Calcium bioavailability and its relation to osteoporosis

Area of Science:

• Nutrition Science
• Bone Health
• Metabolic Physiology

Background:

• Calcium intake positively influences bone mass in premenopausal women and reduces bone loss in postmenopausal women.
• Increased bone mass, even slightly, significantly lowers fracture rates.
• Most research uses calcium supplements, with fewer studies examining dietary calcium manipulation.

Purpose of the Study:

• To evaluate the importance of dietary calcium bioavailability for osteoporosis prevention and treatment.
• To compare calcium absorption from various food sources, including dairy and vegetables.
• To understand the role of food matrix and inhibitors (oxalic/phytic acid) on calcium absorption.

Main Methods:

• Utilized isotopic tracer techniques to label foods with calcium isotopes for absorption evaluation.
• Compared calcium absorption rates from milk (referent) with various vegetable sources.
• Assessed the impact of oxalic and phytic acids on calcium bioavailability from specific foods.

Main Results:

• Calcium absorption from milk typically ranges from 20-40%, influenced by the subject's calcium status.
• Most vegetable sources demonstrate comparable or superior calcium absorption efficiency to dairy.
• High concentrations of oxalic or phytic acid significantly inhibit calcium absorption from certain vegetables.

Conclusions:

• Dietary calcium bioavailability is crucial for skeletal health and osteoporosis management.
• Achieving adequate calcium intake for osteoporosis prevention may necessitate substantial dairy consumption.
• While calcium supplements provide concentrated calcium, they lack other essential skeletal nutrients found in whole foods.