Pregnancy nutrition: What should you eat & what to avoid, according to an expert

Welcome to Ask A Dietitian, a series where Yahoo Canada digs into food trends and popular nutrition questions with registered dietitian Abbey Sharp.

This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis or treatment. Contact a qualified medical professional before engaging in any physical activity, or making any changes to your diet, medication or lifestyle.

Pregnancy is a time of transformation and growth, not just for the expectant mother but also for the developing baby. The nutritional choices made during this period play a pivotal role in the well-being of both.

You've probably heard about "eating for two" — but what exactly should you be eating, and how much? To shed light on the essential nutrients and dietary considerations during pregnancy, we turned to dietitian Abbey Sharp.

Read on for everything you need to know.

What nutrients are essential to babies and pregnant individuals?

Sharp emphasized several nutrients people need to include in their diet during pregnancy.

The first is folate or folic acid — "a B vitamin that prevents neural tube defects like spina bifida," she explained. Folate is found in foods like fortified cereal, dark leafy greens, citrus, dried peas, lentils and beans. But, those who are trying for a baby can start preparing for it sooner, since the neural tube of the baby develops early on.

"It's important to take a prenatal supplement if you're sexually active and can potentially become pregnant," Sharp advised. A 400 mg folic acid supplement is recommended.

The dietitian also said about 40 to 60 per cent of the population has a genetic polymorphism called MTHFR that impairs the conversion of supplemental folic acid into active methylfolate. "If you have this genetic polymorphism, you should definitely be taking a methylfolate-based supplement."

Iron is also "very important" in pregnancy, Sharp claimed, as it helps the formation of red blood cells and prevents anemia, which can lead to premature birth. "In pregnancy, your iron needs double to 27 milligrams," she advised.

Good sources of iron include red meat, poultry, fish, beans, fortified cereals, spinach, and hemp hearts.

To support the baby's bones and circulation, calcium is crucial, Sharp added.

Pregnant people need 1300 milligrams daily from supplements or food sources, including: dairy and salmon with bones, fortified cereals and non-dairy alternatives, orange juice, broccoli, almonds and kale.

Vitamin D is "also key and works alongside calcium," the expert said. It can be challenging to obtain through food alone, so a supplement of at least 1000 IU per day is recommended — especially in the winter.

For healthy brain development Sharp recommends omega 3, adding it's often lacking in people's diets but "particularly important for expectant moms." She suggested a prenatal supplement with DHA omega 3s if you don't regularly consume fatty fish like salmon.

Does 'eating for two' mean doubling the calories?

According to Sharp, pregnant individuals do require additional calories but "it's a lot less than people think."

In the first trimester, calorie needs are negligible. In the second trimester, about 350 extra calories are required, and in the third trimester, between 450-500 extra calories. But there's no one-fits-all approach.

"Not everyone will gain weight at the same pace. Some individuals are very hungry near the start and can't eat as much near the end when there's not much room. Others are very sick at the start and undereat, than catch up later on."

When pregnant, you should aim to gain between 25-35 pounds during pregnancy, but underweight individuals may need to gain more, she warned.

What foods should pregnant and breastfeeding individuals avoid?

During pregnancy, certain foods and drinks should be avoided or limited to ensure the baby's safety. These include:

• alcohol

• undercooked or raw meat

• seafood and fish, dairy, eggs

• soft cheeses

• caffeine (up to 200 milligrams a day or one-and-a-half cup of coffee)

• high-mercury fish (shark, tuna steak, a lot of canned tuna)

• pre-packaged unwashed fruits and vegetables (especially ones like bagged lettuce and cantaloupe)

"The main concern with these foods is food borne illness from listeriosis, salmonella and toxoplasmosis," Sharp explained.

She also added though it's best to avoid high-mercury fish, fish is a "super nutritious source," so low-mercury options like shrimp, salmon, cod, and halibut are encouraged. Light canned tuna is also recommended.

Sharp also warns against excessive consumption of liver due to its high vitamin A content, which can be harmful to the baby.

What's a healthy diet while breastfeeding?

There are few dietary restrictions for breastfeeding, Sharp said.

While some infants may have allergies, research suggests changing the parent's diet may not significantly benefit the baby. But, Sharp said breastfeeding individuals need to consume sufficient calories.

Breastfeeding individuals burn about 20 calories per ounce of milk produced.

"To put that in perspective, when my son was three months old, I was pumping about 45 ounces of milk a day, which equates to about a 900 calorie deficit," Sharp explained.

The only potential considerations of things to avoid are caffeine and alcohol, though "the amounts that get into the breastmilk are miniscule," she said, adding "pumping and dumping" is unnecessary.

"If you want to be conservative, you can feed and then drink (again, dumping does nothing but wastes precious milk).

"The biggest risk of drinking is that you become too drunk to take care of the baby. So, if you can safely care for baby, it's likely not an issue."

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