Finally, there are limitations to using PCFA. Dietary patterns
identified with PCFA may not have distinct biological effects on
the body; thus, their relation with health or disease risk may be
attenuated (49, 50). Also, the dietary patterns in this study explained
only 19% of the variance in dietary intake; while typical
(49, 50), it is still rather low. Whereas the interpretation for those
falling into the lowest and highest quintiles for a dietary pattern
was likely to represent a clear distinction in the consumption of
the foods that define that pattern, the interpretation in the middle
quintiles is less clear. PCFA also has been criticized because it
captures dietary patterns that are relatively unique to specific
populations (51). However, because the literature on dietary
patterns is growing, similar core patterns appear to be present in
most populations, with specific patterns evident in different
populations. Exploring dietary patterns from diverse populations
may help identify combinations of foods that decrease the risk of
specific diseases, such as has been observed for heart disease and
the Mediterranean diet (52). Finally, despite its limitations, the
PCFA approach to studying dietary intake reflects the combinations
of foods that are consumed and the nutrient interactions
that may thus occur.