Cristina Palacios

The Role of Nutrients in Bone Health, from A to Z

Osteoporosis is a major public health problem, affecting millions of individuals. Dietary intake is an important modifiable factor for bone health. Inadequate intake of nutrients important to bone increases the risk for bone loss and subsequent osteoporosis. The process of bone formation requires an adequate and constant supply of nutrients, such as calcium, protein, magnesium, phosphorus, vitamin D, potassium, and fluoride. However, there are several other vitamins and minerals needed for metabolic processes related to bone, including manganese, copper, boron, iron, zinc, vitamin A, vitamin K, vitamin C, and the B vitamins. Although the recommended levels of nutrients traditionally related to bone were aimed to promote bone mass and strength, the recommended levels of the other nutrients that also influence bone were set on different parameters, and may not be optimal for bone health, in view of recent epidemiological studies and clinical trials.

Minerals and vitamins in bone health: the potential value of dietary enhancement.

Nutrition is important to bone health, and a number of minerals and vitamins have been identified as playing a potential role in the prevention of bone diseases, particularly osteoporosis. Despite this, there is currently no consensus on maximum levels to allow in food or as dietary supplements. The benefits of supplementation of populations at risk of osteoporosis with Ca and vitamin D are well established. Prolonged supplementation of Ca and vitamin D in elderly has been shown to prevent bone loss, and in some intervention studies to prevent fragility fractures. Although P is essential to bone health, the average intake is considered to be more than sufficient and supplementation could raise intake to adverse levels. The role of vitamin K in bone health is less well defined, though it may enhance the actions of Ca and vitamin D. Sr administered in pharmacological doses as the ranelate salt was shown to prevent fragility fractures in postmenopausal osteoporosis. However, there is no hard evidence that supplementation with Sr salts would be beneficial in the general population. Mg is a nutrient implicated in bone quality, but the benefit of supplementation via foodstuffs remains to be established. A consensus on dietary supplementation for bone health should balance the risks, for example, exposure of vulnerable populations to values close to maximal tolerated doses, against evidence for benefits from randomised clinical trials, such as those for Ca and vitamin D. Feedback from community studies should direct further investigations and help formulate a consensus on dietary supplementation for bone health.

Nutrition and health: guidelines for dental practitioners.

Good nutrition is vital to overall health, and poor diet and a sedentary lifestyle are major causes of morbidity and mortality worldwide. Nutritional factors are implicated in many oral and systemic diseases and conditions, including obesity, hypertension, dyslipidemia, type II diabetes, cardiovascular disease, osteoporosis, dental caries and some cancers including oral cancers. This review focuses on the evidence for the relations between key nutritional factors and health. Energy intake is related to body weight and obesity, highlighting the importance of lower-energy diets and regular physical activity for body weight maintenance and for preventing obesity. Evidence is presented for the health benefits of high quality carbohydrates, such as whole grain products, and fruits and vegetables, in reducing the risk of cardiovascular disease and cancer. The adverse effects of sugar, sweetened beverages, and trans and saturated fats on several diseases including caries, diabetes and cardiovascular disease are described. The health benefits of unsaturated fats, antioxidants, B vitamins and vitamin D in cardiovascular disease, periodontitis, cancer, and other conditions are documented. Both benefits and harmful effects of dairy product intake on health are discussed. Based on the evidence, nutritional guidelines are provided, as well as key recommendations for preventing obesity. Dentists can play a critical role in motivating and enabling healthy food choices.

No effects of low and high consumption of dairy products and calcium supplements on body composition and serum lipids in Puerto Rican obese adults.

OBJECTIVE Epidemiologic studies have shown that a high calcium intake is related to lower body weight, fat, and serum lipids in obese individuals. However, clinical studies have shown inconclusive results. The present study was conducted to determine if dairy or calcium supplementation alters body composition or serum lipids in Puerto Rican obese adults without dietary energy restriction or exercise. METHODS A 21-wk randomized clinical trial was conducted in 30 obese adults, aged 21-50 y, with usual calcium intakes <700 mg/d. Subjects were randomly assigned to the following: high dairy (∼ 1300 mg/d of calcium from dairy products by substituting foods); high calcium (∼ 1300 mg/d of calcium; ∼ 700 mg/d from diet and 600 mg/d from a supplement); or placebo. Subjects were asked to continue their established dietary intake (except for the high dairy group) and their physical activity during the study. Body weight was measured monthly; body fat, bone, and serum lipids (total cholesterol, high-density lipoprotein, low-density lipoprotein, and triacylglycerol) were measured at baseline and at 21 wk. Pairwise differences in study endpoints among the groups were assessed using ANOVA and post-hoc analysis. RESULTS Grand mean calcium intake was 1200 ± 370 (median 1187) mg/d in the high dairy group, 1171 ± 265 (median 1165) mg/d in the high calcium group, and 668 ± 273 (median 691) mg/d in the control group, which was significantly lower compared to the two treatment groups (P < 0.001). There were no significant group effects in any of the outcome variables. CONCLUSION A high dairy or calcium diet alone did not alter body composition or serum lipids profile in a sample of Puerto Rican obese adults.

Association between adiposity indices and cardiometabolic risk factors among adults living in Puerto Rico

OBJECTIVE To compare the general adiposity index (BMI) with abdominal obesity indices (waist circumference (WC), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR)) in order to examine the best predictor of cardiometabolic risk factors among Hispanics living in Puerto Rico. DESIGN Secondary analysis of measurements taken from a representative sample of adults. Logistic regression models (prevalence odds ratios (POR)), partial Pearsons correlations (controlling for age and sex) and receiver-operating characteristic (ROC) curves were calculated between indices of obesity (BMI, WC, WHR and WHtR) and blood pressure, HDL cholesterol (HDL-C), LDL cholesterol (LDL-C), total cholesterol (TC):HDL-C, TAG, fasting blood glucose, glycosylated Hb, high-sensitivity C-reactive protein (hs-CRP), fibrinogen, plasminogen activator inhibitor-1 (PAI-1) and an aggregated measure of cardiometabolic risk. SETTING Household study conducted between 2005 and 2007 in the San Juan Metropolitan Area in Puerto Rico. SUBJECTS A representative sample of 858 non-institutionalized adults. RESULTS All four obesity indices significantly correlated with the cardiometabolic risk factors. WHtR had the highest POR for high TC:HDL-C, blood pressure, hs-CRP, fibrinogen and PAI-1; WC had the highest POR for low HDL-C and high LDL-C and fasting blood glucose; WHR had the highest POR for overall cardiometabolic risk, TAG and glycosylated Hb. BMI had the lowest POR for most risk factors and smallest ROC curve for overall cardiometabolic risk. CONCLUSIONS The findings of the study suggest that general adiposity and abdominal adiposity are both associated with cardiometabolic risk in this population, although WC, WHR and WHtR appear to be slightly better predictors than BMI.

Sweat mineral loss from whole body, patch and arm bag in white and black girls

Abstract The objective of this study was to compare the loss of minerals in sweat between black and white girls by using four different methods of sweat collection. Sweat was collected from 36 girls during two three-week metabolic studies where they were fed either 1.3 or 4 g of Na/d in a crossover design. Sweat was collected by: 1) 24-h whole body; 2) 24-h back patch; 3) 30-min exercise with patches on the back; and 4) 30-min exercise with arm bags. Sweat losses of sodium, potassium, calcium, and magnesium were similar between races when whole body and patch methods were used. However, while consuming the high-Na diet, black girls excreted less (p

Vitamin D supplementation during pregnancy: Updated meta-analysis on maternal outcomes.

Highlights • Supplementing pregnant women with vitamin D significantly increases 25(OH)D at term but results were inconsistent.• It is unknown at this point what is the clinical significance of this finding but there is some indication that vitamin D supplementation, with or without calcium, may reduce the risk of pre-eclampsia.• More studies are needed to confirm these results and to determine the effects of vitamin D supplementation on the risk of other maternal outcomes, such as gestational diabetes, impaired glucose tolerance, caesarean section, gestational hypertension, other adverse conditions and maternal death.

Determinants of vitamin D status among overweight and obese Puerto Rican adults.

Background/Aims: Low vitamin D status is highly prevalent worldwide, and the major determinants are sun exposure and vitamin D intake. We aimed to measure vitamin D status in a sample of overweight/obese adults in Puerto Rico, an area with plenty of sun exposure, and relate it to vitamin D intake, sun exposure and body composition. Methods: Serum 25(OH)D levels (liquid chromatography-tandem mass spectrometry), body weight and fat (bioimpedance), vitamin D intake and sun exposure (questionnaires) were assessed. Analysis included age-adjusted correlations and multivariate regression. Results: In 98 subjects (66% females; 40–65 years), median serum 25(OH)D levels were 30.7 ng/ml (25–75th percentile 25.0–37.3); 55% had levels >30 ng/ml, 31% had levels between 20 and 30 ng/ml and 14% had levels <20 ng/ml. Total vitamin D intake was 180 IU/day (45–615), and the sun exposure score was 22 (17–27). After adjusting for gender, 25(OH)D levels were significantly correlated with vitamin D intake (r = 0.24, p = 0.018), the sum of sun exposure and vitamin D intake indices (r = 0.34, p = 0.001) and percent body fat (r = –0.25, p = 0.01). After adjusting for age, gender and percent body fat, the sum of sun exposure and vitamin D intake indices remained statistically associated with 25(OH)D levels (β = 1.5, p < 0.01). Conclusions: In this group of overweight and obese individuals, 25(OH)D was significantly related to vitamin D intake, sun exposure and vitamin D intake indices and percent body fat.

Racial differences in potassium homeostasis in response to differences in dietary sodium in girls.

BACKGROUND Racial differences in the renal disposition of potassium may be related to mechanisms for the greater susceptibility to hypertension in blacks than in whites. OBJECTIVE Our objective was to study the racial differences in the renin-angiotensin-aldosterone system and in potassium balance in black and white girls consuming a controlled diet that was low in potassium with 2 amounts of sodium intake (low compared with high). DESIGN The studies reported here were performed in 40 black and 28 white girls, aged 11-15 y, under highly controlled metabolic conditions. The studies comprised 2 sessions of 20-d metabolic balance sessions, at 2 amounts of dietary sodium intake (58 and 170 mmol . L(-1) . d(-1)), in a crossover design and with a constant dietary potassium intake of 50 mmol . L(-1) . d(-1). Repeated-measures analysis of variance was used to test for racial differences in potassium output and retention by sodium intakes. RESULTS Thirty black and 20 white girls completed the study. Urinary potassium excretion was lower in blacks than in whites, regardless of sodium intake (P < 0.05), with no differences in fecal or sweat potassium excretion. Cumulative potassium retention was significantly higher in blacks while consuming the low sodium diet. Plasma aldosterone concentrations after upright posture were significantly lower in blacks than in whites but were similar when supine, as were urinary aldosterone excretion rates. On week 3, blood pressure, body weight, urinary volume, creatinine, and serum sodium and potassium were similar. CONCLUSION The well-known racial difference in urinary potassium excretion appears to be at least in part due to greater renal retention of potassium in black girls.

Magnesium retention from metabolic-balance studies in female adolescents: impact of race, dietary salt, and calcium

BACKGROUND Previously, we showed that black girls retained more calcium than white girls did and that salt loading negatively affected calcium retention. Racial differences likely exist in other bone minerals also, such as magnesium, in response to salt loading during growth. OBJECTIVE We studied racial differences in magnesium metabolism in response to dietary sodium and calcium during rapid bone growth. DESIGN Twenty-seven white and 40 black girls (11-15 y old) were studied for 3 wk while they consumed low-sodium (1.3 g/d) and high-sodium (3.8 g/d) diets by using a randomized-order, crossover metabolic study with 3 dietary calcium intakes; the magnesium dietary intake was fixed at 230 mg/d. Urine and feces were collected during each 3-wk period in 24-h pools and analyzed for magnesium. A mixed-model ANOVA was used to determine the effect of race and dietary sodium with calcium intake as a covariate. RESULTS Salt loading or calcium intake had no significant effect on urinary magnesium excretion. Blacks excreted significantly less urinary magnesium (mean ± SD: 83.8 ± 25.6 mg/d) than did whites (94.9 ± 27.3 mg/d; P < 0.05). No effects were observed in fecal magnesium excretion. Magnesium retention was higher with the low-sodium diet (50.1 ± 44.0 mg/d) than with the high-sodium diet (39.3 ± 49.8 mg/d) (P < 0.05), with no effects of race or calcium intake. Salt loading had no effect on biomarkers. Whites had higher 25-hydroxyvitamin D and insulin-like growth factor binding protein 3 but lower 1,25-dihydroxyvitamin D and parathyroid hormone concentrations. CONCLUSIONS Blacks excreted less urinary magnesium than did whites. Magnesium retention was similar between races but higher with the low-sodium diet. Kinetic studies are needed to fully explain magnesium homeostasis. This trial was registered at clinicaltrials.gov as NCT01564238.