Vitamin B-12 and iron help form red blood cells that transport oxygen to your cells and tissues. Your body needs B-12 for the normal functioning of the nervous and digestive systems. Iron helps form proteins and enzymes and also keeps your immune system healthy. Because rich sources of iron and B-12 occur in animal sources, strict vegetarians may require supplements to prevent deficiencies.
Recommended Allowance of B-12
The amount of B-12 you need depends on your age and lifestyle. For people ages 14 and older, the recommended dietary allowance of B-12 is 2.4 mcg per day. The RDA is 1.8 mcg for children ages 9 to 13, 1.2 mcg for ages 4 to 8 and 0.9 mcg for ages 1 to 3. Infants under 6 months require 0.4 mcg, while infants ages 7 to 12 months require 0.5 mcg. The Food and Nutrition board recommends 2.6 mcg for pregnant women and 2.8 mcg for breastfeeding mothers.
Recommended Allowance of Iron
The RDA of iron is 11 mg for infants ages 7 to 12 months, 7 mg for children ages 1 to 3, 10 mg for ages 4 to 8 and 8 mg for ages 9 to 13. Teenage girls and women have an increased demand for iron due to the blood loss during menstruation. Girls ages 14 to 18 require 15 mg, while boys of the same age require 11 mg. Men ages 19 to 50 require 8 mg, while women require 18 mg. If you are pregnant, you need 27 mg of iron daily to make extra red blood cells needed by you and your fetus.
Deficiencies
A low dietary intake of iron can lead to iron deficiency anemia, resulting in weakness, shortness of breath, headache and lack of energy. Iron deficiency during pregnancy can lead to premature birth or low birth weight. Pregnant women, new mothers and strict vegetarians are likely to have low iron levels. B-12 deficiency can lead to dementia, weakness, weight loss and permanent nerve damage. Vegans, pregnant women and people with digestive disorders are likely to have low levels of B-12.
Dietary Sources
The U.S. Department of Agriculture lists beef, turkey, chicken and liver as rich sources of iron and B-12. These nutrients naturally occur in seafood, such as clams, oysters, salmon and sardines. Iron is found in green vegetables, peas, beans, lentils, nuts and dried fruits. Reasonable amounts of B-12 are found in milk, cheese and yogurt. Choose low-fat or fat-free varieties. Iron and B-12 are also added to fortified products such as breakfast cereals to help boost your daily allowance. Because of their rapid growth, MedlinePlus recommends you give iron-fortified foods or supplements to children ages 1 to 4.
References
- Office of Dietary Supplements: Fact Sheets
- Linus Pauling Institute: Iron; Jane Higdon; January 2006
- MedlinePlus: Iron in Diet; March 2009
- USDA: National Nutrient Database for Standard Reference: Iron
- USDA: National Nutrient Database for Standard Reference: B12
- MedlinePlus: Vitamin B12; February 2011
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