For centuries, women have been told how to eat for pregnancy. Recommendations have changed with the times, but in recent decades the mainstream advice was so generic as to be barely useful. “Eating healthy” was a series of admonishments about what to avoid (alcohol, soft cheeses, high-mercury seafood) and a jumble of vague tips about variety, extra protein, and plenty of fruits and vegetables. Oh, and don’t forget the prenatal vitamin. Women hoping to become pregnant weren’t really part of the nutrition conversation at all. In the past few decades, we’ve paid more attention to preconception health. And in the past few years, we’ve finally gotten some useful advice about nutrition for fertility. The best evidence has come from the Nurses’ Health Study, which tracked 18,000 women over 8 years and gleaned some surprising insights into the eating habits that support healthy ovulation. Here are the highlights from that study:
1. Slow carbohydrates are better than fast carbohydrates.
This means choosing carbohydrate sources with low glycemic load. These carbs increase blood sugar slowly and in moderation. Slow carbs tend to be high in fiber, and include legumes, most vegetables, and whole grains. Fast carbs are often based on white flour, sugar, and added sweeteners like corn syrup, and should be minimized. White breads, white potatoes, white rice, many pastas, cereals, and sweets are fast carbs.
2. Plant proteins should predominate.
Women who eat more protein from plant sources like nuts, beans, and seeds are more fertile than women who favor meat. Fish and eggs had a neutral effect on fertility in the study. While there is no proof (yet) that fertility is impacted by the type of beef or poultry you choose, avoiding the meat from animals that were raised on hormones and unhealthy diets makes good sense. If you eat beef, choose grass fed. If you eat poultry, buy organic. The important point is to limit these foods in the diet.
3. Forget about trans fats.
No one should eat trans fats, but especially not women with pregnancy hopes. Trans fats are found in crackers, chips, French fries, ready made pie crust, margarine, and many processed foods. Trans fats can impair fertility at as little as 4 grams per day. Just one donut will put you over this threshold. If a food serving contains less than half a gram of trans fats, the trans fats do not have to be reported on the nutrition label at all! The result is that we end up eating hidden trans fats in many foods that claim to have none. These add up quickly. Try to avoid the types of foods that are likely to contain trans fats, regardless of labeling.
4. Include one or two servings of whole milk.
Women who had a serving or two of full fat dairy were more fertile than women who had lowfat or nonfat dairy. Removing the fat from dairy changes the ratio of sex hormones in the finished product. This change has a measurable impact on women’s own hormone balance, reducing fertility. This study finding should be enough to convince anyone of just how delicate our reproductive ability really is. There are compelling reasons for some women to avoid dairy (digestive intolerances, inflammation, acne, PMS), but if you enjoy dairy and make it a part of your diet, choose full fat, organic dairy while trying to conceive.
It’s important to note that these suggestions relate only to improved ovulation. When fertility is hampered by anything else, following the recommendations may or may not be helpful. Here are some other general tips for women hoping to become pregnant:
1. Take the right multivitamin.
Select a vitamin with an active form of folate. Folate, or Vitamin B9, helps to prevent neural tube defects in developing embryos and has many other functions in the body. Folate is often referred to as folic acid, but folic acid is a synthetic form that cannot be well utilized by all women. Many of us have a mutation that makes it difficult to convert synthetic folic acid to the active form we need, so the standard 400 mcg of folic acid in a multivitamin may not be sufficient. Prenatal vitamins usually contain 1000 mcg or 1 mg of folate, often in synthetic form. Check for the brand names Quatrefolic or Metafolin in the ingredient list, or ask a pharmacist to assist you in finding a vitamin with the active form of folate. Other considerations are whether to choose a vitamin sourced from whole foods, and which forms of iron, magnesium, and calcium the vitamin contains. Look for an upcoming blog post on this topic.
2. Eat anti-inflammatory foods.
Choose foods that are high in antioxidants, especially dark skinned fruits and vegetables, leafy greens, and omega-3 rich fish and flaxseed. Vitamin C, resveratrol from grape skins, and ellagatannins from pomegranate are a few of the antioxidants being studied for effects on hormone production and fertility. For help in selecting the safest types and amount of seafood, check out EWG’s Seafood Guide, here.
3. Nourish the reproductive system with herbal infusions.
An infusion is a strong herbal tea covered and steeped for 10 to 20 minutes. The best known women’s reproductive herb is red raspberry leaf, which supplies many vitamins and minerals specific to the uterus. Red raspberry leaf is used before conception and in the second half of pregnancy. Preconception alternatives include other Rose Family herbs like blackberry leaf, lady’s mantle, wild strawberry leaf, and rose petals. These can be combined in any proportion to make a pleasant blend. Other nourishing single herbs include nettles and dandelion leaf.
April Ward, MSN, CNM is an integrative women’s health specialist in Skaneateles, NY. To learn more, call 315-200-2349.