Eating for Fertility
What to eat if you want to improve your chances of getting pregnant.
In a
perfect world, a couple’s desire to conceive a baby would be enough to
guarantee a positive pregnancy test. Unfortunately, many would-be parents find
themselves challenged by infertility. Now a new movement says that diet can
play a helpful role in increasing fertility. But can the foods we eat really
make a difference to our ability to reproduce, or is this just another
flash-in-the-pan theory?
Facing Infertility
Although conceiving a child comes easily to the majority of
people, fertility is elusive for some couples. One in six couples is affected
by infertility during their reproductive lifetime (Chavarro et al. 2007). In
fact, infertility is one of the most prevalent chronic health disorders
involving young adults (Smith, Pfeifer & Collins 2003). Both the American
Society for Repro­ductive Medicine and the American Col­lege of Obstetricians
and Gyneco­logists recognize infertility as a disease (The National Infertility Association 2008).
According to The National
Infertility Association, the term infertility is defined as having spent at least 1 year (6 months
for women over age 35) attempting conception without success. Many factors can
affect fertility, including the intricate interplay of hormones; the quality of
sperm and egg; the timing and presence of ovulation; and body weight and
fitness level. Although the causes of infertility vary, ovulation disorders are
present in more than 25% of infertile female partners (Smith, Pfeifer &
Collins 2003).
Fertility & Diet
Recently,
there has been a focus on whether there is a relationship between diet and
reproductive health. Researchers are now examining whether certain foods can
stave off female infertility and increase the chances of conception.
Some of this research was the
foundation for a new book—The Fertility Diet by Jorge Chavarro, MD, ScD, Walter Willett, MD,
DrPH, and Patrick Skerrett (McGraw-Hill 2007)—that says diet is essential to
anyone facing infertility. Essentially, the book’s authors recommend that women
trying to conceive a child make the following dietary changes to increase their
chances of conception:
- Choose
monounsaturated fats instead of dangerous trans fats. - Get protein
and iron from plant sources, not animal sources. - Focus on
complex carbohydrates and a moderate amount of full-fat dairy products. - Take
multivitamins and supplements (Chavarro, Willett & Skerrett 2007).
Ovulatory Disorder Infertility
The focus of the fertility diet is on lowering the risk of a
condition known as┬áovulatory disorder infertility.┬á“Unlike other underlying conditions,
such as blocked fallopian tubes, ovulation is a physiological process likely
modifiable by environmental signals, including diet,” says Chavarro, one of the
authors of The Fertility Diet and
a research fellow in the department of nutrition at the Harvard School of
Public Health.
Chavarro points to research that
examined data from more than 17,500 women participating in the Nurses’ Health
Study II who followed a proposed “fertility diet” (Chavarro et al. 2007). These
women did not have a history of infertility and were trying to conceive or did
conceive over an 8-year study period. At the end of the study, the researchers
determined that the fertility diet—along with lifestyle modifications (i.e.,
physical activity)—might prevent ovulatory disorders in otherwise healthy women
(Chavarro et al. 2007). “The most important point [of our findings] is that
relatively simple changes to diet and lifestyle can have a profound effect on
fertility,” says Chavarro.
Get Healthy, Get Pregnant
Other
experts agree that a healthy lifestyle prepares the way for getting pregnant. “The
best thing you can do to improve your chances of conception is to try to get
healthy,” advises Laurence A. Jacobs, MD, a reproductive endocrinologist and a
partner at The Fertility Centers of Illinois. “Moderation is the key word in
this whole issue. Any extreme is not good. Being underweight or overweight
makes it difficult to ovulate,” he says.
Jacobs’ entire clinical practice
focuses on infertility issues, and the majority of his patients are 35 years
and older. With fertility and diet making headlines these days, Jacobs cautions
his patients not to take what they read out of context. For example, if women
hear that full-fat dairy products
can improve fertility, there is a real danger that they will miss the
moderation message and eat beyond the point of any health benefit. And while Jacobs acknowledges that
there may be strong associations between certain dietary patterns and improved
ovulatory fertility, he also notes that no large randomized trials have
examined the cause and effect of diet on infertility in women. “There are too
many complicating variables [for us to] know which are the best diets out there
for everyone,” warns Jacobs.
Body Weight & Fertility
Body weight, body mass index (BMI) and nutrition status have all
been shown to be closely related to reproductive function (Lim, Noakes &
Norman 2007). Obesity (i.e., having a BMI greater than 30) adversely affects
pregnancy rates, even with fertility drugs or in vitro fertilization treatments
(Jacobs 2007). A weight loss of 5%-10% of body weight can be enough to restore
ovulation in obese patients (Jacobs 2007).
Sadly, most physicians fail to
mention body weight when counseling or treating their fertility patients.
Jacobs is not shy about emphasizing weight loss to his obese patients and for
good reason: excess body fat (or adipose tissue) has been shown to cause
hormonal imbalances by throwing off the delicate functioning of the
hypothalamus and pituitary glands and triggering the body to secrete abnormal
amounts of insulin (Jacobs 2007). This, in turn, can eventually lead to anovulation, or the loss of ovulation (Jacobs 2007).
Ovulation can be thwarted by a
condition called polycystic ovary syndrome (PCOS). More than half of the women who are diagnosed with
PCOS are overweight or obese (Liepa, Sengupta & Karsies 2008). Some experts
have suggested that weight loss is more important than diet composition for
improving reproductive function in overweight women, according to two small
randomized trials involving women with PCOS (Moran et al. 2003; Stamets et al.
2004). But it’s not just the numbers on the scale that count: it’s also the
woman’s body composition—her lean tissue (muscle, bone and organs) versus fat
tissue. To improve their chances of conceiving, some of Jacobs’ overweight
infertility patients wear adjustable weight vests to help them increase muscle
mass, burn more calories and lose weight (Jacobs 2007; Morrison & Jacobs
2007).
The Impact of Insulin
When obese women suffer from PCOS, they become insulin
resistant, meaning
the cells of the body are no longer as sensitive to insulin. This becomes a
vicious cycle because decreased insulin sensitivity causes the body to
overcompensate by producing even higher levels of insulin in order to keep
blood glucose levels normal. High levels of circulating insulin then cause
increased fat storage and ultimately disrupt normal ovarian hormone production,
which increases certain hormones and prevents proper ovulation (Jacobs 2007).
Insulin sensitivity is a main
premise of the fertility diet. “Even though there is more work to be done in
specific patient populations (in regard to infertility), our findings are in
agreement with the overall hypothesis that insulin sensitivity is an important
determinant of ovulatory function and fertility,” contends Chavarro. Other
fertility doctors and researchers agree that diet quality counts. “It’s not so
much low carb, but slow carbs,”
advises Jacobs.
Because insulin resistance is one
of the hallmarks of PCOS, many experts say that women with PCOS should adopt a
diet similar to the one recommended for people with type 2 diabetes (Liepa
Sengupta & Karsies 2008). To avoid surges in blood sugar and insulin
levels, type 2 diabetics need to eat high-fiber whole grains (i.e., “slow carbs”),
which take longer to digest, instead of high-sugar, more refined carbohydrates
(i.e., “fast carbs”), such as soda, white bread and potatoes. “There is strong
evidence showing that diet and lifestyle changes have a greater impact on
insulin sensitivity than even some commonly used diabetes medications,” says
Chavarro.
Sure-Fire Fertility Actions
“We know that it is the synergy of healthy behaviors that
positively impacts fertility,” says Dawn Jackson Blatner, RD, LD, a national
spokesperson for the American Dietetic Association. In addition to physical
activity, certain foods play an important role in balancing hormone levels and
keeping the reproductive system humming along. Blatner recommends getting a
sufficient daily amount of “healthy” fats, such as those contained in fish,
walnuts, almonds and olive oil, and avoiding “unhealthy” fats, such as trans
fats. “Don’t be nervous to get some fat from dairy,” condones Blatner. However,
Blatner is quick to add that women need to be careful about the quantity of healthy fats they get, since fat
calories add up quickly. This applies to both saturated fat from full-fat dairy
and unsaturated fat from nuts and olive oil.
Blatner also agrees with the
authors of The Fertility Diet
that consuming vegetable protein (e.g., beans, soy and nut butters) instead of
animal protein is healthful for fertility. However, she cautions women to rein
in their intake of full-fat dairy products to only one serving each day. It
should be noted that in research studies, the beneficial effect of fats on
fertility rates were seen with as little as two half-cup servings of full-fat
products per week.
Blatner does agree that it is
vital that women who wish to conceive take a daily multivitamin to get adequate
amounts of iron and folic acid. Because so many women forget to take their
daily multivitamin, Blatner suggests they put their vitamins in a place they go
to every day; for example, next to their computer or toothbrush or in the drink
holder in their car.
How Society Affects Fertility 
The way we now live in society is also taking its toll on
fertility rates. Many women are delaying parenthood until later in life; are
stressed with full-time jobs; and have little time to plan healthy meals and
prepare family dinners each night. As a result, people turn to fast foods. “Eating
at McDonald’s and Dunkin’ Donuts is good contraception,” Jacobs says
half-jokingly.
With people consuming large
amounts of saturated and trans fats, sugary beverages and low-fiber
carbohydrates on a regular basis, increased body fat can also cause
infertility. “Simply telling a patient to lose weight does not work,” says
Jacobs. As an alternative, he says, motivation, counseling and behavior
modification need to be the cornerstones for diet and lifestyle changes (Jacobs
2007).
It is too soon to say if the
fertility diet will improve conception rates for women. But it is probably a
good start and is mostly in keeping with many current nutrition standards. “Our
recommendations are unlikely to cause harm to women who wish to try them and
may, on the other hand, help them achieve the goal of becoming pregnant and
serve as a guideline on how to continue a healthy diet afterwards,” Chavarro
concludes.
SIDEBAR: Best Foods for
Fertility
- a
daily multivitamin and mineral supplement, with at least 400 micrograms of
folic acid (100% of the Daily Value [DV]) and 27 milligrams of iron (150% DV) - legumes
and beans (black, kidney, pinto, white, navy, lentils, soy beans and lima) - nut
butters (all-natural peanut butter or almond butter) - fish
(salmon, tuna, halibut, mackerel or herring) - whole
grains (whole-grain bread or tortillas, whole-wheat pasta, brown rice,
whole-grain couscous, quinoa, oats, spelt and amaranth) - full-fat
dairy products (whole milk, regular ice cream or cheese) Caution: Keep portions to no more than 1 cup milk, a half-cup
ice cream or 1 ounce cheese, and limit your full-fat dairy choices to one
serving per day. - dark,
leafy greens/vegetables (spinach, kale and mustard greens, broccoli, asparagus
and brussel sprouts) - healthy
oils (extra-virgin olive oil and canola)
SIDEBAR: Fertility Resources
- The
American Society of Reproductive Medicine: a nonprofit, international
multidisciplinary organization with a mission to provide information,
education, advocacy and standards in the field of reproductive medicine;
www.asrm.org - RESOLVE:
The National Infertility Association, a national organization with more than 50
local chapters that is dedicated to providing education, advocacy and support;
www.resolve.org 
Victoria Shanta Retelny, RD, LD, is a registered
dietitian in private practice in Chicago. She operates a nutrition consulting
business called LivingWell Communications (www.livingwellcommunications.com).
References
Chavarro, J.E., et al.
2007. Diet and lifestyle in the prevention of ovulatory disorder infertility. Obstetrics
& Gynecology, 110 (5), 1050-8.
Chavarro, J.E., Willett,
W., & Skerrett, P. 2007. The Fertility Diet. New York: McGraw-Hill.
Jacobs, L.A. 2007. Weight
loss & conditioning improve fertility. Fertility Today (Spring).
Kovacs, G.T. 2004.
Polycystic ovarian disease: An overview. Reviews in Gynaecological Practice,
4, 97-104.
Liepa, G.U., Sengupta, A.,
& Karsies, D. 2008. Polycystic ovary syndrome (PCOS) and other androgen
excess-related conditions: Can changes in dietary intake make a
difference? Nutrition in
Clinical Practice, 23 (1), 63-71.
Lim, S. S., Noakes, M.,
& Norman, R.J. 2007. Dietary effects on fertility treatment and pregnancy
outcomes. Current Opinion in Endocrinology, Diabetes and Obesity, 14 (6), 465-69.
Moran, L.J., et al. 2003.
Dietary composition in restoring reproductive and metabolic physiology in
overweight women with polycystic ovary syndrome. The Journal of Clinical
Endocrinology & Metabolism, 88
(2), 812-19.
Morrison, G., & Jacobs,
L.A. 2007. Fitness misconceptions, a fitness plan & a big important fact to
improve fertility. Fertility Today
(Winter).
National Infertility
Association. www.resolve.org; retrieved Feb. 2008.
Smith, S., Pfeifer, S.
& Collins, J.A. 2003. Diagnosis and management of female infertility. Journal
of the American Medical Association, 290 (13), 1767-70.
Stamets, K., et al. 2004. A
randomized trial of the effects of two types of short-term hypocaloric diets on
weight loss in women with polycystic ovary syndrome. Fertility and
Sterility, 81 (3), 630-37.
