Food bioactives and bone metabolism

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During pregnancy and lactation, the growing and developing fetus and subsequent baby, depend on their mother for their nutrition. In particular, the developing skeleton creates a demand for many nutrients such as calcium which is provided through the placenta for the fetus and later through mother's milk for the baby. For a mother to provide the required calcium and other minerals, her skeleton undergoes dramatic changes that are regulated by hormones. There are some data to support that a mother's skeleton returns to its pre-pregnancy state. In other words, studies in humans suggest that fracture risk is not greater in women who have had one or more pregnancies and breastfed their children. However, with newer imaging technologies, there is emerging data that there are measurable changes and adaptations to the skeleton, and some of these changes may have a long-term impact on the mother's skeleton. To study the changes to the skeleton that occur during pregnancy and lactation, a rat model is commonly used and because of the multiple offspring in a litter, there is an extra demand on the mother's skeleton compared to humans - this provides a more accelerated model for researchers to study the effects on bone. The rat model also provides an opportunity to study how diet can be used to influence the changes in bone that occur. Our research team has been studying how a type of tea - rooibos tea, that is rich in natural chemicals called polyphenols, can have a positive effect on bone cells, helping bone to form more mineral. The next steps, that we will pursue with this funding, is to use this rat model to test whether providing rooibos tea can help enhance the recovery of bone tissue after the end of lactation, and perhaps even help mother's to recover with stronger bone that may protect against the loss of bone during aging. We will study if there is a specific time in which providing rooibos tea is most helpful to bone. For example, perhaps it is only after lactation that there is a benefit? We will also conduct studies to find a realistic dose of rooibos tea that yields the most benefit and also test whether providing rooibos tea is helpful with repeated recovery of bone after multiple pregnancies. We will also measure whether the bones of the offspring are altered due to mother's receiving rooibos tea. For other polyphenols found in other foods there are some data that there may be benefits to offspring by a maternal diet rich in polyphenols. Positive findings from this study will provide a basis for developing dietary strategies - that may include fortified foods or supplements - to support and even enhance recovery of bone mineral and strength such that a mother has stronger bones after pregnancy and lactation. Companies could also potentially use these findings to develop foods or supplements with higher levels of specific polyphenols to support recovery of bone in mothers.