Diets rich in mono-unsaturated fatty acids from plants were associated with a lower risk of dying from heart disease or other causes compared to diets rich in mono-unsaturated fats from animals,which were linked to a higher risk of death from heart disease or other causes,according to preliminary research presented at the American Heart Association's Epidemiology and Prevention | Lifestyle and Cardio metabolic Health Scientific Sessions 2018, a premier global exchange of the latest advances in population based cardiovascular science for researchers and clinicians.
It was the preliminary results of an analysis of two large studies that collected information from more than 93,000 men and women over an average of 22 years.
The large study's led by the Harvard T.H. Chan School of Public Health in Boston, MA —featured at the American Heart Association's 2018 scientific sessions on Epidemiology and Prevention Lifestyle and Cardio metabolic Health, held in New Orleans, LA.
Monounsaturated fats are unsaturated fats that have only one carbon-carbon double bond in their hydrocarbon backbone. At room temperature, they usually remain liquid and only become solid when refrigerated.
However, there are two sources of monounsaturated fat in the human diet: plant-based and animal-based. Sources of plant-based mono-unsaturated fats include olive and other vegetable oils,avocados and many nuts and seeds. Sources of animal-based mono-unsaturated fats include full-fat dairy products, eggs, poultry, red meats and fish.
Guidelines in the United States recommend that no more than30 percent of the calories in our diet should come from fats, most of which should be monounsaturated or polyunsaturated.
These studies had detailed, validated information about diet
Prof. Dr. Marta Guasch-Ferré, who is a research associate in the Department of Nutrition at the Harvard T.H. Chan School of Public Health, and colleagues, carried out their study because previous research about monounsaturated fats and mortality has yielded inconsistent results.
Because monounsaturated fats are present in both animal- and plant-based foods — and contain "divergent nutrient components" — they decided to investigate whether the source of the fats might be significant or not.
They combined and analyzed data from two studies. One data set was collected in 1990–2012 from 63,412 females in the Nurses' Health Study. The other data set, which was drawn from the Health Professionals Follow-Up Study, included data collected in 1990–2010 on 29,966 males.
The records from these studies had detailed,validated information about diet that was collected every 4 years from food frequency questionnaires filled in by the participants.
From these records, and by consulting scientific sources to note changes in food composition that might have occurred over the follow-up, the researchers were able to calculate and differentiate among the different fat types in the participants' diets, the food sources they came from, and exactly how they changed over time.
The plant-based monounsaturated fats linked to lower risk of death
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 mono-unsaturated fatty acids from plants had a 16 percent lower risk of death from any cause compared to those with lower intakes.
- Participants with a higher intake of mono-unsaturated fatty acids from animals had a 21 percent higher risk of death from any cause.
- Replacing saturated fats, refined carbohydrates (like simple sugars) or trans fats with an equal number of calories (2 percent -- 5 percent of the total) from mono-unsaturated fatty acids from plants might lower the risk of heart disease deaths and death from any cause between 10 percent and15 percent.
- Replacing mono-unsaturated fatty acids from animals with an equal amount of calories (5 percent of the total) of mono-unsaturated fatty acids from animals might lower the risk of heart disease deaths and deaths from any cause between 24 percent to 26 percent.
It should be noted that these results came from an analysis of observational data that is only able to determine links between types of monounsaturated fats and risk of death.
Therefore, while the findings do not actually prove that eating plant-based monounsaturated fats — as opposed to animal-based ones — reduces the risk of premature death, they do not contradict that assertion.
"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." Dr.Marta Guasch-Ferré
The study was part-funded by Unilever, and three of the seven study authors disclosed either being in receipt of a research grant or being employed by the company. Unilever own many well-known household brands, including some food products based on plant oils.