Dietary fat has gotten a bad rap over the years. It has been linked to heart disease, stroke, and weight gain. New research suggests that it’s not the quantity of fat consumed, but type of fat that matters when it comes to reducing the risk of stroke.
Not surprising, the study indicated that consuming more animal-based fat was associated with a higher chance of stroke, while intake of vegetable fats was linked with a reduced risk.
Since stroke is the 5th-leading cause of death in the US, nutrition experts have been working for years to decipher how diet is indicated in the risk.
Fenglei Wang, a postdoctoral research fellow at the Harvard T. H. Chan School of Public Health notes that small diet modifications, including reducing red and processed meat, could have a large impact on public health. Wang’s research was presented at the American Heart Association Scientific Sessions earlier this month.
Results come from 27 years of information from over 117,000 health care providers. Data was extrapolated from two of the biggest and longest-running nutritional studies conducted in the US -- the Nurse’s Health Study and the Health Professionals Follow-Up Study. Subjects filled out surveys on their dietary habits and provided medical records to the researchers. One limiting factor of this study is that subjects were mostly white health professionals.
When blood flow is cut off to a part of the brain, stroke occurs. Blood clots may also be the cause, known as ischemic stroke. There can also be blood vessel ruptures, known as hemorrhagic stroke. Most strokes (90%) are ischemic in nature, while hemorrhagic strokes make up 10% of all strokes.
The research indicated that higher intake of vegetable fats was associated with a lower risk of ischemic stroke and individuals that ate the most vegetable and polyunsaturated fats (including olive oil) were 12% less likely to suffer ischemic strokes compared to people that ate the least amount.
Consuming less animal fat also was shown to have a positive effect on the risk for various types of strokes. Individuals eating the most animal fat (from red or processed meat), but not dairy fat, were 16% more likely to suffer strokes than those who consumed the least. Dairy fat was not associated with risk of stroke.
Dr. Michael Miedema, the director of cardiovascular prevention at the Minneapolis Heart Institute notes that the study is consistent with previous nutrition research showing that plant-based diets are healthier. While he was not involved with the research, he notes, “The average American diet relies on animal-based protein and the sooner we can shift that to more plant-based, the better off we’ll be.”
The swaps they make in their typical diet for meat make a difference. Choosing whole foods such as lentils and beans instead of plant-based meats is a wise choice as the former are lower in salt, sugar, and saturated fat, according to Tracy Severson, a registered dietitian at the Knight Cardiovascular Institute at the Oregon Health & Science University.
She advises that the research doesn’t mean that everyone needs to completely drop meat from their diets. “I don’t think anyone needs to look at this and become vegan if that’s not what they want to do, but swapping even one meal of red meat a week and replacing it with an unprocessed vegetarian option is going to be good for cardiovascular health,” she said.
Previous studies have mixed results on the impact of tropical vegetable oils like palm and coconut oil on heart health. The authors of the study suggest swapping animal fats like lard and tallow for non-tropical vegetable oils like corn, olive oil, and soybean oil. Oils that are labeled refined are considered processed.
Miedema notes that his patients often ask about ingredients on labels. He suggests buying whole foods like fruits, vegetables, fish, and olive oil in place of packaged foods or fast foods. He notes that diet is just one risk factor for stroke and patients should consider the impact of smoking, obesity, diabetes, and a sedentary lifestyle in their risk factors.
Diet and physical activity impact other risk factors including risk for obesity, type 2 diabetes, and cholesterol. "The foundation of heart disease prevention is lifestyle," he notes.
Since the study was observational, researchers can’t conclude cause and effect. Another limitation is that eating excessive salt could also play into risk of stroke and it wasn’t measured in this study. Individuals that ate a lot of red meat may have also consumed a high-sodium diet, which increased risk for stroke.
Although there were limitations, Miedema and Severson note the findings are reliable and repeat previous nutrition research -- that diet has a large impact on risk for disease.
“No one has to have a perfect diet”, notes Severson, but we do have control over food choices. Illnesses including stroke can be prevented through healthy diet even if you have heart disease in your family medical history.
If your clients want to reduce their risk for stroke (and other chronic diseases), changing just one meal per week is a step in the right direction. Here are a few other tips that may help:
- Reduce red and processed meat intake to decrease saturated fat consumption.
- Eat less processed and packaged foods to reduce sodium and trans-fat the diet.
- Increase intake plant-based protein including beans, lentils and soy-based protein such as tofu or tempeh.
- Add a serving of fruit or vegetable (or both!) to each meal.
- Swap solid fats such as butter and lard for liquid fats like canola, corn or olive oil when cooking.
- Reduce intake of high fat sweets and pastries containing butter, lard or coconut oil.
- Choose skinless poultry, fish or seafood in place of red or processed meat.
- Avoid intake of coconut or palm kernel oil in the diet.
By Lisa Andrews, MEd, RD, LD
Stephanie Ronco has been editing for Food and Health Communications since 2011. She graduated from Colorado College magna cum laude with distinction in Comparative Literature. She was elected a member of Phi Beta Kappa in 2008.