[Show abstract][Hide abstract] ABSTRACT: To identify nutrients, foods, and dietary patterns associated with stress fracture risk and changes in bone density among young female distance runners.
Two-year, prospective cohort study. Observational data were collected in the course of a multicenter randomized trial of the effect of oral contraceptives on bone health.
One hundred and twenty-five female competitive distance runners ages 18-26 years.
Dietary variables were assessed with a food frequency questionnaire.
Bone mineral density and content (BMD/BMC) of the spine, hip, and total body were measured annually by dual x-ray absorptiometry (DEXA). Stress fractures were recorded on monthly calendars, and had to be confirmed by radiograph, bone scan, or magnetic resonance imaging.
Seventeen participants had at least one stress fracture during follow-up. Higher intakes of calcium, skim milk, and dairy products were associated with lower rates of stress fracture. Each additional cup of skim milk consumed per day was associated with a 62% reduction in stress fracture incidence (P < .05); and a dietary pattern of high dairy and low fat intake was associated with a 68% reduction (P < .05). Higher intakes of skim milk, dairy foods, calcium, animal protein, and potassium were associated with significant (P < .05) gains in whole-body BMD and BMC. Higher intakes of calcium, vitamin D, skim milk, dairy foods, potassium, and a dietary pattern of high dairy and low fat were associated with significant gains in hip BMD.
In young female runners, low-fat dairy products and the major nutrients in milk (calcium, vitamin D, and protein) were associated with greater bone gains and a lower stress fracture rate. Potassium intake was also associated with greater gains in hip and whole-body BMD.
[Show abstract][Hide abstract] ABSTRACT: Osteoporosis and hypertension are two frequent diseases among the aging population that share a similar etiopathology and often coexist. Moreover, treatment of hypertension affects bone mineral density and, therefore, can worsen osteoporosis. This narrative review considers the influence of the main etiologic factors that contribute to the development of hypertension and osteoporosis and examines the effect of the most often used antihypertensives on bones. A computerized literature search of relevant English publications regarding the etiology of hypertension and osteoporosis as well as the impact of antihypertensives on osteoporosis from 1996 to 2011 was completed in October 2011. The latest update in the search was performed from May to June 2012. The most relevant nongenetic factors in the etiology of osteoporosis and hypertension are low calcium intake, vitamin D and vitamin K deficiency, high consumption of sodium salt, and the effects of different forms of nitric oxide. Thiazide diuretics are the only antihypertensives that have a positive influence on bone mineral density. For other antihypertensive drugs, the data are conflicting, indicating that they may have a potentially negative or positive influence on bone mineral density and fracture risk reduction. Some studies did not find a correlation between the use of antihypertensives and bone mineral density. Due to the frequent coexistence of hypertension and osteoporosis, when selecting long-term antihypertensive therapy the potential effects of antihypertensive drugs on development, worsening, or improvement of osteoporosis should also be considered.
Calcified Tissue International 11/2012; · 2.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: SLC12A3 encodes the thiazide-sensitive sodium chloride cotransporter (NCC), which is primarily expressed in the kidney, but also in intestine and bone. In the kidney, NCC is located in the apical plasma membrane of epithelial cells in the distal convoluted tubule. Although NCC reabsorbs only 5 to 10 % of filtered sodium, it is important for the fine-tuning of renal sodium excretion in response to various hormonal and non-hormonal stimuli. Several new roles for NCC in the regulation of sodium, potassium, and blood pressure have been unraveled recently. For example, the recent discoveries that NCC is activated by angiotensin II but inhibited by dietary potassium shed light on how the kidney handles sodium during hypovolemia (high angiotensin II) and hyperkalemia. The additive effect of angiotensin II and aldosterone maximizes sodium reabsorption during hypovolemia, whereas the inhibitory effect of potassium on NCC increases delivery of sodium to the potassium-secreting portion of the nephron. In addition, great steps have been made in unraveling the molecular machinery that controls NCC. This complex network consists of kinases and ubiquitinases, including WNKs, SGK1, SPAK, Nedd4-2, Cullin-3, and Kelch-like 3. The pathophysiological significance of this network is illustrated by the fact that modification of each individual protein in the network changes NCC activity and results in salt-dependent hypotension or hypertension. This review aims to summarize these new insights in an integrated manner while identifying unanswered questions.
Pflügers Archiv - European Journal of Physiology 12/2013; · 4.87 Impact Factor
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