Maternal high-fat and protein-restricted diets during gestation and lactation: thyroid-mediated disruption of basal metabolism across the lifespan of offspring - a narrative review

Abstract Currently, the planet’s food context suffers from a high number of people in inadequate nutritional situations, either due to excessive consumption of ultra-processed foods or, conversely, from thousands of people lacking access to safe, high-quality food. The importance of good nutrition goes far beyond quality of life, and its impacts can be transgenerational, leading to biomarkers that can lead to several chronic non-communicable diseases (NCDs) and metabolic syndromes, thus providing support for studies that evaluate the impact of exposure to poor nutrition in critical windows of development. Given this context, one organ essential for basal metabolism that can be affected by such conditions is the thyroid, and investigating its tissue effects, as well as its hormonal responses (T3 and T4), is essential to understanding systemic impacts. This topic has been investigated using the Developmental Origins of Health and Disease (DOHaD), which examines how exposure to stressors affects critical developmental periods. Therefore, this narrative review aimed to compile studies that associate poor maternal nutrition with protein malnutrition or lipid exacerbation, and their short-, medium-, and long-term consequences on the thyroid for both mothers and their offspring. We showed that low maternal protein intake can cause sex-specific impacts, leading to changes in circulating T3 and T4 concentrations, changes in placental enzyme activity, and potential immediate effects on basal metabolism. Excessive maternal lipid intake can disrupt endocrine and metabolic homeostasis, leading to altered thyroid hormone levels and changes in breast milk composition that compromise the lactation period. It also promotes hyperglycemia and hyperleptinemia and perturbs thyroid-linked metabolic axes. Therefore, adequate nutrition during critical developmental periods is essential, as disturbances can cause lifelong impairments in thyroid homeostasis.