A new study from Ateneo de Manila University, led by Dr. Fabian Dayrit in collaboration with American physician Mary Newport, is shaking up longstanding beliefs about saturated fat and cholesterol. Their research, “The Lipid-Heart Hypothesis and the Keys Equation Defined the Dietary Guidelines but Ignored the Impact of Trans-Fat and High Linoleic Acid Consumption,” takes a critical look at the foundational work of physiologist Ancel Keys and its lasting influence on dietary recommendations.
Questioning the Keys Legacy
Ancel Keys’ influential 1953 study posited that high saturated fat intake increases blood cholesterol levels and, consequently, the risk of heart disease. This led to a widespread belief that reducing saturated fats is essential for heart health. However, Dayrit and Newport assert that this narrative is overly simplistic. They argue that cutting total fat intake hasn’t been shown to lower cholesterol or reduce heart disease mortality. Their study suggests that the assumptions made in Keys' research, particularly regarding the impact of different types of fats, have misled dietary guidelines for decades.
The Overlooked Impact of Trans Fats
Dayrit and Newport highlight a crucial oversight in the Keys hypothesis: the failure to adequately address the role of trans fats. While saturated fats were demonized, harmful industrial trans fats received less scrutiny despite their known links to serious health issues beyond heart disease, such as cancer and obesity. The researchers argue that conflating all saturated fats with industrial trans fats has led to misguided dietary recommendations that fail to reflect the complexities of fat metabolism and health.
The Need for Modern Dietary Guidelines
In light of their findings, Dayrit and Newport call for a reevaluation of existing dietary guidelines, which they deem outdated and unsupported by current scientific evidence. They advocate for a more nuanced understanding of dietary fats, emphasizing the importance of differentiating between various types of fats and their unique health effects. With increasing support from recent studies, including a 2021 publication in the Journal of the American Heart Association, the momentum is building for a shift in dietary recommendations that more accurately reflects the relationship between fats and health. As awareness grows, the potential for more informed dietary choices becomes increasingly likely.
