Reacción a "Reactions: a meta-analysis shows that vegetarian and vegan diets are associated with a lower concentration of lipids such as cholesterol"

In the scientific field, it is essential to carry out comprehensive studies that compile all available information on certain topics. This is particularly relevant in the field of nutrition, as the results of this information gathering are often used to provide dietary recommendations to the population. In this respect, meta-analyses such as this one play a key role, especially when they compile information from randomised controlled clinical trials, which provide a solid scientific evidence base. 

This particular study focuses on the growing body of scientific information available on the health of plant-based diets, whether vegetarian or vegan. It analyses data from 30 clinical trials conducted over more than 40 years. As a result, the authors show that plant-based diets reduce levels of total cholesterol, LDL-cholesterol and, most importantly, apolipoprotein B by 7%, 10% and 14%, respectively. This provides the highest degree of scientific evidence possible. 

Therefore, these results support the existing knowledge on the subject. However, it is important to note that their implications are currently limited for several reasons. Firstly, the role of plasma cholesterol and LDL-cholesterol in cardiovascular disease has been questioned in recent years. It has been shown that it is the modified LDL particles that have the ability to contribute to the thickening of arteries and thus to the development of cardiovascular disease. One of the most common modifications is oxidation. Unfortunately, the study does not assess the effect of the aforementioned diets on plasma concentrations of oxidised LDL. Secondly, the study does not distinguish between the two types of apolipoprotein B (48 and 100), which are associated with both cholesterol and triglyceride transport, especially in the postprandial period, just after food intake. Since the 1990s, some scientists have suggested that atherosclerosis, i.e. abnormal thickening of the arteries, is actually a disease that occurs after eating. Thirdly, no differences were found in plasma triglyceride levels, whose contribution to this disease is becoming increasingly important. 

In summary, this study consolidates current knowledge on the role of plant-based diets in blood lipid control. However, it does not add much new to what is already known.