Bioavailability of the calcium in fortified soy imitation milk, with some observations on method

Robert P. Heaney, M. Susan Dowell, Karen Rafferty, June Bierman

Research output: Contribution to journalArticle

92 Citations (Scopus)

Abstract

Background: Calcium-fortified soy milk is growing in popularity, particularly among vegetarians, but the bioavailability of its calcium was not previously known. Additionally, the validity of isotopic labeling methods for fortified liquid products had not been established. Objectives: The objectives of this study were to compare the bioavailability of the calcium in fortified soy milk with that of calcium in cow milk and to evaluate the method of labeling soy milk for bioavailability testing. Design: A within- subject comparison of extrinsically labeled cow milk with intrinsically and extrinsically labeled soy milks was undertaken in 16 healthy men. In all tests, 300-mg Ca loads were given as a part of a light breakfast after an overnight fast. The milks were physically partitioned into liquid and solid phases to enable evaluation of tracer distribution. Results: Calcium from intrinsically labeled soy milk was absorbed at only 75% the efficiency of calcium from cow milk. Extrinsic labeling of soy milk did not produce uniform tracer distribution throughout the liquid and solid phases and resulted in a 50% overestimate of true absorbability. Conclusion: Calcium-fortified soy milk does not constitute a calcium source comparable to cow milk, and extrinsic labeling of such calcium particulate suspensions does not produce the uniform tracer distribution needed for bioavailability testing. Hence, intrinsic labeling of the fortificant is required for such liquid suspensions.

Original languageEnglish
Pages (from-to)1166-1169
Number of pages4
JournalAmerican Journal of Clinical Nutrition
Volume71
Issue number5
StatePublished - May 2000

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Soy Milk
milk substitutes
soymilk
Biological Availability
bioavailability
Calcium
calcium
Milk
milk
Calcium Carbonate
tracer techniques
liquids
methodology
Suspensions
Breakfast
vegetarian diet
breakfast
testing
Light
particulates

All Science Journal Classification (ASJC) codes

  • Medicine (miscellaneous)
  • Food Science

Cite this

Bioavailability of the calcium in fortified soy imitation milk, with some observations on method. / Heaney, Robert P.; Dowell, M. Susan; Rafferty, Karen; Bierman, June.

In: American Journal of Clinical Nutrition, Vol. 71, No. 5, 05.2000, p. 1166-1169.

Research output: Contribution to journalArticle

Heaney, RP, Dowell, MS, Rafferty, K & Bierman, J 2000, 'Bioavailability of the calcium in fortified soy imitation milk, with some observations on method', American Journal of Clinical Nutrition, vol. 71, no. 5, pp. 1166-1169.
Heaney, Robert P. ; Dowell, M. Susan ; Rafferty, Karen ; Bierman, June. / Bioavailability of the calcium in fortified soy imitation milk, with some observations on method. In: American Journal of Clinical Nutrition. 2000 ; Vol. 71, No. 5. pp. 1166-1169.
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