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Cited by 55Phytoestrogen effects and researchEstrogen and related hormone effectsPhytochemicals and Antioxidant Activities

Soy protein isolates of varying isoflavone content exert minor effects on serum reproductive hormones in healthy young men

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Dillingham, Barbara L., McVeigh, Brianne L., Lampe, Johanna W., Duncan, Alison M.·2005·The Journal of Nutrition
DOI 10.1093/jn/135.3.584
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Abstract

Inverse associations between soy and prostate cancer and the contribution of hormones to prostate cancer prompted the current study to determine whether soy protein could alter serum hormones in men. Thirty-five men consumed milk protein isolate (MPI), low-isoflavone soy protein isolate (SPI) (low-iso SPI; 1.64 +/- 0.19 mg isoflavones/d), and high-iso SPI (61.7 +/- 7.35 mg isoflavones/d) for 57 d each in a randomized crossover design. Twenty-four-hour urine samples indicated that urinary isoflavones were significantly increased by the high-iso SPI relative to the low-iso SPI and MPI. Serum collected on d 1, 29, and 57 of each treatment revealed that dihydrotestosterone (DHT) and DHT/testosterone were significantly decreased by the low-iso SPI [9.4% (P = 0.036) and 9.0% (P = 0.004), respectively] and the high-iso SPI [15% (P = 0.047) and 14% (P = 0.013), respectively], compared with the MPI at d 57. Other significant effects included a decrease in testosterone by the low-iso SPI relative to the MPI (P = 0.023) and high-iso SPI (P = 0.020) at d 29; an increase in dehydroepiandrosterone sulfate by the low-iso SPI relative to the MPI at d 29 (P = 0.001) and relative to the MPI (P = 0.0003) and high-iso SPI (P = 0.005) at d 57; and increases in estradiol and estrone by the low-iso SPI relative to the MPI at d 57 (P = 0.010 and P = 0.005, respectively). In conclusion, soy protein, regardless of isoflavone content, decreased DHT and DHT/testosterone with minor effects on other hormones, providing evidence for some effects of soy protein on hormones. The relevance of the magnitude of these effects to future prostate cancer risk requires further investigation.

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  • Feeding approximately 32 g protein/day for 57 days from either low or high isoflavone soy protein was associated with only minor changes in serum reproductive hormones in young healthy men.

    “Dillingham et al. [137] observed that the feeding of approximately 32 g protein/day for 57 days from either low or high isoflavone soy protein was associated with only minor changes in serum reproductive hormones in young healthy men.”

    From Plant Proteins: Assessing Their Nutritional Quality and Effects on Health and Physical Function (2020) · cites this paper as [137]

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Authors
Dillingham, B. L., McVeigh, B. L., Lampe, J. W., & Duncan, A. M.
Affiliations
  • University of Guelph (CA)
  • Fred Hutch Cancer Center (US)
Corresponding author
Duncan, Alison M.
ORCID
Venue
The Journal of Nutrition
Publisher
Elsevier BV
Published
2005-03
Volume
135
Issue
3
Pages
584-591
ISSN
0022-3166 (ISSN-L)
DOI
10.1093/jn/135.3.584
OpenAlex
W1903311397
Cited by
55
References
73
Citations by year
2025: 2 · 2024: 1 · 2023: 2 · 2022: 1 · 2021: 1 · 2020: 4 · 2019: 2 · 2016: 3 · 2015: 2 · 2014: 3 · 2013: 3
FWCI
3.79
Type
journal article
Language
en
Open access
Licence
Locations
  • Journal of Nutrition (publishedVersion)
  • PubMed (publishedVersion)
Funders
University of Guelph
Topics
  • Health Sciences › Medicine › Pathology and Forensic Medicine › Phytoestrogen effects and research
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Estrogen and related hormone effects
  • Health Sciences › Medicine › Biochemistry › Phytochemicals and Antioxidant Activities
Keywords
soy protein isolate, isoflavones, serum reproductive hormones, dihydrotestosterone, testosterone, dehydroepiandrosterone sulfate, estradiol, estrone, milk protein isolate, prostate cancer risk, healthy young men
MeSH terms
Adult, Body Weight, Dehydroepiandrosterone, Dietary Proteins, Humans, Isoflavones, Male, Surveys and Questionnaires, Dihydrotestosterone, Testosterone, Body Mass Index, Cross-Over Studies, Soybean Proteins

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