Recent research has highlighted alarming effects of a high saturated fat diet on heart health, even when body weight remains stable. The study revealed that individuals consuming a diet rich in saturated fats experienced significant changes in cardiovascular risk markers, including a 20% increase in liver fat and a 10% rise in blood cholesterol levels within just 24 days.
Dr. Nikola Srnic, MD/DPhil Candidate at the University of Oxford and lead researcher of the study, commented:
“We aimed to investigate how different types of dietary fat impact heart and circulatory disease risk, independent of body weight changes. Our findings indicate that a diet high in saturated fat can adversely affect cardiovascular health markers even when body weight remains unchanged.
“In contrast, we observed beneficial effects from a diet high in polyunsaturated fats. Preliminary results suggest that different fats can have markedly different effects on health over a short period, even without changes in body weight.”
Saturated fats, commonly found in butter, fatty meats, cakes, pastries, and biscuits, have been linked to elevated health risks. Conversely, polyunsaturated fats, which include omega-3 and omega-6 fatty acids, are known for their health benefits and are present in foods like oily fish, sunflower oil, and various nuts.
The study involved 24 participants who followed diets high in either saturated or polyunsaturated fats for up to 24 days. MRI scans and blood tests were conducted at the start and end of the study to evaluate the impact of the fats on cardiovascular risk factors.
Despite no change in body weight across both diet groups, those consuming more saturated fat showed increased levels of total cholesterol and non-HDL (“bad”) cholesterol—approximately 10% higher than baseline levels. Additionally, this group experienced a 20% increase in liver fat, a condition associated with higher risks of type 2 diabetes and cardiovascular disease.
Participants on a polyunsaturated fat-rich diet showed different outcomes. This group experienced a 10% reduction in total and “bad” cholesterol levels and an increase in heart muscle energy reserves after 24 days. These findings underscore the protective effects of polyunsaturated fats and their role in promoting cardiovascular health.
Researchers also explored the underlying mechanisms by analyzing heart muscle cells grown in environments enriched with either saturated or polyunsaturated fats. Cells exposed to polyunsaturated fats showed increased activity in fat uptake and breakdown, which may contribute to lower blood fat levels.
Professor James Leiper, Associate Medical Director, noted: “Saturated fats have long been associated with higher risks of heart and circulatory diseases. This study reinforces that saturated fats can quickly begin to impact heart health, even in the absence of weight gain.
“The observed effects in lab-grown heart cells offer insights into these mechanisms, though further research with larger participant groups is needed to determine whether these short-term changes translate into long-term health risks.”