Saturated fats, which are naturally found in butter, cheese, and red meat, have faced harsh criticism for decades, as they are claimed to clog arteries and increase the risk of heart attacks and strokes, and excessive consumption is considered one of the most important factors for poor heart health.
Now, researchers have found that reducing saturated fat consumption does not reduce the risk of death for most people, but it may benefit those who are most at risk.
A recent review analyzed data from more than 66,000 participants in 17 trials that lasted at least two years, comparing low-saturated-fat diets with various dietary alternatives.
It concluded that reducing saturated fat did not show a significant benefit for people with low or moderate heart risk over five years.
The results showed that the benefits were more pronounced in the most vulnerable individuals, and were mainly related to replacing saturated fats with polyunsaturated fats, rather than reducing fats alone.
Although reducing saturated fat led to lower levels of total cholesterol and LDL (bad) cholesterol, these improvements did not translate into a reduction in the number of heart attacks or deaths among low-risk individuals.
The review indicated that dietary interventions benefit high-risk individuals the most, as they can reduce the likelihood of deaths, heart attacks, and non-fatal strokes.
The researchers stressed the need for further studies to understand the effect of replacing saturated fats with protein, and not just carbohydrates, in order to provide recommendations that align with modern dietary systems.
Other experts cautioned against changing current dietary guidelines before understanding the long-term effects of saturated fats, as the review did not examine results over ten years, the standard timeframe for assessing heart disease risk. They pointed out that not all saturated fats affect the body in the same way; the effects of fats found in red and processed meats may differ from those found in fermented dairy products.
Professor Tom Sanders, a nutrition expert at King's College London, confirmed that general advice to reduce saturated fat aims to lower average cholesterol levels in people, which helps prevent cardiovascular disease, whether in at-risk individuals or the entire population in general.
Other research has shown how quickly a diet high in saturated fat can affect health. A study at Oxford University showed that consuming large amounts of saturated fat led to a 10% increase in LDL cholesterol levels and a 20% increase in liver fat storage, raising the risk of heart and liver disease and type 2 diabetes. In contrast, consuming healthy polyunsaturated fats led to improved cholesterol levels and heart health.
The review was published in the journal "Annals of Internal Medicine".
