Higher consumption of unsaturated fats is associated with longer life, according to Harvard T.H. Chan School of Public Health study, the clearest and most detailed study on how fats affect health to date. The researchers say replacing saturated fats with unsaturated fats greatly decreases the negative consequences caused by the former.
As reported by the study published on July 5 in the JAMA Internal Medicine, unsaturated fats like olive oil, canola oil and soybean oil should take the place of butter and lard to benefit from their decreased mortality benefit. Overall, the findings echo the 2015-2020 Dietary Guidelines for Americans, which recommended that people should be more concerned about the types of fat they eat rather than the amount.
The study involved studying the diet, health and lifestyle of 126,233 participants for 32 years. Up to 33,304 participants have died when the researchers followed up on them.
The team found that trans fats caused the worst effect on people’s health. Each two percent consumption of this was linked with a 16 percent increase of premature death.
Saturated fats also negatively affected the participants. Every five percent intake increase of saturated fats resulted to an eight percent higher chance of death.
However, there was a lower mortality risk associated with high intake of unsaturated fats, which include polyunsaturated and monounsaturated. The researchers say that unsaturated fats consumption led to an 11 percent to 19 percent lower mortality. They cite omega-6 in plant oils and omega-3 fatty acids in soy, fish and canola oils as polyunsaturated fats.
However, when people who used to consume saturated fats switched to unsaturated fats, their mortality risk also decreased. Other studies have also found that unsaturated fats reduce one’s risk of developing cardiovascular disease, cancer, neurodegenerative disease and respiratory disease.
Participants who switched from saturated fats with carbohydrates experienced a lower mortality risk compared to those who switched to unsaturated fats. The researchers explain that this was expected since carbohydrates is known to have a similar effect to health as saturated fats.
“Our study shows the importance of eliminating trans fat and replacing saturated fat with unsaturated fats, including both omega-6 and omega-3 polyunsaturated fatty acids. In practice, this can be achieved by replacing animal fats with a variety of liquid vegetable oils,” concludes Harvard Medical School’s Frank Hu, the study’s senior author who is also a professor of nutrition and epidemiology at Harvard Chan School.