an impressive amount of beneficial substances. What's more, consuming enough of them reduces the risk of many diseases, including obesity, diabetes, heart diseases. Most studies, when asked how much vegetables and fruits an average person should eat to maintain health, state that the threshold is five palm-sized servings. Food can be frozen or freshly harvested, baked, boiled, steamed, or grilled - in any case, you will receive a portion of the nutrients and take a step towards a long healthy life.
