This new study from Austria has been presented on the news with headlines stating, “Vegetarians are less healthy than meat-eaters”. This title alone goes against the many studies that say the opposite such as those from data from the Seventh Day Adventists’ populations. This study is very controversial and the study design has been highly criticized. There appears to be a multitude of limitations.
The term vegetarian has a fairly loose definition. What exactly does it mean? Within this group we have vegans, fruitarians, lactovegetarians, lactoovovegetarians and even at times includes people who say they are vegetarians who are classified as “almost vegetarians” who allow some dairy and fish intake into their diets. Other people simply say they are vegetarians because they exclude red meat in their diet. We call these people “sometimes vegetarians”.
True vegans have some problems with their diets that requires some creative planning to provide high-quality protein using legumes and whole grains. These proteins must provide all amino acids needed for protein synthesis. The essential amino acid deficient from one food protein are supplied by those of another protein in the same meal or in the next. For example, many legumes do not provide enough methionine, and cereals are limited in lysine. When combined, the body is supplied with adequate amounts of both amino acids, so cereals and legumes complement each other.
The true vegan diet an also pose a risk for adequate iron, vitamin D, and vitamin B12. So inclusion of some fortified foods, such as whole-grain, ready-to-eat breakfast cereal or a balanced vitamin and mineral supplement is advised
Here are limitations of the study by the authors
“Potential limitations of our results are due to the fact that the survey was based on cross-sectional data. Therefore, no statements can be made whether the poorer health in vegetarians in our study is caused by their dietary habit or if they consume this form of diet due to their poorer health status. We cannot state whether a causal relationship exists, but describe ascertained associations. Moreover, we cannot give any information regarding the long-term consequences of consuming a special diet nor concerning mortality rates. Thus, further longitudinal studies will be required to substantiate our results. Further limitations include the measurement of dietary habits as a self-reported variable and the fact that subjects were asked how they would describe their eating behavior, without giving them a clear definition of the various dietary habit groups. However, a significant association between the dietary habit of individuals and their weight and drinking behavior is indicative for the validity of the variable. Another limitation concerns the lack of detailed information regarding nutritional components (e.g. the amount of carbohydrates, cholesterol, or fatty acids consumed). Therefore, more in-depth studies about nutritional habits and their effects on health are required among Austrian adults. Further studies should e.g. investigate the influence of the various dietary habits on the incidence of different cancer types. To our knowledge this is the first study ever in Austria to analyze differences in terms of dietary habits and their impact on health. We admit that the large number of participants made it necessary to keep the questions simple, in order to cover the large sample. Overall, we feel that our results are of specific interest and contribute to extant scientific knowledge, notwithstanding some limitations regarding causes and effects.”