What affects iron absorption?
Iron absorption is considered the amount of iron that the body takes up and uses from food. Most people absorb 10-15% of dietary iron, but this absorption is influenced by several factors.
Factors that influence iron absorption include:
- Storage levels of iron
- has the most influence on iron absorption
- when body stores are low, iron absorption increases & when iron stores are high, absorption decreases to help protect against toxic effects of iron overload
- Type of dietary iron consumed
- Absorption of heme iron from meat proteins is about 15-35%
- Absorption of non-heme iron found in plants ranges from 2-20% & depends on dietary factors
- Certain dietary factors
- Vitamin C helps improve non-heme iron absorption
- Tannins (in tea), calcium, polyphenols, phytates (in legumes) may decrease iron absorption
How much iron is recommended daily?
Recommended Dietary Allowances for Iron for Infants (7-12 months), Children & Adults
| Age | Males(mg/day) | Females(mg/day) | Pregnancy(mg/day) | Lactation(mg/day) |
| 7 to 12 months |
11 |
11 |
N/A |
N/A |
| 1 to 3 years |
7 |
7 |
N/A |
N/A |
| 4 to 8 years |
10 |
10 |
N/A |
N/A |
| 9 to 13 years |
8 |
8 |
N/A |
N/A |
| 14 to 18 years |
11 |
15 |
27 |
10 |
| 19 to 50 years |
8 |
18 |
27 |
9 |
| 51+ years |
8 |
8 |
N/A |
N/A |
Source: http://ods.od.nih.gov/factsheets/iron
What is the function of iron?
Oxygen distribution – Iron is the core of hemoglobin and myoglobin, which is the oxygen-carrying component of the red blood cell that picks up oxygen from the lungs and deliver oxygen to tissues & muscles throughout the body. The ability of red blood cells to carry oxygen is dependent on the presence of iron in the hemoglobin molecule. If we lack iron, we will produce less hemoglobin, and therefore supply less oxygen to our tissues.
Energy Production – Iron plays an important role in energy production, proper fat utilization, and immune system functioning.
What are symptoms of iron deficiency?
- Fatigue
- Weakness
- Low stamina & exercise tolerance
- Difficulties concentrating
- Increased susceptibility to infections
- Hair loss
- Dizziness
- Headaches
- Brittle nails
- Apathy
- Depression
Who is at risk for being iron deficient?
- People who donate blood regularly
- Women with excessive menstrual bleeding
- Those on medications that interfere with iron absorption (ie. antacids)
- Pregnant & lactating
- Elderly, vegetarians, and children with inadequate dietary intake
- Those with medical conditions causing internal bleeding
- People with parasitic infections
What are vegan sources of iron?
|
Iron Content of Selected Vegan Foods |
||
|
Food |
Amount |
Iron (mg) |
| Soybeans, cooked | 1 cup |
8.8 |
| Blackstrap molasses | 2 Tbsp |
7.2 |
| Lentils, cooked | 1 cup |
6.6 |
| Quinoa, cooked | 1 cup |
6.3 |
| Tofu | 4 oz |
6.0 |
| Spirulina | 1 tsp |
5.0 |
| Tempeh | 1 cup |
4.8 |
| Lima beans, cooked | 1 cup |
4.4 |
| Pumpkin seeds, raw | 1/4 cup |
4.2 |
| Swiss chard, cooked | 1 cup |
4.0 |
| Black beans, cooked | 1 cup |
3.6 |
| Pinto beans, cooked | 1 cup |
3.5 |
| Spinach, cooked | 1/2 cup |
3.2 |
| Chickpeas, cooked | 1 cup |
3.2 |
| Potato | 1 large |
3.2 |
| Kidney beans, cooked | 1 cup |
3.0 |
| Prune juice | 1 cup |
3.0 |
| Beet greens, cooked | 1 cup |
2.7 |
| Tahini | 2 Tbsp |
2.7 |
| Peas, cooked | 1 cup |
2.5 |
| Black-eyed peas, cooked | 1 cup |
2.3 |
| Cashews | 1/4 cup |
2.1 |
| Brussels sprouts, cooked | 1 cup |
1.9 |
| Bok choy, cooked | 1 cup |
1.8 |
| Bulgur, cooked | 1 cup |
1.7 |
| Raisins | 1/2 cup |
1.6 |
| Almonds | 1/4 cup |
1.5 |
| Apricots, dried | 15 halves |
1.4 |
| Soy yogurt | 6 oz |
1.1 |
| Tomato juice | 8 oz |
1.0 |
| Green beans, cooked | 1 cup |
1.2 |
| Kale, cooked | 1 cup |
1.2 |
| Sunflower seeds | 1/4 cup |
1.2 |
| Broccoli, cooked | 1 cup |
1.1 |
| Millet, cooked | 1 cup |
1.1 |
| Sesame seeds | 2 Tbsp |
1.0 |
Adapted From: http://www.vrg.org/nutrition/iron.htm
Sources:
http://ods.od.nih.gov/factsheets/iron
http://www.vrg.org/nutrition/iron.htm
http://www.vrg.org/nutshell/vegan.htm
http://www.whfoods.com/genpage.php?tname=nutrient&dbid=70