Breastfeeding increases the risk of newborn readmission. Now what do we do?

The Pediatric Insider

© 2019 Roy Benaroch, MD

An August 2018 paper in Academic Pediatrics found an unsettling conclusion: breast-fed newborns have about double the risk of needing to be hospitalized in their first month of life, compared to babies who were formula-fed. The numbers are solid, and they jibe with the real-life experience of many pediatricians, including me. So what should we do about it?

The study itself looked at about 150,000 healthy, normal newborns born in Northern California hospitals from 2009 to 2013. The study authors were able to collect data on how these babies were fed in the few days following birth from hospital records (dividing them into groups of all-breast, all-formula, and a mixed group that did some of both.) They were then able to track these babies over the first month of their lives to see which ones ended up hospitalized for any reason. Most of the hospitalizations were related to dehydration and jaundice, which are closely linked to inadequate feeding.

The good news is that relatively few of these babies ended up back in the hospital – whether bottle-fed, breast-fed, or both, most babies did great. But babies who were breast-fed were much more likely than formula-feeders to end up underfed and hospitalized. Among vaginal deliveries, the risk of rehospitalization was 2.1% for bottle-fed babies versus 4.3% for breast-fed babies (the risk for mixed feeders was in between.) That’s about double the risk. Mathematically, the “number needed to harm” was 45. That is, for every 45 babies exclusively breast fed, one extra baby would end up in the hospital. Not good.

Among Caesarian births, the differential was less, with an increased risk of hospitalization of 2.1% (breast) versus 1.5% (formula). Both of these numbers are lower than the risk of rehospitalization for vaginal deliveries, probably because c-section babies already spend an extra day or two in the hospital. This provides more time for good feeding to be established (whether breast, bottle, or both.)

Does this mean we should discourage breast feeding? Of course not. Most breast-fed babies do great, and there are some health advantages of breastfeeding. But we need to be honest with ourselves, and honest with moms who are trying to do the best thing for their babies. Nursing isn’t perfect. It’s not a perfect food*, and it’s not a perfect method. There are pros and cons to both nursing and formula feeding, and parents (and babies) deserve an honest appraisal.

Nursing moms also need support. That includes “technical support” (ie “How to do it”) but also emotional and medical support – which should include time for rest, and an honest evaluation of how both moms and babies are doing. There is a role for formula, both for moms who choose to use it and for situations where babies aren’t getting enough to eat. Families, pediatricians, nurses, and lactation specialists all need to work together, without guilt or finger-pointing, to help keep babies and moms healthy.

*Human breast milk is an inadequate source of vitamin D from birth, and an inadequate source of iron by 4-6 months of life.

Early solids, better sleep

The Pediatric Insider

© 2018 Roy Benaroch, MD

Current American and UK guidelines call for exclusive breastfeeding of all infants until six months. That’s not especially realistic, and relatively few parents do it, but it’s an “aspirational” sort of recommendation that’s been around a while.

Earlier solids now seem to be gaining some traction. Early peanut introduction (in a 4 to 6 month window) can help prevent peanut allergy. Though the evidence that this is true for other foods is less clear, we know earlier foods won’t make allergies more common or worse.

And now, there’s good evidence for another reason why waiting until 6 months might not be the best choice: babies who start solids earlier might just sleep better.

A British study published in July, 2018 looked at about 1300 breastfed infants from Great Britain and Wales, randomized at three months of age to either begin solids right away, or wait until about six months of age. Questionnaires were completed every one to three months, tracking their health, sleep habits, and other factors until age three. The results seem to back up some conventional wisdom many grandmas have been saying for years: feeding babies earlier than six months helps them sleep better.

Parents weren’t forced to start solids exactly at a certain age, but on average most of the babies in the early group started by 4 months, and most of the babies in the late group started between 5 and 6 months. While the differences in sleep weren’t huge, they were significant:

• Early-fed babies slept, on average, 7 minutes more per night; the peak of the difference was at 6 months of age, when early-fed babies slept over 16 minutes longer.
• Early-fed babies were less likely to wake at night, averaging 2 fewer awakenings per week.
• Later-fed babies were twice as likely to be reported to have “serious sleep problems” by their parents.

Bonus: the early-fed babies were just as likely to continue breastfeeding. Often, exclusive breastfeeding has been recommended to continue for six months; but it turns out that introducing solids early did not lead to early cessation of nursing. Moms can do both.

There’s been some concern that early introduction of solids may increase obesity risk, but the evidence for this is not conclusive, either. So: early solids seem associated with less food allergy, better sleep, no impact on breastfeeding, and (probably) no effect on obesity. It’s looking like the “wait until six months” recommendation, so widely ignored, might not be a reasonable recommendation after all.

So when should you start? Babies need to reach certain motor and cognitive milestones, so they can take a mouthful off of a spoon. The four-to-six month window seems very reasonable to me. Sit together, eat as a family, share your foods, and enjoy the mess!

More about introducing solids to babies:

What’s the exact, best age to start solids for your baby?

Introducing solids to baby: Which ones, and when?

What should a seven-month-old baby eat?

Fixing peanut allergy by eating peanuts

Want to avoid celiac? Don’t delay wheat past six months

Don’t waste your money on follow-up formulas and their ilk

The Pediatric Insider

© 2017 Roy Benaroch, MD

Leave it to marketers to find as many ways as possible for parents to waste their money.

A growing market is developing for what’s variously called “follow up formulas,” “toddler drink”, or “toddler milk.” Short version for those of you in a hurry: don’t bother buying these. You do not need to waste your money. Details below, after a (very) brief lesson on how to feed a baby.

 

How to feed a baby in the developed world, 21^st century edition

Like all mammals, our newborns depend on liquid nutrition (AKA “milk.”) Mother’s milk works great for most families; commercial infant formula is a great choice, too. Between 4-6 months, start introducing complementary foods, using whatever the family is eating, kind of mushed up into a puree. You can use commercial baby foods, too, or commercial baby cereals and things – they’re not necessary, but they’re handy and easy. As babies grow from 6 to 9 to 12 months, they should take more and more of their food from first a spoon, and then by feeding it to themselves when their motor skills are up to the task. Be prepared for mess. At 12 months, if you’re bottle feeding, switch from commercial formula to whole or 2% or skim milk; if you’re nursing, feel free to continue. Have family meals for the next 18 years or so, and later on make your kids take you out to dinner on their dime. Ha!

 

Notice: nowhere in there is any mention of “toddler milk” or “followup formula” – those products are not recommended by the American Academy of Pediatrics or the American Academy of Family Physicians. Honestly, they have no use at all for routine use in children. So what are they, where did they come from, and why are the formula companies selling them? It’s time for the details!

Traditional commercial baby formula is an option to replace breast feeding for the first 12 months of life. Babies younger than that shouldn’t be fed straight up cow’s milk (unless, of course, we’re talking about a baby cow.) Baby humans need a different blend and amount of (especially) protein, and have different nutritional needs that are best met by human milk or a commercial copy of human milk, AKA “baby formula.”

But: and here’s the key thing: by 12 months of life, baby humans can do fine with cow’s milk as part of their diet. Remember, by now they should also be eating a good variety of other foods, so they’re not depending on milk, alone, for their nutrition.

A gallon of milk costs about $3.00, less if you catch a sale at Kroger. A gallon of infant formula costs about $21.00 (that’s reconstituted from powder, using the prices I found at Walmart today.) Are you starting to figure out where the idea of “follow up formula” came from?

It’s ingenious – these products are packaged to look like baby formula. And they have clever names that imply parents should be moving to them from baby formula, using words like “transitions” or “next step.” Some are named in a way that implies they’re a special kind of milk – “toddler milk” – that’s somehow superior to ordinary milk. Hats off to the marketers – they’ve come up with a product that’s much more expensive than the alternative (milk), and that’s completely unnecessary. But it’s selling, so I guess they win.

Look, I’m glad the good people at Mead-Johnson, Ross, Gerber, and even those faceless generic companies are producing good quality baby formulas. But I’m not so glad they’re trying to extend their markets by creating the illusion that infants past 12 months need their products. Spend your money on what your children really need – a variety of foods, or books, or a slide for the backyard. Save for college, or a family vacation. But you really don’t need to keep spending money on special milk or formula past your baby’s first birthday. The formula companies already got plenty of your moolah – don’t feel bad about keeping a little more for yourself.

 

Just for fun: below is a comparison of macronutrient compositions of cow’s milk versus infant formula versus 2 kinds of followup formulas (Enfagrow, marketed for 9-18 months, and Similac Go & Grow, marketed for 12-24 months.) Compared to milk, the big nutritional difference with these followup formula is more calories, and especially more calories from carbohydrates. That is not what American children need.

 

	Kcal/8 oz	Fat, g	Protein, g	Carbs, g	cost, gallon
Whole milk	136	7	7	10	$3.00
2% milk	122	5	8	11	$3.00
skim milk	86	0	8	12	$3.00
Enfamil	168	9	3	18	$21.76
Enfagrow	160	8	4	17	$17.92
Similac	160	9	3	17	$21.40
Sim go & grow	150	8	4	16	$13.95

 

Obesity: It’s not just the sugar

The Pediatric Insider

© 2017 Roy Benaroch, MD

For a while, fat was the culprit – eating too much fat was making us fat. We were swamped by low-fat products, like cheese and salad dressings and even low-fat potato chips. Briefly, Burger King even offered low-fat French fries (Those quickly disappeared from the menu. Don’t mess with the fries.) Yet, with or without the low-fat foods, obesity rates continued to climb.

More-recently, sugar has emerged as the “deadly villain” in the obesity epidemic. Forget the fat – it’s the sugar, or the refined high fructose corn syrup, that’s messing with our metabolism and expanding waistlines. Just cut back—or eliminate—added sugar, and our weight problems will be over.

But a recent study from Australia shows that maybe it’s not so simple as blaming the sugar, either. Researchers there found that, on a population level, reduced sugar consumption was associated with an increasing rate of obesity. It’s funny how real-world data seems to clash with our little pet theories sometimes.

The authors used data about food consumption from several different academic and government sources, creating graphs of overall per capita sugar consumption among Australian adults and children from 1980 and 2011. Although the exact numbers vary by demographic groups, there was a clear overall trend towards less sugar intake over those years. They then looked at obesity rates, based on national surveys.

The combined data is in the graph below. Sugar consumption is in blue, and though it goes up and down some years, the overall trend is downwards. In red you can see the Australian obesity rates. There’s more data in the paper about specific groups (men versus women, children versus adults), but overall the trend is clear: less sugar consumption is associated with more obesity.

The authors conclude, “There may be unintended consequences of a singular focus on refined sugars…”

So if it’s not the sugars, and it’s not the fat, what is it? I think it’s unlikely that there is a single boogeyman, or a “one thing” we can point our fingers at as the culprit. Obesity has many contributors, including decreasing physical activity, eating bigger portions, and eating more frequently. Low-quality “fast food” is quick and convenient, but it’s certainly not cheap in the long run. A ton of extra sugar can’t be good for your teeth, and is one source of extra calories you don’t need. But it’s not just the sugar that we’re eating too much.

What’s the exact, best age to start solids for your baby?

The Pediatric Insider

© 2017 Roy Benaroch, MD

A commenter objected to advice I’ve given about when to start complementary foods in infancy:

Why, when the WHO, UNICEF, and the AAP all recommend exclusive breastfeeding until 6 months of age, do you still have the introduction of solid foods at 4 months. It’s confusing for women who want to do the right thing for their child to come across your articles on starting solids at this age. Study after study show the benefits for both mother and child of exclusive breastfeeding until 6 months.

I wouldn’t rely on WHO and UNICEF recommendations. I’m not so sure that what they say is entirely relevant to babies in the developed world. I’m going to focus here on the AAP recommendations, which reflect the needs of babies in the USA and other highly developed countries.

Current AAP recommendations are deliberately vague about the precise timing of introducing solids. They say that complementary foods shouldn’t be introduced “until 4 to 6 months” – see the phrasing in this abstract and under point 2 of this article. Since AAP recommendations automatically expire 5 years after they’re published, there isn’t a valid AAP published statement on this exact issue right now. These two citations reflect the most-recent recommendation: solids can be introduced during a window of time, from 4 to 6 months.

Why then? Earlier solids are associated with obesity and nutritional problems; later solids are associated with feeding issues, iron deficiency, and an increased risk of allergy. The 4 to 6 month window maximizes nutrition while minimizing allergy risk, and works well for most babies.

But it is a window, not an exact time. We don’t have any research that says 4 months is perfect, or 5 months is perfect, or 6 months is perfect. I know of no studies from a developed country that show an important health advantage of starting to feed at six months rather than four, or starting at four months instead of six.  Probably all of these times are fine. The absolute best time depends on a baby’s development and temperament (as well as the family’s style and feeding preferences.) There’s no perfect, one-size-fits-all answer here.

When I talk about this with families, I try to figure out what the baby thinks about all of this. A 4-month-old baby who’s watching his siblings eat intently, or lunging at their food, or becoming disinterested in the breast or bottle – that’s probably a baby that’s ready to be fed solid foods. Babies of the same age who aren’t so interested in food, those babies can wait another month or so. And if solids aren’t going well at first, it’s fine to stop and wait a few weeks before trying again. We can make all of the plans we want, as parents and pediatricians – but the bottom line is that this is one of many decisions that babies help make on their own. Good for them!

Previous:

When to start solid foods, and what to start with

Want to avoid celiac? Don’t delay wheat past six months

Whole milk best for children? Not so fast

The Pediatric Insider

© 2016 Roy Benaroch, MD

A flurry of recent reports has supported the health benefits of whole-fat milk. Increased dairy fat has been linked to lower rates of diabetes, and to improved cardiovascular health. The traditional advice – that low-fat or skim milk can help reduce weight, and help improve health – may have been based on faulty assumptions about the way ingested dairy fat affects metabolism. These new studies of dairy fit in with a shift away from the “fat is bad” story to a more nuanced “some fat is bad, but other fat is good, and it’s complicated” way of looking at things.

But it’s important to remember that none of the studies driving this change were done in kids. We don’t really know the long-term health impact of full- versus low- versus no-fat milk in infants or children, and there are still some good reasons to think that lower fat dairy might be a good choice for many families.

Until about ten years ago, the AAP recommended full-fat milk starting at age 1. That changed in 2008, when a position statement about cardiovascular health supported the use of reduced-fat dairy products starting at 12 months of age if there were any concerns about overweight or a family history of obesity or heart disease (that would include just about everyone.) This recommendation was based on research showing three things: (1) growth and neurologic function was the same in children raised on low-fat milk (ie, extra fat was not needed for brain and body development); (2) lipid profiles and weights were healthier in children raised on low-fat milk; and (3) children who consumed low-fat milk tended to have healthier diets, overall, than kids drinking whole milk.

That position statement “expired”, as all AAP statements do, 5 years after it was published. Currently, the AAP officially has no position on the relative merits of these varieties of milk. (They do have a position vaguely endorsing chocolate milk in schools, and another position strongly discouraging unpasteurized milk. All AAP policies can be searched here. There are a lot of them.)

The bottom line, now: there really isn’t any solid, new information from studies in children since that 2008 AAP position. Though I agree that the adult studies are compelling, adults and children are very different, especially when looking at metabolism, growth, and the long-term health consequences of dietary choices. For example, milk constitutes a much higher proportion of caloric intake in kids than in adults (children drink more milk, and they’re smaller. Usually.) They need proportionally more calcium and vitamin D and phosphorus for growing bones. And we know overweight children are very likely to continue to struggle to maintain a healthy weight as adults.

The best current evidence in children supports the use of reduced fat milk. If that changes, I’ll let you know.

 

Can having a sibling help protect against overweight?

The Pediatric Insider

© 2016 Roy Benaroch, MD

An interesting new study published in the April, 2016 edition of Pediatrics shows that the birth of a younger sibling is associated with a dramatic decrease in the risk of obesity. I don’t think this ought to sway people towards having more children, but it might offer some insight into other ways to help children keep a healthy weight.

The study recruited families from 1991-1998 (yes, it’s old data. I’m not sure why it took so long to get this written and published.) About 700 children ended up participating. Through in-person visits and phone interviews, the study children were followed from birth through about first grade, tracking who ended up having younger siblings born. The authors then compared children who had younger siblings versus those who remained the only child in the household.

The numbers look strong. Having a younger sibling born between ages 2 to 4 (and especially between 2 to 3 years of age) led to a robust decrease in the upwards trajectory of a child’s BMI. In fact, children who didn’t have a younger child born while they were in preschool had three times the risk of obesity.

Crazy, huh? Three times the risk? Statistically speaking, that’s a big change. This study was unable to show why the birth of a younger sibling helped children keep a more-healthy weight. The authors suggest two possible mechanisms, or ways that having a younger sibling could be protective. Perhaps it changes the way parents feed their children. Other research has shown that ‘restrictive’ feeding practices, like limiting portions or different kinds of foods, are associated with an increased risk of obesity – and maybe having a younger child to look after leaves parents unable to monitor feedings as closely. Allowing young children more control over their food choices does lead to healthier eating and healthier weight gain.

Another idea: children who get younger siblings may themselves become more active, by playing with their little brothers and sisters. They might also become “food leaders”, trying to show their siblings how to eat healthy.

There may be other mechanisms at work here. I’m certainly not convinced I know why the study worked out this way. I do know that healthy weights aren’t about counting calories, only eating “healthy foods”, or buying organic. Hopefully further insights along these lines of this study can help with counseling even single-child families about mealtime and lifestyle routines that can best keep families healthy.

Extra iron can help infant motor development

The Pediatric Insider

© 2016 Roy Benaroch, MD

A randomized, controlled study from China might be able to teach us something about infant nutrition in the US: iron isn’t just to prevent anemia. It’s essential for motor development, too. And breastfed babies, especially, might not be getting enough.

It’s a clever study. They started with a group of women, who had already been randomized to get either extra iron or a placebo during their pregnancies. After their babies were born, the infants were randomized again to get either an iron supplement or placebo from age 6 weeks to 9 months. So there were really 4 groups, in the end, sorted by whether they had iron during pregnancy/infancy: placebo/placebo, iron/placebo, placebo/iron, and iron/iron. That design was chosen to figure out just when iron supplementation made a difference to infant motor development. The authors postulated that the more iron, taken for longer, the better. They were wrong, but that doesn’t mean we can’t learn from their missed guess.

The babies then had multiple tests of motor development performed. There were about 300 babies in each of the four groups, and the results were consistent among various ways of measuring the babies’ motor skills. Bottom line: iron supplementation during infancy improved motor skills by a considerable margin; iron supplementation during pregnancy didn’t make much difference.

The amount of iron given was smaller than what we’d typically give using a common infant multivitamin with iron in the United States. There were no adverse effects from the iron, which is expected. It is a myth that the ordinary doses of iron given to babies in formula or as a supplement causes constipation or any other problems. I think moms believe that myth because they get constipated during pregnancy, when they’re on higher doses of iron (typically 300 or 325 mg a day), but those doses are way way higher than what babies get (less than 10 mg a day.)

Another important caveat: the study was done in a poor area of rural China, in the Hebei province. Most of the babies, including the once who received iron supplementation, were still iron deficient on their blood tests; 80% of them were breastfeeding at 9 months. So the population isn’t really the same as what we’d see in the developed world. Still, when a safe, cheap, and easy intervention makes a big difference, that’s something to notice.

With this study in mind, should all babies just get a little extra iron? Formula-fed babies probably don’t need an extra supplement, unless they were premature or have other health issues that put them at risk for insufficient iron. But breastfed babies – they almost certainly need extra iron, especially by 4-6 months of age when their storage iron from birth starts to run down. Some complementary foods offer good iron, like fortified cereals, meats, and eggs, but some four month old infants don’t seem quite ready for those kinds of meals yet (many do, though—give it a try!) There’s also some evidence that you can prevent iron deficiency in infants by delaying clamping of the umbilical cord for a few minutes after birth. Will that help improve motor development, as seen with the supplements used in this study? Maybe.

There are really no important down sides to giving an iron supplement to infants. In fact, the only one I can think of is that they might stain teeth, so rinse the mouth or wipe teeth afterwards. A typical dose is one dropper of an iron-containing infant vitamin once a day, but check with your doctor for the best dose for your baby. And remember, with those improved motor skills, Junior might be able to get the cap off herself. So keep iron, vitamins, and all other meds well away from the reach of children.

Many medications are safe for nursing moms

The Pediatric Insider

© 2016 Roy Benaroch, MD

An exhaustive new review should provide reassurance for nursing moms: many medications are safe for you to take, and genuinely serious reactions are very rare. Moreover, most serious reactions that do occur are to just a handful of medications. Common sense can be a good guide to keeping nursing babies safe when their moms take medication.

In this study, from February 2016, the authors did a truly comprehensive search of the literature for all studies and case reports of problems caused by medications in breast milk. The same authors had done a similar study in 2002, and decided it was time for an update.

Some of the findings:

• About 60% of reported reactions occurred during the first month of life; and 80% during the first two months. This makes sense—the youngest babies consume the most milk per weight, and also have the least ability to metabolize medications.
• 70% of adverse reactions were to medications that affect the brain, including narcotic pain medicines, antidepressants, and antipsychotic medications.
• All of the deaths reported (there were only 2) involved one or more narcotic pain medications.
• The use of multiple nervous system depressants at the same time increased the risk of serious reactions.

The bottom line: be careful especially with the youngest babies, especially when using multiple medicines, and especially when using medicines like narcotics that are known to cause slow and shallow breathing. That doesn’t mean nursing moms can’t take these medicine, but it does mean that they ought to take advantage of non-narcotic pain medicines, first, and if they do take narcotics their babies need to be monitored closely. A “pump and dump” strategy can be employed if mom needs potent pain medicines for a short time. It is not reasonable to expect nursing moms to live with untreated pain.

A great resource for nursing moms and the doctors who give them advice is the Lactmed database from the National Institutes of Health. You can look up just about any medication there, and see what studies are available to give you real and reliable information on milk transfer and potential issues with nursing babies. Some of the information is quite technical, but it’s better than the vague handwaving found in other places.

Speaking of which: one of the worst places to look for safety info for breastfeeding moms are the official “product inserts” of medications. They pretty much always say that nursing moms can never take any medicine (I don’t think they’re allowed to eat any food, either. Just water and rocks. Safety first!) Remember: product inserts are written by lawyers, for lawyers. They’re there to fulfill the crazy byzantine regulatory framework of the FDA. And to ward off lawsuits, and possibly vampires too. They’re not there to give parents or doctors useful information.

The health of moms is important, too. Often, moms stop taking their own medications out of fear that it may harm their nursing baby. Reviews like this, looking at what’s actually published and documented, provide some useful reassurance for moms and babies alike.

Can more vitamin D improve the health of nursing moms and babies?

The Pediatric Insider

© 2016 Roy Benaroch, MD

“Breast is best” is a simple, catchy phrase—but to be honest, it’s one that should be followed by a bunch of asterisks and qualifiers. Some mother-baby pairs have a hard time with nursing, and need support and understanding (rather than a simple dismissal of their concerns.) And breast milk, we know, isn’t a great source of absorbable iron, which is especially an issue for premature babies. But the biggest drawback of human breastmilk, compared with commercial formula, is that it is an inadequate source of vitamin D.

A new study shows that this doesn’t have to be the case. Perhaps insufficient vitamin D isn’t really a fundamental problem with breast milk, but a problem with mom’s vitamin D intake.

Backing up a second – we’ve known for a long time that breast-fed babies are much more at-risk for nutritional rickets than formula-fed babies. This is especially true for families with dark skin. Rickets is caused by insufficient vitamin D, and can lead to poor growth, bowed limbs, and other health problems. For most of human history our vitamin D came from sunlight exposure. The skin of babies and mothers can manufacture vitamin D, though it requires sunlight to do it. Darker skin is less efficient at making vitamin D than lighter skin.

To combat the risk of insufficient vitamin D in breast-fed babies, the AAP has recommended a daily vitamin D supplement, starting from birth. In practice, this recommendation is followed maybe 20% of the time. Parents don’t like to give their newborns medicine, and I think pediatricians are reluctant to focus on the possible inadequacies of human breast milk.

In the current study, researchers sought to determine if giving higher doses of vitamin D to nursing moms could result in enough vitamin transfer in their milk. 334 mother-infant pairs were recruited, and randomized into three groups. In group one, moms were given an ordinary vitamin supplement, and their babies a vitamin D supplement (400 IU/day, matching the current recommendation.) In group 2, the babies were given no extra D, but moms took 2400 IU/day; in group three, moms were given 6400 IU each day. Babies and moms underwent regular blood and urine tests to see if these doses resulted in good vitamin D levels in the babies, and to see if these doses caused any metabolic problems with vitamin D, phosphorus, or calcium metabolism.

There was a relatively high drop-out rate—of the original 334 pairs, just 148 stuck with the plan for exclusive breastfeeding, and were thus able to complete the trial (families who discontinued breastfeeding or added formula supplements were not included in the final analysis.)

All of the babies who received regular supplementation had robust vitamin D levels and normal biochemical testing – we know, if that 400 IU a day for babies is given, it works. That was group 1. Group 2, where moms were given vitamin D 2400 IU/day,  was a failure—they actually stopped this arm of the study early, because many of the babies in this group did not have adequate vitamin D levels on their blood tests. But the babies in group 3 – who themselves received no direct vitamin D supplements, but whose moms got 6400 IU/day—did as well as group 1, with perfectly good vitamin D levels and no evidence for any side effects or problems. And, bonus, their moms also benefitted, with normal vitamin D levels and no side effects.

A reasonable question, though—is 6400 IU of D a day safe for moms to take? A prior guideline from the Institute of Medicine had suggested an upper limit of 2000 IU/day (though that has since been increased to 4000); the Endocrine Society now sets their upper limit at 10,000. During the past decade many studies have used adult D supplementation in the range of thousands of units per day, and according to the authors of this paper not a single adverse event was observed.

This study supports a safe alternative for families, and perhaps one that’s easier to do. Moms are used to taking prenatal vitamins, and continuing to take them while nursing. Adding 6,000 IU of D to the typical 400 in a prenatal isn’t expensive, and seems to be safe and effective at making sure their babies get enough D. Breast milk can have enough D – but only if mom gets her own supplement.