Breastfed Children at Risk of RICKETS

Or so the Daily Express told me today.  And if the Daily Express says it in capitals, it must be true right?

Yawn.

Even before opening the study I'm wondering how such dodgy reporting makes it past any editor with a modicum of self respect.

Breastfed children aren't at risk of rickets because they're breastfed; breastmilk doesn't magically sap their vitamin D stores leaving them depleted and deficient.

The Express article goes on to say:

"According to the UK Department of Health, all infants and young children aged six months to five years should take a daily supplement containing vitamin D in the form of vitamin drops, to help them meet the requirement set for this age group of 7-8.5 micrograms of vitamin D per day. 

However, those infants who are fed infant formula will not need vitamin drops until they are receiving less than 500ml of infant formula a day, as these products are fortified with vitamin D."

This means when formula fed infants are taking less than 500ml of vitamin D fortified formula, they too are at risk of rickets without supplementation.

UNICEF state to give formula to a year - meaning this is really valid for all mums who have infants older than 12 months not drinking formula.

According to the royal college of paediatrics and child health:

Rickets was common in Victorian times and was eradicated by the use of cod-liver oil and fortifying food with Vitamin D. It is the commonest childhood complication of vitamin D deficiency (VDD) and is caused by a lack of dietary calcium or problems with the supply, metabolism or utilisation of vitamin D. There are many possible reasons for this - lack of good quality sunlight in the UK, not exposing ourselves to sunlight (covering up with clothing, sun creams, staying indoors, and immobility).

So rickets can actually be caused by either lack of dietary calcium or vitamin D deficiency.  Most people take it as given we get enough calcium, others aren't so convinced.

Anyway the study in question was exploring infants 1-5 years, with the mean age being 24.5 months.

It's a group of "urban Canadian children" that were studied; so I of course wondered what the diet of a
typical urban Canadian kid was like. Not great as it goes. Some key points I found:

"A notable proportion of the diets of 1-3 year-old children contain total fat in quantities below the recommended range. (http://www.hc-sc.gc.ca)"

Since vitamin D is fat soluble, this may not accurately represent those with a different diet.

The final analysis included 2508 children, the average age of which was 24.5 months.   They read the levels of serum 25-OHD (generally considered the most reliable method) as a marker of vitamin D levels and the average was 32 nanograms per milliliter.  130 or 5% of the children had levels less than 20 nanograms per milliliter (considered deficient).

This next bit is key:

The median total duration of breastfeeding was 10.5 months (IQR = 6–14 months)

Anyway let's plough on. 

53% of children in the study received vitamin D supplements whilst the rest didn't.

What they discovered was infants who were breastfed and given a vitamin D supplement remained within totally normal levels, regardless of how long they were breastfed.  Those over 12 months who didn't receive a supplement were more at risk of experiencing a drop.

The researchers add:

"Age, total daily milk (cow’s milk and formula) consumption, skin type, and season of blood sampling were statistically significant covariate"

Meaning their diet, skin type and what time of year they were tested in, all impacted on the outcome.

For those that don't know, vitamin D recommendations are tricky and vary widely.  It depends on your skin pigmentation (the paler the less sunshine is needed, the darker the more), how strong the sun is i.e. how close to the equator you are and how much you get via other sources like diet.

This means probably quite obviously that those at the biggest risk of vitamin D deficiency are those who:
a: Have a darker skin type and live in location where sunlight levels are low
b: Are born to mothers who are vitamin deficient.
c. Are frequently covered heavily (particularly head) when outdoors or who spend little time outdoors.
d. Don't either eat foods containing d or fortified with

The connection in this study is really quite simple.  An infant who continues to breastfeed is less likely to consume cow's milk (or drink smaller quantities), something showed to be an influential factor in the study. And what you might not know, is due to the dark winters, all Canadian milk sold according to food law is fortified with vitamin D - thus breastfeeding toddlers aren't getting or are getting less of this supplement.

In the end they concluded absolutely nothing that we didn't already know:

"Vitamin D supplementation during breastfeeding beyond age 1 year may minimize the risk of serum 25-OHD levels less than 20 nanograms per milliliter".

Let's remember that by 1 year of age, breastmilk isn't supposed to be the only source of vitamin D for an infant, far from it.   Indeed breastmilk is usually considered insufficient to prevent vitamin D deficiency in exclusively breast-fed infants if sunlight exposure is limited.  And of course, along with sunshine, there is also diet.

I did start out including diet in this entry, but it became too long - therefore I've split in and will post all about food and D shortly.

Give the breastfed baby via their mother?
We know the amount of vitamin D in breastmilk depends upon mom's vitamin D status, yet an option that rarely mentioned is to supplement the breastfeeding mums to increase amounts available via breastmilk.  Studies have repeatedly shown supplementing mum to be a satisfactory option which is as effective as supplementing baby direct.

Supplement anyway, UK levels are set too low?

There has been lots of speculation recently over whether UK levels are too low, with some countries recommending much higher amounts.  It's not really that simple though (what is?). 

First going beyond deficiency and normal levels, into therapeutic use of vitamin D to prevent or treat other diseases - the evidence is actually not as cut and dried as some would have you believe.

This 2014 review looked promising when researchers concluded:

 "Despite a few hundred systematic reviews and meta-analyses, highly convincing evidence of a clear role of vitamin D does not exist for any outcome, but associations with a selection of outcomes are probable."

But as you can see from the rapid responses here, it has been criticised for containing too many flawed studies that warped the overall findings.  Other studies have some now asking if we've been wrong about the benefits of vitamin D, and whether low levels associated with disease might be correlation rather than causal.

It also isn't (according to many) easy as just isolating one vitamin and throwing huge amounts into the human body.  The way that vitamins and minerals work together is interconnected. How well vitamin D works depends on the amount of other vitamins and minerals that are present in your body. The other vitamins and minerals needed to help vitamin D work well are called cofactors.

"To get the most benefit from vitamin D, you must have other cofactors in your body. Vitamin D has a number of cofactors; the ones listed below are the most important.

• Magnesium

• Vitamin K

• Zinc

• Boron

• Vitamin A "

from here

In short not getting enough vitamin D increases an infants risk of getting rickets, not breastfeeding.