Olive Oil for Prediabetes: Can It Reduce Liver Fat?

randomized-controlled-trial PMID: 28323952

Quick Summary: A recent study found that eating a diet rich in monounsaturated fats (like those found in olive oil) for 12 weeks helped reduce liver fat in people with prediabetes. The study also showed improved insulin sensitivity.

What The Research Found

Researchers looked at how different diets affected people with prediabetes. They found that a diet high in monounsaturated fatty acids (MUFAs), like those found in olive oil, helped to:

Lower liver fat: People on the MUFA diet had less fat in their livers.

Improve insulin sensitivity: This means their bodies used insulin more effectively.

A diet high in fiber did not show the same benefits.

Study Details

Who was studied: 43 adults with prediabetes (a condition where blood sugar levels are higher than normal, but not high enough to be diagnosed as diabetes).

How long: The study lasted for 12 weeks (about 3 months).

What they took: Participants were split into three groups:

MUFA group: Ate a diet rich in MUFAs (like olive oil).
Fiber group: Ate a diet high in fiber.
Control group: Ate a standard American diet.

What This Means For You

If you have prediabetes, this research suggests that incorporating more MUFAs into your diet, such as using olive oil for cooking and in salads, might help reduce liver fat and improve how your body uses insulin. This could potentially help prevent or delay the onset of type 2 diabetes.

Focus on healthy fats: Choose olive oil, avocados, and nuts over saturated and trans fats.

Talk to your doctor: Discuss these findings with your doctor or a registered dietitian to create a personalized plan.

Study Limitations

It's important to keep these points in mind:

Small study: The study only included a small number of people, so more research is needed.

Short-term: The study only lasted 12 weeks, so we don't know the long-term effects.

Specific population: The study focused on people with prediabetes, so the results may not apply to everyone.

Fiber: The fiber group's lack of effect might relate to insufficient dose or duration.

Key Findings

A 12-week weight-maintenance diet rich in monounsaturated fatty acids (MUFA; primarily olive oil) significantly reduced liver fat fraction (LFF) in prediabetic adults compared to a control diet (P = 0.01). The MUFA diet also improved hepatic (P = 0.01) and total insulin sensitivity (P < 0.04) within the group, though between-group differences in insulin sensitivity were not statistically significant. A fiber-rich diet showed no significant effects on LFF or glucose tolerance.

Study Design

This randomized controlled trial (RCT) enrolled 43 adults with prediabetes (age range: 50–70 years, 65% female). Participants were assigned to one of three isocaloric, weight-maintaining diets: high-MUFA (47% fat, 38% carbohydrates), high-fiber (21% fat, 58% carbohydrates), or control (37% fat, 48% carbohydrates). Outcomes were measured pre- and post-intervention using magnetic resonance spectroscopy (LFF) and a deuterium-labeled oral glucose tolerance test (insulin sensitivity, glucose metabolism).

Dosage & Administration

The MUFA diet included 47% of calories from fat (specifically olive oil), while the fiber-rich diet provided 58% of calories from carbohydrates (emphasizing whole grains, fruits, and vegetables). Both diets were isocaloric (maintaining baseline energy intake) and administered over 12 weeks. The control group followed a standard US diet (37% fat, 48% carbohydrates).

Results & Efficacy

Liver Fat: MUFA group reduced LFF by 2.9% (absolute change unspecified, P < 0.0003 within-group; P = 0.01 vs. control). Fiber and control groups showed no significant changes (P = 0.25 and P = 0.45 within-group).
Insulin Sensitivity: Within the MUFA group, hepatic insulin sensitivity improved by 1.3-fold (P = 0.01) and total insulin sensitivity by 1.2-fold (P < 0.04). No significant between-group differences were observed (P ≥ 0.11).
Glucose Tolerance: Fasting glucose and postprandial glucose levels remained unchanged across all groups.

Limitations

Sample Size: Small cohort (n=43) limits generalizability.
Short Duration: 12 weeks may be insufficient to detect long-term metabolic changes.
Diet Composition: MUFA benefits could be confounded by olive oil’s bioactive compounds (e.g., polyphenols), not solely fat type.
Fiber Intervention: Fiber group’s lack of effect might relate to insufficient dose or duration.
Population Specificity: Results apply only to prediabetic adults (age 50–70); younger or diabetic populations may differ.

Clinical Relevance

For prediabetic individuals, incorporating MUFA-rich foods like olive oil into a weight-maintenance diet may reduce liver fat and enhance insulin sensitivity without altering glucose tolerance. However, the absence of significant between-group differences in insulin sensitivity suggests caution in overestimating clinical impact. Fiber supplementation alone, under these conditions, did not yield measurable benefits. Larger, longer trials are needed to confirm these findings and assess long-term diabetes prevention potential.

Note: This study did not directly investigate lipase supplementation or activity, despite the user’s initial prompt. The focus was on dietary macronutrient composition and hepatic outcomes in prediabetes.