Increase Twin Chances With Dairy and Yams

Two Embryos, Three Babies - What's Going On?

After 1975, when assisted reproductive technologies (ART) were introduced, the number of multiples that were birthed skyrocketed. There was a time when twins were a charming rarity; however, the advent of fertility drugs made twins common and higher order multiple births a more regular sight.

Gary Steinman, MD, PhD, an attending physician at Long Island Jewish (LIJ) Medical Center in New Hyde Park, New York, in a recent study of the mechanisms of twinning, confirmed that the use of in vitro fertilization (IVF) methods increases the incidence of monozygotic twinning.

Monozygotic twinning is the name given to twins that are born from one fertilized egg and share 100% identical DNA. The confirmation came after studying incidence where the transfer and/or implantation of two embryos results in three infants. He proposed that the addition of more calcium or the reduction of a chelating agent in the IVF incubation media might deal with this complication.

Drink Your Milk - You Might Have Twins

However, another interesting point he discovered was that women who eat a lot of animal products, particularly dairy, are five times more likely to have twins.

The reason for this seems to be insulin-like growth factor (IGF), a protein that is released by the liver of all animals (humans included) in response to growth hormone. It circulates in the blood and finds its way to the animal's milk supply. IGF increases the sensitivity of the ovaries to follicle stimulating hormone (FSH) and increased ovulation results.

There are some studies indicating that the survival of embryos in the early stages of development may be helped by IGF. Vegan women have a 13 percent lower concentration of IGF in their blood than women who consume dairy products.

Growth Hormones in Cows = Twins in Humans?

Continuing on with the theme of growth hormones, Dr. Steinman suggests that, "The continuing increase in the twinning rate into the 1990s, however, may also be a consequence of the introduction of growth-hormone treatment of cows to enhance their milk and beef production."

When he compared the twinning rates of women who ate a regular diet, vegetarian diet with dairy, and a vegan diet, the findings showed that vegan women had only one-fifth the number of twins as women who eat dairy.

These findings corroborate the information that African-American women tend to have higher levels of blood IGF genetically than Asian and Caucasian women and twinning rates among these groups parallel the IGF blood levels. "

This study shows for the first time that the chance of having twins is affected by both heredity and environment, or in other words, by both nature and nurture," said Dr. Steinman.

So, it seems that a woman's chance of having twins is linked to the blood level of insulin-like growth factor. He does go on to suggest that a dietary change, especially in countries that allow the use of growth hormone in their cattle, could help to alter the phenomena.