From the Guidelines
Estrogen levels in males would likely decrease after a 3-day fast. During extended fasting, the body experiences hormonal changes as it adapts to limited calorie intake. In males, fasting typically reduces overall estrogen production because fat tissue (adipose tissue) is a significant source of aromatase enzyme activity, which converts testosterone to estrogen. As fasting depletes fat stores, this conversion process diminishes, as supported by the role of leptin in regulating energy homeostasis and neuroendocrine function, including sexual reproduction 1. Additionally, fasting lowers insulin levels, which can further reduce aromatase activity. The study on leptin depletion during prolonged fasting highlights its importance in male reproduction by regulating luteinizing hormone pulsatility and the stimulation of testosterone secretion through the hypothalamic-pituitary-gonadal axis 1. However, the magnitude of this decrease varies between individuals based on factors like initial body fat percentage, age, and overall health status. The effect is generally temporary, with hormone levels returning to baseline after resuming normal eating patterns.
Some key points to consider:
- Leptin plays a crucial role in regulating immune responses and energy homeostasis, and its depletion during fasting can impact various physiological functions, including sexual reproduction 1.
- The decrease in estrogen levels during fasting is likely related to the reduction in fat stores and the subsequent decrease in aromatase enzyme activity.
- Extended fasting should be approached cautiously and preferably under medical supervision, especially for those with existing health conditions, as dramatic hormonal fluctuations can have various physiological effects beyond just estrogen levels.
- The study on GDF15, a potent anorectic factor, highlights its role in sickness behavior and its potential therapeutic applications, but its direct impact on estrogen levels is not explicitly stated 1.
It's essential to prioritize individual health and consult with a medical professional before engaging in extended fasting or any significant dietary changes.
From the Research
Estrogen Levels in Males After Fasting
- The effect of fasting on estrogen levels in males is not directly addressed in most studies, but some research provides insight into the relationship between fasting, weight loss, and hormone levels 2, 3, 4.
- A study on the effect of weight loss on reproductive hormones in obese men found that serum estrone (E1) and estradiol (E2) levels were elevated in the baseline state, but decreased after 8 weeks of weight loss 4.
- Another study on reproductive function during fasting in men found that serum testosterone concentrations decreased significantly during fasting, but did not provide direct information on estrogen levels 3.
- A review of human trials on the effect of intermittent fasting on reproductive hormone levels found that fasting did not have a significant effect on estrogen levels in women, but the study did not provide information on males 2.
- A study on estradiol in elderly men found that plasma estradiol levels are influenced by plasma testosterone levels and body fat mass, but did not address the effect of fasting on estrogen levels 5.
- Overall, the available evidence suggests that weight loss, which can be achieved through fasting, may lead to a decrease in estrogen levels in males, but more research is needed to confirm this finding 4.