The Foods to Avoid When You’re Pregnant

THE FOODS TO AVOID WHEN YOU’RE PREGNANT

Rachel Meltzer Warren

THE GIST

  • Pregnant women are more susceptible to foodborne illness than most people because their immune systems are weakened. 
  • Microbes like salmonella, campylobacter and Toxoplasma gondii can be harmful to a pregnancy, but experts are particularly concerned about Listeria monocytogenes, a bacterium that can cause infection that can have devastating consequences. 
  • To minimize listeria risk, avoid foods most likely to carry it, such as certain types of processed meats (unless they’ve been thoroughly heated), smoked fish, soft cheeses and unpasteurized milk and dairy products. 
  • Although research on moderate alcohol consumption during pregnancy is mixed, experts have said that abstinence is the safest bet.
  • Unless your doctor suggests otherwise, you can keep your morning coffee, as long as you limit yourself to 200 milligrams of caffeine or less per day. 
  • Worried you ate the wrong thing? Don’t stress. Discuss it with your doctor, who can give you tips on what, if anything, to do next. 

WHAT TO DO

Take care with certain types of processed meats

  • There are dozens of bacteria, viruses and parasites that can linger in foods and cause illness. Experts are particularly concerned about listeriosis — a bacterial infection that can cause seemingly mild or even nonexistent symptoms in pregnant women, but which can be especially dangerous to an unborn baby — including causing miscarriage, preterm labor or stillbirth. 

Listeria infections during pregnancy are rare. Between 2009 and 2011, according to the Centers for Disease Control and Prevention, there were just 227 cases in pregnant women in the United States. But research suggests that pregnant women may be up to 20 times more vulnerable to a listeria infection than the rest of the population. 

“Your immunity is altered when you’re pregnant, and that makes you more susceptible to serious consequences of foodborne illness,” said Dr. Zoe Kiefer, M.D., M.P.H., an ob-gyn at Beth Israel Deaconess Medical Center in Boston. Nearly one-quarter of all listeria cases in pregnant women in the United States result in fetal loss or death of the newborn, according to the C.D.C. 

Listeria outbreaks tend to occur in certain ready-to-eat meat products such as hot dogs, sausages, and store-bought, meat-based salads such as those made with chicken or ham. Cold cuts and deli meats are a common source, too. In fact, on April 17, 2019, the C.D.C. reported that at least eight hospitalizations and one death were linked to a listeria outbreak among sliced deli meats and cheeses at several deli counters across four states. Other outbreaks have been caused by refrigerated pâtés, meat spreads, smoked seafood, carpaccio, produce like cantaloupe and lettuce, and dairy products like ice cream and soft cheeses (more on cheese below). 

Instead of cutting these high-risk foods from your diet completely, Mary Saucier Choate, M.S., R.D.N., a food safety field specialist at the University of New Hampshire Extension, recommended cooking foods that can be eaten hot to an internal temperature of 165 degrees, or until steaming, since high temperatures kill the bacteria. A hot open-faced turkey sandwich or a fully cooked hot dog would do the trick. Or, consider making your own alternatives, such as freshly prepared salmon salad (made from canned salmon), egg salad or a peanut butter and banana sandwich.

Experts have said to keep fruits and veggies (with the exception of sprouts; more on that below), in your diet unless there’s an outbreak. Cooking produce is another way to minimize potential risk, said Dr. Haley Oliver, Ph.D., an associate professor of food science at Purdue University.

In general, keeping kitchen surfaces clean, thoroughly washing fruits and veggies and properly storing them (like keeping cut melon refrigerated) can help keep you protected. 

  • Be flexible with fish choices

Fish is packed with nutrition and is an important addition to many people’s diets, especially if you’re expecting. It’s not only high in protein and essential vitamins and minerals, but supplies healthy omega-3 fatty acids that aid in your brain and heart health, and in your baby’s brain and retina development. 

That doesn’t make fish an all-you-can-eat food when you’re pregnant, though. Most fish contain some level of mercury, a metal that can cause brain damage as well as vision and hearing problems for babies exposed in the womb. But certain types tend to contain more mercury than others. Large, long-living fish like bigeye tuna, swordfish, shark, king mackerel and orange roughy have the highest mercury levels and are best avoided. 

Federal health agencies recommend that pregnant women eat two to three servings (8 to 12 ounces) of fish per week, including a variety of low-mercury fish including cod, flounder, salmon, sardines, shrimp or canned light tuna; or one serving per week of moderate-mercury fish like halibut, snapper or albacore tuna. 

There is debate, however, over whether some types of tuna are safe for pregnant women to eat at all. In 2014, Consumer Reports analyzed Food and Drug Administration data and found that while canned light tuna on average was low in mercury, the amount varied greatly from can to can, with some containing unsafe levels of the toxin. Since there’s no way to tell which can is which, or which type of tuna the can contains, the group recommends avoiding all types of tuna while you’re pregnant. Talk with your doctor about the best diet plan for you.

  • Take care with raw foods

Raw fish known to harbor parasites (such as the anisakiasis worm, which can cause abdominal pain, nausea, vomiting and diarrhea) are typically frozen before they’re sold for consumption as sushi in the United States. Freezing can also halt the growth of bacteria like salmonella, which may be present. 

But freezing is not foolproof against foodborne illness, explained Dr. Christina A. Mireles DeWitt, Ph.D., an associate professor of food science and technology at Oregon State University. And it doesn’t prevent cross contamination. Most people’s immune systems can handle the temporary G.I. distress resulting from eating a contaminated food, said Dr. DeWitt, but pregnant women and their babies are at higher risk for complications (as are young children and the elderly or immune-compromised), so it’s best to avoid uncooked fish, such as sushi and raw oysters, when you’re pregnant.

It’s also best to avoid raw or undercooked meat. While most pregnant women are advised to avoid cleaning their cat’s litter boxes due to the increased risk of infection from Toxoplasma gondii — a parasite that thrives in cat feces — about half of the yearly toxoplasmosis infections in the United States result from eating food. Common sources include undercooked pork, lamb and wild game meat; as well as raw fruits and vegetables (which could contain infected soil).

Consult the F.D.A.’s “heat chart” for instructions on how to ensure your meat is fully cooked. And wash your hands with soap and warm water after touching soil, sand, raw meat, cat litter or unwashed vegetables. The F.D.A. also recommends thoroughly washing and, if possible, peeling, fruits and veggies before eating.

  • Abstain from alcohol

While some studies suggest that light-to-moderate drinking — defined as no more than one drink per day for women — is no big deal during pregnancy, there’s enough evidence to the contrary for many experts to agree that no amount of alcohol is safe. A 2013 review of 34 studies, for example, concluded that women who drank up to three drinks per week throughout their pregnancies were more likely to have children with behavioral issues like poor impulse control or difficulty interacting with other kids than women who didn’t drink at all.

Drinking during pregnancy has been linked to an increased risk of fetal alcohol spectrum disorders, such as fetal alcohol syndrome, which can lead to facial abnormalities, improper growth and intellectual disabilities. A 2018 study published in the journal JAMA estimated that as many as 5 percent of children in the United States have an F.A.S.D. 

“We really don’t know what amount is safe,” said Dr. Kiefer. So for now, skip the booze.

  • Avoid unpasteurized drinks

Pasteurization, or the process of heating foods to kill harmful bacteria, has made many foods safe for pregnant women to consume. But be on the lookout for milks, juices, dairy and other products that haven’t gone through the process.

Raw, unpasteurized milk can harbor germs like listeria, salmonella, campylobacter or cryptosporidium. In 2014, the American Academy of Pediatrics said that since no studies have found any benefits of drinking unpasteurized milk, pregnant women who drink milk and milk products should only consume those that have been pasteurized. (The same advice goes for infants and children.)

Most juices sold in the United States are pasteurized, including all that are shelf-stable. But some refrigerated juices sold at certain types of stores like high-end chains, local organic juice joints, corner bodegas or farm stands may not be. If you don’t see a label stating a drink has been pasteurized, ask whether it has been. If they’re not sure if it has, skip it.

  • Be choosy about cheeses

As with refrigerated meat and unpasteurized dairy products, cheese can harbor listeria and other pathogens. But unlike the “cook it or skip it” recommendation for meat products, the advice on cheese isn’t always straightforward. 

In general, the softer — and wetter — a cheese gets, the more you have to worry about pathogens surviving and growing. Bacteria like moisture, said Dr. Dennis D’Amico, Ph.D., a professor of food microbiology at the University of Connecticut, so pathogens tend to grow on soft cheeses more quickly than they grow on harder ones. 

“As you go from a mozzarella with high moisture to something like a cheddar or a Monterey Jack, the risk is starting to go down,” said Dr. D’Amico. Dry, hard cheeses such as a traditional Parmigiano or a Pecorino Romano have virtually zero risk of foodborne illness, said Dr. D’Amico. 

Soft cheeses made with unpasteurized milk are by far the riskiest: C.D.C. estimates suggest they’re as much as 160 times more likely to cause foodborne listeria infection than soft cheeses made with pasteurized milk. But even pasteurized soft cheeses are not risk-free: A 2018 C.D.C. report revealed that there were 12 times more listeria outbreaks linked to pasteurized soft cheeses between 2007 and 2014 than there were between 1998 and 2006. One such outbreak in 2015 hospitalized 28 people — six of whom were pregnant. Latin-style cheeses, like Queso Fresco, have been implicated in more outbreaks than other types. 

While the F.D.A. says it’s O.K. for pregnant women to eat soft cheeses made with pasteurized milk, Dr. D’Amico and other experts have suggested that pregnant women consider avoiding them to be safe.

  • If you drink coffee, stick to one cup

Decades of research has linked consumption of coffee and other sources of caffeine to increased risks for miscarriage, preterm birth and low birth weight babies. But the research isn’t clear on how much is safe to consume. Most public health groups, including the American College of Obstetricians and Gynecologists, agree that limiting caffeine to no more than 200 milligrams per day will not majorly increase such risks. 

“I tell my patients it’s O.K. to have one cup of coffee daily,” said Dr. Kiefer, no matter your stage of pregnancy. 

But caffeine content can vary depending on what you drink. At Starbucks, a shot of espresso has 75 milligrams of caffeine; whereas its Tall-sized brewed coffee drinks have closer to 190 to 280 milligrams. The English breakfast tea I ordered at the coffee shop that day probably had around 50 milligrams. 

Also keep in mind that caffeine can pop up in unassuming places, such as in decaf coffee, colas, iced teas, energy drinks, kombucha and chocolate. 

  • Avoid raw eggs

Eggs can carry salmonella, a bacteria that can cause infections resulting in fever, nausea, vomiting, diarrhea and dehydration. And if you’re infected during pregnancy, symptoms can be so severe that they may lead to serious complications for both you and baby.

Salmonella can’t withstand high heat, so eggs cooked to 160 degrees or more will be safe to eat. Cook eggs thoroughly until the whites and yolks are firm and no clear or runny sections remain. 

Most liquid eggs sold in refrigerated cartons are pasteurized and likely won’t have the potential to make you sick. Pasteurized shell eggs probably can’t make you sick either, though these are harder to find. Also remember that raw eggs can be found in seemingly innocuous foods and drinks, too, such as Hollandaise sauce, Caesar dressing, eggnog, raw cookie dough, aioli, meringue, mousse and tiramisu. 

After handling raw eggs, wash your hands and disinfect surfaces they’ve touched to prevent cross contamination. 

  • Go nuts

Past A.A.P. guidelines have advised pregnant women to avoid eating peanuts — and to delay introducing them to high-risk children (such as those whose parents have allergies) until age 3 — so as to prevent peanut allergies in their children. But as peanut allergies increased despite this advice, and more research emerged, the A.A.P. rescinded that recommendation in 2008 (and reaffirmed their stance in 2019). 

However some pregnant women still haven’t gotten that memo. 

If anything, newer research suggests that allergen exposure may reduce food allergy risk. A 2014 study of more than 8,000 women and their offspring published in JAMA Pediatrics, for example, found that moms who ate peanuts and tree nuts (like almonds or walnuts) five or more times per week during, shortly before or shortly after their pregnancies had kids who were 69 percent less likely to develop nut allergies than those whose moms ate them less than once per month. 

That’s good news, since nuts are good sources of the protein, healthy fats and vitamins and minerals that pregnant women need. 

  • Avoid sprouts

All raw sprouts — including alfalfa, mung bean, radish and clover—are risky for pregnant women. “Seeds may become contaminated by bacteria in animal manure in the field or during the postharvest stage,” said Choate, the food safety field specialist at the University of New Hampshire Extension. These bacteria can grow to high levels during sprouting, and are impossible to wash out. To play it safe, ask for your sandwich with no alfalfa sprouts, and for the bean sprouts to be left off your pad Thai.

  • Review the recalls

Every few days it seems there’s another healthy food we’re told to avoid due to an outbreak, from romaine lettuce to tahini to sliced melon. To stay on top of the latest news, sign up to get notified about alerts and recalls from both the F.D.A. and the Department of Agriculture by email here. You’ll also get an email when the recall is over, so you won’t unnecessarily need to limit your diet for longer than you have to. 

WHEN TO WORRY

Ate something on the “do not eat” list? Don’t freak out. The chances that one slip-up will damage your pregnancy are relatively slim, said Dr. Kiefer. “If a patient calls me and says, ‘I had a ham sandwich,’ I try to reassure them that they’re probably O.K.” 

You do need to worry, however, if you experience symptoms that could signal actual food poisoning, such as nausea, vomiting, diarrhea, fever, chills or dizziness; or any signs of preterm labor such as cramping or bleeding. If you have any of these symptoms or if you’re unable to keep fluids down for more than a few hours at a time, call your doctor or head to the E.R. so you can be monitored for hydration and treated as needed. 

As for that before-you-knew-you-were-pregnant party night, bring it up with your doctor. While experts have said that no amount of alcohol is safe, one isolated exposure to alcohol may not cause problems for you or your baby, said Dr. Kiefer. Talk with your doctor about concerns you have regarding drinking at any point in pregnancy, especially if you’ve had any significant alcohol intake since your last period. 

SOURCES

Dr. Zoe Kiefer, M.D., M.P.H., an ob-gyn at Beth Israel Deaconess Medical Center in Boston, January 2019

Mary Saucier Choate, M.S., R.D.N., a food safety field specialist at the University of New Hampshire Extension, January 2019

Dr. Christina A. Mireles DeWitt, Ph.D., an associate professor in food science and technology and director of the Oregon State University Seafood Research and Education Center, January 2019

Dr. Dennis D’Amico, Ph.D., a professor of food microbiology at the University of Connecticut, January 2019

Dr. Haley Oliver, Ph.D., an associate professor of food science at Purdue University, March 2019

“A.C.O.G. Practice Advisory: Update on Seafood Consumption During Pregnancy,”The American College of Obstetricians and Gynecologists, March 2019

“Talking About Juice Safety: What You Need to Know,” Food and Drug Administration, March 2019

“Consumption of Raw or Unpasteurized Milk Products by Pregnant Women and Children,” American Academy of Pediatrics Policy Statement, January 2014

Listeriosis Outbreaks Associated With Soft Cheeses, United States, 1998-2014,” Emerging Infectious Diseases journal and the Centers for Disease Control and Prevention, June 2018

“Cheese Microbial Risk Assessments — A Review,” Asian Australasian Journal of Animal Science, March 2016

“The Effects of Early Nutritional Interventions on the Development of Atopic Disease in Infants and Children: The Role of Maternal Dietary Restriction, Breastfeeding, Hydrolyzed Formulas and Timing of Introduction of Allergenic Foods,” Pediatrics, March 2019

“Listeria (Listeriosis),”Centers for Disease Control and Prevention, March 2019

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