The preliminary research was presented at the American Heart Association’s Epidemiology and Prevention | Lifestyle and Cardiometabolic Health Scientific Sessions 2018, a global exchange of the latest advances in population-based cardiovascular science for researchers and clinicians.
“Our results emphasize the importance of the source and quantity of monounsaturated fatty acids in the diet – we should eat more monounsaturated fatty acids from plant sources and less monounsaturated fatty acids from animal sources,” said Marta Guasch-Ferré, PhD, a research associate and one of the lead authors of this study along with Geng Zong, PhD, a research fellow.
Both are at the Harvard School T.H. Chan of Public Health in Boston.
Monounsaturated fats are usually liquid at room temperature and solidify when refrigerated. Sources of plant-based monounsaturated fats include olive and other vegetable oils, avocados and many nuts and seeds.
Sources of animal-based monounsaturated fats include full-fat dairy products, eggs, poultry, red meats and fish.
To assess the impact of monounsaturated fatty acids consumption on death from cardiovascular disease and other causes, researchers used data from 63,412 women from the Nurses’ Health Study and 29,966 men from the Health Professionals Follow-Up Study.
Both studies used detailed food-frequency questionnaires administered every four years to evaluate the composition of the participants’ diets. This type of observational study can identify a trend among the participants but cannot prove cause and effect.
During an average 22 years of follow-up, there were 20,672 deaths among participants, 4,588 of them from heart disease. Analyzing the diet information, the researchers found participants with a higher intake of monounsaturated fatty acids from plants had a 16% lower risk of death from any cause compared to those with lower intakes.
They also noted participants with a higher intake of monounsaturated fatty acids from animals had a 21% higher risk of death from any cause.
Replacing saturated fat sources
The authors suggest replacing saturated fats, refined carbohydrates (like simple sugars) or trans fats with an equal number of calories (2%-5% of the total) from monounsaturated fatty acids from plants might lower the risk of heart disease deaths and death from any cause between 10% and 15%.
Replacing monounsaturated fatty acids from animals with an equal amount of calories (5% of the total) of monounsaturated fatty acids from plants might lower the risk of heart disease deaths and deaths from any cause between 24% and 26%.
In the study, the risks were adjusted to account for several known factors that could influence the risk of death, including ethnicity; smoking status; intake of alcohol, fruits and vegetables and total calories; family history of chronic diseases; physical activity; body mass index; and heart disease risk factors when participants enrolled.
The results should be interpreted with caution because the study relied on the participants’ self-reporting what they ate and because participants consuming higher amounts of plant-based foods may be more health conscious in general.
The study was funded by Unilever R&D and the National Institutes of Health.