Iron is the most plentiful trace mineral in the human body. The primary function of iron is as an oxygen carrier in the hemoglobin of your red blood cells. Iron also plays a role in immune health, energy metabolism and brain development. Approximately 90 percent of the iron in your body is recycled and reused, and the rest is excreted from the body.
Types of Iron
Iron exists in two forms: heme and non-heme. Heme iron is the type of iron that makes up the hemoglobin in your red blood cells and the myoglobin in your muscles. Heme iron is more easily absorbed by the body. You obtain heme iron from animal foods, such as meat, fish and poultry. Non-heme iron is found in plant foods, such as grains, legumes and rice. In addition to iron, these plant foods contain other substances, called phytates, which inhibit the absorption of non-heme iron. Polyphenols in tea and protein in soy products also inhibit the absorption of non-heme iron. According to "Nutrition and You" by Joan Salge Blake, your body absorbs only 10 to 15 percent of the non-heme iron you eat.
Vitamin C and Iron
You can increase the percentage of non-heme iron your body absorbs by consuming non-heme iron foods with vitamin C. Vitamin C works with the acid in your stomach to change the structure of non-heme iron, increasing its absorption. According to "Nutrition and You" by Joan Salge Blake, consuming just 25 mg of vitamin C with non-heme iron can double absorption and consuming 50 mg of vitamin C with non-heme iron can increase the absorption rate sixfold.
Vitamin C Supplements
Vitamin C supplements are available in many forms. According to the Linus Pauling Institute, there is no evidence that one form is more easily absorbed than the other, although the most common forms are ascorbic acid and sodium ascorbate. Ascorbic acid is generally more acidic, which may be beneficial when taking vitamin C supplements to increase the absorption of non-heme iron. Because of the increased acidity, however, ascorbic acid supplements are more likely to cause gastrointestinal side effects, such as nausea, diarrhea and stomach cramps.
Upper Tolerable Intake Level
When choosing a vitamin C supplement, keep in mind that the Food and Nutrition Board sets an upper tolerable intake level, or UL, for the vitamin. This level is the highest amount of the vitamin that you can consume in a day without experiencing adverse effects. Your vitamin C supplement should contain less than 2,000 mg of vitamin C. Although excess vitamin C does not lead to toxicity, it can increase the possibility of kidney stone formation.
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