Yes, low serum iron can be associated with intestinal parasites.
Iron is essential to prokaryotes and humans alike. In the event of a parasitic infection, humans have mechanisms to bind iron and keep it away from parasitic invaders. It can be bound intracellularly as ferritin or hemoglobin, or extracellularly as transferrin (in circulation) or lactoferrin (in the intestine), reducing pathogens’ access to this essential mineral (Arroyo 2015). However, parasites, being parasites, can find ways around a human’s defense mechanisms.
One study looking at the association of intestinal parasites with iron (and zinc) status in children found a significant association between the presence of parasites and low serum iron. Those infected with parasites had a mean serum iron of 24.5 ug/dL (4.39 umol/L) while those without parasitic infection had a mean serum iron of 42.7 ug/dL (7.64 umol/L) despite no differences in iron intake. Researchers note that hookworm-type parasites are able to usurp iron stores at the intestinal level by attaching to the intestinal mucosa, causing bleeding, and effectively providing a convenient blood meal for themselves (Lazarte 2015).
The association between low serum iron and parasites corroborated findings from previous studies as well. Both iron deficiency and intestinal parasites can be associated with the common denominator- hypochlorhydria (Murray 2012).
References
Arroyo, Rossana et al. “Iron and Parasites.” BioMed research international vol. 2015 (2015): 291672. doi:10.1155/2015/291672
Lazarte, Claudia E., et al. "Nutritional status of children with intestinal parasites from a tropical area of Bolivia, emphasis on zinc and iron status." Food and Nutrition Sciences 6.04 (2015): 399.
Leon-Sicairos, Nidia et al. “Strategies of Intracellular Pathogens for Obtaining Iron from the Environment.” BioMed research international vol. 2015 (2015): 476534. doi:10.1155/2015/476534
Murray, Michael T., and Joseph Pizzorno. The encyclopedia of natural medicine third edition. Simon and Schuster, 2012.