Details

Autor(en) / Beteiligte

• Roughead, Zamzam K.

Titel

Influence of Total Diet on Calcium Homeostasis

Ist Teil von

• Calcium in Human Health, p.191-207

Ort / Verlag

Totowa, NJ: Humana Press

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Changes in dietary practices offer a sensible, food-based, low-cost approach for modification of risk factors and prevention of osteoporosis. However, defining the effects of diet on bone health has not been a simple task becauseof the following reasons: Bone is complex. Bone is a composite material with both organic and inorganic components. By weight, bone is 70% mineral and 5C8% water, and the rest is organic material. The inorganic phase of bone is approx 95% calcium hydroxyapatite arranged in plate-like crystals; the organic phase is primarily proteins with approx 98% type I collagen, plus a variety of noncollagenous proteins including important regulatory proteins, cytokines, and growth factors (1).This specialized, vital, metabolically active, connective tissue provides not only structural framework, protection for vital organs, locomotion, and hematopoesis, but also serves as a buffering reservoir and aids the kidneys and lungs in the tight regulation of the body’s hydrogen ion concentration. This latter metabolic function of bone has received considerable attention in the area of nutrition research and bone health.Food is complex. In addition to energy, food provides a host of essential nutrients and bioactive nonnutrients with multifaceted metabolic functions and interactions. These components can affect calcium homeostasis not only through a direct effect on acidCbase balance, but also through systemic or cellular processes. Previously, the bulk of studies investigating the effects of diet on bone metabolism have focused primarily on the influence of single nutrients on calcium homeostasis. The strength of this reductionistic approach is that it affords a focused investigation of both the specific role and the mechanism of action of a given nutrient; however, this approach does not address the various interactions between nutrients and nonnutrients that result when we consume whole foods in a mixed diet.The body is complex and adaptable. The response of the body to dietary stimuli spans the entire range from localized cellular responses such as changes in osteoblast and/or osteoclast activity and paracrine/autocrine signals, to systemic, whole-body responses such as changes in renal acidCbase excretion, and endocrine (hormonal/growth factor) changes. The recent observations that renal acid excretion adapts over time in response to dietary changes point to the often understated quality of the human body—its innate capability to adapt to a given stimulus over time.