Long-term iodine deficiency and excess inhibit β-casein and α-lactalbumin secretion of milk in lactating rats

Ying Zhang; Xin Zhao; Na Zhao; Yan Song; Zixuan Zhang; Xinbao Zhang; Haohao Meng; Xiru Wang; Le Shan; Wanqi Zhang; Zhongna Sang

doi:10.1016/j.jnutbio.2024.109812

Long-term iodine deficiency and excess inhibit β-casein and α-lactalbumin secretion of milk in lactating rats

J Nutr Biochem. 2024 Nov 26:137:109812. doi: 10.1016/j.jnutbio.2024.109812. Online ahead of print.

Authors

Ying Zhang¹, Xin Zhao², Na Zhao³, Yan Song¹, Zixuan Zhang⁴, Xinbao Zhang¹, Haohao Meng¹, Xiru Wang¹, Le Shan¹, Wanqi Zhang⁵, Zhongna Sang⁶

Affiliations

¹ Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Key Laboratory of Environmental Nutrition and Population Health, Key Laboratory of Prevention and Control of Major Diseases in the Population, Ministry of Education, Tianjin Medical University, Tianjin, China.
² Department of Hand Microsurgery, Tianjin Hospital, Tianjin, China.
³ Department of General Surgery, Tianjin Medical University General Hospital, Tianjin, China.
⁴ Department of Preventive Medicine Specialty, School of Public Health, Jilin University, Changchun, China.
⁵ Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Key Laboratory of Environmental Nutrition and Population Health, Key Laboratory of Prevention and Control of Major Diseases in the Population, Ministry of Education, Tianjin Medical University, Tianjin, China. Electronic address: wqzhang@tmu.edu.cn.
⁶ Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Key Laboratory of Environmental Nutrition and Population Health, Key Laboratory of Prevention and Control of Major Diseases in the Population, Ministry of Education, Tianjin Medical University, Tianjin, China. Electronic address: sangzhongna@tmu.edu.cn.

PMID: 39603394
DOI: 10.1016/j.jnutbio.2024.109812

Abstract

Iodine is critical for thyroid hormone synthesis and developmental programming in the first 1,000 days of life. The effect of maternal iodine on milk protein secretion remains unknown. We aimed to explore the effect of long-term maternal iodine deficiency and excess on milk protein secretion in lactating rats and its mechanisms preliminarily. Animal models of iodine deficiency and excess were generated by treating Wistar rats a low-iodine diet and deionized water with different potassium iodide concentrations from reproductive age to lactation. Under iodine deficiency, CSN2 and α-LA secretion of milk was inhibited in early and mid-lactation, respectively, and the inhibition of milk CSN2 and α-LA secretion weakened in late lactation. Under iodine excess, milk CSN2 secretion was inhibited in early lactation, and the inhibition of milk CSN2 and α-LA secretion was more pronounced in late lactation. Under iodine deficiency and excess, the concentrations of CSN2 and α-LA and protein expression levels of THRα1, THRβ1, and PRLR in the mammary gland decreased. These results demonstrate the negative impact of long-term maternal iodine malnutrition on milk protein secretion.

Keywords: Breast milk iodine concentration; Iodine; Lactation; Milk proteins.