A temporary report published within the Journal of Health, Population, and Nutrition describes the effect of vegetarian diets on all-cause mortality in adults in america.

Study: Vegetarian diets and risk of all-cause mortality in a population-based prospective study in america. Image Credit: Yulia Furman / Shutterstock.com

Background

Chronic diseases, including cardiovascular and metabolic diseases and cancer, account for many deaths within the U.S. Between 1990 and 2010, about 26% and 22% of all-cause and cardiovascular disease-related mortality within the U.S., respectively, occurred because of an unhealthy weight loss program.

In recent a long time, the vegetarian weight loss program has gained significant popularity, mainly due to its health and environmental advantages. Plant-based vegetarian diets are known to cut back the danger of heart problems and diabetes by lowering blood cholesterol and improving insulin sensitivity.

Plant-based foods contain higher amounts of fibers, vitamins, minerals, and bioactive compounds, in addition to lower amounts of total and saturated fats, as in comparison with animal-based foods. Despite these health advantages, some vegetarian diets that exclude every kind of animal products, comparable to a vegan weight loss program, may cause vitamin B12 deficiency, as animal food products are the one natural source of this essential micronutrient.   

In the present study, scientists investigate the association between vegetarian or vegan diets and all-cause mortality amongst U.S. residents who’ve registered for the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial.     

Study design

A complete of 117,673 participants from the PLCO Cancer Screening Trial were included within the study. All participants accomplished the Weight-reduction plan History Questionnaire that was provided to them in the course of the trial.

Data on all-cause mortality were obtained from follow-up questionnaires and the National Death Index database. The typical follow-up period was 18 years.

Based on self-reported weight loss program data, the participants were categorized into 4 groups. These groups included vegan, which excluded all animal products, lacto- and ovo-vegetarian, which included dairy products and eggs, pesco-vegetarian, which included fish and seafood, and omnivore, which included all animal products.     

Essential observations

The evaluation of self-reported weight loss program history questionnaires revealed that about 99.3% of study participants were omnivores, 0.3% were lacto- or ovo-vegetarians, 0.3% were pesco-vegetarians, and 0.1% were vegans.

As in comparison with vegetarians or vegans, omnivorous participants were more prone to smoke and drink alcohol and had a lower likelihood of completing a school degree. Furthermore, omnivorous participants had the very best body mass index (BMI) values, followed by vegans, lacto- and ovo-vegetarians, and pesco-vegetarians.

After the study follow-up period of 18 years, death occurred in 39,763 participants, which included 39,547 omnivores, 88 lacto- and ovo-vegetarians, 67 pesco-vegetarians, and 61 vegans. No statistically significant difference in the danger of all-cause mortality was observed between the study groups.

After adjusting for age, sex, study center location, and trial arm, pesco-vegetarians were related to a significantly lower risk of all-cause mortality than omnivores. Nevertheless, after adjusting for all covariates, including smoking status, pack-years of smoking, alcohol consumption, race/ethnicity, education, BMI, and comorbidities, no significant difference in mortality risk was observed between the omnivorous and vegetarian groups.

Likewise, the comparison between vegetarian groups, which comprised vegan and lacto- and ovo-vegetarian diets, and non-vegetarian groups, which included omnivorous and pesco-vegetarian diets, also showed no statistically significant difference in mortality risk after full adjustment.

Study significance

No significant impact of vegetarian diets on all-cause mortality risk was observed in a U.S. population of middle-aged and older adults. Over 90% of the study population identified as omnivores, whereas the remaining study participants self-identified as lacto- and ovo-vegetarians, pesco-vegetarians, or vegans.  

After adjusting for socioeconomic and lifestyle aspects and comorbidities, no significant differences in all-cause mortality risk were observed between omnivores and vegetarians.

Notably, the study lacks information on the particular duration of following a vegetarian or vegan weight loss program. Thus, it is feasible that the duration of following a vegetarian or vegan weight loss program may not be sufficient for the study participants to have the standard health advantages. Furthermore, there might be a possibility of misclassification for every weight loss program group, because the participants reported their vegetarian weight loss program status based on only two questions regarding foods they excluded from their diets.

Given the study limitations, scientists advise that future studies investigating the association between vegetarian diets and mortality risk consider the duration of following vegetarian diets.