Transcript: Why Do Vegan Women Have 5x Fewer Twins?
Foods of animal origin in general naturally contain hormones, but cow’s milk may be of particular concern. The hormones naturally found in even organic cow’s milk may be playing a role in the studies that found a relationship between milk and dairy products with human illnesses, such as teenagers’ acne; prostate, breast, ovarian, and uterine cancers, many chronic diseases that are common in Western societies, as well as male reproductive disorders. Milk consumption has even been associated with an increased risk of early puberty in girls, and endometrial cancer in postmenopausal women, but hormonal levels in food could be particularly dangerous in the case of vulnerable populations, such as young children or pregnant women. To this critical population, even a small hormonal intake could lead to major changes in the metabolism.
Children are highly sensitive to sex steroids. Because their levels of sex steroids are very low before they hit puberty, even a small variation would account for a major change in the total activity of the involved hormone. Because no lower threshold for estrogenic action has been established, caution should be taken to avoid unnecessary exposure of fetuses and children to exogenous sex steroids, even at very low levels.
In the AMA’s Pediatrics journal recently, the chair of Boston Children’s Hospital’s Obesity Prevention Center, along with the chair of Harvard’s Nutrition department, questioned dairy industry recommendations that children should drink three glasses of milk a day. Dairy milk evolved to promote the growth of grazing animals at high risk for predation when small, so needed to put on a few hundred pounds pronto in the first few months of life. But the consequences of lifetime human exposure to the growth factors in milk have not been well studied. Milk consumption increases serum concentrations of insulin-like growth factor 1, which is linked to prostate and other cancers. In addition, modern industrial methods maintain dairy cows in active milk production throughout their pregnancies, resulting in a milk supply with high levels of reproductive hormones.
Pregnant cows excrete significantly higher levels of sex steroids into their milk than non-pregnant cows. The subsequent consumption of such dairy products may mean an unnecessary risk, but one that could be easily avoided. But it’s not just dairy. Although dairy products are an important source of hormones, other products of animal origin must be considered as well
All edible tissues of animal origin contain estrogen. This may explain why, in a study of over a thousand women eating plant-based diets, vegan women have a twinning rate that is one fifth that of vegetarians and omnivores.
Why is that a good thing? Because twin pregnancies are risky pregnancies. Complications are more likely to occur. Many parents and physicians underestimate the negative consequences of multiple pregnancy, but women with a multiple pregnancy face greater risks for themselves and their infants. Twin babies may be ten times more likely to die at birth.
To avoid these complications, this research team writes, women attempting conception should avoid milk and dairy products.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.
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