What we eat affects our health and can increase or reduce the risk of disease, directly changing life expectancy. How many times, however, in the wake of enthusiasm, have we started following a diet considered healthy and then quickly abandoned it as it was too different from our habits? The good piece of news comes from a very recent scientific research, which indicates that the longevity diet is not unique but varied, presenting as many as four diets capable of lengthening life and protecting against disease. Today we are talking about what emerged in the work published in the JAMA Network magazine by a group of scientists from the prestigious Harvard T.H. Chan School of Public Health in Boston (Shan et al, JAMA Network, 2023).
Four diets for a single purpose, lengthening life
Scientists analyzed data regarding the health and lifestyle of 75230 women and 44085 men, all healthy at the beginning of the study and followed for 36 years. The volunteers had to fill out a questionnaire every 4 years in which the adopted diet, understood as food choices, was specified. Based on the indications, the scientists were thus able to calculate four indices, corresponding to the degree of adherence to four food regimes considered healthy, such as the Guidelines 2015, the Mediterranean Diet, a healthy vegan diet and the healthy diet developed by Harvard University. We will discuss these four diets in detail in the following paragraph, but in the meantime we can say that the common feature is that they all involve the intake of whole grains, fruit, vegetables, dried fruit and legumes. What emerged is that it is sufficient to have a high score for even just one of these four indices to present a reduction in the risk of premature death and a decrease in the risk of developing cardiovascular and respiratory diseases and cancers. In addition, higher adherence to the Mediterranean diet and the diet developed by Harvard University has been shown to reduce the risk of premature death from neurodegenerative diseases.
The four diets in more detail
The study considers four diets assessed as healthy. As we will see, these diets are very similar although they have their own characteristics that differentiate them from the others. The Guidelines 2015 are a set of recommendations developed by the United States Departments of Agriculture and Health and Human Services. Among the recommendations, we find that it is important to follow a varied diet without excesses, which includes the intake of green, red and orange vegetables, legumes, especially beans and peas, whole fruit and not in the form of juices, cereals, at least half of which are whole grains, low fat dairy products, fish, poultry, eggs and nuts. In addition, it is asked to considerably limit foods with added sugars, saturated fats, such as those contained in fatty meats, sausages, butter, margarine and cream, and sodium. The Mediterranean Diet provides, as in the previous case, a high intake of fruit and vegetables, legumes, fish, whole grains, dried fruit and is also based on the use of extra virgin olive oil, which is a cornerstone. The healthy vegan diet includes a diet based on foods exclusively of plant origin and considered healthy, therefore whole fruit, vegetables, dried fruit, legumes, tea and coffee, while excluding or severely limiting foods such as refined cereals, foods rich in sugars and foods of animal origin. Finally, the guidelines developed by Harvard University were designed to reduce the risk of chronic diseases. These guidelines provide for a consumption of 5 portions of vegetables per day, preferring green leafy vegetables, 4 portions of fruit per day, 5 to 6 portions of whole grains, a portion of protein chosen from one of these sources, dried fruit, legumes and vegetable proteins such as tofu, fish once a week and to season oils such as extra virgin olive oil, canola, peanut and safflower oil.
So here's some good news regarding the link between nutrition and health. There is not only one long life diet and there are different ways to adhere to it, based on personal needs, habits and foods that can be found more easily where we live. We can choose the lifestyle that best suits us so that we can easily follow it and reap important benefits, reduce the risk of disease and lengthen life span.