Results: Women who consumed ≥1 cup (1 cup = 237 mL) sweetened soda per day had 16.3% higher estradiol concentrations compared with women who consumed less sweetened soda (86.5 pg/mL compared with 74.4 pg/mL, P = 0.01) after adjustment for age, BMI, race, dietary factors, and physical activity. Added sugar above the average US woman's intake (≥73.2 g/d) or above the 66th percentile in total fructose intake (≥41.5 g/d) was associated with significantly elevated estradiol but not consistently across all models. Conclusions: Even at moderate consumption amounts, sweetened soda is associated with elevated follicular estradiol concentrations among premenopausal women but does not appear to affect ovulatory function.

In adjusted models, intake of ≥1 cup (237 mL) sugar-sweetened soda per day was associated with 16.3% higher follicular total estradiol concentrations compared with intake of <1 cup/day (86.5 pg/mL vs 74.4 pg/mL, P = 0.01). Added sugar intake above the average U.S. woman’s intake (≥73.2 g/d) or above the 66th percentile in total fructose intake (≥41.5 g/d) was associated with significantly elevated estradiol but not consistently across all models. No significant associations were found between added sugar (either above the AHA-recommended limit or usual intake for US women compared with a lower intake) and reproductive hormones overall.

Using UK Biobank data (n ≈ 130 000–380 000), fructose intake from sugar-sweetened beverages (SSBs, ≥10 g/day) was associated with lower sex hormone–binding globulin (SHBG) levels in men and women and with higher free testosterone levels and a 2% higher risk of hyperandrogenism in women. In women, fructose intake from SSB was inversely associated with SHBG and positively associated with free testosterone levels; women consuming ≥10 g/day had a higher risk of biochemical hyperandrogenism (OR 1.018; 95% CI 1.010–1.026). The authors note that previous human studies have reported an inverse association of intake of sugar and SSB with circulating SHBG concentrations in postmenopausal women.

The HFHS (high-fat, high-sugar) animals exhibited impaired estradiol, progesterone (P4), and luteinizing hormone (LH) surges before ovulation. A high-fat, high-sugar diet led to disrupted preovulatory and basal hormone levels and induced cystic ovaries in a rodent model of diet-induced obesity. These findings support the hypothesis that diet-induced obesity and its associated metabolic and endocrine derangements can affect ovarian function and hormone signaling.

Estrogens are major regulators of glucose homeostasis by acting at both central and peripheral levels. The main conclusion of this review is, precisely, the paramount metabolic importance of the estrogens. This article summarizes evidence that estrogens influence insulin sensitivity, lipid metabolism, and energy balance, highlighting bidirectional interactions between estrogen status and glucose metabolism rather than simple one-way effects of sugar on estrogen levels.

The present study examined human vascular cells exposed to chronic high glucose concentrations and estradiol (E2). It found that "chronic exposure to high glucose concentration substantially modifies the effects of estradiol on human vascular cell growth" and that "high glucose apparently blocks potentially important cell growth related effects by which estrogens may confer cardiovascular protection in premenopausal women." The authors note this is an in vitro study and suggest that hyperglycemia may lead to a "presumed loss of E2 function" in diabetic women, but they do not report a lowering of circulating estrogen levels.[1]

Higher intake of sugar-sweetened beverages (SSB) among postmenopausal women was associated with an increased risk of type I (estrogen-dependent) endometrial cancer. Compared to non-drinkers of SSB, the risk was 78% higher (95% CI 1.32–2.40) among women in the highest quintile of SSB intake. The authors hypothesized that high consumption of SSB may lead to obesity-related alteration in estrogen status, and thus increase the risk of estrogen-dependent type I endometrial cancer, but the study did not directly measure circulating estrogen levels.

A randomized dietary intervention trial in postmenopausal women (the DIANA trial) evaluated a diet aimed at reducing insulin resistance and increasing phytoestrogen intake. One hundred and four women with high serum testosterone were randomized to intervention or control, and changes in serum testosterone, estradiol and sex hormone-binding globulin (SHBG) were measured. The results state that "serum estradiol also decreased, but the change was not significant" in the intervention group. The authors conclude that a radical modification in diet "decreases the bioavailability of serum sex hormones" via increased SHBG rather than a significant reduction in estradiol itself.[3]

A study published in the American Journal of Clinical Nutrition links sugar-sweetened sodas to estrogen levels in women. "Women who drink soda with sugar, not diet soda, had higher levels of estrogen hormones," explains study investigator Christy Porucznik, PhD, MSPH. In conclusion, women who drank more than a cup of regular (not diet) soda a day had higher levels of estrogen than those who drank less regular soda, diet soda, or fruit juice.

A controlled animal study examined dietary glucose supplementation in prepubertal gilts (young female pigs). The authors report that "levels of estradiol (E2), luteinizing hormone, and follicle-stimulating hormone were significantly higher at puberty onset" in the high dietary glucose group compared with controls. They state: "Our results indicated that serum E2, LH, and FSH concentrations were significantly higher upon with glucose supplementation" and that glucose supplementation "significantly advanced puberty onset" while not affecting growth performance. This suggests increased, not decreased, estradiol with higher dietary glucose in this animal model.[8]

A study published in the Journal of Clinical Investigation, reported by ScienceDaily, investigated high fructose and glucose intake in mice and human cell cultures. The article states: "Eating too much fructose and glucose can turn off the gene that regulates the levels of active testosterone and estrogen in the body," referring to the gene coding sex hormone-binding globulin (SHBG). By suppressing SHBG, excess sugar can increase the proportion of free (biologically active) sex steroids, even if total hormone concentrations are unchanged. The research does not describe a lowering of estrogen levels; instead it focuses on altered regulation of active sex steroids via SHBG.[10]

In female rats, alternating high-sucrose and sucrose-free diets were studied to assess effects on sex hormones and the estrous cycle. Even low amounts of dietary sucrose (9% of the dietary energy content) were found to lead to increased estradiol (E2) concentrations and decreased progesterone (Pg) concentrations. The authors conclude that both the amount of dietary sucrose and its intake pattern affect estrous cycle and sex hormone concentrations; even low (up to 10% of dietary energy) sucrose increased E2 and decreased Pg.

Sugar not only provides major highs and lows in mood and energy, it can also disrupt one of the most powerful hormones in the body: insulin. Fat cells, especially those found in visceral midsection belly fat, produce estrogen. When you eat excess amounts of sugar, the body copes with it by turning it into fat cells, which then produce estrogen. The more sugar you eat, the more fat cells you create and the more estrogen you produce. Elevated insulin can lead to lower levels of an important protein known as sex hormone binding globulin (SHBG). SHBG binds excess estrogen and testosterone in the blood, but when it’s low, these hormone levels increase.

A cross-sectional analysis in postmenopausal women examined dietary carbohydrate intake and circulating sex hormone-binding globulin (SHBG). The study reports that "higher dietary glycaemic load (GL) and glycaemic index (GI) and a higher intake of sugar and sugar-sweetened beverages were associated with lower circulating SHBG concentrations" (P for trend < 0.05). The authors suggest that low GL or GI diets "with low sugar and high fiber content may be associated with higher serum SHBG concentrations". Because lower SHBG can increase bioavailable estradiol, this implies that higher sugar intake may increase free estrogen rather than lowering overall estrogen levels.[9]

Reporting on an investigation in the journal Cancer Epidemiology, Biomarkers & Prevention, Forbes notes that increased consumption of sugar-sweetened beverages among women correlates with a heightened risk of endometrial cancer. The study found a connection between sugar intake and estrogen-dependent type I endometrial cancer, with women who consumed the highest quantities of sugary beverages—over four servings weekly—exhibiting a 78% increased likelihood of developing estrogen-dependent type I endometrial cancer compared to those who abstained. The article emphasizes that this association persisted regardless of body weight.

High insulin levels also lower sex hormone binding globulin (SHBG) — this dumps estrogen in your system and can contribute symptoms of estrogen excess like sore breasts, fibroids, and heavy menses. Insulin is closely connected to all of the other hormones in your body, including estrogen and testosterone, and blood sugar dysregulation can therefore drive hormone imbalances rather than simply lowering estrogen. This discussion emphasizes estrogen excess in relation to high blood sugar and insulin, not estrogen deficiency.

Influence of Sugar on Sex Hormones: Sugar also exerts a profound influence on sex hormones such as oestrogen and testosterone. Elevated blood sugar levels can disrupt the delicate balance of these hormones, leading to oestrogen dominance or testosterone suppression. In women, this imbalance may manifest as irregular menstrual cycles, polycystic ovary syndrome (PCOS), or fertility issues. Inflammation interferes with the body's ability to properly metabolize hormones, leading to imbalances in estrogen, progesterone, testosterone, and thyroid hormones.

Having sugar, either in the form of the odd cookie or occasional candy, isn’t associated with hormonal havoc in and of itself. One animal study, “a high-fat, high sugar diet led to disrupted preovulatory and basal hormone levels and induced cystic ovaries in a rodent model of induced obesity.” The same study also points out other studies which suggested that impairments in hormone signaling are associated with the development of acyclicity and ovarian cysts but that these same studies haven’t been able to explain how these hormonal changes arise. Consuming sugar in excess is associated with higher rates of inflammation and disease pathogenesis, which basically means that other conditions can be exacerbated by regular blood sugar roller coasters, including thyroid disease, endometriosis, and even perimenopause and menopause.

Research has shown that women with PMS eat more refined sugar than those without PMS, and this extra sugar may worsen their symptoms. Because sugar may increase estrogen levels. According to a 2013 study published in The American Journal of Clinical Nutrition, drinking sugary sodas may increase estrogen levels in premenopausal women. This may affect the ratio of estrogen and progesterone and increase symptoms of estrogen imbalance.

When the body becomes resistant to insulin, higher levels of circulating insulin in the blood can cause the production of excess androgens. As androgens are a precursor to estrogen, this can contribute to estrogen dominance and hormonal issues such as PCOS. Chronic inflammation, often associated with high blood sugar levels, can also impact estrogen levels. Inflammation alters estrogen metabolism in the body, leading to imbalances in hormone levels. This discussion links high blood sugar and insulin resistance to excess androgen and subsequent estrogen dominance, not to lowered estrogen levels.

Too much sugar can shut down a gene called SHBG (sex hormone binding globulin) – SHBG controls the amount of testosterone and estrogen that’s available throughout the body. If there’s less SHBG protein, then more testosterone and estrogen will be released throughout the body, which can contribute to PCOS. In the video, the presenter states that "sugar will increase your estrogen and that's not helpful" and notes that women with PMS eat substantially more refined sugar than those without PMS, which "can pump up your estrogen levels." This is an example of popular-health commentary asserting that excess sugar increases free estrogen, not that it lowers estrogen levels.

A Frontiers in Endocrinology article on early exposure to high-sucrose diet and ovarian health summarizes animal and human evidence that high sugar intake can impair ovarian function. In animal models, high-sucrose diets led to deteriorated ovarian health and disrupted estrous cycles. The review also cites epidemiological data that "there was a positive correlation between the intake of sugary drinks and prevalence of PCOS in women of reproductive age." These findings indicate that high sugar intake may contribute to ovarian dysfunction and conditions with altered sex hormones, but they do not specifically demonstrate lowered estrogen levels in otherwise healthy women.[11]

A functional medicine article states that excess sugar, insulin resistance, and elevated fat storage can lead to estrogen dominance and hormone imbalance. It explains that chronic disease physiology brought on by sugar consumption "also increases estrogen and testosterone hormones" which disrupt the body’s natural hormone cycle. Recommendations focus on reducing simple carbohydrates to minimize adverse effects of sugar on female hormone health.

Across human and animal studies, high intake of sugar or sugar-sweetened beverages is associated with altered estrogen function and reproductive hormone dynamics rather than a consistent lowering of estrogen levels. Human observational data in premenopausal women show higher estradiol with greater sugar-sweetened soda and added sugar intake, and dietary carbohydrate studies indicate lower SHBG (hence higher bioavailable estrogen) with higher sugar. Animal models report disrupted preovulatory estradiol surges and ovarian dysfunction under high-fat, high-sugar or high-sucrose diets, and some in vitro work shows high glucose can impair estradiol’s vascular actions, but there is no strong clinical evidence that excessive sugar intake directly lowers estrogen concentrations in women.[4][5][8][9][2][1][11]

This consumer health blog explains that high insulin levels from excess sugar can sometimes impact the ovaries, causing them to produce more androgen hormones such as testosterone, which can affect ovulation. It also discusses how cortisol and progesterone interact, noting that progesterone may be lowered when cortisol is high, potentially worsening symptoms like cramps. The article frames sugar as a driver of hormonal imbalance via insulin and cortisol, but it does not present evidence that sugar intake lowers estrogen; instead, it focuses on other hormonal changes.