by Lewis Chang, PhD
A new dietary intervention trial demonstrated that a low-caloric lacto-ovo vegetarian diet and low-caloric Mediterranean diet were equally effective in reducing body weight and fat mass in healthy individuals, with different beneficial effects observed for blood lipids.1
Previous epidemiological studies and meta-analyses of clinical trials have found various health benefits associated with the vegetarian diet and Mediterranean diet. Researchers from University of Florence (Italy) recently conducted the first randomized crossover study to directly compare the effects of these two diets in a group of clinically healthy adults with a low-to-moderate cardiovascular risk profile.1
The study published in Circulation1 included 118 participants who were overweight (BMI ≥25 kg/m2) and had at least one of the following criteria: total cholesterol >190 mg/dL, low-density lipoprotein cholesterol (LDL-C) >115 mg/dL, triglycerides >150 mg/dL, and glucose >110 but <126 mg/dL. They were randomly assigned to a low-caloric lacto-ovo vegetarian diet or a low-caloric Mediterranean diet for 3 months. Afterwards, they crossed over to the other dietary treatment for 3 months. Both diets were designed to provide the same amount of calories, consisting of 50-55% of energy from carbohydrate, 25-30% from fat, and 15-20% from protein. Clinical evaluations were conducted regularly during the study.
The study found that:1
- On average, both diets were equally effective in reducing body weight (by 1.77-1.88 kg, or 3.90-4.14 lb), BMI (by 0.64-0.67 kg/m2), and fat mass (by 1.23-1.46 kg, or 2.71-3.22 lb)
- No between-group differences existed for oxidative stress markers and inflammatory cytokines except for interleukin-17, which improved only in the Mediterranean diet group
- The vegetarian diet was more effective in reducing LDL-C, whereas the Mediterranean diet was more effective in reducing triglycerides
- The vegetarian diet led to a statistically significant (but clinically irrelevant) reduction in vitamin B12 levels
These results suggest that both vegetarian and Mediterranean dietary patterns may be beneficial in improving cardiovascular risk profile, with some differential effects in blood lipids. Those who consume a vegetarian diet for an extended period may consider using dietary supplements to ensure adequate vitamin B12 level.
Why is this Clinically Relevant?
- For individuals seeking a dietary approach to improve health, both vegetarian diet and Mediterranean diet can be beneficial
- Both diets are effective in reducing body weight and fat mass, although there are differential effects on blood lipids
1. Sofi F, Dinu M, Pagliai G, et al. Low-calorie vegetarian versus Mediterranean diets for reducing body weight and improving cardiovascular risk profile: CARDIVEG Study (Cardiovascular Prevention With Vegetarian Diet). Circulation. 2018;137(11):1103-1113.