TABLE 1.
Factors affecting bioavailability of selected micronutrients that were noted in the Dietary Reference Intake (DRI) publications
| Factors | Examples |
| Chemical form | |
| Selenium | Selenomethionine and selenocysteine compared with selenite and selenate |
| Iron | Ferrous compared with ferric iron |
| Nonheme compared with heme | |
| Fortification compounds readily or poorly soluble in the gastric juice1 | |
| Fortification compounds with a built-in enhancer, ie, Na Fe EDTA1 | |
| Dietary factors | |
| Calcium | Phytate (inhibitor) |
| Oxalate (inhibitor) | |
| Iron | Polyphenols (inhibitor) |
| Phytate (inhibitor) | |
| Muscle tissue1 (enhancer) | |
| Ca, legume proteins, casein1 (inhibitor) | |
| Ascorbate (enhancer) | |
| Carotenoids | Emulsifiers (enhancer) |
| Fats (enhancer) | |
| Antioxidants (enhancer) | |
| Gentle cooking (enhancer) | |
| Zinc | Phytate (inhibitor) |
| Concentration (quantity ingested) | |
| Calcium | |
| Zinc | |
| Iron | |
| Vitamin B-12 | |
| Supplements better absorbed than dietary sources | |
| Carotenoids | |
| Folic acid | |
| Zinc? (4) | |
| Host status | |
| Iron | |
| Host pathophysiology | |
| Vitamin B-12 | Lack of intrinsic factor |
| Excretion | |
| Vitamin B-12 | Defective enterohepatic circulation |
| Interactions | |
| β-Carotene | Other carotenoids |
| Zinc | Iron |
| Copper | |
| Iron/vitamin A | |
1
Not included in DRI publications.