Hope to get pregnant now or someday? The foods you choose—and avoid—can help ensure that all systems are go when you’re ready. Get the latest holistic wisdom in this Q&A with Victoria Maizes, MD, author of Be Fruitful: The Essential Guide to Maximizing Fertility and Giving Birth to a Healthy Child(Scribner, 2013).

Are women today having a more difficult time getting pregnant?

Delicious Living: Are women today having a more difficult time getting pregnant than their grandmothers did?

Victoria Maizes, MD: Yes. One factor is age; women are having kids later than they used to, and the older you get, the more challenging it is to conceive. But another huge obstacle is endocrine disruptors that are now common in everyday chemicals: in the pesticides in our food, in our personal care and cleaning products, and even in our furniture. It’s easy for reproductive hormonal function to be thrown out of whack from exposure like this. For example, http://www.ncbi.nlm.nih.gov/pubmed/23347089; http://www.ncbi.nlm.nih.gov/pubmed/23672405" target="_top">numerous studies conclude that bisphenol-A (BPA), a chemical found in the lining of many canned foods, contributes to infertility.

What should women eat to boost fertility?

DL: Avoid BPA-lined cans, check. So what should women eat to boost fertility?

VM: The Mediterranean diet, which reduces risk of heart disease, cancer, and Alzheimer’s, also increases the likelihood of conception, both au naturel and in vitro. It focuses on abundant unrefined grains, legumes, fish, vegetables, and fruit; olive oil is the principle oil.

Studies also suggest that to improve fertility you should eat more vegetable protein and less animal protein, so frequently substitute beans and nuts for meat or poultry.

And here’s a surprise: Choose whole fat rather than low-fat or nonfat dairy products. When dairy companies remove the fat from milk, this alters its hormonal content. Estrogen and progesterone prefer fat, so when milk is being separated, those hormones go into that removed fat layer. Androgens (“male hormones”) prefer the watery layer—hence a glass of low-fat milk gives you more male hormones and fewer female hormones.

Dairy companies also usually add either nonfat milk powder or whey protein to cover skim milk’s naturally bluish tint. There is evidence that when animals’ diets are enriched with whey protein, the androgenic effects decrease fertility.

What about fish?

DL: What about fish?

VM: You want to reduce exposure to mercury—abundant in shark, swordfish, king mackerel, and tilefish—because it’s a neurotoxin and a developing fetus’s nervous system is exquisitely sensitive in the first weeks of pregnancy. But you don’t want to avoid all fish because it’s the best source of omega-3 fatty acids, which are critical to baby’s brain development and can help prevent postpartum depression. I recommend enjoying two to three meals a week with wild salmon, sardines, herring, or black cod.

Are processed foods linked to infertility?

DL: Are processed foods linked to infertility?

VM: Processed foods are filled with exactly the wrong kinds of carbohydrates and fats. The carbs are high on the glycemic index, which bumps up blood sugar, which in turn spikes insulin. Elevated insulin reduces a circulating protein called sex hormone–binding globulin (SHBG). SHBG’s task is just what its name implies: It binds estrogen, progesterone, and testosterone so that only small amounts circulate in the blood in the free or active form. Of all these sex hormones, SHBG has a preference for binding testosterone; so less SHBG means more unbound testosterone in the bloodstream, altering the overall hormonal balance to be more male dominant, which in turn can make it harder to get pregnant.

Many processed foods also contain trans fat, which raises the body’s inflammation levels—a fertility zapper—and increases insulin resistance, which leads the pancreas to secrete more insulin.

Avoid soda, too. In Harvard’s Nurses Health Study II, soda intake—including caffeinated, noncaffeinated, diet, and sugary versions—correlated to reduced fertility.

Why is weight gain linked to infertility?

DL: Why is weight gain linked to infertility?

VM: Fat cells produce estrogen, which leads to higher blood levels, interfering with normal feedback signals to the brain. Weight gain can also alter the menstrual cycle, leading to a shorter luteal phase (second half); that means less time for the embryo to implant in the uterus lining. Obesity also lowers an egg’s quality by altering its follicular fluid composition and hormone levels while increasing inflammation. Lower egg quality may lead to greater difficulty in becoming pregnant, a greater risk of early miscarriage, and poorer IVF outcomes.

What part do supplements play in fertility?

DL: What part do supplements play in fertility?

VM: The American Academy of Family Medicine, the American Board of Obstetrics and Gynecology, and the American Academy of Pediatrics all recommend that women of childbearing age take a multi. Prenatal multivitamins make it easier to conceive and less likely that you will miscarry; they also reduce the risk of neural tube, heart, and other birth defects. And, three recent studies revealed an association between preconception folic acid intake prior and a lower risk of autism.

Multivitamins and supplements can vary tremendously, so choose them with care. Your multi should contain 400–600 mcg folic acid, 18 mg iron, and 150 mcg iodine.

I also recommend up to 2,500 IU vitamin A palmitate or acetate, or retinyl palmitate; 15,000 IU beta-carotene; 1,000 IU vitamin D; 2.4 mcg vitamin B12; and 200–400 IU vitamin E (mixed tocopherols are best), daily.

As for trace minerals, look for small amounts of copper, zinc, magnesium, potassium, and calcium in your multi.

I also recommend that most women take an omega-3 fatty acid supplement because these essential fats are scarce in the American diet. Look for molecularly distilled fish oil with about 300–400 mg DHA for your baby’s developing brain and about 500–600 mg EPA to prevent postpartum depression. Take it with your largest meal of the day because the body needs fat to absorb omegas efficiently.

What environmental toxins interfere with hormones?

DL: What are the top environmental toxins that can interfere with hormones?

VM: In addition to BPA (mentioned above), I’m concerned about phthalates, which are used to make plastics more flexible and are found in nail polish, hair spray, and perfumes. Men exposed to more phthalates have lower sperm counts, reduced sperm quality, and significantly lower testosterone levels. Then there are polybrominated diphenyl ethers (PBDEs), persistent environmental pollutants found in furniture, mattresses, and carpets. Although their intended use is as flame-retardants, their unintended side effect is abnormal thyroid function, which can impair fertility.