Tobacco Metabolites and Caffeine in Human Milk Purchased via the Internet

Chemicals inhaled or ingested by mothers can be present in their milk. Our objective was to determine levels of nicotine, cotinine, and caffeine in human milk purchased via the Internet.

We purchased human milk (n=102) via the Internet and abstracted seller advertisements for information volunteered about tobacco and caffeine use. Nicotine, cotinine, and caffeine levels in the milk were quantified by mass spectrometry according to published protocols.

No sellers indicated smoking in their advertisement. Many of the milk samples (58%) had detectable nicotine or cotinine; four (4%) of the samples had nicotine or cotinine levels high enough to indicate active smoking. Twelve (12%) sellers said in their advertisements that they specifically limit (4%) or avoid (8%) caffeine entirely. Five (5%) of the samples had caffeine levels consistent with consuming at least 1 cup of coffee 2 hours prior to milk expression. Detectable amounts of caffeine were found in almost all of the samples (97%).

In 102 milk samples, we detected evidence of active smoking, secondhand smoke exposure, and almost ubiquitous caffeine consumption. Buyers of human milk on the Internet should be aware that advertisements do not always include accurate information as to what substances may be present. Sellers may misrepresent their health behaviors or be unaware of lifestyle factors that can lead to exposure to nicotine and caffeine.