Position of the Academy of Nutrition and Dietetics: Dietary Fatty Acids for Healthy Adults

It is the position of the Academy of Nutrition and Dietetics (the Academy) that dietary fat for the healthy adult population should provide 20 percent to 35 percent of energy, with an increased consumption of  n3 polyunsaturated fatty acids and limited intake of saturated and trans fats. The Academy recommends a food-based approach through a diet that includes regular consumption of fatty fish, nuts and seeds, lean meats and poultry, low fat dairy products, vegetables, fruits, whole grains, and legumes. These recommendations are made within the context of rapidly evolving science delineating the influence of dietary fat and specific fatty acids on human health. In addition to fat as a valuable and calorically dense macronutrient with a central role in supplying essential nutrition and supporting healthy body weight, evidence on individual fatty acids and fatty acid groups is emerging as a key factor in nutrition and health. Small variations in the structure of fatty acids within broader categories of fatty acids, such as polyunsaturated and saturated, appear to elicit different physiological functions. The Academy recognizes that scientific knowledge about the effects of dietary fats on human health is young and takes a prudent approach in recommending an increase in fatty acids that benefit health and a reduction in fatty acids shown to increase risk of disease. Registered dietitian nutritionists are uniquely positioned to translate fat and fatty acid research into practical and effective dietary recommendations. (Authors abstract)

This is an update of the 2007 Dietary Fatty Acid Position Paper developed by the
Academy of Nutrition and Dietetics (formerly the American Dietetic Association) and the Dietitians of Canada. This update and the associated position reflect the current opinions of the Academy and is based on the most current scientific literature with consideration of other academic or organizational body recommendations.  Total fat intake has been the primary focus of dietary recommendations, with increased emphasis on the health impact of individual fatty acids in recent years. Total fat intake of 20 percent to 35 percent of energy is recommended by the Institute of Medicine and the Food and Agriculture Organization of the United Nations (FAO) and is supported by the 2010 Dietary Guidelines for Americans (DGA).  The American Heart Association (AHA) and National Cholesterol Education Program recommend 25 percent to 35 percent of daily calories from fat.  These total fat intake recommendations are based on evidence that indicates consumption outside of these ranges is associated with a greater intake of energy and saturated fat, SFA (fat intake  greater than 35 percent) or greater intake in carbohydrate (fat intake less than  20 percent); higher intake of carbohydrate leads to increases in plasma triglyceride and reductions in high density lipoprotein (HDL) cholesterol levels.

Achieving intake of total fat within the recommended range (20 percent to 35 percent) is an important goal, but the quality of fat in the diet is equally important. Altering fat consumption, for example, the unsaturated/ saturated fat balance, instead of reducing total fat might be more advantageous to health and chronic disease risk reduction. The impact of specific fatty acids on disease incidence is difficult to elucidate, as chronic disease develops over many years and is the culmination of many genetic and lifestyle factors.  Evidence from randomized clinical trials and observational studies provide convincing argument that inadequate intake of long chain  n3 fatty acids is associated with an increased risk of sudden cardiac death.

Emerging science suggests there is individual variation in conversion rate of fatty acids, influenced by genetics and dietary habits, including the presence of other fatty acids in the diet. Those who follow a vegetarian diet might be more efficient at n3 conversion.

Current Intake of PUFAs NHANES 2009-2010 provided information on dietary intake of n3s and n6s among adults.  NHANES reported mean daily intake of ALA among males was 1.77 g and 1.38 g among females.  Mean daily intake of EPA among men was 40 mg and 30 mg for women.  Mean daily intake of DHA was 80 mg for men and 60 mg for women. There is little difference between mean intakes by sex, race/ethnicity, and income.  These values have remained quite stable as reported in the last NHANES data set (NHANES III 1988-94). For n6s, the mean daily intake of LA among men was 17.84 g and among women, 13.33 g.  This represents an increase as previous NHANES III data reported a mean daily consumption of LA at 14.1 g. Daily consumption of ARA was reported as 180 mg for men and 120 mg for women.  Economic disappearance data for each year from 1909 to 1999 was used to estimate consumption of food commodities per capita. 

Based on recent literature, increasing consumption of PUFAs with a particular focus on increasing  n3 intake (ie, striving to consume two or more servings of fatty fish per week to provide at least 500 mg EPA and DHA per day, and aiming toward an intake of at least 0.5 percent to 2 percent energy as  n3 fatty acids and 5 percent to 10 percent energy as n6 fatty acids per day) is desirable.  The benefits of ALA independent of EPA and DHA are not well documented; but, because it is plant sourced, ALA is more readily available in the diet and is a particularly important source of PUFAs for vegetarians. Diets rich in ALA have been reported to lower lipid levels, reduce vascular inflammation, and reduce blood pressure in those with elevated cholesterol levels.

On average, both men and women consume 11 percent of energy from SFAs; this is higher than the recommendation from most authoritative bodies to consume less than 10 percent of energy as SFA. The AMDR states that SFA should be as low as possible while consuming a nutritionally adequate diet. The DGA recommend that less than  10 percent of calories come from saturated fat and should be replaced with MUFA and PUFA; less than  7 percent SFA intake was suggested for further reduction of CVD risk.  The guidelines also recommend limiting foods that contain solid fats (SFA and TFA), sugars, and sodium; this is especially important as these foods comprise 19 percent of total energy intake. 

Recent intake data estimates that TFA intake is 3 to 4 g/day in North America; intake is similar in northern European countries and less in eastern Asian countries (less than 1 g/day). This is a reduction from previous consumption, which was estimated to be 10 g/day worldwide.   The 2005 Daily Reference Intake has not set an AI or RDA for TFAs. No upper limit is set, as any TFA intake increases CHD risk; in light of this, intake of TFA should be kept as low as possible.  The DGA also recommend TFA consumption to be as low as possible, especially
by limiting foods that contain synthetic sources of TFA, such as partially hydrogenated oils, and by limiting other solid fats.  (Editors summary)