By: Maayan S. Heller for Uterus1
For centuries people have wondered if there’s something they can do to affect the outcome of a pregnancy. Witch doctors, midwives, seers, moon cycles, tides and ‘old wives’ are just some of those who have been consulted. But if a new study is right, women who want twins may find their answer in a glass of milk.
|CanDiet Influence Fertility?|
Proving what definitely affects the likelihood of a woman getting pregnant is difficult, because there are so many variables, but some foods have been linked to an increase in fertility, so if you’re hoping to get pregnant, here are some diet-related notes for you to consider:
Oysters: there is some scientific proof that eating oysters can boost fertility. They’re packed with zinc, which plays a role in semen and testosterone production in men, and in ovulation and fertility in women. But don’t eat oysters at every meal – you don’t want to consume beyond the RDA of zinc (9 mg/day).
Vitamins: vitamins in general have been linked to fertility – both in men and women. Studies have found that fertility is lower in both men and women who don’t have enough Vitamin C (RDA is 60 mg, or one orange), but women shouldn’t overdose on C because it can dry up cervical fluid, preventing sperm from reaching the egg.
Caffeine: AVOID IT. Studies have found that your chances of becoming pregnant can drop by almost one-third if you or your partner consume lots of caffeine (high is listed as 300-700 mg; one cup of regular coffee has 100 mg and regular tea has 30 mg).
Alcohol: men’s alcohol consumption doesn’t seem to affect fertility, but for women who have one drink per day, they may be decreasing their chances of getting pregnant by half. Even two drinks in a week can bring down your odds.
Cigarettes: cigarettes have been tied to decreased fertility in both men and women.
Fruits and Veggies: a recent study by a group of researchers at Harvard found that 79 percent of infertile couples had a lower-than-average intake of antioxidant-rich foods, like fruits and vegetables.
Calories: obesity is considered a leading fertility obstacle in women, so for some women, cutting calories can boost fertility.
According to research, American women whose diets include dairy products might be five times as likely to deliver fraternal twins. One explanation may be found in dairy products from cows that were injected with an artificial growth hormone.
The research was conducted by Gary Steinman, M.D., Ph.D., an assistant clinical professor of obstetrics at the Albert Einstein College of Medicine, who has conducted multiple investigations into what affects twin births.
“About nine years ago I delivered a set of monozygotic [identical] quadruplets, of which there are about 60 sets known in the world today,” says Dr. Steinman. “This stimulated my interest in the mechanisms by which the twinning process takes place.”
In his most recent published study, Dr. Steinman looked at medical records of more than 1,000 mothers who were vegan (and therefore consumed no dairy at all) and compared them to those of mothers who regularly ate dairy products.
From this and previous studies, Dr. Steinman found a connecting link.
“It appears that insulin-like growth factor is central to the twinning process,” he explains. “Certain variables which control the level of this factor are inherited – like family history, race, maternal height – and others can be consciously modified by changes in the environment – like dairy products, malnutrition, parity, lactation, age at conception.”
Studies done on rats, mice and cattle have found convincing evidence that increased levels of growth hormone are tied to increased ovulation.
Cow’s milk naturally has a growth hormone in it, but many dairy farmers inject another synthetic version of the hormone into their cattle to increase size and milk production. It also has another effect: Cows with higher levels of the hormone produce more twins.
Dr. Steinman’s hypothesis is that increased levels of insulin-like growth factor (IGF) in women will likewise increase the likelihood that they will become pregnant with twins. And according to his study, his expectation seems to be supported, namely that “the chance of twinning correlates directly with the level of IGF.”
However, the conclusions of Dr. Steinman’s study only suggest that a dairy-rich diet can increase the likelihood of having twins – they do not find conclusive proof.
“It seems reasonable to start with an observational study [such as Dr. Steinman’s], but you have to have something more,” says David Cohen, M.D., a University of Chicago associate professor of obstetrics/gynecology and Chief of the section of Reproductive Endocrinology and Infertility.
“It does have biological plausibility,” he adds. “It’s kind of a ‘you are what you eat’ argument.”
However, without doing vigorous further testing, Dr. Cohen says, “it’s just an observation.” While drawing firm conclusions might be “a bit too far reaching” at this point, he says there are definitely potential connections and the hypothesis “seems worth testing further in a more controlled manner.”
Many factors have been linked to the rate of twin births, including dietary influences and genetics. The incidence of twin births in the U.S. has risen in recent years, and Dr. Steinman’s continuing research seeks to understand why that’s happened and what affects those statistics.
“In the U.S. between 1992 and 2001, the overall twinning rate rose by 32 percent whereas in the U.K. it increased by 16 percent,” he explains. “One of the differences between the two countries during that time period was that growth hormone was not allowed to be given to cows in England whereas it was in America.”
While Dr. Steinman’s research proposes a connection between a dairy-rich diet and the chances for twins, he has expressed that it needs to be confirmed before specific recommendations can be made regarding health and diet.
So if you’re hoping for twins, you can drink a little more milk, but maybe don’t put all your eggs in one basket just yet...