Mjölk och järn.

[King Grub]

Nu kan vi ta död på myten att mjölk och kalk skulle vara negativt för järnupptaget.

American Journal of Clinical Nutrition, Vol. 80, No. 2, 404-409, August 2004. Calcium from milk or calcium-fortified foods does not inhibit nonheme-iron absorption from a whole diet consumed over a 4-d period. Lisbeth Grinder-Pedersen, Klaus Bukhave, Mikael Jensen, Liselotte Højgaard and Marianne Hansen

Background: Single-meal studies have indicated that calcium inhibits iron absorption in humans. However, numerous dietary factors influence iron absorption, and the effect of calcium may not be as pronounced when calcium is served as part of a whole diet.

Objective: We investigated the effect of 3 sources of calcium served with the 3 main meals on nonheme-iron absorption from a 4-d diet.

Design: 59Fe absorption was estimated from whole-body retention measurements in 14 women aged 21?34 y, each of whom consumed four 4-d diets in a randomized crossover design. The diets differed in the source of calcium as follows: a basic diet (BD) with a low content of calcium (224 mg Ca/d), a BD with a glass of milk served at each meal (826 mg Ca/d), a BD with calcium lactate (802 mg Ca/d), and a BD with a milk mineral isolate containing calcium (801 mg Ca/d). The 2 latter calcium sources were added to selected foods of the BD (rye bread, white bread, chocolate cake, and orange juice), and these foods were consumed with the 3 meals. All diets provided 13.2 mg Fe/d.

Results: No significant differences in nonheme-iron absorption were found between the BD and the BD supplemented with milk, calcium lactate, or the milk mineral isolate [7.4% (95% CI: 5.3%, 10.5%), 5.2% (3.5%, 7.9%), 6.7% (5.0%, 8.9%), and 5.1% (3.2%, 7.9%), respectively; P = 0.34].

Conclusion: Consumption of a glass of milk with the 3 main meals or of an equivalent amount of calcium from fortified foods does not decrease nonheme-iron absorption from a 4-d diet.

[Wain]

Finns väl en hel del äldre studier som säger ungefär samma sak. Exempelvis:

Am J Clin Nutr. 1998 Jul;68(1):96-102.
Effect of calcium supplementation on daily nonheme-iron absorption and long-term iron status.

Minihane AM, Fairweather-Tait SJ.

Institute of Food Research, Norwich Research Park, Colney, United Kingdom.

The short-term effect of calcium supplements (1200 mg Ca/d) on daily nonheme-iron absorption was measured in 14 healthy adult volunteers by using stable isotope extrinsic labeling and fecal monitoring techniques. Mean (+/- SEM) nonheme-iron absorption from a low-calcium (< 320 mg/d), moderately high-iron (15 mg/d) diet was 15.8 +/- 2.1%, but in the presence of calcium (400 mg/meal) as calcium carbonate, absorption fell significantly to 4.7 +/- 1.4% (P < 0.001). The long-term effect of consuming calcium supplements with meals (1200 mg Ca/d) on body iron (functional and storage iron) was investigated in 11 iron-replete adults over a 6-mo period. An unsupplemented control group (n = 13) was also monitored to correct for any seasonal changes in the biochemical measurements. There were no changes in any of the hematologic indexes, including hemoglobin, hematocrit, zinc protoporphyrin, and plasma ferritin resulting from the calcium supplementation. The results clearly show that long-term supplementation with calcium did not reduce plasma ferritin concentrations in iron-replete adults consuming a Western-style diet containing moderate to high amounts of calcium in most meals.


Nutr Clin Care. 2002 Sep-Oct;5(5):231-5. Related Articles, Links
The effect of calcium consumption on iron absorption and iron status.

Harris SS.

New England Research Institutes.

Recent increases in recommended calcium intakes recognize the important role of calcium in skeletal health, but many Americans, especially women, consume far less than recommended amounts. A potential drawback to encouraging increased calcium intake is suggested by the extensive literature showing an adverse effect of high calcium intake on dietary iron absorption, at least in short, highly controlled, experimental studies. However, the applicability of short-term studies involving test meals to long-term iron absorption and iron status is limited given the variety of foods and food combinations in self-selected diets and the ability of individuals to adapt to reduced iron intake. In general, studies of whole diets and studies conducted over several weeks tend to show no effect of increased calcium intake on iron absorption. In addition, experimental studies of calcium and iron status measures such as serum ferritin show no long-term effect of calcium supplementation on iron status. Prevention and treatment of iron deficiency should emphasize adequate consumption of iron-rich foods and, when indicated, the use of iron supplements. Recommended calcium intakes are important for skeletal health and do not appear to increase the risk for iron deficiency in healthy people.

etc.