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The Effect of Maternal Nutrient Status on the Composition of Human Milk

Updated: Oct 4, 2020

Research Paper by Ifunanya Onyima, MS, RD

Breastfeeding is becoming more and more common in the United States as researchers continue to study the benefit of feeding an infant by-breast instead of formula-feeding by a bottle. According to the CDC'S most current Breastfeeding Report Card, about 81% of women in the U.S. who have ever been pregnant had tried breastfeeding at least once during the newborns infancy.3 Many positive health outcomes are associated with infants who were breastfed, including regulated insulin secretion and GIP stimulation1, decreased risk of future obesity for the infant2,4, and transfer of specialized immune factors from the mother to the baby. The composition of breast milk is a strong contributing factor to its association with positive health benefits. Besides the immune factors that are crucial the health of the infants immune system, breast milk also contains many essential vitamins and minerals, fatty acids, and proteins. Feeding an infant by breast is also very cost-effective - the mother naturally creates the milk, so there is a lesser need to seek an outside source for nourishing an infant. This paper explores the unique composition of breast milk and its role in promoting positive health outcomes for the infants that drink it.

The two research studies discussed within this paper focus on the composition of breast milk and the many nutrients it delivers to a baby. The studies also focus on the mother and how the mother's current physical state affects (or doesn’t affect) the composition of their milk.

“Even after prolonged fasting and significant lack on intake, that breast milk composition still manages to stay consistant”

The affects of maternal nutrient status on the concentrations of iron, zinc and copper were observed in the 2004 study published to The American Journal of Clinical Nutrition.5 The researchers were aiming better understand the mechanism by which minerals cross through the mammary glands. Samples of breast milk from 191 Honduran and Swedish mothers were collected nine months after the pregnancy had occurred. The concentrations of the minerals were measured with atomic absorption spectrometry. Iron, copper and zinc were measured within the mothers via blood tests. This study concluded that none of the measured minerals were significantly correlated with their concentrations in the mother’s blood plasma. The results of this study suggest that there may be a mechanism that requires active transport to move minerals against their concentration gradient (low to high concentration) in order to get the optimum amount of the mineral into the milk supply and into the baby.

I believe that this study was well done, besides the small sample size. I appreciated how the researchers gathered mothers from two different geographical areas, as opposed to only one ethnic group to study. The method of gathering the data was used with reliable tests and materials – the researchers did not have to depend on subjective information for data.

The second article looked at how the composition of breast milk was affected by women who were fasting during Ramadan.6 The researchers were interested in how the nutritional status of a mother affected her breast milk. 26 lactating women from the United Arab Emirates were recruited for this study. Total fat, lactose, non-fat and total solids, triglycerides and cholesterol content in the women’s breast milk were measured, once between the second and fourth week of Ramadan, and again two weeks after the last day of Ramadan. The result of the study was no significant change in any of the

measured substances in the mother’s breast milk during or after the Ramadan holiday. This study suggest that, even after prolonged fasting and significant lack on intake, that breast milk composition still manages to stay consistant.

Similar to the previous study, the data in the second one was collected and obtain via very accurate measures with scientific equipment, not using subjective information. This sample size was small, which could of resulted in skewed data. Both studies suggest that maternal breast- milk content does not change significantly based on the mother’s nutrient status.

Breast milk is a very unique substance that supports the growth of newborns during their first months of life. The studies discussed in this paper she evidence supporting the idea that the mother’s nutrient status during any period of lactation will have little or no impact on the nutrient content of her breast milk, possibly ensuring that her breast milk will always be adequate for her baby during it’s first months of growth.


1 - Lucas A et. Al. (March 7, 1981). Metabolic and Endocrine Responses to a Milk Feed in Six-Day-Old Term Infants: Differences Between Breast and Cow’s Milk Formula Feeding. US National Library of Medicine. National Institute of Health. 70(2). Retrieved from

2 - Kramer, M. Do Breast-Feeding and Delayed Introduction of Solid Foods Protect Against Subsequent Obesity? Elsevier. 98(6). Retrieved from

3 - Breastfeeding Report Cards. (2017, April, 10). Retrieved from

4 - Singhal A., Lanigan J. Breastfeeding, Early And Later Obesity. Wiley Online Library. 8(s1). Retrieved from

5 - Domellof, M et al. Iron, Zinc and Copper Concentrations in Breast Milk are Independent of Maternal Mineral Status. American Society of Cinical Nutrition. 79(1). Retrieved from

6 - Galadan S et a. Fasting During the Holy Month of Ramadan Does Not Change the Composition on Breast Milk. Elsevier. 21(6). Retrieved from

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