Vegetarians appear to have a healthier biomarker profile than meat eaters, and this applies to adults of any age and weight and is unaffected by smoking and alcohol consumption, according to a new study of 166,000 UK adults, being presented this week at the European Congress on Obesity ( ECO), held online this year.
Biomarkers can have poor and good health effects, promote or prevent cancer, cardiovascular and age-related diseases and other chronic conditions, and have been widely used to assess the impact of diet on health. However, the evidence for metabolic benefits associated with being vegetarian is unclear.
To understand whether dietary choices can make a difference in the levels of disease markers in blood and urine, researchers from the University of Glasgow conducted a cross-sectional study analyzing data from 177,723 healthy participants (aged 37-73) in the UK Biobank study. , who reported no major changes in diet over the past five years.
Participants were classified according to their self-reported diet as vegetarian (do not eat red meat, poultry, or fish; 4,111 participants) or meat eaters (166,516 participants). Researchers examined associations with 19 blood and urine biomarkers related to diabetes, cardiovascular disease, cancer, liver, bone and joint health, and kidney function.
Even after accounting for potentially influential factors including age, sex, education, ethnicity, obesity, smoking and alcohol intake, the analysis found that vegetarians had significantly lower levels of 13 biomarkers than meat eaters, including: total cholesterol; Low-density lipoprotein (LDL) cholesterol — the so-called ‘bad cholesterol; Apolipoprotein A (associated with cardiovascular disease), Apolipoprotein B (associated with cardiovascular disease); gamma-glutamyl transferase (GGT) and alanine aminotransferase (AST) — liver function markers that indicate cell inflammation or damage; insulin-like growth factor (IGF-1; a hormone that promotes the growth and proliferation of cancer cells); urate; total protein; and creatinine (a marker of worsening kidney function).
However, vegetarians also had lower levels of beneficial biomarkers including high-density lipoprotein ‘good’ (HDL) cholesterol and vitamin D and calcium (linked to bone and joint health). In addition, they had significantly higher levels of blood fats (triglycerides) and cystatin-C (suggesting poor kidney status).
No link was found for blood sugar levels (HbA1c), systolic blood pressure, aspartate aminotransferase (AST; a marker of liver cell damage) or C-reactive protein (CRP; an inflammatory marker).
“Our findings give real food for thought,” said Dr Carlos Celis-Morales of the University of Glasgow in the UK, who led the study. “In addition to not eating red and processed meat, which is linked to heart disease and some cancers, people who follow a vegetarian diet tend to eat more vegetables, fruits and nuts, which contain more nutrients, fiber and other potentially beneficial compounds. To help explain these nutritional differences That may explain why vegetarians have lower levels of disease biomarkers that can lead to cell damage and chronic disease.”
The authors note that although their study was large, it was observational, so no direct cause-and-effect conclusions can be drawn. They also note several limitations, including that they tested biomarker samples only once for each participant, and it is possible that biomarkers may fluctuate depending on factors unrelated to diet, such as existing diseases and unmeasured lifestyle factors. They also noted that food frequency was dependent on participants reporting their food intake using questionnaires, which are not always reliable.