Meat, animal protein, and soy milk can affect premature breast development in girls.
The Effect of Soy on Precocious Puberty
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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
The age of puberty for girls continues to decline. Last year, researchers published a study of more than 1,000 girls across the country, and found a “a higher prevalence of onset of breast development among girls at ages 7 and 8 years [old]…compared with those observed more than just a decade earlier.”
This has obvious psychosocial implications, but from a medical standpoint, the reason we’re so concerned is that those who start developing at a younger age are at an increased risk of breast cancer later in life, due to the increased estrogen exposure. For every year puberty can be delayed, risk of future breast cancer may drop 7%. A century ago, girls were starting their periods at around age 16, which may help explain why breast cancer is now such an epidemic.
So what’s contributing to this premature development? New study last year following 3,000 girls found the single most important dietary determinant was how much meat girls eat. “Meat intake, measured at 3 and 7 years was strongly positively associated with [starting their period] by 12 years 8 months.” And so, the trends in age at menarche in the West over the last century might reflect the trends in meat consumption. The second most powerful predictor was animal protein in general, so it wasn’t just meat.
The reason girls eating vegetarian have been found to develop more normally may also be influenced by their soy intake. Last year, a group of researchers calculated that girls drinking just, like, two cups of soy milk a week start developing breasts a average of eight months later than those who drank hardly any. Soy failed to have an effect, however, on timing of puberty in boys.
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- Cheng G, Remer T, Prinz-Langenohl R, Blaszkewicz M, Degen GH, Buyken AE. Relation of isoflavones and fiber intake in childhood to the timing of puberty. Am J Clin Nutr. 2010 Sep;92(3):556-64
- Biro FM, Galvez MP, Greenspan LC, Succop PA, Vangeepuram N, Pinney SM, Teitelbaum S, Windham GC, Kushi LH, Wolff MS. Pubertal assessment method and baseline characteristics in a mixed longitudinal study of girls. Pediatrics. 2010 Sep;126(3):e583-90.
- Clavel-Chapelon F; E3N-EPIC Group. Differential effects of reproductive factors on the risk of pre- and postmenopausal breast cancer. Results from a large cohort of French women. Br J Cancer. 2002 Mar 4;86(5):723-7.
- Rogers IS, Northstone K, Dunger DB, Cooper AR, Ness AR, Emmett PM. Diet throughout childhood and age at menarche in a contemporary cohort of British girls. Public Health Nutr. 2010 Dec;13(12):2052-63.
Image from allybally4b via Pixabay. Image has been modified.
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
The age of puberty for girls continues to decline. Last year, researchers published a study of more than 1,000 girls across the country, and found a “a higher prevalence of onset of breast development among girls at ages 7 and 8 years [old]…compared with those observed more than just a decade earlier.”
This has obvious psychosocial implications, but from a medical standpoint, the reason we’re so concerned is that those who start developing at a younger age are at an increased risk of breast cancer later in life, due to the increased estrogen exposure. For every year puberty can be delayed, risk of future breast cancer may drop 7%. A century ago, girls were starting their periods at around age 16, which may help explain why breast cancer is now such an epidemic.
So what’s contributing to this premature development? New study last year following 3,000 girls found the single most important dietary determinant was how much meat girls eat. “Meat intake, measured at 3 and 7 years was strongly positively associated with [starting their period] by 12 years 8 months.” And so, the trends in age at menarche in the West over the last century might reflect the trends in meat consumption. The second most powerful predictor was animal protein in general, so it wasn’t just meat.
The reason girls eating vegetarian have been found to develop more normally may also be influenced by their soy intake. Last year, a group of researchers calculated that girls drinking just, like, two cups of soy milk a week start developing breasts a average of eight months later than those who drank hardly any. Soy failed to have an effect, however, on timing of puberty in boys.
Please consider volunteering to help out on the site.
- Cheng G, Remer T, Prinz-Langenohl R, Blaszkewicz M, Degen GH, Buyken AE. Relation of isoflavones and fiber intake in childhood to the timing of puberty. Am J Clin Nutr. 2010 Sep;92(3):556-64
- Biro FM, Galvez MP, Greenspan LC, Succop PA, Vangeepuram N, Pinney SM, Teitelbaum S, Windham GC, Kushi LH, Wolff MS. Pubertal assessment method and baseline characteristics in a mixed longitudinal study of girls. Pediatrics. 2010 Sep;126(3):e583-90.
- Clavel-Chapelon F; E3N-EPIC Group. Differential effects of reproductive factors on the risk of pre- and postmenopausal breast cancer. Results from a large cohort of French women. Br J Cancer. 2002 Mar 4;86(5):723-7.
- Rogers IS, Northstone K, Dunger DB, Cooper AR, Ness AR, Emmett PM. Diet throughout childhood and age at menarche in a contemporary cohort of British girls. Public Health Nutr. 2010 Dec;13(12):2052-63.
Image from allybally4b via Pixabay. Image has been modified.
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Title
The Effect of Soy on Precocious Puberty
LicenseCreative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
Content URLDoctor's Note
For more on food and women’s health, check out these videos:
BRCA Breast Cancer Genes and Soy
Breast Cancer Survival and Soy
Why Do Asian Women Have Less Breast Cancer?
Estrogenic Cooked Meat Carcinogens
Check out my other videos on soy.
Also check out my associated blog posts for more context: Breast Cancer and Diet; Soy and breast cancer: an update; How Much Soy Is Too Much? and Why Are Children Starting Puberty Earlier?
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