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Recent study reveals lactating Chinese women have shockingly low vitamin D levels

Posted on: March 30, 2017   by  Vitamin D Council


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.”

They continued,

“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.  


Y. Zhao, et. al. Vitamin D status and the prevalence of deficiency in lactating women from eight provinces and municipalities in China. PLOS One, 2017.

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