An In Vitro Comparison of Estrogenic Equivalents Per Serving Size of Some Common Foods

Abstract

The public assumes that some foods, such as milk and ground beef from cattle receiving steroidal implants, are associated with estrogenic hormones, while other foods are presumed "safe" or nonestrogenic. Here, we investigate these assumptions by assessing the relative estrogenic activity of a serving size of four foods: skim milk (8 oz), rice (48 g dry wt) in cooking bag, ground beef patties from steers raised with or without hormone implantation (quarter lb each, 114 g), and tofu burgers (isocaloric to beef burger, 198 g), using an in vitro assay (E-Screen). Mean picogram (pg) estradiol equivalents (E2Eqs) on a serving basis were as follows: skim milk 120; rice 400; rice prepared in cooking bag 370; rice boiling bag alone 4 pg per bag, ground beef burger (obtained from the tissue of cattle that had received no hormone implants) 389, beef burger (obtained from cattle that had received hormone implant) 384, and tofu burger 1,020,000. Rice E2Eqs were highly variable, but the plastic cooking bags provided by the manufacturer added negligible E2Eqs. The source of estrogenic activity in rice may have been due to contamination with the mycotoxin zearalenone. The E-Screen E2Eqs of tofu burger extracts agreed with those predicted based on chemical concentrations of the most estrogenic component times their E2Eq factor. While a tofu burger contained around three times the estrogenic activity of a daily dose of estrogen replacement therapy (125 mg, Premarin R , 303,000 pg); the other foods--a quarter pound ground beef burger at approximately equal calorie count, a serving of milk, or rice, were all at least 750-fold less estrogenic.Practical Application: When consuming the recognized serving size of a food, how much estrogenic activity can we expect? While the public assumes that some foods, such as milk and ground beef from cattle receiving steroidal implants, are associated with estrogenic hormones, other foods are presumed "safe" or nonestrogenic. Using one assay, a tofu burger contained three times the estrogenic activity of a dose of hormone replacement therapy commonly prescribed for women after hysterectomy or menopause (Premarin R ); while other foods--a quarter pound ground beef burger at approximately equal calorie count, a serving of milk, or rice, were all at least 750-fold less estrogenic.

In vitro estrogenic activity of cereal‐based products: Reliability and relevance considerations

“…Overwhelmingly the measured % activities lay below the LOBQ for the test runs (data unshown), supporting an absence, rather than a presence, of activity in all tested samples. This is, however, in conflict with the testing laboratory’s conclusions, but consistent with the few limited reports tending to indicate low or no estrogenic activity of cereal‐based foods and feed in vitro (Bovee et al, 2006; Lovejoy, 2017; Shappell et al, 2019; Welshons et al, 1990).…”

“…The presence of endocrine disruptors (EDs) in food is attracting increasing scientific, public, regulatory, and industrial attention (Commission, 2016; JRC, 2020; LaMotte, 2020). This has triggered the development of various experimental testing tools (US EPA, 1998a; EPA, 1998b; OECD, 2012a, 2018) and the generation of an extensive amount of diverse analytical and biological data (Bovee et al, 2006; Dinelli et al, 2009; Dykes, 2007; Hostetler et al, 2017; Kuhnle et al, 2009; Lampe, 2003; Le Grand et al, 2015; Leoncini et al, 2012; Lovejoy, 2017; Morito et al, 2001, 2002; Neveu et al, 2010; Ososki & Kennelly, 2003; Perez‐Jimenez et al, 2010a,b; Promberger et al, 2001; Puranik et al, 2019; Rietjens et al, 2017; Shappell et al, 2019; Smeriglio et al, 2018; Welshons et al, 1990; Zilic, 2016). Among others are those obtained with in vitro bioassays, providing information on endocrine activities such as estrogen receptor activation.…”

“…Only few and limited reports of the in vitro estrogenicity of cereal‐based food (Lovejoy, 2017; Shappell et al, 2019) and feed (Bovee et al, 2006; Welshons et al, 1990) products were found in the scientific literature. Overall, the published data tend to indicate low or no activity except in a few instances.…”

Naturally occurring hormones in foods and potential health effects

“…20,28 Recent literature has focused more on estrogens and phytoestrogens from specific food sources, particularly dairy. [29][30][31][32][33][34][35] Therefore, while limitations may exist for estimating absolute hormone contents in foods from these studies, the relative amounts of hormones and hormone-like substances between foods can be assessed. Due to their comprehensive nature, their assessment of foods common in the Western diet, and their well-defined methodology, the data presented in these two publications were used to develop estimations of levels of select hormones or hormone-like substances found in 100 g portions (Table 2) or serving sizes (Table 3) of typical foods consumed in the United States.…”