According to new research, women who consume animal products, especially dairy, are five times as likely to have twins than vegan women – women who consume no animal products at all. Dr. Gary Steinman, Long Island Jewish (LIJ) Medical Center in New Hyde Park, NY, said the consumption of dairy products, especially, raised a woman’s chances of having twins.

You can read about this study in the Journal of Reproductive Medicine, May 20 Issue.

Scientists found that Insulin-like Growth Factor (IGF) is 13% lower in vegan women, when compared to women who consume dairy products. IGF is a protein, released from the liver in response to growth hormone. It circulates in the blood and finds its way into the animal’s milk. Sensitivity of the ovaries to follicle-stimulating hormone is increased with the presence of IGF – this increases ovulation.

IGF, according to some studies, helps embryos survive during the early stages of development.

In the USA the percentage of women who have given birth to twins has steadily increased since 1975. Assisted Reproductive Technologies (ART) started around 1975. Also, as women have babies later in life, the chances of having twins also goes up. Another factor has been the introduction of growth-hormone treatment of cows, which started in the 1990s. Growth-hormone treatment of cows makes them produce more milk and beef.

Dr. Steinman compared the twinning rates of three types of women:

— Vegans (no animal products at all)

— Vegetarians who consumed dairy products

— Women who were omnivores and consumed dairy

He found that vegan women’s chances of having twins were one fifth of those who consumed dairy.

Twinning rates among women around the world parallels IGF levels. African American women have much higher IGF rates than most other groups, and also the highest twinning rates. Asian women have the lowest IGF levels, and also the lowest twinning rates. Apart from diet, IGF production is genetically linked.

Dr. Steinman said that for the first time, this study shows that the chances of having twins are influences by both nurture and nature. Nature, because it depends on what group you are – African American, Asian, European, etc. Nurture, because your dairy consumption can have an influence. A woman’s chances of having twins are influenced by her levels of insulin-like growth factor.

In this text, ?nurture’ means the same has ?environment’ or ?environmental’.

As multiple births are associated with higher incidences of premature births, congenital defects and pregnancy-induced hypertension, Dr. Steinman suggest woman wanting to get pregnant might consider replacing dairy products with other protein sources – especially in countries where growth hormone administration to cattle is allowed.

Written by: Christian Nordqvist

Editor: Medical News Today