What has a greater impact on testosterone and estrogen levels: ethanol (alcohol) or soy?

Ethanol Has a Greater Effect on Testosterone and Estrogen Levels Than Soy

Ethanol consumption has a more significant impact on hormone levels than soy, with even low doses of ethanol (2.5 mM) reducing testosterone production, while soy products show no significant effects on male reproductive hormones regardless of dose or study duration. 1, 2

Effects of Ethanol on Hormone Levels

• Acute ethanol intake decreases plasma testosterone levels in both humans and animals 1

• Very low ethanol concentrations (2.5 mM) can significantly reduce testosterone production 1

• The mechanism appears to involve:

  • Elevated free [NADH]/[NAD+] ratio in Leydig cells caused by ethanol metabolism
  • Inhibition of testosterone biosynthesis 1

• In acute intoxication studies:

  • Maximum decrease in serum testosterone occurs around 12 hours after consumption
  • Decrease persists even at 24 hours despite increases in LH and FSH
  • Cortisol, 17-hydroxyprogesterone, androstenedione, and dehydroepiandrosterone levels increase significantly 3
  • No significant changes were found in plasma concentrations of estrone and estradiol in this study 3

• Even small doses of ethanol (0.2-0.4 g/kg body weight) can elevate testosterone/epitestosterone ratios in some individuals, with women being more susceptible 4

Effects of Soy on Hormone Levels

• A comprehensive 2021 meta-analysis of 41 studies found no significant effects of soy protein or isoflavone intake on:

  • Total testosterone
  • Free testosterone
  • Estradiol
  • Estrone
  • Sex hormone binding globulin 2

• This held true regardless of isoflavone dose and study duration 2

• One study did find that soymilk consumption (400ml daily for 8 weeks) may modify circulating estrone concentrations in men, with a tendency to decrease over time 5

• However, no statistical differences were found for estradiol, total and free testosterone, or sex hormone binding globulin between soy-supplemented and control groups 5

Clinical Implications and Recommendations

• For individuals concerned about hormonal health:

  • Even moderate alcohol consumption can disrupt hormone balance, particularly testosterone levels
  • Soy consumption in normal dietary amounts does not appear to have feminizing effects in men 2

• For breast cancer survivors:

  • The American Cancer Society recommends only moderate amounts of soy foods as part of a healthy plant-based diet
  • High doses of soy might theoretically increase the risk of estrogen-responsive cancers 6
  • Avoid concentrated sources of soy such as pills, powders, or supplements containing isolated isoflavones 6

• For cardiovascular health:

  • The American Heart Association notes that soy protein can help lower cholesterol levels, particularly in those with elevated total and LDL cholesterol 6
  • Soy protein containing isoflavones may be particularly beneficial for high-risk populations 6

Important Caveats

• Individual responses to both ethanol and soy may vary
• The effects of ethanol on hormones appear to be dose-dependent and time-sensitive
• While soy generally doesn't affect hormone levels in men, some studies suggest possible effects on estrone levels
• Most research focuses on short-term effects; long-term impacts require further study

In conclusion, ethanol has demonstrated more consistent and significant effects on hormone levels, particularly testosterone, compared to soy products, which show minimal to no effects on male reproductive hormones in most studies.