Vitamin B6, also known as pyridoxine, has many essential functions in the body. As with most nutrients, B6 requirements are increased during pregnancy and lactation. It is not difficult to meet B6 requirements from dietary sources. Most prenatal supplements also contain 100% of the FDA's recommended Daily Value, or DV, for B6.
B6 Functions
According to the Office of Dietary Supplements, B6 is a water-soluble vitamin that is needed for over 100 enzymes involved in protein metabolism. It is essential for red blood cell metabolism; B6 deficiency can lead to a form of anemia similar to iron deficiency anemia. For the immune system, B6 helps maintain the health of organs that make white blood cells; B6 deficiency can decrease antibody production and suppress immune response. B6 also aids in nervous system function, the conversion of tryptophan to niacin, and maintaining normal blood glucose levels.
B6 During Pregnancy
According to the Institute of Medicine, the requirement for vitamin B6 during pregnancy is 1.9 mg daily; during lactation, 2.0 mg daily. This compares to a recommendation of 1.3 mg daily for females aged 19 to 30 years. On food labels, the %DV is based on 2.0 mg per day. While breastfeeding, do not take more than 2 mg daily in supplement form, as not enough is known about the safety of higher doses.
B6 Sources
One of the easiest ways you can meet the B6 recommendation from food is to eat a fortified cereal for breakfast or as a snack---a ¾ cup serving of many fortified cereals provides 100% DV for B6. Check the label, though, as amounts vary. You can get 50% DV by eating ½ fillet of salmon or halibut. A medium baked potato with the skin and a medium banana each provide 35% DV. Canned garbanzo beans contain 30% DV in ½ cup. A chicken breast provides 25% DV. A packet of fortified instant oatmeal or 3 oz. pork loin contains 20% DV. Three ounces roast beef or trout provides 15% DV. You can get 10% DV for B6 from 1 oz. sunflower seeds, 6 oz. tomato juice, ½ c. avocado, 3 oz. salmon or canned tuna or ¼ c. wheat bran.
B6 in Prenatal Supplements
Most prenatal vitamin and mineral supplements contain vitamin B6. The amount ranges from 2 mg, or 100% DV, to 20 mg, or 1000% DV. The American Pregnancy Association cautions against taking more than the Recommended Daily Allowance of any nutrient--in this case, 2 mg B6--during pregnancy unless under the direction of your health care provider.
Morning Sickness
The American College of Obstetrics and Gynecologists considers B6, or pyridoxine, a first-line treatment for morning sickness, or nausea and vomiting caused by pregnancy. According to the NIH's National Library of Medicine (NLM), B6 may be more effective in improving symptoms of severe nausea than mild to moderate nausea. The dosage for nausea and vomiting is much higher than the DV---10 to 25 mg three or four times a day. The NLM cautions that this dosage should only be taken with your doctor's supervision---the long-term use of high doses may cause brain and nerve problems and high doses can cause newborns to have seizures.
References
- Office of Dietary Supplements: Vitamin B6
- Institute of Medicine: Dietary References Intakes: Vitamins
- USDA National Nutrient Database: Vitamin B-6 Content of Selected Foods
- National Guideline Clearinghouse: ACOG Nausea and Vomiting of Pregnancy
- NIH National Library of Medicine: Pyridoxine (Vitamin B6)
- American Pregnancy Association: Prenatal Vitamins
