Infertility is a complex condition that is caused by a number of factors. The rate of infertility has been steadily on the rise over the past 10 years. Currently, infertility is estimated to affect one in every eight couples of reproductive age.
The American Society of Reproductive Medicine defines infertility as “the inability to conceive after one year of regular, unprotected intercourse.” If a woman is over age thirty-five, the diagnostic time frame is shortened to six months. On average, a fertile heterosexual couple has a 20 to 25 percent chance of conceiving during any one-month cycle in which regular sexual intercourse occurs without the use of contraception. It is estimated that about half of sexually active heterosexual couples (of reproductive age) will become pregnant within six months, and about 70 80 percent will achieve a pregnancy within one year.
Nutrition and Infertility
In recent years, medical science has begun to closely examine the roles of nutrition and dietary quality in improving fertility for both male and female partners. There are many “implantation diets,” “miracle foods,” and “fertility superfoods” discussed in the mainstream media, but there is very little concrete evidence to back up most of these claims.
Nonetheless, nutrition is an important part in increasing fertility potential. Food choices can positively affect reproductive function in a number of ways. Specific foods are believed to support reproductive efforts, promote the health of a woman’s eggs and a man’s sperm, and provide crucial nutrients for hormonal function, production, and balance. In addition to the direct impact of a nutritious diet on fertility, healthy food choices are critical to build up nutrient stores and supply all of the building blocks necessary for fetal growth and development.
Many of the food sources that are thought to fuel fertility are similar to the Mediterranean diet. This diet is rich in plant-based foods, namely whole grains, fruits, vegetables, and healthy fats. A Spanish study of more than 2,000 women determined that only 17 percent of women who followed a strict Mediterranean diet reported fertility issues, compared to 26 percent of women who ate a more “western diet” containing fatty meats and highly processed foods.
These findings remain consistent even with the use of assisted reproductive technology (ART such as IUI, IVF, and ICSI). Researchers have documented a 40 percent increase in successful ART outcomes when participating individuals consumed a Mediterranean diet.
A hallmark feature of the Mediterranean diet is its high antioxidant content. Antioxidants are nutrients that fight inflammation and neutralize free radicals. Free radicals refer to unstable electrons that damage cellular health and the DNA within a cell. Not surprisingly, antioxidants are also one of the most important dietary constituents in improving fertility status, for both women and men.
The ovum (egg) and sperm are highly sensitive to oxidative stress caused by free radicals. Antioxidants help to protect the egg and sperm from possible corresponding damage. The best sources of antioxidants are brightly colored fruits and vegetables, such as blueberries, pomegranates, citrus fruits, raspberries, spinach, bell peppers, avocados, and beets. To boost the antioxidant content of one’s diet, try to fill half of the plate with fruits and vegetables at every meal and snack.
The antioxidant beta-carotene, which is found predominantly in deep yellow and orange produce (carrots, sweet potatoes), encourages cell growth and may even help to prevent early miscarriage. Furthermore, beta-carotene is suspected to play a role in hormonal regulation. It is densely concentrated within the corpus luteum, which produces most of the progesterone required to sustain a pregnancy. Watermelon and asparagus provide the body with a bounty of the antioxidant glutathione, which is important for egg quality. Kale is another powerhouse vegetable. It contains nutritional elements needed for estrogen metabolism.
Pineapple also reaps a lot of attention in fertility promotion. Pineapple does offer beta-carotene, as well as an enzyme called bromelain, which studies have shown to mildly support implantation through its anti-inflammatory properties. Yet consuming bromelain in the form of a dietary supplement is discouraged, as the dose may be too high and can actually impede conception.
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Vitamins and Minerals
Vitamins E and C are two vitamins with well-documented antioxidant properties. The fluid surrounding the egg follicle (located in the ovary) is rich in vitamin E, thus forming a protective barrier around the egg. Vitamin C is thought to influence progesterone production and has been measured in significant quantities after an egg is released from its follicle during ovulation. Likewise, new research suggests that a high intake of vitamins E and C may be especially helpful in decreasing the inflammation associated with the development and progression of endometriosis. Endometriosis is a common cause of infertility and a medical condition that affects 2 to 10 percent of American women.
Folic acid (vitamin B9) is another important nutrient throughout the pre-conception period and early pregnancy. Adequate folic acid intake has been linked to improvements in female fertility. Research conducted at Harvard University concluded that women who consumed at least 400 micrograms of folic acid per day (in either food or supplemental form) were 40 percent less likely to be diagnosed with ovulatory infertility over a period of eight years.
Sufficient amounts of folic acid are also essential to prevent neural tube defects or serious abnormalities of the fetal brain and spinal cord. A fetus’ neural tube develops in the first month of pregnancy, so defects often occur before a woman even realizes she is pregnant.
Good dietary sources of folic acid include:
- Whole grains
- Fortified cereals (Oatmeal Squares, Life, Special K, Wheat Chex, All-Bran, Mueslix, Product 19, Total)
- Green leafy vegetables (spinach, mustard greens, turnip greens)
- Winter squash
- Brussels sprouts
- Beans (pinto, black, kidney, navy, chickpeas)
- Sunflower seeds
In addition, several minerals are considered to be exceptionally supportive of conception. Zinc is integral to cell division and progesterone production foods rich in zinc can also prevent testosterone from being converted to estrogen. Both zinc and selenium have been positively correlated with oocyte (egg cell) yield, and selenium is associated with increased sperm motility.
The best sources of zinc include:
- Lean meats
- Nuts (peanuts, cashews, pecans)
- Seeds (sunflower and pumpkin seeds)
*Brazil nuts and most types of fish contain abundant selenium.
Heart-healthy unsaturated fats, specifically those obtained from seafood and plants, are other major parts of a fertility diet. All fish is loaded with protein and iron, nutrients that help to support fetal growth and the physical changes to a woman’s body during pregnancy.
Fatty fish, in particular, are rich in omega-3 fatty acids. Omega-3 fatty acids reduce inflammation, protect the integrity of the eggs and sperm, and enhance fertility. The body is unable to manufacture omega-3 fatty acids on its own, so these essential fatty acids must be acquired from dietary sources.
Salmon, sardines, herring, herring, trout, mackerel, anchovies, oysters, and mussels are all categorized as high in omega-3 fatty acids. Approximately 8 to 12 oz. of fatty fish per week (two to three servings) is recommended prior to and throughout pregnancy. Most fatty fish are low in mercury and will not pose any increased risk of toxicity to a fetus.
Additionally, nuts, seeds, avocados, olive oil, and canola oil are all packed with monounsaturated fats. The anti-inflammatory properties of monounsaturated fats can improve fertility and promote regular ovulation.
Researchers at the Harvard School of Public Health noted that women who consumed the highest amount of plant-based monounsaturated fats (specifically in the form of avocados) during the IVF cycle were 3.4 times more likely to be successful in conceiving a child.
However, not all dietary fats benefit fertility status. Total avoidance of trans fats is strongly recommended, not only for the purpose of augmenting fertility status, but also to decrease the risk of chronic disease.
Trans fats are man-made fats found primarily in shelf-stable and highly processed foods (commercial baked and snack foods, stick margarine, foods made with partially hydrogenated oils, some animal products). Consumption of trans fats can trigger insulin resistance, a condition of high insulin levels in the blood. High insulin levels elicit numerous metabolic disturbances that can negatively affect ovulation.
Simple carbohydrates and refined grains (white bread, white rice, pasta, processed crackers and chips, instant oatmeal, boxed mashed potatoes, baked goods, sweetened cereal, candy, sweetened beverages) also contribute to the development of insulin resistance.
These foods are digested very quickly, stimulating the pancreas to overproduce the hormone insulin. As previously mentioned, high insulin levels can inhibit ovulation. Rates of ovulatory infertility are markedly elevated in individuals who routinely drink sugar-sweetened beverages (fruit juices, soda, energy drinks, sweetened coffee, and teas).
These negative effects are most pronounced in women with polycystic ovary syndrome (PCOS). PCOS is the most widespread cause of female infertility in developed countries. It is estimated to affect one in 10 women of reproductive age.
Complex carbohydrates are digested relatively slowly and have a more gradual effect on blood sugar and insulin release. Complex carbohydrates include:
- Whole grains such as brown and wild rice
- Whole wheat pasta, whole wheat bread products (rolls, bagels, English muffins, pitas, buns, tortillas)
- Whole grain chips and crackers
- Whole grain cereals
- Rolled and steel-cut oats
These foods provide the body with a steady, extended supply of energy. Whole grains are also superb sources of fertility-friendly B vitamins, which support the release of the ovum and promote uterine implantation.
Consuming adequate amounts of high-quality protein is indisputably vital for the creation and repair of all body tissues, as well as for the manufacture of hormones, enzymes, and blood cells. Yet research evidence suggests that excessive protein intake may impair fertility.
One study revealed that women with the highest protein intake were 41 percent more likely to have struggled with ovulatory infertility than women who ate the lowest amount of protein. Ovulatory problems have been identified as the cause of infertility in about 20 percent of women seeking help in becoming pregnant.
Researchers have concluded that the majority of such cases may be preventable by adjusting diet and lifestyle. A study by the Harvard School of Public Health also recorded infertility to be 39 percent more likely in women with a high intake of animal protein. In contrast, women who ate primarily plant-based protein were substantially less likely to be diagnosed with ovulatory infertility.
The avoidance of processed meats is theorized to be especially protective against ovulatory dysfunction. The results of this study inferred that the risk of ovulatory disorders was cut in half when 5 percent of a woman’s total calorie intake was composed of plant-derived protein. Therefore, increased consumption of plant-based protein sources (beans, lentils, nuts, seeds, and tofu) may amplify fertility.
If you choose to eat animal protein, ensure that all meats and poultry are grass-fed and free-range, and have not been treated with any antibiotics or hormones. Grain-fed beef is higher in saturated fat than grass-fed, which leads to more inflammation in the body. Synthetic antibiotics and hormones may also disrupt fertility.
Also note, some health professionals believe eggs to be an exception to the current ideology regarding animal protein in a pre-conception diet. This dissent is related to the cholesterol content of eggs all of the body’s steroid hormones (cortisol, DHEA, testosterone, estrogen, and progesterone) are built from dietary cholesterol. In the absence of adequate “building blocks,” the body cannot create or maintain ideal concentrations of reproductive hormones. Eggs provide an excellent source of choline, a nutrient that helps prevent birth defects. It also assists with the development of infant brain function.
The current fertility-related literature recommends minimizing the consumption of highly processed soy foods. These are foods that contain large quantities of soy protein isolate (the form of soy that is usually found in protein powders and energy bars). Some research implies that concentrated soy-based products may wield estrogen-mimicking properties. Thus they could bind with estrogen receptors and modify hormonal balance. Conversely, no risks to fertility have been observed with moderate consumption of whole, unprocessed soy foods (edamame, tempeh) and fermented soy (miso, natto).
A growing body of research literature indicates that eating or drinking moderate amounts of full-fat dairy products daily may support female fertility. Several large scientific studies have discovered that women who consumed high-fat dairy were 27 percent less likely to be infertile.
Comparatively, regular consumption of low-fat dairy products has been suspected to increase the risk of ovulatory infertility. Researchers have determined that women who consumed two or more servings of low-fat dairy per day had an 85 percent greater risk of infertility compared to women who ate less than one serving of low-fat dairy per week.
Therefore, women hoping to become pregnant may benefit from eating one to two servings of full-fat dairy per day. This al could be met by snacking on full-fat Greek yogurt, mixing fruit into 4 percent cottage cheese, adding a slice of cheese to a sandwich, or stirring whole milk (instead of skim milk) into tea. Interestingly, these promising findings do not appear to be applicable to males. Heavy dairy consumption has been linked to poor sperm motility and concentration in men.
Appropriate hydration is recognized to be just as important as nutrient-dense food choices in the optimization of fertility. Water plays a key role in transporting hormones, developing follicles, and thinning out biological fluids. Inversely, caffeine, and alcohol act as diuretics and can be dehydrating. The use of these substances may prevent mucus membranes from staying moist, consequently affecting the consistency of cervical mucus and ejaculate fluid.
Scientific research has also drawn a connection between a high intake of caffeine (especially coffee) and an increased chance of miscarriage. Caffeine can cross the placenta, so caffeine intake from coffee, soft drinks, energy drinks, and teas should be limited to under 200 milligrams a day (the equivalent of 10 oz. regular coffee) if pregnant or hoping to become pregnant. Alcohol is also believed to alter the hormonal balance and possibly damage sperm motility. To maximize fertility, it is recommended that both men and women restrict alcohol intake to no more than two or three alcoholic drink equivalents spaced out over a week.
Maintaining a healthy weight should be a priority for both partners, whether two people hope to conceive naturally or opt to under fertility treatments. If a person is overweight, excess energy is stored in the adipose (fat) tissue, which causes deficits in the pool of oxidizable fuels available for the reproductive system. This deters reproduction by negatively impacting sex hormone secretion and the overall function of chemical messengers in the reproductive system. Extra body weight is also correlated with a higher incidence of insulin resistance, which can further disturb ovulation patterns.
od evidence exists that a man’s body mass index (BMI) has a major impact on sperm quantity and quality. Similarly, too much or too little body fat can make a woman’s menstrual cycle irregular, causing her to ovulate inconsistently or not at all.
The ovaries and fat cells also regulate estrogen production, which affects ovulation. If a woman is overweight or obese, she may be producing too much estrogen. If a woman is too thin, she may not be producing enough estrogen. Women who are underweight are also at a higher risk for preterm birth and are more likely to have a baby of low birth weight.
Food Allergies and Intolerances
If either partner has any allergies, intolerances, and/or sensitivities to foods, these foods should definitely be avoided during efforts to conceive. Ingestion of offending foods will cause an immune and/or inflammatory response that can hinder fertility.
If you are trying to conceive, talk to your provider about dietary options that are best for you.
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