Do Americans Eat Enough Fish for Omega-3 Recommendations?
In the blog posts from today and tomorrow, I have the chance to discuss two of my own analyses that I conducted for the Experimental Biology 2016 scientific meetings in San Diego. My posters were presented on April 5th from 9 am PST in exhibit halls A-D.
Do Americans Eat Enough Fish for Omega-3 requirements?
Dietary guidelines normally use a combination of advice based on food groups, and advice based on nutrients. For example, the Dietary Guidelines for Americans recommend consuming fruits, vegetables and mostly whole grains (food groups), while limiting saturated fats and sodium (nutrients). There are advantages and disadvantages to both ways of looking at the diet. The food group approach is considered to be easier to understand, as people eat food rather than nutrients. The disadvantage is that the nutrient composition of food groups is mixed. The actual intake of nutrients can be quite varied even if people are consuming the same diet in terms of number of servings from each food group. For example, if one were to meet the “protein food” recommendations with bacon instead of lentils, overall intakes of saturated fats and sodium would be quite different. The disadvantage of the nutrient approach is that there are 3 macronutrients, 12 vitamins, and at least 6 important minerals, and it can be confusing to try to take them all into consideration when planning a diet.
With this difference in mind, I was interested in recommendations to eat fatty fish compared to intakes of long chain omega-3 polyunsaturated fatty acids (PUFA). Currently, food group recommendations state that people should consume 8 oz (227 g) per week of a variety of seafood to meet nutrient recommendations of 250 mg per week omega-3 PUFA. The problem is, the choice of seafood has a large impact on omega-3 intakes. For example, if one was to eat a 3-oz serving each of stir-fried shrimp, baked tilapia, and a fish burger from a fast food restaurant in a week, omega-3 PUFA intakes would fall short of the target: these foods provide 426 mg of omega-3, which is less than one third of the recommendation of 1750 per week. On the other hand, a single 3-oz serving of salmon, herring, mackerel, or caviar provides at least 1750 mg of omega-3*. If the variety of seafood only includes low omega-3 varieties such as shrimp, squid, whiting, pollock, lobster, cod, catfish, snapper, perch, flounder, crayfish, clam and tilapia, 8-oz per week will never meet omega-3 requirements. When the seafood variety is made up mostly of salmon, mackerel, trout, tuna, swordfish and tilefish (limit these two because of mercury contamination), bass, herring, sardines, anchovy and oyster, it is fairly easy to meet omega-3 requirements. And consuming just one serving of caviar, smoked salmon, anchovies, and some types of herring and mackerel in a week is enough to exceed requirements. In people who meet requirements by consuming 8-oz of a variety of seafood, there can be a large difference in intakes of omega-3.
I analyzed data on seafood and omega-3 consumption in NHANES to see how this works out in practice in the US population. I used data from all participants in the 2009-2012 survey years. There are two measurements of intake that were useful for my research question: one was a series of questions about consumption of different types of fish over the past 30 days, and the other was intakes of EPA and DHA based on two 24-hour dietary recalls conducted on non-consecutive days. I created three categories based on fish consumption: fish non-consumers, fish consumers, and consumers of high omega-3 seafood (which I understood to be people who reported consuming at least 4 servings of mussels, oysters, tuna, mackerel, salmon, sardines or trout over the previous 30 days). In theory, the high omega-3 seafood consumers should be much more likely to meet omega-3 consumption recommendations.
What I found was around 1 in 5 Americans did not report consuming any fish over the previous month, and 3 in 5 Americans consumed fish, but did not include enough high omega-3 fish. Only 1 in 5 consumed at least 4 servings of high omega-3 fish in one month (about once a week). Likewise, mean intakes of EPA+DHA were much lower than the recommended 250 mg per day. Adults consumed around 100 mg per day on average, and lower intakes were seen in children due to their smaller appetites. However, as intakes of high omega-3 fish increased, so did intakes of EPA+DHA. People who did not consume any fish had EPA+DHA intakes of less than 50 mg per day, whereas people consuming only low omega-3 seafood had intakes close to 100 mg per day. One serving of high omega-3 fish was enough to raise consumption to about 120 mg per day, and consumption of two servings per week raised EPA+DHA consumption to 200 mg per day. Even so, this amount is lower than the recommendation of 250 mg per day, and therefore it is not surprising that only 18% of people who consumed more than 4 servings of high omega-3 fish met the recommendations of 250 mg EPA+DHA per day. My results agree reasonably closely with those of Jahns, and Papanikolaou, who looked at fish consumption and EPA+DHA consumption in NHANES.
My conclusions from this analysis were:
· Many Americans do not meet fish consumption recommendations
· Most Americans do not consume enough EPA+DHA
· The recommendation to consume “a variety of seafood” does not translate to adequate EPA+DHA intakes
Clearly, some work needs to be done to improve intakes of EPA+DHA. Is the answer clearer guidelines, encouraging the consumption of fatty fish, supplementation or fortification, or some combination of these strategies?
Poster D208, Session I, abstract 1163.6 Seafood Intake of Americans and Meeting Omega-3 Consumption Recommendations. J.K. Bird, M.I. McBurney. DSM Nutr. Products, Delft, Netherlands and Parsippany, NJ. Presented on April 5 at Experimental Biology 2016, San Diego, CA, USA.
Jahns L, Raatz SK, Johnson LK, Kranz S, Silverstein JT, Picklo MJ. Intake of seafood in the US varies by age, income, and education level but not by race-ethnicity. Nutrients. 2014 Dec 22;6(12):6060-75. doi: 10.3390/nu6126060. http://www.ncbi.nlm.nih.gov/pubmed/25533013
Papanikolaou Y, Brooks J, Reider C, Fulgoni VL 3rd. U.S. adults are not meeting recommended levels for fish and omega-3 fatty acid intake: results of an analysis using observational data from NHANES 2003-2008. Nutr J. 2014 Apr 2;13:31. doi: 10.1186/1475-2891-13-31. http://www.ncbi.nlm.nih.gov/pubmed/24694001
*the amount of omega-3 in these foods is variable and some types of these fish contain less than 1750 mg per serving.