While no specific studies have been done on phenylalanine and pregnancy, some women may assume that because it is a naturally occurring amino acid, supplements are also safe to take. However, the supplements could have a higher-than-normal concentration or different form of phenylalanine than that found in food. If you are pregnant, phenylalanine supplements should probably be avoided.
Phenylalanine and Pregnancy: An Overview
Phenylalanine is an amino acid found in many foods and is also used in dietary supplements. While a normal intake of phenylalanine through foods is safe and beneficial for pregnant women, it is not known if phenylalanine supplements are equally safe for use during pregnancy. Therefore, you should not take these supplements during pregnancy without your healthcare provider's approval and supervision.
Is Phenylalanine Safe for Pregnant Women?
A normal dietary intake of phenylalanine is safe for almost everyone, including pregnant women, despite what you may read on the Internet (see Dangers of Phenylalanine for more information).
However, it is not known if phenylalanine supplementation is safe for pregnant women. There are no reliable studies showing that such supplements are either safe or unsafe for use during pregnancy. It might seem logical to assume that phenylalanine supplements would be perfectly safe for pregnant women, since phenylalanine is an amino acid that is found naturally in many foods. But just because a normal dietary intake through food is safe, it cannot be assumed that using supplements medicinally is equally safe. Perhaps the higher levels could cause problems, or perhaps the phenylalanine in supplements is slightly different from the phenylalanine found in foods. Until more information is available, it is best to wait until after pregnancy to try phenylalanine supplements.
Women with phenylketonuria (PKU) should not take phenylalanine, especially during pregnancy. This could cause severe birth defects and other problems. PKU is a rare genetic condition in which the body does not process phenylalanine normally.
Written by/reviewed by: Kristi Monson, PharmD;Arthur Schoenstadt, MD
Last reviewed by: KristiMonson, PharmD;
List of references (click here):
Jellin JM, editor. Pharmacist's Letter/Prescriber's Letter Natural Medicines Comprehensive Database Web site. Available at: http://naturaldatabase.com/. Accessed March 6, 2008.
Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrates, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). Washington, DC: National Academy Press, 2005. Available at: http://books.nap.edu/openbook.php?record_id=10490&page=R1. Accessed March 6, 2008.
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