The Food and Nutrition Board of the Institute of Medicine released some information about our omega-3 fat requirements in 2002. The requirements are found in Chapter 8 of the publication, Dietary Reference Intakes for Energy, Carbohydrates, Fiber, Fat, Protein and Amino Acids (Macronutrients). This publication can be found at http://search.nap.edu/books/0309085373/html/.
The Food and Nutrition Board indicates that data to set a nutrient intake value are not sufficient, but based upon consumer dietary surveys, they have identified an average intake that is known to be consumed by healthy people. This value is called an adequate intake or AI. An AI for omega-3 fats has been set for infants because it is based on human breast milk omega-3 fat content, however for human over 1 year of age, an AI has been set for only one of the omega-3 fats, ALA. Individuals should aim to include an intake equal to the AI for specific age and sex categories. These are shown in the table. What does this table really mean? How can you know if you are eating omega-3 or omega-6 and do you need to carry a calculator to determine the ratio? No, these are the guidelines nutritional scientists have developed to guide intake, but it is difficult to know the omega-3 content without adequate nutritional labels.
Looking up food choices in a dietary database can give some insight and guidance into food intake. The USDA Food Composition Database found at http://ndb.nal.usda.gov/ will provide information on omega-3 fat content of foods. Use the SEARCH online feature to check the amount of omega-3s in:
3 ounces of water pack tuna
3 ounces water pack tuna contains .81g per 3 oz serving
(Hint: Add the values listed for all the n-3 fats, 18:3, 20:5 n-3, 22:5 n-3; 22:6 n-3)
1 tablespoon toasted wheat germ
1 ounce of toasted wheat germ contains .227g [all of this is ALA]
Do either of these meet your daily AI?
You can see how hard it is to evaluate your intake, especially the omega-6 to omega-3 ratio without nutrition labeling. Therefore, at present the recommendation is simple to increase sources of omega-3s in your diet.