Iron and Calcium

Just posted this on the RNY and Texas forums and I thought I would share with you guys, too!!! As a nursing student, I have had to take a nutrition class and this information on iron and calcium absorption comes straight out of my nutrition text book, Understanding Nutrition by Ellie Whitney and Sharon Rady Rolfes. Now, keep in mind this information is written for the masses and NOT geared to WLS folks, but the mechanism is still the same, even if the numbers are not. IRON "Iron absorption depends in part on its source. Iron occurs in two forms in foods: as heme iron, which is found only in foods derived from the flesh of animals, such as meats, poultry, and fish; and as nonheme iron, which is found in both plant-derived foods and animal-derived foods. On average, heme iron represents about 10% of the iron a person consumes in a day. Even though heme iron accounts for only a small proportion of the intake, it is so well absorbed that it contributes significant iron: about 25% of heme iron is absorbed. By comparison, only 17% of nonheme iron is absorbed, depending on dietary factors and the body's iron stores. In iron deficiency, absorption increases, and in iron overload, absorption decreases. Iron Absorption-Enhancing Factors: *MFP factor (found in meat, fish, and poultry) *Vitamin C (ascorbic acid) *Citric acid and lactic acid from foods and the hydrochloric acid from the stomach *Sugars (including the sugars in wine) Iron Absorption-Inhibiting Factors: *Phytates and fibers (whole grains, nuts, and vegetables) *Oxalates (spinach, beets, rhubarb) *Calcium and phosphorus (milk and dairy) *EDTA (food additives) *Tannic acid and other polyphenols (tea and coffee) Maximizing Iron Absorption: In general, the bioavailability of iron in meats, fish, and poultry is high; in grains and legumes it is intermediate; and in most vegetables, especially those high in oxalates (spinach, beets, rhubarb) it is low. For the maximum absorption of nonheme iron, eat meat for MFP and fruits and vegetables for vitamin C. Iron Supplements: Iron from a supplement is less well absorbed than from that of food, so the doses have to be high. The absorption of iron taken as ferrous sulfate or as an iron chelate is better than that from other sources of iron supplements. Absorption also improves when supplements are taken between meals or at bedtime on an empty stomach, and with liquids other than milk, tea, or coffee, which inhibit absorption. Taking iron supplements in a single dose instead of several doses per day is equally effective and may improve a person's willingness to take it. CALCIUM Many factors affect calcium absorption, but on average, adults absorb 25% of the calcium they ingest. The stomach's acidity helps to keep calcium soluble, and vitamin D helps to make the calcium-binding protein needed for absorption. Whenever the body needs calcium, the body increases its production of the calcium-binding protein to improve calcium absorption. Calcium Absorption-Enhancing Factors: *Stomach acid *Vitamin D *Lactose *Growth hormones Calcium Absorption-Inhibiting Factors: *Lack of stomach acid *Vitamin D deficiency *High phosphorus intake *High-fiber diet *Phytates (whole grains, nuts, and vegetables) *Oxalates (spinach, beets, rhubarb) Also, calcium and iron are absorbed by attaching to receptors on individual cells. They compete for the same receptors and calcium has a higher affinity for those receptors, therefore they will bind and be absorbed before the iron will and the iron will simply be excreted in the fecal waste. THAT is why they shouldn't be taken together." Sharyn nurse2b

Thanks Sharyn, I find it interesting that phytates, oxalates and fiber inhibit the absorption of both iron and calcium. They are so good for us. Is the key not to eat them with our supplements? I guess I should switch to taking my iron in the evening so I can enhance it's absorption by having a glass of wine. I must do what I must do. Rachelle

Yep, they bind to these minerals and you just poop 'em out. What a waste of a good supplement. As far as the wine & iron combo, the sacrifices we must make!!! Sharyn nurse2b