Zinc deficiencies and breastfeeding
Last week Bryan posted the following:
Also, I have read a few article [sic] that state some essential minerals can not be passed through the breast. They suggest supplements for both mom and baby. Zinc is the big one I have found. Now, why don’t the “Breast is best” sites ever mention the need to supplement?
Maternal zinc deficiency can slow fetal growth (7). Zinc supplementation has improved growth rate in some children who demonstrate mild to moderate growth failure and who also have a zinc deficiency (22). Human milk does not provide recommended amounts of zinc for older infants between the ages of 7 months and 12 months, so breast-fed infants of this age should also consume age-appropriate foods containing zinc or be given formula containing zinc (2). Alternately, pediatricians may recommend supplemental zinc in this situation. Breastfeeding also may deplete maternal zinc stores because of the greater need for zinc during lactation (23). It is important for mothers who breast-feed to include good sources of zinc in their daily diet and for pregnant women to follow their doctor’s advice about taking vitamin and mineral supplements.
I wonder what else they are hiding…
While the information in Bryan’s post is correct, what he’s taken from it doesn’t seem to be. Based on his statement that the “breast is best” people are hiding things, it seems he believes breastfed babies are often deprived of zinc. This just isn’t true. Though it’s true that maternal zinc deficiency can be a problem, zinc deficiencies are extremely rare. There’s usually no need for additional supplementation after solids are started.
Most breastfed babies begin eating solid foods after six to eight months of age. Some breastfed babies begin solid foods sooner. The website he quotes states that human milk doesn’t provide the recommended amounts of zinc for older infants between the ages of 7 months and 12 months so breast-fed infants of this age should also consume age-appropriate foods…
In other words, breast milk provides enough zinc for up to 7 months of age. Kellymom, the breastfeeding authority on the web states that
Healthy full-term breastfed babies do not need additional zinc past what they get from breastmilk and (after 6-8 months) from complementary foods. Good sources of zinc include meat (especially red meat) and yogurt. Signs of a mild zinc deficiency include: lessened appetite, lowered immune function, limited activity, growth faltering. Low birth weight, small for gestational age and premature infants are at risk for zinc deficiency.
It doesn’t appear from either source that the majority of infants are suffering from a lack of zinc so I’m not entirely sure what he thinks the breastfeeding community is hiding. Doctors recommend that nursing mothers continue to take a prenatal vitamin for additional supplementation. But according the research on Kellymom:
If you eat a reasonably-well balanced diet, vitamin supplements are not considered necessary for breastfeeding mothers.
Except in special circumstances, women in developed countries are not likely to have nutritional deficiencies that will affect their milk.
The Recommended Intakes (RI) for nutrients have a wide safety margin built in – if you do not meet the RI for a nutrient, it does not mean that you are deficient. If a mother does not get adequate amounts of certain nutrients (such as vitamin B6, vitamin B12 or iodine) it can decrease nutrient levels in her milk, however this is usually only a problem in areas of malnutrition. The best solution in such cases is to improve or supplement the mother’s diet. For other nutrients (including folic acid, iron, calcium, copper, magnesium, zinc) milk levels will be fine even if the mother’s intake is too low.
* The nutrients most likely to be of concern for a woman eating an average (unsupplemented) American diet of 2700 calories per day are calcium and zinc. However, your intake of calcium or zinc does not affect breastmilk levels of these minerals, so if supplements are needed, they are for your benefit — not baby’s.
(Hamosh, 1991; Lawrence & Lawrence, 2005)
* For mothers who are cutting calories:
Mothers who get 2200 calories per day may need extra calcium, zinc, magnesium, thiamin (vitamin B1), vitamin B-6 & vitamin E.
Mothers who get 1800 calories per day may need extra calcium, zinc, magnesium, thiamin, vitamin B6, vitamin E, folic acid, riboflavin (vitamin B2), phosphorus and iron.
Breastmilk levels of calcium, magnesium, phosphorus, zinc, iron and folic acid are fine even if your diet is deficient. If supplements are needed, they are for your benefit — not baby’s.
Levels of B vitamins in breastmilk are related to the mother’s intake, but a deficiency in the mother serious enough to affect her breastfed baby is very rare in the United States.
(Hamosh, 1991; Lawrence & Lawrence, 2005)
* Mothers who eat no animal products or are otherwise at risk for vitamin B-12 deficiency need to get adequate amounts of vitamin B12 from supplements or fortified foods.
* Mothers who have little exposure to sunlight need to get adequate amounts of vitamin D from supplements or vitamin D-rich foods.
* Mothers who smoke cigarettes may benefit from additional iodine.
So if your diet is reasonably healthy and you have no known vitamin or mineral deficiencies, rest easy. Your breastfed baby should be fine.
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January 22nd, 2008 at 1:38 am
This hit the nail on the head. When I brought this subject up to my LC last week, she shook her head and said that zinc deficiencies are rare. In all of her years of experience, she had never had a patient with zinc deficiencies.