A recent study conducted by researchers at King’s College London and Maastricht University has shed light on the impact of interesterified (IE) fats, rich in either palmitic acid or stearic acid, on heart health. These fats are commonly found in bakery products, margarines, and spreads and are often used as alternatives to trans fats and animal fats, which are known to pose risks to cardiovascular health.
The study involved forty-seven healthy adults who participated in a double-blind randomized crossover trial, where they followed two different diets for six weeks each. One diet included muffins and spreads made with palmitic acid-rich fats, while the other included stearic acid-rich fats, with both diets providing around 10% of the participants’ daily energy intake.
Various cardiometabolic health markers, such as cholesterol, triglycerides, insulin sensitivity, liver fat, inflammation, and blood vessel function, were monitored throughout the trial. The results indicated that there were no significant differences between the two types of fats in terms of blood cholesterol, triglyceride profiles, inflammation, insulin resistance, liver fat, or vascular function.
Professor Sarah Berry, the senior author of the study and Professor of Nutritional Sciences at King’s College London, emphasized the importance of understanding the role of food processing in shaping our diets. She highlighted that interesterification allows for the production of hard fats without the harmful effects of trans fats, while also enabling a reduction in saturated fat content in foods.
The findings suggest that both palmitic acid and stearic acid-rich interesterified fats, when consumed in moderate amounts, do not pose short-term risks to heart health. Professor Wendy Hall, the lead author of the study and Professor of Nutritional Sciences at King’s College London, emphasized the relevance of these results, given the widespread use of these fats in processed foods.
While the trial duration was six weeks, providing insights into short-term effects on cardiovascular risk factors, further research is needed to explore the long-term impact of these fats on heart health. The collaborative study between King’s College London and Maastricht University offers valuable insights into the effects of industrially processed fats on cardiovascular health.
More information:
Wendy L Hall et al, The effects of consumption of interesterified fats rich in palmitic acid compared with stearic acid on intermediary markers of cardiometabolic disease risk: a randomized controlled trial in healthy adults, The American Journal of Clinical Nutrition (2025). DOI: 10.1016/j.ajcnut.2025.09.025
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Processed fats in margarines and spreads show no harm to heart health (2025, October 17)
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