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).

DL: 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, numerous studies conclude that bisphenol-A (BPA), a chemical found in the lining of many canned foods, contributes to infertility.

DL: So what should women eat to boost their 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 principal 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 further decrease fertility.

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 of wild salmon, sardines, herring, or black cod.

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.

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 change a woman’s menstrual cycle, leading to a shorter luteal phase (second half); that means less time for the embryo to implant in the uterus lining. And obesity 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 outcomes for couples utilizing in-vitro fertilization.