Food and Fertility: What Should Women Consume When Trying to
Peter Kovacs, MD, PhD
A young fertile couple's chance of conceiving in the first
month they try is 25%-30%. By the end of the first year, about 85% of couples
achieve a success; the remaining 15% are diagnosed with infertility.
Infertility has many known causes (e.g. ovulatory defect,
tubal occlusion, low sperm counts), and many factors lower the chance of
pregnancy (e.g. older age, lower ovarian reserve, endometriosis). There are
modifiable and nonmodifiable risk factors for infertility or reduced fertility.
Although some factors can't be altered (e.g. age and ovarian reserve), others,
such as body weight and lifestyle habits, are modifiable.
Patients frequently ask providers to offer them guidance on
the ideal diet to improve their chances of conceiving and carrying a pregnancy
to term. A recent review by Chiu and colleagues summarizes the available
epidemiologic literature on the reproductive benefits of diets and dietary
conclusions are drawn from this review:
Folic acid. Folic acid is important for germ cell production
and pregnancy. The recommended daily dose to prevent neural tube defects is
400-800 µg. Women who take folic acid-containing multivitamins are less likely
to be anovulatory, and the time to achieve a pregnancy is reduced. Those who
consume more than 800 µg of folic acid daily are more likely to conceive with
assisted reproductive technology (ART) than those whose daily intake is less
than 400 µg.
Vitamin D. Vitamin D may affect fertility through receptors
found in the ovaries and endometrium. An extremely low vitamin D level (< 20
ng/mL) is associated with higher risk for spontaneous miscarriage risk. Some
reports suggest that women with adequate vitamin D levels (> 30 ng/mL) are
more likely to conceive after ART when compared with those whose vitamin D
levels are insufficient (20-30 ng/mL), or deficient (< 20 ng/mL). These
findings, however, are inconclusive.
Carbohydrates. Dietary carbohydrates affect glucose
homeostasis and insulin sensitivity, and by these mechanisms can affect
reproduction. The impact is most pronounced among women with polycystic ovary
syndrome (PCOS). In women with PCOS, a reduction in glycaemic load improves
insulin sensitivity as well as ovulatory function. Whole grains have
antioxidant effects and improve insulin sensitivity, thereby positively
Omega-3 supplements. Omega-3 polyunsaturated fatty acids
lower the risk for endometriosis. Increased levels of omega-3 polyunsaturated
fatty acids are associated with higher clinical pregnancy and live birth rates.
Protein and dairy. Some reports suggest that dairy protein
intake lowers ovarian reserve. Other reports suggest improved ART outcomes with
increased dairy intake. Meat, fish, and dairy products, however, can also serve
as vehicles for environmental contamination that may adversely affect the
embryo. Fish, on the other hand, has been shown to exert positive effects on
Dietary approach. In general, a Mediterranean diet is favoured
(high intake of fruits, vegetables, fish, chicken, and olive oil) among women
diagnosed with infertility.
With respect to overall diet, women are advised to follow a
caloric intake that won't contribute to being overweight or obese. Obesity is
on the rise among younger people, including children. Obese women have a lower
chance of conceiving and are less likely to have an uncomplicated pregnancy.
Proper weight can be maintained with an appropriate diet and regular exercise.
Finally, women must abstain from substances that are
potentially harmful to pregnancy (e.g., smoking, alcohol, recreational drugs,
high caffeine intake).