By: Jovana K.
The WHO and UNICEF identify breast milk as an ideal source of nutrition for the developing infant because, unlike infant formula, breast milk contains a rich source of maternal hormones, enzymes and immune boosters that promote the infant's physiological and physical development. However, the quality of breast milk depends on the mother's diet and lifestyle. Most pregnant and breastfeeding women cover 95% of their body with clothing garments, wear sunscreen, spend much of their time in areas shielded from the sun and consume multivitamins that contain between 200 and 400 IU of vitamin D.
Studies administering 400 IU of vitamin D/d have failed to improve nutritional status of pregnant and breastfeeding women, which is why 40-80% of this population is vitamin D deficient [25(OH)D < 10 ng/ml]. Breast milk of vitamin D deficient mothers provides 15-40 IU of vitamin D per litre of breast milk, which is a mere 10% of the daily recommended intake (DRI). According to the developmental origin of health and disease, suboptimal nutrition during critical stages of development may reprogram the physiological and physical development of an organism, and this reprogramming may have long-term consequences on human health.
Recent studies suggest that vitamin D insufficiency in early life is a risk modifying factor for many chronic diseases including osteomalacia, rickets, multiple sclerosis, schizophrenia, coronary heart disease, type 1 diabetes and/or cancer. As a result, national organizations like the Canadian and American Paediatric Society, Health Canada and the FDA recommend that all breastfed, healthy term babies receive a daily vitamin D supplement of 400 IU/d. But the question remains of whether these recommendations are being followed.
The 2003 Canadian Community Health Survey revealed that 50% of
breastfeeding mothers did not supplement their infant's diet with
vitamin D. Similar trends were also reported in the US. However,
it appears that supplementation practices may be changing. This
year at the CSNS Conference, Sina Gallo, a PhD student from
McGill University working with Dr. Hope Weiler presented novel
data on vitamin D supplementation practices of newborn infants
living in Montreal, Canada. Out of 343 mothers that had
completed a cross-sectional telephone survey, 90% reported some
breast feeding during the first 6 months of life and 53% had done
so exclusively (surprisingly, much higher than previous Canadian
reports). Of those exclusively breast fed, 78% received the daily
recommended vitamin D intake of 400 IU. The main reason for
stopping vitamin D supplementation before 6 months of age
(average age stopped was 22 weeks) was that mothers began to
formula feed their infants, and as all infant formulas are
fortified with vitamin D the mothers assume that supplementation
could be stopped. However, if an infant is not consuming at least
1 litre (32 oz) of formula per day, it will not be able to meet
the daily recommended vitamin D intake since vitamin D is scarce
in other sources of an infant's diet. Both breastfed and formula
fed infants may be at risk for having insufficient vitamin D
during critical windows of development, which long-term may pose
a threat to adult health. Health Canada is currently working on
establishing novel DRI recommendations for vitamin D and
clinicians are anxiously awaiting these new DRIs to be
specified.
