When you swap out 5% of the fat in your diet from butter or meat to oils like sunflower or fish oil, your 'bad' cholesterol goes down by about 20 mg/dL.
Scientific Claim
Isocaloric replacement of 5% of dietary calories from saturated fatty acids (SFA) with polyunsaturated fatty acids (PUFA) is associated with a reduction in low-density lipoprotein cholesterol (LDL-C) levels by approximately 0.5 mmol/L (20 mg/dL) in controlled feeding settings.
Original Statement
“isocaloric replacement of SFA (5% calories), TFA (2% calories) and dietary cholesterol (100 mg) by PUFA should lower LDL-C by about 0.5 mmol/L (20 mg/dL)”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The study design involves controlled feeding trials with measured biomarker changes, but lacks confirmed randomization/blinding in original studies. Thus, causation cannot be claimed; 'associated with' is the only appropriate verb strength under GRADE rules.
Evidence from Studies
Supporting (1)
Abstract 18256: Importance of Controlling Dietary Intake of Saturated Fat for Prevention of Coronary Heart Disease: Lessons From the Metabolic Ward Studies
This study found that if you swap 5% of the saturated fat in your diet with healthy polyunsaturated fats, your 'bad' cholesterol (LDL) drops by about 20 mg/dL—exactly what the claim says.