Sunday, March 16, 2014

Oxygen Transport

I was researching iron, an essential mineral, for various reasons and discussing it with my husband. I decided this might be good information to share. Not to make you worry. Not to make you run to the doctor. Just to encourage you to look at your diet and make sure it is varied enough to provide all the minerals and nutrients you need. If you feel like your iron levels may be low, add more iron-rich foods and talk to your healthcare provider. Do not take an iron supplement without talking to him/her; more is not better!

What is iron and why do we need it?

Iron is a mineral needed by our bodies. Iron is a part of all cells and does many things in our bodies. For example, iron (as part of the protein hemoglobin) carries oxygen from our lungs throughout our bodies. Having too little hemoglobin is called anemia. Iron also helps our muscles store and use oxygen.

Iron is a part of many enzymes and is used in many cell functions. Enzymes help our bodies digest foods and also help with many other important reactions that occur within our bodies. When our bodies don't have enough iron, many parts of our bodies are affected. (from the Centers for Disease Control & Prevention)

How much do I need?

This depends on your age, gender, and overall health, says WebMD:

Infants and toddlers need more iron than adults, in general, because their bodies are growing so quickly. In childhood, boys and girls need the same amount of iron -- 10 milligrams daily from ages 4 to 8, and 8 mg daily from ages 9 to 13.

Starting at adolescence, a woman's daily iron needs increase. Women need more iron because they lose blood each month during their period. That's why women from ages 19 to 50 need to get 18 mg of iron each day, while men the same age can get away with just 8 mg.

After menopause, a woman's iron needs drop as her menstrual cycle ends. After a woman begins menopause, both men and women need the same amount of iron -- 8 mg each day.

You might need more iron, either from dietary sources or from an iron supplement, if you:
  • Are pregnant or breastfeeding
  • Have kidney failure (especially if you are undergoing dialysis, which can remove iron from the body)
  • Have an ulcer, which can cause blood loss
  • Have a gastrointestinal disorder that prevents your body from absorbing iron normally (such as celiac disease, Crohn's disease, or ulcerative colitis)
  • Take too many antacids, which can prevent your body from absorbing iron
  • Have had weight loss (bariatric) surgery
  • Work out a lot (intense exercise can destroy red blood cells)
If you are a vegetarian or vegan, you may also need to take an iron supplement, because the body doesn't absorb the type of iron found in plants as well as it absorbs the iron from meat.
 

What foods are rich in iron?


Top Iron-Rich Foods list from the National Institutes of Health

Table 1: Selected Food Sources of Heme Iron [10]
FoodMilligrams
per serving
% DV*
Chicken liver, pan-fried, 3 ounces11.061
Oysters, canned, 3 ounces5.732
Beef liver, pan-fried, 3 ounces5.229
Beef, chuck, blade roast, lean only, braised, 3 ounces3.117
Turkey, dark meat, roasted, 3 ounces2.011
Beef, ground, 85% lean, patty, broiled, 3 ounces2.212
Beef, top sirloin, steak, lean only, broiled, 3 ounces 1.69
Tuna, light, canned in water, 3 ounces1.37
Turkey, light meat, roasted, 3 ounces1.16
Chicken, dark meat, meat only, roasted, 3 ounces1.16
Chicken, light meat, meat only, roasted, 3 ounces0.95
Tuna, fresh, yellowfin, cooked, dry heat, 3 ounces0.84
Crab, Alaskan king, cooked, moist heat, 3 ounces0.74
Pork, loin chop, broiled, 3 ounces0.74
Shrimp, mixed species, cooked, moist heat, 4 large0.32
Halibut, cooked, dry heat, 3 ounces0.21

Table 2: Selected Food Sources of Nonheme Iron [10]
FoodMilligrams
per serving
% DV*
Ready-to-eat cereal, 100% iron fortified, ¾ cup 18.0100
Oatmeal, instant, fortified, prepared with water, 1 packet11.061
Soybeans, mature, boiled, 1 cup 8.848
Lentils, boiled, 1 cup6.637
Beans, kidney, mature, boiled, 1 cup5.229
Beans, lima, large, mature, boiled, 1 cup4.525
Ready-to-eat cereal, 25% iron fortified, ¾ cup4.525
Blackeye peas, (cowpeas), mature, boiled, 1 cup4.324
Beans, navy, mature, boiled, 1 cup4.324
Beans, black, mature, boiled, 1 cup3.620
Beans, pinto, mature, boiled, 1 cup 3.621
Tofu, raw, firm, ½ cup3.419
Spinach, fresh, boiled, drained, ½ cup3.218
Spinach, canned, drained solids ½ cup2.514
Spinach, frozen, chopped or leaf, boiled ½ cup1.911
Raisins, seedless, packed, ½ cup1.69
Grits, white, enriched, quick, prepared with water, 1 cup1.58
Molasses, 1 tablespoon0.95
Bread, white, commercially prepared, 1 slice0.95
Bread, whole-wheat, commercially prepared, 1 slice0.74


Drink red wine, tea or coffee? These drinks might inhibit your iron absorption! Read more from reputable websites and talk to your doctor if you have concerns.


Action Item: If you fall into a higher-iron needs category, track your intake for a week and see how you're doing.

For Further Reading: Read these articles to learn more, especially about iron absorption. Iron Rich Foods, What You Need to Know About Iron Supplements, Iron and Iron Deficiency, Iron

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