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Nutrient Bioavailability during Reproduction

Nutrient Bioavailability during Reproduction. Janet C. King, Ph.D. Director and Professor Western Human Nutrition Research Center University of California, Davis. Bioavailability. Fraction of the ingested nutrient that is used for normal physiological functions or storage.

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Nutrient Bioavailability during Reproduction

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  1. Nutrient Bioavailability during Reproduction Janet C. King, Ph.D. Director and Professor Western Human Nutrition Research Center University of California, Davis

  2. Bioavailability Fraction of the ingested nutrient that is used for normal physiological functions or storage

  3. Endogenous Factors Influencing Bioavailability • Body ‘status’ of the nutrient, i.e. need • growth • pregnancy • lactation • previous intake of the nutrient • Gut Function • Efficiency of digestion • Transit time • Presence of disease

  4. Effect of Pregnancy and Lactation on the Bioavailability of: • Calcium and Zinc • Regulated by Gastrointestinal Tract • Selenium • Regulated by Kidney

  5. Calcium and Zinc Needs for Pregnancy and Lactation PG + 6 Mo Lactation % Bone Calcium 65 g 7% Zinc 370 mg 80% PG + 24 Mo Lactation % Bone Calcium 140 g 14% Zinc 640 mg 140%

  6. Sources of Calcium or Zinc for Pregnancy and Lactation *Diet Intake FETUS/MILK SMALL INTESTINE BONE Absorption Accretion *Net retention ECF/PLASMA *Mobilization Endog.Secretion Resorption *Net retention Filtration Reabsorption KIDNEY

  7. Calcium and Zinc Metabolism during Pregnancy and Lactation: Longitudinal Studies L. D. Ritchie, E. B. Fung, L.R. Woodhouse, C. Donangelo, R. Roehl, S.A.Abrams, B.Halloran, C. Cann, M. Van Loan, J.R. Turnlund, and J.C. King

  8. Study Design Diet X X X X X X Abs X X X X X X Blood X X X X X X Urine X X X X X X Milk X Concep- tion Birth 2 wks 8-10 Wks 24- 26 Wks 34- 36 Wks 6 mo after menses 7-9 Wks Pre- PG Pregnancy Lactation

  9. Changes in Calcium and Zinc Intakes

  10. Fractional Absorption of Calcium and Zinc

  11. Changes in Urinary Excretion of Calcium and Zinc

  12. Changes in Lumbar Spine Bone Mineral Content: QCT

  13. Calcium Homeostasis: Late Pregnancy Adjustments Diet Intake: +300 mg Ca/d FETUS SMALL INTESTINE BONE +300 mg/d Net Absorption: 380 mg/d ECF/PLASMA Filtration: +80 mg/d KIDNEY

  14. Zinc Homeostasis: Late Pregnancy Adjustments Diet Intake: +3 mg Zn/d Fetus SMALL INTESTINE BONE 0.7 mg/d Net Absorption: 1.0 mg/d ECF/PLASMA Filtration: + 0.3 mg/d KIDNEY

  15. Calcium Homeostasis: Lactation Adjustments Diet Intake: +65 mg Ca/d MILK SMALL INTESTINE BONE 215 mg/d ECF/PLASMA Net Resorption 120 mg/d Reabsorption 95 mg/d KIDNEY

  16. Zinc Homeostasis: Lactation Adjustments Diet Intake: +1 mg Zn/d Milk SMALL INTESTINE BONE 2.0 mg/d Net Absorption: 1.3 mg/d ECF/PLASMA Net Resorption: 0.9 mg/d Filtration: 0.2 mg/d KIDNEY

  17. Conclusion • The fraction of ingested calcium and zinc retained increases during pregnancy and lactation. • Adjustments for pregnancy differ from lactation. • Adjustments for calcium differ from zinc

  18. Effect of Low Calcium Intakes on Calcium Metabolism during Pregnancy and Lactation • Nine parous women from Rio de Janeiro • Usual calcium intake: 440 mg/d • Calcium intake increased by 75 mg/d in LP • No supplemental calcium • Studied at 10-12, 34-36 wks gestation; 7-9 wks lactation

  19. Effect of Maternal Status on Calcium Absorption

  20. Effect of Maternal Status on Urinary Calcium Excretion

  21. A Comparison of Selenium Bioavailability in Pregnant and Nonpregnant Women Christine A. Swanson, Donald C. Reamer, Claude Veillon, Janet C. King, and Orville A. Levander

  22. Selenium Balance NP (n=6) EP (n=6) LP (n=4) Se Intake, µg/d 150 154 158 Fecal Se, µg/d 28 33 28 Urinary Se, µg/d 111 100 96 Balance, µg/d 11 21 34

  23. Recommended Multivitamin Mineral Supplement for Pregnancy* Nutrient Amount Iron 30 mg Zinc 15 mg Copper 2 mg Calcium 250 mg Vitamin B6 2 mg Folate 300 µg Vitamin C 50 mg Vitamin D 5 µg * IOM, 1990

  24. Gaps in Knowledge • Bioavailability of chemical forms of nutrients in supplements • Interaction of nutrients provided in prenatal supplements • Effect of food on the bioavailability of nutrients in prenatal supplements • UL for nutrients during pregnancy and lactation

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