When people find out I’m a dietitian, one of the questions I get asked most frequently is, “How do you feel about multivitamins?” I usually try and find out why they’re asking before I respond, because the answer really depends. One size doesn’t fit all!
Hippocrates is widely credited as saying, “Let thy food be thy medicine.” For centuries, this simple advice has served people well; before the dawn of protein shakes and fish oil, a balanced diet generally equated to overall healthfulness. Vitamin and mineral supplements have become ubiquitous in modern society, however, and manufacturers are adept at convincing us that the key to good nutrition lies in a pill or a powder. Most healthy people with a varied, balanced diet can meet all of their nutrient needs through food. Besides, the Food and Drug Administration does not review or approve supplements for safety, and they can contain extra substances like enzymes and botanicals that may cause reactions with other medications.
Pregnant women have greater nutrient needs than the general population, and while most of these can be met through food, that’s not the case with all. Most women are told to start a prenatal vitamin as soon as (or before) they find out they’re pregnant. Prenatal vitamins provide some nutrients, like folic acid, that are critical in the early stages of pregnancy. But always consult your physician before starting a vitamin or mineral supplement if you’re pregnant (or trying to get pregnant).
First, let’s focus on a few vitamins and minerals that require extra attention during pregnancy: vitamin A, vitamin D, iron, calcium, folic acid, omega-3 fatty acids and choline.
Table 1: Nutrient Needs Before, During and After Pregnancy
What it does: While most of us associate vitamin A with vision, it does a lot more than just that! Especially for developing fetuses, vitamin A promotes cell division and differentiation. It also promotes optimal immune function.
How to get it: Vitamin A comes in two forms: retinol (the active form, generally found in animal foods and supplements) and beta carotene (a vitamin A precursor found in plant foods). Carotenoids are responsible for giving fruits and vegetables their color: bright orange and green vegetables are great sources of beta carotene. Be careful to limit your intake of retinol during pregnancy, though, because excessive intake early in pregnancy can lead to birth defects and may weaken bone mass. Never consume more than 3,000 μg vitamin A. Focus on eating an array of vegetables and you’ll easily meet your vitamin A needs for pregnancy and lactation.
What it does: Vitamin D is important in developing strong bones and muscles. It works to promote absorption of calcium in both mothers and babies, and has a role in immune function. Studies also point to vitamin D as a protective factor against childhood asthma.
How to get it: Aside from salmon and tuna, most foods are relatively low in vitamin D; fortified dairy products, breakfast cereals and orange juice are all good choices. Women living at northern latitudes above 40 degrees and those with darker skin should consult their physicians about extra vitamin D supplementation, since their vitamin D levels tend to be lower to begin with.
What it does: Iron is a primary component in hemoglobin, a molecule within red blood cells responsible for delivering blood to organs and tissues. It also plays a role in the developing immune system, brain and nervous system of fetuses.
How to get it: There are two forms of iron: heme and non-heme. Heme iron is abundant in meat, seafood and poultry. Non-heme iron is found in plant sources like leafy green vegetables and legumes. Fortified foods like breakfast cereals are also high in non-heme iron.
*Tip: vitamin C helps the body absorb iron. Pair iron-rich foods with a source of vitamin C like citrus fruits, juice, tomatoes or strawberries to boost absorption.
What it does: Besides playing a role in building strong bones and teeth, calcium is important in regulating cellular function, muscle contractions, nerve transmission and heartbeat.
How to get it: During pregnancy women’s bodies become highly efficient at absorbing calcium, so the RDA doesn’t change for pregnant or lactating women. However, most women don’t consume enough calcium before pregnancy, so it may be worthwhile to consider a calcium supplement while you’re pregnant and breastfeeding. Dairy foods are high in calcium, as are fortified orange juice and tofu, and greens like broccoli.
*Tip: make sure to buy a supplement containing calcium carbonate or calcium citrate because they’re highly absorbable by the body.
What it does: Folate, or folic acid, is a B vitamin critical in preventing neural tube defects (NTD’s) like spina bifida. These NTD’s can occur in the first month of development, before many women even know they’re pregnant, so it’s important for all women of childbearing age take at least 400 mg of folic acid daily. Folate can also prevent anemia in pregnant women, preterm birth and miscarriage.
How to get it: Most commercially produced grain products in the US are fortified with folic acid (such as breakfast cereals and rice). Other sources include leafy green vegetables and legumes.
Omega-3 Fatty Acids
What it does: Polyunsaturated fats, of which omega-3’s are just one variety, are important in the development of fetal brain and eye tissue, and they may play a role in preventing perinatal depression.
How to get it: Fish and shellfish are the best natural sources of polyunsaturated fatty acids such as omega-3’s. Walnuts, vegetable oils and flaxseeds are also high in this particular type of fat. Prenatal vitamins generally don’t contain any fatty acids, so meeting your needs during pregnancy and lactation can be a challenge if you don’t consume fish. Fish oil or DHA (a specific omega-3 fatty acid) supplements could be a good choice.
What it does: Choline is an essential nutrient in fetal brain, liver and central nervous system development. Animal studies have shown choline to be an essential component of hippocampal development, the part of the brain responsible for memory and the production of nerve cells. It also works in conjunction with folate to prevent neural tube defects.
How to get it: Choline is naturally abundant in foods like eggs, pork, beef and fish. Most dietary supplements don’t contain enough (or any) choline, so including choline-rich foods in your diet during pregnancy is important.
Pregnant women require additional nutrients to support the development of their fetuses and to keep their bodies functioning optimally. While most of these needs can be met through a well-balanced, healthy diet, a prenatal vitamin can help fill in some of the gaps with nutrients like folate and vitamin D. Just be sure to consult your physician before starting any over-the-counter supplements.
In next week’s blog post, we’ll explore fish and seafood consumption during pregnancy (what level is safe, what kinds to eat and what’s best to avoid). Stay tuned!
Food and Drug Administration Office of Women’s Health http://www.fda.gov/downloads/forconsumers/byaudience/forwomen/ucm382018.pdf
Moores, Susan, MS, RD. “Safe Sources of Omega-3 Fats for Pregnant Women.” http://www.eatright.org/resource/health/pregnancy/what-to-eat-when-expecting/pregnant-safe-sources-of-omega-3-fats
“Dietary Reference Intakes (DRI’s): Recommended Dietary Allowances.” Food and Nutrition Board, National Institutes of Health. https://fnic.nal.usda.gov/sites/fnic.nal.usda.gov/files/uploads/recommended_intakes_individuals.pdf
Ward, Elizabeth MS, RD Expect the Best. 2009. Wiley & Sons, Hoboken, NJ.