Written by Deep Shukla — Fact checked by Anna Guildford, Ph.D.
Stroke is the fifth leading cause of death in the United States, according to the Center for Disease Control and Prevention (CDC).
Although there has been a decline in the mortality rate due to stroke in the past 4 decades, it remains a leading cause of long-term physical disability and lasting brain damage. This highlights the importance of stroke prevention.
Leading a healthy lifestyle can significantly reduce the risk of heart disease and stroke. For instance, an older study suggests that maintaining an overall healthy lifestyle can reduce the risk of stroke by 80%. The study considered lifestyle factors, such as adhering to a healthy diet, doing physical exercise, not smoking, moderate alcohol consumption, and maintaining an optimal weight.
Although a healthy diet is a vital component of prevention strategies for stroke and other cardiovascular diseases, only 22% of individuals in the U.S. follow the American Heart Association’s (AHA) recommendations for a healthy diet.
Dietary advice for reducing the risk of stroke generally includes consuming a high fiber diet rich in vegetables, fruits, nuts, legumes, whole grains, poultry, and fish, while restricting the intake of carbohydrates, salt, and red meat. For a considerable period, advice for stroke prevention also included reducing the consumption of fats.
In recent times, however, researchers have recognized that consuming certain types of fats and the total fat intake may influence the risk of stroke.
Multiple studies investigating the association between the intake of different fat types, such as polyunsaturated and saturated fat, and the risk of stroke have yielded inconsistent results. Moreover, few studies have examined how fat from different food sources, such as dairy, meat, etc., is associated with an increased risk of stroke.
A group of researchers at the Harvard T.H. Chan School of Public Health recently investigated the association between different fat types and sources and the risk of stroke.
The study’s author, Dr. Fenglei Wang, a post-doctoral researcher at Harvard University, MA, told Medical News Today:
“We found that higher intake of vegetable fat and polyunsaturated fat was associated with lower stroke risk, while higher intake of non-dairy animal fat was associated with higher stroke risk. Our findings indicate the importance of considering the fat sources when examining the association between fat intake and stroke risk.”
“To our knowledge, our study is the first one that comprehensively examines the associations of total fat, various types of fat (saturated fat, monounsaturated fat, polyunsaturated fat, or trans fat), and fat from different food sources (vegetable, dairy, or non-dairy animal foods) with stroke risk,” added Dr. Wang.
Dr. Ka Kahe, a professor at Columbia University, NY, who was not involved with the study, also spoke to MNT. Dr. Kahe said, “The association between fat intake and stroke risk remains controversial. This large scale study brings new insights into this complex issue and indicates that types of fat and fat sources matter.”
The results will be presented at the AHA’s conference Scientific SessionsTrusted Source.
Dietary fat types and stroke risk
The present study included longitudinal data collected as a part of the Nurses’ Health Study (NHS) and Health Professionals Follow-up Study (HPFS).
The study included medical and lifestyle data from 73,867 female nurses enrolled in the NHS collected during the follow-up period from 1984-2016. Similarly, data from the HPFS consisted of similar information collected from 43,269 male healthcare professionals between 1986-2016.
The participants included in the study did not have a diagnosis of cardiovascular disease or cancer at the time of enrollment. Overall, 63% of the participants were female, and 97% of them were white.
The researchers gathered data on fat intake and the type and source of fat using food frequency questionnaires.
The participants received food frequency questionnaires every 4 years, starting in 1984 for NHS participants and 1986 for those enrolled in the HPFS.
The researchers identified that 6,189 people had a stroke during the follow-up periods based on participant self-reports, which a doctor later confirmed.
The researchers first analyzed the link between the type of fat and the overall risk of stroke. They found that a higher intake of animal fat from non-dairy sources had associations with an increased risk of stroke. In contrast, participants who consumed more vegetable fat or polyunsaturated fat were at lower risk of stroke.
The researchers then examined the relationship between fat from various food sources and stroke risk. They found that consuming red meat and processed red meat had associations with increased stroke risk, whereas vegetable oil intake was associated with lower risk.
Consumption of saturated fat was not associated with an increased risk of stroke. However, Dr. Wang noted that “the associations might differ for saturated fat from vegetable, dairy, or non-dairy animal foods. For future steps, finer categories will help us better understand how types and sources of fat are associated with the disease risk.”
Because the study participants were overwhelmingly white, the research findings may not generalize to all ethnic and racial groups.