Both Low Extra-Virgin Olive Oil and Plant-Based Diet Reduce LDL More Effectively: Recipe for Heart Health

The study published in the Journal of the American Heart Association suggests reducing extra-virgin olive oil intake within a whole-food, plant-based diet may help lower LDL cholesterol levels in individuals at risk for atherosclerotic cardiovascular disease (CVD).

Whole-food, plant-based vegan diets that are low in oils, and Mediterranean diets rich in EVOO are known to lower cardiovascular disease risk factors. However, the ideal amount of dietary fat, especially EVOO, remains uncertain. Andrea M. Krenek, Food Science and Human Nutrition Department University of Florida Gainesville FL, USA, and colleagues aimed to compare the effects of consuming a high versus low amount of EVOO within a whole‐food plant‐based diet (WFPBD) vegan diet pattern on LDL‐C and other cardiometabolic markers in the Recipe for Heart Health (RFHH) trial. They hypothesized that the WFPBD would reduce LDL-C levels and that LDL-C would decrease more significantly from baseline during the low EVOO phase of the WFPBD.

For this purpose, the researchers conducted a randomized crossover trial with weekly cooking classes, adults with a cardiovascular disease risk of 5% or higher followed a whole-food, plant-based diet with extra virgin olive oil (EVOO) for four weeks each, switching between high (4 tablespoons/day) and low (<1 teaspoon/day) EVOO levels. The trial included a 1-week washout period between the two diet phases.

The primary outcome was the difference in LDL-C from baseline. Secondary outcomes included changes in other cardiometabolic markers. Linear mixed models were used to evaluate changes from baseline between diet phases, adjusting for age, sex, and changes in body weight.

The study led to the following findings:

• In 40 participants, fat intake comprised 48% and 32% of energy during the high and low EVOO phases, respectively.
• Both diets resulted in comparable reductions in LDL‐C, total cholesterol, apolipoprotein B, high‐density lipoprotein cholesterol, glucose, and high‐sensitivity C‐reactive protein.
• With diet‐sequence interactions for LDL‐C, differences were detected between diets by diet order (mean high to low: Δ‐12.7mg/dL versus low to high: Δ+15.8 mg/dL).
• Low to high order led to increased glucose, total cholesterol, and high‐density lipoprotein cholesterol.
• Over period 1, LDL‐C reductions were −25.5 post‐low versus −16.7 mg/dL post‐high EVOO, which diminished over period 2.

"Both plant-based diet patterns improved cardiometabolic risk profiles compared to baseline diets, with more pronounced reductions in LDL-C observed after the low EVOO diet. However, adding EVOO following a period of low intake may limit further decreases in lipid levels," the researchers concluded.

Study limitations include potential carryover effects from diet sequences despite washout periods and a short study duration, which might have missed long-term metabolic changes. Uncontrolled macronutrient distribution affects insights into EVOO’s role in appetite and fat consumption. The impact of the COVID-19 pandemic on recruitment, recall bias in dietary assessments, and inadequate food options for capturing dietary patterns are also noted. Future research should address these issues and include more diverse samples.

Reference:

Krenek AM, Mathews A, Guo J, Courville AB, Pepine CJ, Chung ST, Aggarwal M. Recipe for Heart Health: A Randomized Crossover Trial on Cardiometabolic Effects of Extra Virgin Olive Oil Within a Whole-Food Plant-Based Vegan Diet. J Am Heart Assoc. 2024 Jul 24:e035034. doi: 10.1161/JAHA.124.035034. Epub ahead of print. PMID: 39045758.