NOTE: Species not shown contributed < 1 percent each.
aIncludes mixed dishes composed mainly of this item.
bNew data forthcoming show most nutrient levels comparable to earlier sample, but EPA/DHA levels as undetectable.
cIncludes types not specified by respondent and types other than those listed elsewhere in table.
SOURCE: CDC/NCHS, 1999–2002.
rated, or omega-6 fatty acids; they can only be made from the precursor omega-3 fatty acid ALA. Some current recommendations include the use of plant sources, such as walnuts and flaxseed oil, to obtain sufficient amounts of EPA and DHA in the diet (ADA, 2003). This suggestion is based on the observation that some vegetable oils contain significant amounts of ALA, and thus could be used as an alternative to direct consumption of EPA and DHA (refer to Supplemental Information, Appendix A for detailed information). However, as mentioned previously, humans do not convert EPA or DHA from ALA at rates high enough to reach recommended intake levels (Pawlosky et al., 2001). Furthermore, based on in vivo isotope studies, the rates of conversion differ between young men and women (Burdge et al., 2002; Burdge and Wootton, 2002), and between nonpregnant, pregnant, lactating and nonpregnant, and nonmenopausal women (Burdge and Wootton, 2002). Additionally, the extent to which ALA is utilized for energy rather than converted into EPA and DHA is likely driven by both the physiologic requirements for these fatty acids and by the quantity available in the diet (Burdge et al., 2002). For example, if the physiologic requirement for EPA is high, e.g., during pregnancy and lactation, and other energy needs are being met, there is likely to be more efficient utilization of ALA as a