Last updated on: 4/9/2008 9:18:00 AM PST
Does Drinking Milk Inhibit Iron Absorption and Contribute to Anemia?
General Reference (not clearly pro or con)
The U.S. Department of Health and Human Services provided the following information about anemia in its online resource titled "Diseases and Conditions Index," published on its website (accessed Jan. 8, 2008):
"Anemia is a condition in which a person's blood has a lower than normal number of red blood cells (RBCs), or the RBCs don't have enough hemoglobin. Hemoglobin-an iron-rich protein that gives the red color to blood-carries oxygen from the lungs to the rest of the body. In people with anemia, the blood does not carry enough oxygen to the rest of the body...
Many kinds of anemia, especially those caused by deficiencies of iron or vitamins, may be prevented from recurring by eating a diet rich in those nutrients or by taking the appropriate supplements."
Jan. 8, 2008 - United States Department of Health and Human Services
Louis A. Kazal, Jr., MD, Physician at Dartmouth-Hitchcock Community Health Center, wrote in an Oct. 1, 2002 article titled "Prevention of Iron Deficiency in Infants and Toddlers," in the American Family Physician:
"The primary prevention of iron deficiency anemia in infants and toddlers hinges on healthy feeding practices. In infants, the introduction of cow's milk in the first year of life is the greatest dietary risk factor for the development of iron deficiency and iron deficiency anemia. Cow's milk is low in iron, and its iron is poorly absorbed. In addition, it decreases the absorption of iron from other dietary sources. Therefore, the strict avoidance of cow's milk in the first 12 months of life is essential in preventing iron deficiency anemia...
In the second year of life, cow's milk continues to cause problems in maintaining iron stores, and its consumption should be limited to less than 24 oz per day, with some clinicians calling for a stricter limit of 16 oz per day."
Oct. 1, 2002 - Louis A. Kazal, Jr., MD
Maria A. A. Oliveira, PhD, and Mônica M. Osório, PhD, Professors in the Nutrition Department at the Universidade Federal de Pernambuco, wrote in their 2005 article "Cow's Milk Consumption and Iron Deficiency Anemia in Children," published in the Journal de Pediatria:
"Foods that are sources of dietary protein can both increase and reduce the absorption of nonheme iron [iron contained within a protein]. Animal tissue (beef, pork, liver, chicken and fish) increases the absorption of this micronutrient. On the other hand, casein and whey proteins from cow's milk account for the greater proportion of the protein present in the majority of infant formulae and foods and have a negative influence on iron uptake...
Cow's milk has approximately four times more calcium than human milk, which can contribute to low iron absorption. The practical nutritional implications of the inhibitory effect of calcium on iron uptake were demonstrated by Hallberg et al. when they observed that the consumption of milk or milkshake with hamburgers or the addition of cheese to a pizza reduced nonheme iron absorption by 63, 47 and 61%, respectively. This maximum inhibitory effect is achieved with an approximate intake of 150-200 mg of calcium, which is the equivalent to that contained in one glass of milk or a piece of cheese, for which reason the authors recommend that these should not be consumed regularly at the main iron-providing meals, particularly by those who have increased iron requirements (children, adolescents and women of fertile age)."
2005 - Maria A. A. Oliveira, PhD
Mônica M. Osório, PhD
The Physicians Committee for Responsible Medicine (PCRM) wrote in its article titled "Vegetarian Diets for Children: Right from the Start," published on its website (accessed Jan. 7, 2008):
"Growing children...need iron found in a variety of beans and green, leafy vegetables. The vitamin C in vegetables and fruits enhances iron absorption, especially when eaten together with an iron-rich food...[f]ew people are aware that cow's milk is very low in iron and can induce a mild, chronic blood loss in the digestive tract, which can reduce iron and cause an increased risk of anemia."
Jan. 7, 2008 - Physicians Committee for Responsible Medicine (PCRM)
Jeffrey W. Hull, MD, FAAP, practicing pediatrician, wrote the following in his online resource "Parents' Common Sense Encyclopedia," posted on his website (accessed Jan. 8, 2008):
"Cow milk tends to irritate the human intestine. Cow milk binds iron in the intestine and carries it out in the stool, and in excessive amounts leads to iron deficiency. The milk literally sucks the iron out of the body."
Jan. 8, 2008 - Jeffrey W. Hull, MD, FAAP
The National Dairy Council, a dairy marketing and nutrition organization, wrote in its Oct. 1999 Nutrition & Health News Alert titled "Little Kids Can Benefit from Calcium, Without Concern About Iron Loss," published on its website:
"Iron and calcium are two nutrients important for young children's growth and development. Despite suggestions that too much calcium may decrease iron storage in red blood cells, a new study shows higher calcium intakes do not impact iron absorption. Researchers placed preschool children ages 3-5 on two diets: a low-calcium diet (about 500 mg) and a high-calcium diet (about 1,000 mg). The results showed no difference in iron absorption. Additionally, children who increased their calcium intakes also increased their calcium absorption, which may benefit bone growth and development. Milk, cheese and yogurt foods were the primary sources of calcium for children in the study. The authors conclude that kids can benefit from more calcium without negatively affecting their iron absorption or increasing the risk of iron deficiency anemia."
Oct. 1999 - National Dairy Council (NDC)
Judith R. Turnlund, PhD, Chemist at the Human Nutrition Research Center of the United States Department of Agriculture, wrote in a 1990 article titled "Milk's Effect on the Bioavailability of Iron from Cereal-Based Diets in Young Women by Use of In Vitro and In Vivo Methods," published in the American Journal of Clinical Nutrition:
"This study was designed to compare the effect of milk...on the bioavailability of iron in young women, a population group at risk for iron deficiency because of menstrual-blood losses...
Iron absorption averaged 8.97% with milk and 8.04% without milk... [m]ore iron was absorbed from the diets with milk than from the diets without milk for seven of the eight subjects. Only subject 23 absorbed more iron from the diet without milk. However, the difference between the two treatments was not significant...
In summary, the results of this study suggest that the addition of milk to cereal-based diets does not affect iron absorption sufficiently to improve iron nutriture, as in vitro [outside an organism] tests suggest it might. Neither does the addition of milk to cereal-based diets inhibit iron absorption."
1990 - Judith R. Turnlund, PhD
Sharla K. Ames, PhD, Researcher, and Bekey M. Gorham, RD, Research Nutritionist, both of the Children's Nutrition Research Center of the United States Department of Agriculture, and Steven A. Abrams, MD, Professor of Pediatrics at Balyor College of Medicine, wrote in their 1999 article titled "Effects of High Compared with Low Calcium Intake on Calcium Absorption and Incorporation of Iron by Red Blood Cells in Small Children," published in the American Journal of Clinical Nutrition:
"This study was designed to evaluate the relation between calcium intake and calcium absorption and iron incorporation into red blood cells...
We performed a multitracer, crossover study of the absorption of calcium and red blood cell incorporation of iron in 11 preschool children aged 3-5 y who had been adapted for 5 wk to low- (502 ± 99 mg) and high- (1180 ± 117 mg) calcium diets...
Increasing the subjects' calcium intake was done by providing menus with relatively more calcium, principally from dairy sources...
For the studies with high calcium diets, 120 mL milk was used; 60 mL milk was used in the low-calcium diets...
We suggest that small children may benefit from calcium intakes similar to those recommended for older children with no adverse effects on dietary iron utilization."
1999 - Steven A. Abrams, MD
Sharla K. Ames, PhD
Bekey Gorham, MS, RD