Reading food labels is so important and now more than ever. According to a recent report by the Environmental Working Group (EWG), a national environmental health research and advocacy organization, many products on grocery shelves have excessive amounts of added nutrients, which can lead to harmful side effects, especially for kids age eight and younger as well as pregnant women.

The detailed report focuses on two popular fortified food categories: breakfast cereals and snack bars. The EWG reviewed more than 1,550 cereals and 1,000 snack bars and found 114 cereals fortified with 30 percent or more of the adult daily value for vitamin A, zinc, and/or niacin, and 27 common brands of snack bars with 50 percent or more.

"Heavily fortified foods may sound like a good thing, but it when it comes to children and pregnant women, excessive exposure to high nutrient levels could actually cause short- or long-term health problems," said Renee Sharp, EWG's research director and co-author of the report, in a press release. "Manufacturers use vitamin and mineral fortification to sell their products, adding amounts in excess of what people need and more than might be prudent for young children to consume."

Since vitamin A is a fat-soluble vitamin, it is more susceptible to toxicity because your body stores it, whereas any excess of a water-soluble vitamin is excreted. Too much vitamin A can lead to liver damage, skeletal defects, and hair loss, and during pregnancy excessive A can result in developmental abnormalities in the fetus. And since most woman who are pregnant are taking a pre-natal vitamin that includes A, it is very important to know how much you are consuming from other sources.

Vitamin A is found two different ways in the diet: It comes either from animal sources and is called retinoids (which includes retinol) or from plants and is called carotenoids (which includes beta-carotene). The body converts beta-carotene to vitamin A, so beta-carotene does not accumulate in the body like retinoids and is not harmful to a fetus.

So what should you do?

1. Make sure your daily prenatal vitamin does not contain more than 5,000 IU of vitamin A and make sure to not take other supplements with additional vitamin A.

2. Continue to eat foods naturally rich in beta-carotene such as carrots, sweet potatoes, kale, spinach, apricots, and cantaloupe.

3. Read labels carefully to see if a product is fortified with vitamin A. Since you should be getting enough naturally in your diet and with your pre-natal vitamin, I would suggest limiting these foods.

4. Do not, however, assume that you should limit all fortified foods, especially cereal, since they can be good sources of other important nutrients for pregnancy, like folic acid and iron.