Maternal Zinc for Baby Health

According to the U.S. Centers for Disease Control and Prevention (CDC), the month of August has the highest number of births making a recent study all the more relevant. Researchers from George Washington University's School of Public Health and Health Services in Washington, D.C., found that zinc supplementation in pregnant women may contribute to the health of their children.

Previous research has revealed little about how maternal zinc intake influences the growth of babies both in the womb and after birth. Zinc is necessary for the functioning of more than 300 different enzymes and plays a vital role in an enormous number of biological processes.

The study assessed the effect of maternal zinc supplementation during pregnancy on infant growth through one year of age.

The trial of prenatal zinc supplementation was conducted from 1995 to 1997 in Lima, Peru among 1,295 at 15.6 +/- 4.6 weeks gestation. The women were assigned to receive daily supplements with zinc (15 milligrams of zinc + 60 milligrams of iron + 250 micrograms of folic acid) or without zinc (60 milligrams of iron + 250 micrograms of folic acid) through pregnancy to one month after delivery.

At birth, 546 infants were followed for 12 months to assess growth. Measures of body size and composition were collected monthly, and morbidity and dietary intake surveillance was carried out weekly.

The study found that infants born to mothers prenatally supplemented with zinc had significantly larger average growth measures beginning in month four and continuing through month 12. Prenatal zinc was associated with greater weight, calf circumference, chest circumference and calf muscle area.

The authors concluded that maternal zinc supplementation in this population was associated with offspring growth, which is suggestive of lean tissue mass accretion.

Comments

[Chris]

There is a recent study by Christian, Darmstadt, Wu, et al. that gave pregnant Nepalese women daily supplements of either vitamin A with folic acid, folic acid plus iron, folic acid plus iron plus zinc or a multiple supplement containing these and 11 other nutrients. Interestingly - symptoms of birth asphyxia increased by about 60% (p<0.05) in infants of women who received the multiple micronutrient supplement compared with the control (vitamin A). This study didn't support the idea that supplementation would improve symptoms of neonatal morbidity in the first 10 days of life or at six weeks of age. Although it doesn't speak to the effects of zinc on growth, the asphyxia observed in this study should not be overlooked. For more information about zinc in particular, there is also a nice review by Cole and Lifshitz (2008) that speaks of zinc and growth retardation.

[kotakeripik]

Very informative article!

http://maternal.bestwomancare.com/

[bom]

I wonder how long this effect will last. Five years, 10 years or throughout lifetime? It would be great if it lasts throughout a person's lifetime. Too bad this study was not done in my parents’ time or else they would have known to supplement themselves with zinc, and I would have not been this short.

[Ashley]

The Departments of Nutrition and Epidemiology, Harvard School of Public Health and Muhimbili University College of Health Sciences conducted a trial to evaluate zinc supplementation in relation to pregnancy outcomes, T-cell counts, and hematologic indicators among 400 HIV-1 infected pregnant women in Tanzania. The study revealed no noteworthy discrepancies in birth weight, duration of gestation, or fetal and neonatal mortality between women in the zinc and placebo groups. Due to a lack of compelling evidence concerning zinc supplementation, the authors concluded that the evidence did not support the addition of zinc to prenatal supplements in pregnant HIV-infected women.

[TTND]

I thought every pregnant woman has to take some kind vitamin that contains zinc, iron, folic acid, and others. The amount depends on each individual. What is the dose range for zinc supplements in pregnant women?

[SpecialK]

It’s fairly well known that zinc deficiency in pregnant women results in slower fetal growth, so it stands to reason that zinc supplementation could improve it. The RDAs for zinc in pregnant and lactating women are higher than those for other adults. Re: the study in Nepalese women, without knowing more details it’s hard to compare findings in these women with those in the Peruvian women. It would be interesting to learn more about whether it was the zinc in the multi-supplement or another nutrient that caused the asphyxiation problem, or whether it was something else in the environment.

[Emma]

I agree with TTND. Vitamin that contains zinc, iron, folic acid and others is really very essential for pregnant woman.

[Ann]

Zinc is very important for the human body. Too little zinc can lead to slow growth and a damaged immune system. Too much zinc can also have harmful effects, such as reduced levels of good cholesterol. If we can go back to many generations ago, many pregnant women didn't take multivitamins with extra zinc, and those babies were born healthy. I think your daily diet plays a very important role for both the Mom and baby.

[ley]

A study conducted by UK doctors suggests that zinc supplementation during pregnancy could actually impair the development of the child. Although it is recommended that undernourished women residing in developing countries supplement with extra zinc to enhance birth weight and immune function of the baby, doctors from the Institute of Child Health in London have questioned this advise after hearing results from a study by Professor Sally Grantham McGregor who assessed the mental development of 168 infants in Bangladesh. In this study, the pregnant mothers were divided into two groups (the first group received 30mg of zinc every day during pregnancy, and the second group received a placebo). After the study was concluded, the doctors noted that the infants born to the pregnant mothers of the second group had higher scores for mental/psychomotor development, or the ability to control movement. Mary Nolan of the National Childbirth Trust stated, “few women in western countries need extra zinc during pregnancy… if women are eating a well-balanced diet, which in terms of zinc, includes wholemeal bread and cereals, then they really have nothing to worry about. They will be getting what their body needs.”

[lauren]

In regard to TTND’s comment, zinc is essential for pregnancy because it is required for proper cell division in our bodies. Low zinc levels have been associated with low-birth weight, premature birth, growth retardation and preeclampsia. However, too much zinc can also lead to depressed absorption of other minerals such as copper. It is recommended that people do not exceed 15mg of zinc a day.

[Lilly]

The recommended dose of zinc for pregnant women is 11mg per day. This need for zinc is 38 percent higher than that of a non-pregnant woman. All pregnant women should be taking prenatal multivitamins already. Many women even end up going to the doctor to get a prescription for behind-the-counter prenatal vitamins. Most, if not all, prenatal vitamins exceed the 11mg of zinc needed per day in each tablet. Even over-the-counter products, such as Stuart Prenatal, and store-brand generics that do not require a prescription exceed the recommended 11mg. If a woman is already following the doctor’s orders by taking a prenatal multivitamin, there is no need to further supplement with more zinc on top of her daily prenatal vitamin, since the daily requirement for zinc for a pregnant woman is already met by her prenatal vitamin.

[Josh]

Women are advised to take plenty of folate during pre-pregnancy and early pregnancy; however, high-dose supplements of folate can block intestinal absorption of zinc, creating a potentially dangerous deficiency. Limiting folate intake to not more than 800mg can help avoid this problem. Because of this potential interference, it may be fine to take extra zinc.

[Lois]

Like Josh explained earlier, folate (folic acid) is highly recommended to be taken by pregnant women. Folic acid is taken at higher doses during early pregnancy to prevent a certain birth defect called spina bifida. The spinal cord’s development occurs within the first 28 days of pregnancy. During these 28 days, a lack in folic acid intake can result in spina bifida, the lack of closure of the vertebrae and the exposure of the spinal cord. Therefore, folic acid supplementation (up to 1 milligram per day) has been recommended by doctors for pregnant women.

[Tara]

What about zinc lozenges for the common cold? Are they safe for the baby if mothers have a few while expecting? Normally, when you suck on zinc lozenges, you experience the action of a little extra zinc enhancing the immune system, therefore, decreasing the incidence of colds. Too much zinc (over time) will suppress immunity. Prenatal supplements already provide the daily requirement for zinc. Problems associated with too much zinc come from continued ingestion of excessive doses. A few zinc lozenges here and there should not be a problem since they are not being taken on a daily basis.

[naomi]

Unlike folic acid, I find that zinc supplementation is often under-emphasized during pregnancy. Many women of childbearing age may have mild-to-moderate zinc deficiency. Zinc deficiency can cause preterm birth and can affect infant growth. The daily requirement for zinc during pregnancy is 15mg, but a higher dose might be needed because folic acid can interfere with zinc absorption. So folate intake should be limited to 800mg.

[Alice A.]

It seems that 12 months is a relatively short time to determine the ongoing results of zinc supplements on pregnant women. I am also wondering if children are still given child doses of vitamins/minerals? If so, is zinc included? I remember growing up and being told that if you had little white spots under your finger nails, that you were experiencing a zinc deficiency. I don’t know if that is true, but I did, at one time, have a couple of those spots and was never given zinc. The spots subsequently disappeared.

[Choc]

Zinc deficiency is a problem worldwide, especially in developing countries where diets are based on cereals, vegetables and legumes that have low or moderate levels of zinc. A short-term study showed a difference in femur length of fetuses in women who received zinc supplementation; however, it is unknown if these effects continued through childhood. However, the study was conducted in Peru, where the dietary intake is about 8mg/day; significantly lower than the daily recommended amount of 16 mg/day. Should children be receiving supplements with zinc?

[Ree]

I’m not sure how much zinc is contained in the multivitamins that we give our children like Flintstones. My concern is that we might not consider the total amount consumed. There is zinc in some of the meats, nuts and whole grain foods we eat, particularly in the fortified cereals we give our children. We probably want to avoid the problems of giving too much zinc like Tara suggested. Are we getting all the zinc we need through normal eating habits?

[Samantha]

Does anyone know what type of foods contain high levels of zinc? Also, I know it is important for expectant moms to take vitamins and such for nutrients for the baby, but I am beginning to think that taking too much of too many different supplements could be a bad thing. Some of the comments point out detrimental effects like decreased rates of development and the asphyxia found in the study mentioned by Chris. How does one find a good balance?

[Jerry]

I think this study should have also monitored the cognitive development of the babies along with their growth. The study Ley mentions makes me wonder that while the babies appear to be healthier than the ones who didn't receive the zinc, maybe other aspects of their growth and development were negatively affected.

[Judy J.]

There is a 2007 study that indicates that zinc is a woman’s ally when she’s not pregnant, too. A researcher in Texas found that zinc in certain doses seems to help prevent pre-menstrual symptoms and cramps during menstruation, though he notes that the current U.S. recommended daily allowances (RDAs) don’t allow enough intake to gain this affect. I hope more can be done in this area to provide relief for women who experience debilitating cramps every month. Maybe there are other non-medicinal ways to handle this now?

[kay kelley]

Although the infants grew in calf and chest circumference, and had increased body weight, there is no mention of the comparative overall health of the babies.

[Lucy]

I am not surprised by the findings of this study since the literature states that zinc improves fetal growth. However, it’s also important to be aware of the harmful effects of too much zinc and the interaction with folate. Judy, I had no idea that zinc can be used for menstrual cramps too, thanks for sharing!!