Targeting vitamin D deficiency in breastfeeding women is especially important, as research has shown that children’s vitamin D levels are only a fraction of their mother’s levels. A recent study published by the journal PLOS One evaluated the prevalence and risk of deficiency in postpartum, lactating Chinese women.
Researchers conducted analyses of the vitamin D levels of 2,004 lactating women between 1-10 months postpartum from 8 different Chinese provinces and municipalities.
Here are some common trends found after analysis:
- 44% of the lactating women were from Southern China, with latitudes ranging from North 21° to North 30°.
- The remaining 56% resided in Northern China with latitudes ranging from North 34° to North 48°.The the bottom 25th percentile of vitamin D levels was 10.5 nmol/L (4.2 ng/ml), the median vitamin D level was 15.8 nmol/L (6.32 ng/ml), and the 75th percentile was 24 nmol/L (9.2 ng/ml).
- 85.3% of the women were considered vitamin D deficient (25(OH)D<30 nmol/L, 12 ng/ml).
- 2.1% of the women had adequate serum levels (25(OH)D>50 nmol/L, 20 ng/ml).
- Only 6 of lactating women had vitamin D levels greater than 75 nmol/L (30 ng/ml).
The researchers evaluated some of the risks associated with vitamin D deficiency in these women:
- Vitamin D levels of lactating women were significantly lower during October-January (14.0nmol/L, 5.6 ng/ml) than during February-May (18.0nmol/L, 7.2 ng/ml) (P<0.001).
- The odds of vitamin D deficiency in the winter were 2.56 times higher than in the spring (OR 2.56, 95%CI: 1.91–3.43).
- Women who were of the Dai ethnicity had higher vitamin D levels (22.5nmol/L, 9 ng/ml) than Hui women (Chinese Muslims) (9.0nmol/L, 3.6 ng/ml) (P<0.001).
- For every 10,000 CNY annual income per capita increase, serum vitamin D increased 1.04 times (P<0.001).
The researchers concluded,
“In summary, vitamin D deficiency in lactating women was highly prevalent in winter and spring regardless of them living in south or the north in China. Vitamin D status in lactating women was mainly associated with season, ethnicity and income.”
“It is urgent to study the strategy and implement interventions on vitamin D supplementation for improving vitamin D status of lactating women.”
This study reveals that lactating mothers in China are severely vitamin D deficient. As a result, these individuals are unable to supply their infants with with adequate vitamin D through their breast milk. It is important for mothers to supplement themselves or supplement their babies with vitamin D3 in the case of low vitamin D levels. For infants, and children under 25 lbs, the Vitamin D Council recommends supplementing with 1,000 IU of vitamin D3. For mothers who would like to supply their babies vitamin D from their breast milk, research has shown that women need 6,400 IU in order to maintain a healthy vitamin D level for the baby.