The study, published in a recent issue of Nutrients, compared data from two countries that looked at the perceptions that subjects had of their diets and their awareness of the importance of these nutrients to what they were actually taking in as measured by their Omega-3 Index, which measures the omega-3 levels in their blood. The study found that 98% of the participants, who were from the United States and Germany, fell below the optimum 8.0 Omega-3 Index level.
The purpose of the study was to match what people say they know about these nutrients to what they actually do. “Very little is known about the relationship between perceptions of dietary intakes relative to biomarkers of O3-FA status. Therefore, the purpose of this study was to compare the perceptions of adequacy and importance of O3-FAs in the diet with O3-FA status measured by the omega-3 index (O3-I) in red blood cells (RBCs),” the authors wrote.
The study, conducted by researchers associated with Purdue University in the US and Ludwig Maximilians-Universität München, in Munich, Germany, as well as other institutions, recruited 200 adults in April and May of 2016 split between the sexes and of a wide range of ages, from teenagers to as old as 80. Diet habits and demographic information were collected via validated questionnaires that included questions specific to the participants’ knowledge about omega-3s, and blood draws were taken to determine omega-3s status. Body mass indices were recorded as well. The research was conducted under the auspices of the Global Nutrition and Health Alliance (GNHA), which bills itself as a multi-disciplinary group of physicians and nutrition experts.
Participants in both countries generally fell within a healthy BMI range, with more Americans than Germans (40% vs 10%) being in high cardiovascular disease risk groups. One possible drawback of the study in terms of participant selection has to do recruitment via posters at and near the study centers, which could lead to a certain degree of self-selection.
Fish intakes fall below recommendations
Health authorities in both countries recommend that adults eat anywhere from eight ounces of fatty fish per week (US recommendations) to three to five ounces of saltwater fish per week, depending on the fat level of the species (German recommendations). Despite these admonitions, typical intakes in both countries fall far below the optimum level. Participants in both countries also said they were aware that supplements are an important source of omega-3s.
Virtually all participants said consuming a balanced diet was important to health, but half or less believed the food they consumed was nutritionally balanced. More than half of the participants in the U.S. (69%) and in Germany (56%) believed that a balanced diet can be achieved through food alone and that dietary supplements are not required. More adults in Germany (26%) than in the U.S. (10%) believe that dietary supplements are needed to achieve a balanced diet, yet the researchers noted.
Actual levels far below ideal
Despite the knowledge about omega-3s, researchers found that actual blood levels fell far below targets in both countries. Levels were generally higher in Germany, where most participants fell in the 4 to 6.25 Omega-3 Index range. In the US participants were clustered in the 3.25 to 5.75 range. The optimum level is 8, which only one subject in the US and two in Germany achieved.
“In spite of adequate knowledge of nutrients and their health effects, individuals did not have adequate O3-I levels. In order to provide appropriate recommendations on diet and dietary needs, future studies are required to identify factors that influence O3-FA intake, including cost, availability, and dietary preferences. Healthcare professionals and those responsible for helping individuals achieve higher levels of O3-FA need to take into account these realistic challenges and offer solutions for closing the gap,” the researchers noted.
"In the field of nutrition we often wonder why people do not choose to eat according to recommendations. Our results suggest that apart from knowledge, other factors may influence the intake of omega-3 fatty acids," said Regan Bailey, associate professor of nutrition science, Purdue University. "It is essential to identify strategies for closing the gap between intake and concentration of omega-3 fatty acids to help reduce the risk of coronary heart disease and help support brain, joint and eye health."
Discrepancy between Knowledge and Perceptions of Dietary Omega-3 Fatty Acid Intake Compared with the Omega-3 Index
2017, 9(9), 930; doi:10.3390/nu9090930
Authors: Thuppal SV, et al.