The Healthy Truth About Soy for Moms (and Babies!)
How safe is soy? The shape-shifting little bean has garnered significant medical and media attention in recent years. Some studies tout its health benefits, while others warn of its dangers. What's a mom to believe? Here's what experts have to say...
What's So Special about Soy?
Soy has been cultivated for over 5,000 years because it is a good, relatively inexpensive source of protein that also delivers calcium, potassium, fiber, and folate. Soy can be eaten as beans, tofu, and milk, as a fermented product (like miso, tempeh, and soy sauce), and in thousands of other forms, some made with Textured Vegetable Protein, a soy flour product. With such flexibility, it’s no wonder soy is a go-to food for vegetarians and health-conscious omnivores alike.
Does Soy Provide Health Benefits?
Soy is low-fat and cholesterol-free, so it can be a valuable ingredient in a balanced diet. Tiffani Hays, assistant director of pediatric nutrition at the Johns Hopkins Children’s Center, emphasizes that soy protein and soy fiber have healthful benefits for adults and children alike. Additionally, the Mayo Clinic’s review of the scientific evidence to date also reveals that including soy foods in a balanced diet low in cholesterol and saturated fat may provide moderate reductions in blood cholesterol levels and possibly provide some relief of hot flashes during menopause. Experts characterize other claims, such as the assertion that soy might help prevent breast cancer, as “unclear.” Rest assured, studies are on-going.
What Makes Soy "Scary"?
Soy contains isoflavones. Isoflavones, also called phytoestrogens (“phyto” means plant), work in the body like weaker forms of the hormone estrogen. Estrogen is associated with certain cancers, including some forms of breast cancer—hence the controversy. Some investigations show that isoflavones boost estrogen; others say that they may also block estrogen; yet others suggest that isoflavones are adaptive, boosting and blocking, like molecular rugby players. It can be alarming to think that a veggie dog might unbalance one’s hormones, but jumping to such conclusions would be over-simplifying a complex (and much-studied) food.
Safe Soy Intake Guidelines
The science indicates that one to three daily servings of soy is safe part of a varied diet. No conclusive evidence has shown that dietary soy negatively affects human reproduction, development, or endocrine function. Even so, if you’re worried about over-doing isoflavones you can track your intake, either by glancing at the nutritional information on the soy food package or by going to the USDA
isoflavone database, here. An 8-ounce glass of soymilk, for example, contains between 20 and 30 mg of isoflavones, and a 1/2 cup of tofu contains about 32 mg. In Asian countries, where soy is a regular part of the diet, the average isoflavone consumption is about 25-35 mg per day, so that gives you an idea of reasonable amount of soy to include in your diet.
Is Soy Safe for Moms Trying to Conceive?
Soy is a safe part of healthy eating, even for those who are trying to conceive, according to the American Congress of Obstetricians and Gynecologists (ACOG). Although dietary soy has not been found to affect fertility, worries abounded in 2005 when one much-reported British study showed that genistein, a compound found in soy, could, to some degree, when isolated, “sabotage” human sperm in a petri dish. This led the study’s researcher to hypothesize that it might be worthwhile for women who were trying to conceive to avoid soy for a few days preceding and following ovulation. No recommendations from the ACOG followed this study; in fact, there are no USDA guidelines for soy food intake because it is not considered a danger.
Is Soy Safe for Pregnant and Nursing Women?
Soy is, indeed, safe for pregnant and nursing women. One study of Japanese women who consumed large amounts of soy confirmed the transfer of isofavonoids in utero, but scientists found no negative outcomes as a result. Women who are nursing and eating soy (and with practice you
could do both at the same time) pass on negligible amounts of isoflavones in their milk.
Is Soy a Safe Food for My Baby Boy?
Licensed Nutritionist Tiffani Hays assures parents that the data and studies show no ill-effects of regular soy consumption in boys, so soy is a safe and healthful food for boys and girls alike. Although study after study has confirmed that soy isoflavones do not “feminize” boys, fears about phytoestrogen persist. They probably arise from simple speculation about possible cause-and-effect (“Hmm, estrogen is a female hormone…”). Despite the worries, and some fervid Internet claims, long-term studies have demonstrated that children who consumed soy do not suffer in reproductive development, hormones or endocrine function as adults. It should be noted, however, that the American Academy of Pediatrics only recommends soy formula for a very small segment of the infant population and stresses that breast milk is the best milk. (Read more soy formula guidelines here.)
How Can I Include Soy in My Diet?
The best way to include soy in your diet, advises Tiffani Hays, is to eat “the most natural form of the food.” She warns that many products on the shelves are made with soy protein, a highly processed food, and you just don’t get the same health benefits from these commercial products. “The less processed, the better,” Hays counsels. With that in mind, you’ll find that edamame, as a snack or a side dish, is a delicious way to enjoy a little soy. Tofu, which comes in a variety of flavors and textures, is also good bet. Try using silken tofu as a base for homemade smoothies and vegetable dips, or add regular firm tofu to scrambled eggs or as part of a stir-fry. If soy milk is more your style, drink up, but be sure you’re buying the kind fortified with calcium and vitamin D, especially if it replaces cow’s milk in your diet.
Is Soy Safe for the Whole Family?
Don’t hog all the miso, Mom! As soon as your child is old enough to eat solid foods, give soy a try. “Soy is great for adding variety, textures, and flavors to a healthy diet,” nutritionist Hays says. Baked tofu is ever-so-squishably-yummy, and edamame is the perfect finger food for toddlers. Of course, you should always monitor your child’s eating to avoid the risk choking, and if your child is at high risk for allergies, it’s best to wait until after his first year to introduce soy, a common allergen. (Most kids outgrow their soy allergies by age 5.)
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