Risk of persistent cobalamin deficiency in adolescents fed a macrobiotic diet in early life

BACKGROUND: Cobalamin deficiency has been described in children consuming macrobiotic diets. OBJECTIVE: We investigated whether moderate consumption of animal products is sufficient for achieving normal cobalamin function in 73 adolescents who had received a macrobiotic diet until 6 y of age and had then switched to a lactovegetarian, lactoovovegetarian, or omnivorous diet (macrobiotic adolescents). DESIGN: Hematologic indexes and serum concentrations of methylmalonic acid (MMA), total homocysteine (tHcy), and folate were measured. Current consumption frequency of animal products and cobalamin intake from dairy products were assessed by questionnaire. Data from 94 age-matched adolescents who received an omnivorous diet from birth were used as a reference. RESULTS: Serum cobalamin concentrations were significantly lower and concentrations of MMA and folate and mean corpuscular volume (MCV) were significantly higher in macrobiotic adolescents than in control adolescents: of macrobiotic adolescents, 21% had abnormal MMA concentrations (>0.41 micromol/L), 37% had abnormal cobalamin concentrations (<218 pmol/L), 10% had abnormal tHcy concentrations (> 12.8 micromol/L), and 15% had abnormal MCV (> 89 fL). In macrobiotic adolescents, dairy products (200 g milk or yogurt and 22 g cheese/d) supplied on average 0.95 microg cobalamin/d; additionally, these adolescents consumed fish, meat, or chicken 2-3 times/wk. In girls, meat consumption contributed more to cobalamin status than the consumption of dairy products, whereas in boys these food groups were equally important. CONCLUSIONS: A substantial number of the formerly strict macrobiotic adolescents still had impaired cobalamin function. Thus, moderate consumption of animal products is not sufficient for restoring normal cobalamin status in subjects with inadequate cobalamin intake during the early years of life.     

Signs of impaired cognitive function in adolescents with marginal cobalamin status

BACKGROUND: Lack of cobalamin may lead to neurologic disorders, which have been reported in strict vegetarians. OBJECTIVE: The objective of this study was to investigate whether cognitive functioning is affected in adolescents (aged 10-16 y) with marginal cobalamin status as a result of being fed a macrobiotic diet up to an average age of 6 y. DESIGN: Data on dietary intake, psychological test performance, and biochemical variables of cobalamin status were collected from 48 adolescents who consumed macrobiotic (vegan type) diets up to the age of 6 y, subsequently followed by lactovegetarian or omnivorous diets, and from 24 subjects (aged 10-18 y) who were fed omnivorous diets from birth onward. Thirty-one subjects from the previously macrobiotic group were cobalamin deficient according to their plasma methylmalonic acid concentrations. Seventeen previously macrobiotic subjects and all control subjects had normal cobalamin status. RESULTS: The control subjects performed better on most psychological tests than did macrobiotic subjects with low or normal cobalamin status. A significant relation between test score and cobalamin deficiency (P: = 0.01) was observed for a test measuring fluid intelligence (correlation coefficient: -0.28; 95% CI: -0.48, -0.08). This effect became more pronounced (P: = 0.003) within the subgroup of macrobiotic subjects (correlation coefficient: -0.38; 95% CI: -0.62, - 0.14). CONCLUSION: Our data suggest that cobalamin deficiency, in the absence of hematologic signs, may lead to impaired cognitive performance in adolescents.     

Decreases in bone mineral content by dietary all-trans retinoic acid precede decreases in bone mineral density in a weanling rat model of cigarette smoke-induced lung injuries

Research has indicated that excessive vitamin A can have deleterious impacts on bone. Retinoic acid (RA), the most active metabolite of vitamin A, has been tested in clinical trials for treatment of lung cancer and emphysema. These trials are not measuring Bone Mineral Content (BMC) or Bone Mineral Density (BMD). In this study, we used an animal model to determine potential deleterious effects of all-trans RA on bone mass when used as a means to protect against or treat cigarette smoke-induced lung injuries, and also to evaluate BMC as a potential early indicator of osteoporosis risk. Twenty-four male weanling rats were fed either a control diet or a RA-supplemented diet. Half of each group was exposed to 40 cigarettes per day, 5 days per week, for 4 weeks. BMC and BMD were measured at weeks 2 and 4. RA supplementation in all groups significantly decreased (p < 0.05) only BMC at week 2 and both BMC and BMD (both p < 0.05) at week 4. The same results were observed when BMC was expressed relative to body weight. These data suggest that caution should be used when RA is used to treat smoke-related lung injuries.     

银川市中小学生骨密度和骨矿含量

了解银川市儿童青少年骨密度及骨矿含量,为促进儿童青少年骨骼发育及预防骨质疏松提供科学依据.方法 采用现况研究,运用分层整群抽样方法,在银川市抽取1 614名7~18岁儿童青少年进行问卷调查、体格测量和骨密度及骨矿物质含量测量.结果 被试平均全身骨密度为(0.89±0.12) g/cm2,平均全身骨矿含量为(1 548.40±.477.04)g.随着年龄的增加,儿童青少年骨密度和骨矿含量水平均呈上升趋势.男女骨密度和骨矿含量随年龄的变化曲线均出现了“2次交叉”,骨密度的第1次交叉在11岁,第2次在15岁;骨矿含量的第1次交叉在10岁,第2次在14岁.且骨密度和骨矿含量的第1次交叉前和第2次交叉后男生均高于女生,差异均有统计学意义(P值均<0.05).回族和汉族儿童青少年骨密度和骨矿含量水平差异均无统计学意义(￡值分别为-1.876,-1,838,P值均>0.05).结论 银川地区儿童青少年骨密度和骨矿含量随年龄增长而增加并受性别影响.应对儿童青少年定期进行骨密度和骨矿物含量的测量,以及早预防骨质疏松的发生.     

High-fat diets affect energy and bone metabolism in growing rats

Background

High-fat diets are usually associated with greater weight (W) gain and body fat (BF). However, it is still unclear whether the type and amount of fat consumed influence BF. Additionally, dietary fat intake may also have consequences on skeletal health.

Objective

To evaluate in healthy growing rats the effects of high-fat diets and type of dietary fat intake (saturated or vegetable oils) on energy and bone metabolism.

Methods

At weaning, male Wistar rats (n?=?50) were fed either a control diet (C; fat?=?7% w/w) or a high-fat diet (20% w/w) containing either: soybean oil, corn oil (CO), linseed oil (LO), or beef tallow (BT) for 8?weeks. Zoometric parameters, BF, food intake and digestibility, and total and bone alkaline phosphatase (b-AP) were assessed. Total skeleton bone mineral density (BMD) and content (BMC), BMC/W, spine BMD, and bone volume (static-histomorphometry) were measured.

Results

Animals fed BT diet achieved lower W versus C. Rats fed high-fat vegetable oil diets showed similar effects on the zoometric parameters but differed in BF. BT showed the lowest lipid digestibility and BMC. In contrast, high vegetable oil diets produced no significant differences in BMC, BMC/W, BMD, spine BMD, and bone volume. Marked differences were observed for LO and BT groups in b-AP and CO and BT groups in bone volume.

Conclusion

BT diet rich in saturated fatty acids had decreased digestibility and adversely affected energy and bone metabolisms, in growing healthy male rats. There were no changes in zoometric and bone parameters among rats fed high vegetable oil diets.     

Effects of taurine supplementation on bone mineral density in ovariectomized rats fed calcium deficient diet

Taurine supplementation has been shown to have a beneficial effect on femur bone mineral content in ovariectomized rats. It therefore seemed desirable to find out whether the beneficial effect of taurine on ovariectomized rats fed calcium deficient diet could also be reproduced. Forty female Sprague-Dawley rats were divided into two groups. One group was OVX and the other group received sham operation (SHAM), and received either control diet or a taurine supplemented diet for 6 weeks. All rats were fed on calcium deficient diet (AIN-93: 50% level of calcium) and deionized water. Bone mineral density (BMD) and bone mineral content (BMC) were measured in spine and femur. The serum and urine concentrations of calcium and phosphorus were determined. Bone formation was measured by serum osteocalcin and alkaline phosphatase (ALP) concentrations. Bone resorption rate was measured by deoxypyridinoline (DPD) crosslinks immunoassay and corrected for creatinine. Urinary calcium and phosphorus excretion, osteocalcin in blood and cross link value were not significantly different among the groups. Within the OVX group, the taurine supplemented group had not higher femur bone mineral content than the control group. This study established the need for a study on the taurine effect on bone with different calcium levels.     

Effect of multivitamin supplementation on the homocysteine and methylmalonic acid blood concentrations in women over the age of 60 years

Summary Background Deficiency of folic acid, vitamin B₆ and/or vitamin B₁₂ can result in elevated total plasma homocysteine concentrations (tHcy), which are considered to be a risk factor for vascular disease. Studies have shown that supplementation of the three vitamins can lower tHcy even in subjects with tHcy in the normal range. Aim of the study The aim of this study was to evaluate the effect of a 6 month supplementation with vitamin B₆, B₁₂ and folate on the concentrations of total plasma homocysteine and serum methylmalonic acid (MMA) of elderly women. Methods The study was designed as a randomized placebo controlled doubleblind trial, and 220 healthy women (aged 60–91 years) were involved. The vitamin and mineral capsule contained pyridoxine (3.4 mg), folic acid (400 µg) and cobalamin (9 µg) in addition to other micronutrients. Blood concentrations of folate, cobalamin, tHcy, MMA and the activity coefficient of erythrocyte alpha-aspartic aminotransferase (alpha-EAST) were measured at baseline and after 6 months of supplementation. Dietary intake was evaluated at the beginning and the end of the intervention by two 3–day diet records. Results Median concentrations of serum cobalamin, serum folate and erythrocyte folate increased significantly and tHcy and alpha–EAST activity (indicative of improved status of vitamin B₆) coefficient decreased significantly in the supplemented group. Median MMA concentration of the supplemented group was significantly lower than that of the placebo group after the intervention. The vitamin supplementation had a greater decreasing effect on the tHcy concentration of volunteers with lower vitamin and higher tHcy initial concentrations. In a linear regression model, baseline tHcy, serum folate, age and alpha–EAST activity coefficient were significantly correlated with the change in tHcy. The change in MMA in the supplement group was significantly associated to the baseline MMA values. Conclusions Our results show that a 6 month supplementation including physiological dosages of B vitamins improves the status of these nutrients and reduces tHcy in presumed healthy elderly women.     

Excess body fat negatively affects bone mass in adolescents

ObjectiveThe aim of this study was to investigate the effects of excess body fat on bone mass in overweight, obese, and extremely obese adolescents.MethodsThis study included 377 adolescents of both sexes, ages 10 to 19 y. Weight, height, body mass index (BMI), bone age, bone mineral content (BMC), and bone mineral density (BMD) were obtained by dual-energy x-ray absorptiometry. The results were adjusted for chronological age and bone age. Comparisons according to nutritional classification were performed by analysis of variance, followed by Tukey test. Linear regression models were used to explain the variation in BMD and BMC in the L1–L4 lumbar spinal region, proximal femur, and whole body in relation to BMI, lean mass, fat mass (FM), and body fat percentage (BF%), considering P < 0.05.ResultsFor all nutritional groups, average bone age was higher than chronological age. In both sexes, weight and BMI values increased from eutrophic to extremely obese groups, except for BMD and BMC, which did not differ among male adolescents, and were smaller in extremely obese than in obese female adolescents (P < 0.01). Significant differences were observed for FM and BF% values among all nutritional groups (P < 0.01). Positive, moderate to strong correlations were detected between BMD and BMC for BMI, lean mass, and FM. A negative and moderate correlation was found between BMC and BF%, and between BMD and BF% at all bone sites analyzed in males and between BF% and spine and femur BMD, in females.ConclusionThe results reveal a negative effect of BF% on bone mass in males and indicate that the higher the BF% among overweight adolescents, the lower the BMD and BMC values.     

Effects of alcohol on bone mineral and mechanical properties of bone in male rats

The effect of ethanol on bone mineral is poorly understood. In this study we have investigated whether ethanol affects bone mineral content (BMC), bone mineral density (BMD) measured by dual energy X-ray absorptiometry, and the mechanical properties of the tibia and femora in male Sprague-Dawley rats without histopathological signs of liver disease or nutritional deficit. Thirty-five male rats were fed a liquid diet containing 15% ethanol and glucose. An equivalent iso-volumetric amount of glucose-containing liquid was fed to the controls (n = 35). After an initial difference in weight, we found no difference in weight gain from week 1 to week 6. All animals were killed at 6 weeks. We found no evidence of ethanol-induced liver disease in a histopathological evaluation. The BMD and BMC were found to be lower in the ethanol group. No differences between the groups were found in the mechanical properties or in the length and size of the femora. We suggest that alcohol may have a toxic effect on bone in male rats known not to suffer from any histopathological hepatic lesions.     

Vitamin B-12 status is associated with bone mineral content and bone mineral density in frail elderly women but not in men

Subclinical vitamin B-12 deficiency is common in the elderly. Encouraged by early indications, we investigated the plasma vitamin B-12 status in association with bone mineral content (BMC) and bone mineral density (BMD) in frail elderly people. Data of 194 free-living Dutch frail elderly (143 women and 51 men) were available. BMC and BMD were measured by dual energy X-ray analysis. Biochemical analyses were performed on plasma or serum including vitamin B-12, methylmalonic acid, homocysteine, 25-hydroxy vitamin D and parathyroid hormone. Women had higher plasma vitamin B-12 (288 and 238 pmol/L, respectively) and lower plasma homocysteine levels (15.8 and 21.3 micro mol/L, respectively) than men. Of the total explained variance of BMC and BMD in women (46 and 22%, respectively), 1.3-3.1% was explained by plasma vitamin B-12, in addition to weight and height or energy intake. In men, the variance of BMC and BMD was explained by weight, smoking and/or height (total R(2) was 53 and 25%, respectively), but not by plasma vitamin B-12. Osteoporosis occurred more often among women whose vitamin B-12 status was considered marginal or deficient than in women with a normal status, i.e., the prevalence odds ratios (after adjustment for weight, age and calcium intake) (95% confidence intervals) were 4.5 (0.8;24.8) and 6.9 (1.2;39.4), respectively. These results suggest that vitamin B-12 status is associated with bone health in elderly women. Future studies on bone health should take into account a possible role of vitamin B-12 status in different populations.     

Vitamin B-12 status in a macrobiotic community

Vitamin B-12 status was assessed in a group of 110 adults and 42 children from a macrobiotic community in New England. Dietary and anthropometric information also was obtained. Fifty-one percent of the adults had low concentrations of serum vitamin B-12, which inversely correlated with duration of macrobiotic diet practice. Urinary methylmalonic acid (MMA) excretion was inversely correlated with serum vitamin B-12, and 30% of adults sampled had high urinary MMA. Fifty-five percent of children had high urinary MMA, and MMA was higher in the group that consumed a macrobiotic diet during their entire lifetime. Children were relatively short in stature and weight, and decreased stature was associated with high urinary MMA. In both adults and children vitamin B-12 status was better with more consumption of dairy products or with higher tertile of reported frequencies of vitamin B-12 consumption of various animal products. Vitamin B-12 status appeared to be unrelated to consumption of several vegetarian foods.     

The relationship of dietary and lifestyle factors to bone mineral indexes in children

OBJECTIVE: To identify factors related to children's bone mineral indexes at age 8 years, and to assess bone mineral indexes in the same children at ages 6 and 8 years. DESIGN: Bone mineral content (BMC [g]) and bone mineral density (BMD; calculated as g/cm 2 ) were measured by dual-energy x-ray absorptiometry (DEXA) in children and their mothers when the children were 8 years of age. A subset of children had an earlier DEXA assessment at age 6 years. Children's dietary intake, height, weight, and level of sedentary activity were assessed as part of a longitudinal study from ages 2 months to 8 years. SUBJECTS/SETTING: Fifty-two healthy white children (25 male, 27 female) and their mothers. Main outcome measures Children's total BMC and BMD at age 8 years. STATISTICAL ANALYSES PERFORMED: Correlations and stepwise multiple regression analyses. RESULTS: Factors positively related to children's BMC at age 8 years included longitudinal intakes (ages 2 to 8 years) of protein, phosphorus, vitamin K, magnesium, zinc, energy, and iron; height; weight; and age ( P < or = .05). Factors positively related to children's BMD at age 8 years included longitudinal intakes of protein and magnesium ( P < or = .05). Female sex was negatively associated with BMC and BMD at age 8 years ( P < or = .05). Children's bone mineral indexes at ages 6 and 8 years were strongly correlated ( r =0.86, P < .0001 for BMC; r =0.92, P <.0001 for BMD). CONCLUSIONS: Because many nutrients are related to bone health, children should consume a varied and nutrient-dense diet.     

硒锌水平对染铅大鼠股骨中微量元素及矿物质含量的影响

目的　以大鼠为模型 ,观察饲料中添加不同亚硒酸钠 (Se 0 1、0 5和 1 0mg kg)、乳酸锌 (Zn 10、5 0和 2 0 0mg kg)对醋酸铅 (Pb 0、2 0 0mg kg)所致骨骼毒性的拮抗作用。方法　断乳一周Wistar雄性大鼠按体重随机被分成 10组 ,每组 10只。其中 10组添加了不同铁、锌和铅水平的饲料 ,12周后处死大鼠测定股骨生长发育有关指标 ,结果　染铅抑制大鼠骨骼的生长发育 ,降低骨骼中矿物质含量和骨密度 ,补充硒锌后能改善大鼠股骨的重量和长度 ,增加股骨矿物质含量和骨密度 ,同时降低骨铅含量。结论　需要进一步研究铅影响骨骼生长发育的机制     

铁和锌对染铅大鼠股骨矿物质含量和骨密度的影响

目的　以大鼠为模型 ,观察饲料中添加不同铁 (1 0、5 0和 2 5 0mg kg)和锌 (1 0、4 0和 2 0 0mg kg)水平对低剂量铅 (0和 2 0 0mg kg)毒性的拮抗作用。方法　断乳一周Wistar雄性大鼠按体重随机被分成 1 1组 ,每组 1 0只。其中 1 0组饲以不同铁、锌和铅水平的饲料 ,另设 1组为未染铅正常对照 ,饲以基础正常饲料 ,1 2周后处死大鼠测定股骨生长发育有关指标。结果　研究发现 ,铅污染抑制大鼠骨骼的生长发育 ,能降低骨骼中矿物质含量和骨密度 ,补充铁锌后能改善大鼠股骨的重量和长度 ,增加股骨矿物质含量和骨密度 ,同时会增加骨铅含量。提示　需要进一步研究铅影响骨骼生长发育的机制     

Influence of cognitive eating restraint on total-body measurements of bone mineral density and bone mineral content in premenopausal women aged 18-45 y: a cross-sectional study

BACKGROUND: We examined the relation between cognitive eating restraint (CER) and total-body measurements of bone mineral density (BMD) and bone mineral content (BMC). OBJECTIVE: Our objective was to determine whether women with CER had lower total-body BMD and BMC than did other women. DESIGN: Premenopausal women, 90-150% of ideal weight, had measurements of their BMD and BMC made and completed questionnaires on physical activity, weight history, body size satisfaction, dieting history, eating behavior, and childbearing history. Bone measurements were examined for differences between groups with low and high CER scores by using analysis of covariance and quartiles of body weight to adjust for body size differences. CER was assessed by using the Three-Factor Eating Inventory and was defined as a score > or =9; normal eating restraint (NER) was defined by a score <9. Total-body BMC, BMD, and fat and lean masses were measured by dual-energy X-ray absorptiometry. RESULTS: Fifty-two percent of the women were classified as having CER. Women with CER were significantly more dissatisfied with their bodies. Analysis of covariance, with weight as the covariate, indicated a significant difference in BMC between women in preplanned pairs from the 5 lowest and 5 highest CER levels. No significant differences in BMD were observed between groups. Significantly lower BMC was found in women with high CER scores and body weights <71 kg than in those with high CER scores and weights > or =71 kg. CONCLUSIONS: BMC was significantly differently between women with low and high CER scores. BMC was significantly lower in women with body weights <71 kg and classified with CER. Lower BMC in women with high CER scores may indicate an increased risk of osteoporosis.     

Fermented soybeans by Rhizopus oligosporus reduce femoral bone loss in ovariectomized rats

BACKGROUND/OBJECTIVES

Soy isoflavones are structurally similar to estrogen and bind to estrogen receptors, suggesting that they exhibit estrogenic activities; therefore, they are referred to as phytoestrogens. Fermentation may affect the bioavailability of isoflavones altering soy isoflavone glycosides in the form of aglycones. Thus, this study investigated the effects of fermented soybeans by Rhizopus oligosporus on bone metabolism in both young rats as a pilot test and in ovariectomized (ovx) old rats as a model of menopause.

MATERIALS/METHODS

In the pilot test, a total of 24 seven-week-old female Sprague-Dawley (SD) rats were fed one of three diets for a period of four weeks: casein, unfermented soybean product, or fermented soybean product by R. oligosporus. In the ovx rat model, 20-week-old SD rats weighing 260-290 g underwent either sham-operation (n = 10) or bilateral ovariectomy (n = 30) and were then fed the AIN-93M diet for one week. Thereafter, rats were fed sham-casein, ovx-casein, ovx-soybean, or ovx-fermented soybean diet for five weeks. After decapitation, femoral bones were isolated and preserved in 9% formalin for assessment of bone mineral density (BMD), bone mineral content (BMC), and bone-breaking strength (BBS).

RESULTS

Ovx rats showed significantly increased weight gain and decreased uterine wet weight. Of particular interest, ovx rats fed fermented soybeans showed increased uterine wet weights compared to control rats. Fermented soybean diet caused a significant increase in plasma 17-β estradiol concentrations in young rats, and 17-β estradiol levels were enhanced in ovx rats to match those of sham-operated ones. Significantly lower femoral BMD and BMC were observed in ovx rats compared to sham-operated controls, whereas bone areas did not differ statistically among the groups. In addition, BBS tended to be increased in ovx rats fed soybeans and fermented soybeans.

CONCLUSIONS

Supplementation of fermented soybeans could have preventive and therapeutic effects against osteoporosis in postmenopausal women.     

Soy isoflavones: no effects on bone mineral content and bone mineral density in healthy,menstruating young adult women after one year

BACKGROUND: The effects of isoflavone-enriched soy protein on human bone mineral content (mass) and density in healthy, menstruating young adult females have not been examined in a comparative prospective investigation. Peri- and post-menopausal women have been reported to show beneficial effects of isoflavones on bone measurements. Therefore, young women may also be able to improve their accrual of peak bone mineral content (BMC) and bone mineral density (BMD) during the early adult years of bone consolidation with an isoflavone-enriched diet. OBJECTIVES: In this controlled, double-blind intervention, we tested the hypothesis that an isoflavone-rich soy protein diet increases BMC and BMD in young adult females over a period of one year in comparison to a control group receiving soy protein that has isoflavones removed. DESIGN: Young healthy women of any ethnic background, 21 to 25 years of age, were divided into two groups, placebo (n = 13) and supplement (n = 15). The soy protein supplement was enriched with isoflavones ( approximately 90 mg of total isoflavones/day), whereas the control protein diet was isoflavone-deficient, even though it contained the same amount of soy protein and other ingredients as the isoflavone-rich diet. Dual-energy x-ray absorptiometric (DXA) measurements of BMC and BMD were made at baseline and at 6 and 12 months. DXA estimates of body composition, including fat mass and lean body mass, were generated from whole-body BMC measurements. BMI was calculated as weight (kg) over height (m) squared. Physical activity was assessed, and three-day dietary records were taken at entry (baseline) and at 6 and 12 months. RESULTS: No changes in BMD after 12 months were found in either the isoflavone-treated (treatment) group or the isoflavone-deficient (control) group. Other variables also remained essentially constant over the 12-month period, including normal menstrual patterns in both the treatment and control groups. CONCLUSIONS: The isoflavone-rich soy preparation had no effects on BMC and BMD over a 12-month period in young healthy adult females with normal menses. An isoflavone-rich supplement appears to have little or no effect on bone in young adult women with normal ovarian function, at least over this 12-month study period.     

Association of protein intake with bone mineral density and bone mineral content among elderly women: The OSTPRE fracture prevention study

Abstract

It has been hypothesized that high protein intakes are associated with lower bone mineral content (BMC). Previous studies yield conflicting results and thus far no studies have undertaken the interaction of body mass index (BMI) and physical activity with protein intakes in relation to BMC and bone mineral density (BMD).

Objective

To evaluate the associations of dietary total protein (TP), animal protein (AP) and plant protein (PP) intakes with BMC and BMD and their changes. We tested also the interactions of protein intake with, obesity (BMI ≤30 vs. >30 kg/m2) and physical activity level (passive vs. active).

Design/ Setting

Prospective cohort study (Osteoporosis Risk-Factor and Fracture-Prevention Study).

Participants/measures

At the baseline, 554 women aged 65-72 years filled out a 3-day food record and a questionnaire covering data on lifestyle, physical activity, diseases, and medications. Intervention group received calcium 1000 mg/d and cholecalciferol 800 IU for 3 years. Control group received neither supplementation nor placebo. Bone density was measured at baseline and year 3, using dual energy x-ray absorptiometry. Multivariable regression analyses were conducted to examine the associations between protein intake and BMD and BMC.

Results

In cross-sectional analyses energy-adjusted TP (P≤0·029) and AP (P≤0·045) but not PP (g/d) were negatively associated with femoral neck (FN) BMD and BMC. Women with TP≥1·2 g/kg/body weight (BW) (Ptrend≤0·009) had lower FN, lumbar spine (LS) and total BMD and BMC. In follow-up analysis, TP (g/kg/BW) was inversely associated with LS BMD and LS BMC. The detrimental associations were stronger in women with BMI<30 kg/m². In active women, TP (g/kg/BW) was positively associated with LS BMD and FN BMC changes.

Conclusions

This study suggests detrimental associations between protein intake and bone health. However, these negative associations maybe counteracted by BMI>30 kg/m2 and physical activity.

     

Bone mineral density and content during weight cycling in female rats: effects of dietary amylase-resistant starch

Background

Although there is considerable evidence for a loss of bone mass with weight loss, the few human studies on the relationship between weight cycling and bone mass or density have differing results. Further, very few studies assessed the role of dietary composition on bone mass during weight cycling. The primary objective of this study was to determine if a diet high in amylase-resistant starch (RS₂), which has been shown to increase absorption and balance of dietary minerals, can prevent or reduce loss of bone mass during weight cycling.

Methods

Female Sprague-Dawley (SD) rats (n = 84, age = 20 weeks) were randomly assigned to one of 6 treatment groups with 14 rats per group using a 2 × 3 experimental design with 2 diets and 3 weight cycling protocols. Rats were fed calcium-deficient diets without RS₂ (controls) or diets high in RS₂ (18% by weight) throughout the 21-week study. The weight cycling protocols were weight maintenance/gain with no weight cycling, 1 round of weight cycling, or 2 rounds of weight cycling. After the rats were euthanized bone mineral density (BMD) and bone mineral content (BMC) of femur were measured by dual energy X-ray absorptiometry, and concentrations of calcium, copper, iron, magnesium, manganese, and zinc in femur and lumbar vertebrae were determined by atomic absorption spectrophotometry.

Results

Rats undergoing weight cycling had lower femur BMC (p < 0.05) and marginally lower BMD (p = 0.09) than rats not undergoing weight cycling. In comparison to controls, rats fed RS₂ had higher femur BMD (p < 0.01) and BMC (p < 0.05), as well as higher values for BMD and BMC measured at the distal end (p < 0.001 and p < 0.01) and femoral neck (p < 0.01 and p < 0.05). Consistent with these findings, RS₂-fed rats also had higher femur calcium (p < 0.05) and magnesium (p < 0.0001) concentrations. They also had higher lumbar vertebrae calcium (p < 0.05) and magnesium (p < 0.05) concentrations.

Conclusion

Weight cycling reduces bone mass. A diet high in RS₂ can minimize loss of bone mass during weight cycling and may increase bone mass in the absence of weight cycling.     

The effect of a vegetarian and different omnivorous diets on urinary risk factors for uric acid stone formation

Summary. Background: About 10–15% of all urinary stones are composed of uric acid. A high urinary uric acid excretion, a low urine volume and an acidic urinary pH value are suggested to be the most important risk factors for uric acid stone formation. Aim of the study: The effect of a vegetarian diet and different omnivorous diets on the risk of uric acid crystallization was investigated. Methods: Ten healthy male subjects ingested a self-selected meat-containing diet (SD) for two weeks, and three different standardized diets for a period of 5 days each. The Westerntype diet (WD) was representative of the usual dietary habits,whereas the balanced omnivorous diet (OD) and the ovo-lacto-vegetarian diet (VD) were calculated according to the requirements. Results: The risk of uric acid crystallization was highest on the ingestion of diets SD and WD, due to the high urinary uric acid excretion and the acidic urinary pH. The relative supersaturation with uric acid declined significantly by 85% on the intake of diet OD, consequent to the decrease in uric acid excretion and concentration and the increase in urinary pH value. The ingestion of the vegetarian diet VD led to a further significant reduction in the risk of uric acid crystallization by 93% compared to diet WD. Conclusions: The results indicate that the intake of a balanced vegetarian diet with a moderate animal protein and purine content, an adequate fluid intake and a high alkali-load with fruits and vegetables results in the lowest risk of uric acid crystallization compared to the omnivorous diets.