An analysis of the subject of nutrition and bone growth
Nutrition and bone health pdf
Thus it is important to maintain strong support for basic research, even as existing research findings are applied to the everyday practice of medicine. A recently discovered hormone from fat cells, leptin, has also been shown to have effects on bone Elefteriou et al. How is this response lost in those individuals who develop bone disease? Due to concerns that individuals do not get enough vitamin D through sunlight, recommendations for intake are set at a level to be adequate for individuals having no sun exposure. Reduced sex hormones: Lower estrogen levels appear to make it harder for bone to regenerate. Hormone therapy was widely used to prevent this, but this practice is now controversial because of the risks of increased breast cancer, strokes, blood clots, and cardiovascular disease with hormone therapy see Chapter 9. Thus, striving to lower sodium intake while increasing calcium intake to the recommended levels is a good strategy for supporting bone health. As mentioned in the Calcium section above, several meta-analyses of randomized controlled trials have shown that combined calcium and vitamin D supplementation decreases fracture incidence in older adults 30, 32 , In addition, one meta-analysis found that site-specific exercise may help to improve and maintain BMD in men over age 30 Kelley et al, The composition of the mineral and matrix, the fine structure of the trabecular bone, the porosity of the cortical bone, and the presence of micro-fractures and other forms of damage in bone are all important in determining bone strength. The anti-fracture efficacy of specific bone turnover or bone mass modifying agents has always been tested in vitamin D and calcium replete patients,36 except for hormone replacement therapy.
Adults aged 19 years and above should consume 1, milligrams mg of calcium a day. A training program for 21 men over 60 resulted in a 39 percent increase in upper body and a 38 percent increase in lower body strength, as well as a 3 percent increase in femoral neck BMD Ryan et al.
Fluoride Fluoride has a high affinity for calciumand most fluoride in the body is stored in calcified tissues, i. Wiley AS. This hormone normally regulates cartilage and bone development in the fetus, but it can be over-produced by individuals who have certain types of cancer.
As suggested earlier, this study design cannot prove that physical activity causes a reduction in risk, since there is an inherent bias in the study—i. Total body T and lumbar spine LS values were used in the analyses. However, the normal bone architecture has been disrupted, leading to weak bones and the potential for fractures and deformities even though the bones may appear dense on an x-ray. In particular, high-sodium intake in conjunction with low-calcium intake may be especially detrimental to bone health The Early Bone Loss and Frailty Stages Older Adults Most randomized clinical trials examining the effect of calcium and vitamin D on bone health have focused on postmenopausal women and the elderly, so the role of these nutrients in promoting bone health is more clearly established for this age group. The anti-fracture efficacy of specific bone turnover or bone mass modifying agents has always been tested in vitamin D and calcium replete patients,36 except for hormone replacement therapy. Other Important Hormones Growth hormone from the pituitary gland is also an important regulator of skeletal growth. Pathogenesis of osteoporosis. Age plays a significant role in the onset of osteopenia and the risk of osteoporosis. In addition to calcium, magnesium, and other multivalent cations, calcium-sensing receptors sense amino acids, specifically L-amino acids, thereby modulating parathyroid hormone secretion. This estrogen is important for the bones of men as well as women. Calcitonin Calcitonin is a third calcium-regulating hormone produced by cells of the thyroid gland, although by different cells than those that produce thyroid hormones Sexton, Findlay et al. However, vitamin D deficiency is known to cause inadequate mineralization of the growing skeleton, leading to rickets Goldring et al. Several factors can limit the production of vitamin D by the skin, including where one lives those who live in northern latitudes during the winter months do not get adequate exposure to sunlight Webb et al.
While for most individuals the problem is too little calcium, it is important to remember that too much calcium does not have any additive benefit, and can have negative effects in some individuals. As shown in Figurethe participation by both men and women declines with age, with women being consistently less active than men Schiller et al.
However, others have shown that size-corrected BMC in prepubertal children was negatively associated with size and growth in infancy in both premature children 8 and in those born at term 9indicating that a high growth rate in infancy may have a negative influence on bone mineralization before puberty.
Calcitriol Calcitriol is the hormone produced from vitamin D Norman, Okamura et al. In animals, vitamin A toxicity hypervitaminosis A is associated with poor bone growth, loss of bone mineral content, and increased rate of fractures Even if phylloquinone and menaquinones have different effects on bone health, there is only limited evidence to suggest that supplementation with one form of vitamin K, rather than the other, would be more effective in preventing age-related bone loss in humans, especially since the body can convert phylloquinone into menaquinone While their effects tend to be small, these include caffeine, protein, and excess phosphorus intake i.
BMC, BA, height, and weight were transformed to natural logarithms before analyses In adults, vitamin D deficiency leads to a softening of the bone a condition known as osteomalacia that can also lead to fractures and deformities. Ethnicity: White people and Asian people have a higher risk than other ethnic groups.
based on 26 review