Nutrition Concerns of Insufficient and Excessive Intake of Dietary Minerals in Lactating Women: A Cross-Sectional Survey in Three Cities of China

Objective
Objectives of this study were 1) to investigate the mineral intake by Chinese lactating women, 2) to explore the dietary source of minerals, and 3) the ratios between different dietary minerals.
Methods
A total of 468 lactating women in 5–240 days post-partum participated in this study. Food intakes by participants were measured using one time of 24-hour dietary recall, and minerals from food were calculated based on the Chinese Food Composition Table, second edition.
Results
In post-partum, women had inadequate food intake. 81.0% of women’s daily intake of dairy products was lower than 300g, and 97.1% of women’s daily intake of salt over 6g. For mineral intake, there were 81.8%, 59.0%, 47.6%, 45.7% and 66.8% of women’s calcium, magnesium, iron, zinc and selenium intake lower than the estimated average requirement, respectively, and 91.7% of women’s excessive intake of sodium. The calcium/phosphorus and sodium/potassium ratios were 0.41±0.26/1 and 3.13±2.89/1, respectively. Considering the dietary sources of minerals, 27.3%, 25.3% and 30.1% of iron, zinc and calcium were from animal-based food, respectively, and 60.3%, 66.1% and 58.0% of iron, zinc and calcium were from plant-based food, respectively. The phosphorus-protein ratio was 0.014±0.003/1. Lactation stage was associated with nutrient intake. Women within 30 days post-partum and the ones who live in Guangzhou had a significantly lower intake of certain minerals, while women with a high education experience had a high intake of calcium, potassium, iron and zinc. Productive age, whether obese or not, and delivery ways were not associated with mineral intakes (P all >0.05).
Conclusion
Chinese women in three studied cities had an inappropriate food intake and resulted in both insufficient and excessive intakes of certain minerals.

### 研究目标
本研究的研究目标共三项：其一，探究中国哺乳期妇女的矿物质摄入现状；其二，剖析矿物质的膳食来源构成；其三，明确不同膳食矿物质间的比例关系。

### 研究方法
本研究共纳入468名产后5~240天的哺乳期妇女。采用单次24小时膳食回顾法（24-hour dietary recall）采集受试者的食物摄入数据，并依据第二版《中国食物成分表（Chinese Food Composition Table）》计算食物来源的矿物质含量。

### 研究结果
产后哺乳期妇女存在膳食摄入不足的问题。81.0%的妇女每日乳制品摄入量低于300g，97.1%的妇女每日食盐摄入量超过6g。在矿物质摄入方面，分别有81.8%、59.0%、47.6%、45.7%及66.8%的妇女钙、镁、铁、锌及硒的每日摄入量低于估计平均需要量（estimated average requirement, EAR）；另有91.7%的妇女钠摄入量超标。钙磷比与钠钾比分别为0.41±0.26与3.13±2.89。从矿物质的膳食来源来看，动物性食物分别贡献了27.3%的铁、25.3%的锌及30.1%的钙，植物性食物则分别贡献了60.3%的铁、66.1%的锌及58.0%的钙。磷蛋白比为0.014±0.003。哺乳期阶段与营养素摄入存在关联：产后30天内的妇女以及居住在广州的妇女，其部分矿物质的摄入量显著偏低；而受教育程度较高的妇女，其钙、钾、铁及锌的摄入量更高。产妇年龄、肥胖状态及分娩方式与矿物质摄入量均无显著关联（所有P值均>0.05）。

### 研究结论
本研究覆盖的三个城市中的中国哺乳期妇女，存在膳食摄入不合理的情况，部分矿物质既存在摄入不足，也存在摄入过量的问题。