An increase in dietary n-3 fatty acids decreases a marker of bone resorption in humans

Does maternal long chain polyunsaturated fatty acid status in pregnancy influence the bone health of children? The Southampton Women's Survey

In this large, population-based, prospective, mother-offspring cohort study, maternal long chain polyunsaturated fatty acid (LCPUFA) status during pregnancy was found to be positively associated with bone mass in the offspring at age 4 years. The findings suggest that variation in intrauterine exposure to n-3 and n-6 LCPUFAs may have potential consequences for skeletal development.

INTRODUCTION

Maternal diet in pregnancy has been linked to childhood bone mass, but the mechanisms and nutrients involved are uncertain. Long-chain polyunsaturated fatty acids (LCPUFAs) have been shown to affect bone metabolism, but the relationship between maternal fatty acid status and bone mass in the offspring remains unknown.

METHODS

We evaluated the association between maternal LCPUFA status in late pregnancy (34 weeks gestation) and bone density in their children at age 4 years within 727 mother-child pairs taking part in the Southampton Women's Survey.

RESULTS

Concentrations of the n-3 LCPUFA component of maternal plasma phosphatidylcholine were positively associated with a number of bone mineral measures at the age of 4 years; these associations persisted after adjustment for maternal body build, walking speed and infant feeding. Relationships were most evident for eicosapentaenoic acid (r = 0.09, p = 0.02 for whole body areal bone mineral density [aBMD] and r = 0.1, p = 0.008 for lumbar spine aBMD) and for docosapentaenoic acid (r = 0.09, p = 0.02 for whole body aBMD and r = 0.12, p = 0.002 for lumbar spine aBMD).

CONCLUSIONS

These findings suggest that variation in early exposure to n-3 and n-6 LCPUFA may have potential consequences for bone development and that the effects appear to persist into early childhood.

The effects of n-3 long-chain polyunsaturated fatty acids on bone formation and growth factors in adolescent boys

INTRODUCTION

Animal studies indicate that n-3 long-chain polyunsaturated fatty acids (LCPUFAs) increase bone formation. To our knowledge, no studies have examined this in growing humans. This study investigated whether bone mass and markers of bone formation and growth were (i) associated with docosahexaenoic acid (DHA) status and (ii) affected by fish oil supplementation, in adolescent boys.

METHODS

Seventy-eight healthy, slightly overweight 13- to 15-y-old boys were randomly assigned to breads with DHA-rich fish oil (1.1 g/d n-3 LCPUFA) or control for 16 wk. Whole-body bone mineral content (BMC), bone area (BA), bone mineral density (BMD), plasma osteocalcin, and growth factors were measured at wk 0 and wk 16, as well as diet, physical activity, and n-3 LCPUFA status in erythrocytes.

RESULTS

Fish oil strongly increased DHA status (P = 0.0001). No associations were found between DHA status and BMC, BA, BMD, or the markers of bone formation and growth at baseline. Furthermore, the fish oil intervention did not affect any of the outcomes as compared with control. However, dose-response analyses revealed a positive association between changes in DHA status and plasma insulin-like growth factor-1 (IGF-1) during intervention (β = 0.24, P = 0.03, n = 78).

DISCUSSION

DHA status and fish oil supplementation were not associated with bone mass or markers of bone formation in adolescent boys, but IGF-1 increased with increasing DHA status.

A systematic review of omega-3 fatty acids and osteoporosis

Some epidemiological evidence suggests that diets high in omega 3 fatty acids (n-3 FAs) may be beneficial for skeletal health. The aim of this systematic review was to determine if randomized controlled trials (RCTs) support a positive effect of n-3 FAs on osteoporosis. A systematic search was performed in PubMed and EMBASE databases. We included RCTs with skeletal outcomes conducted in adults or children (> = 1 year old) using n-3 FA fortified foods, diets or supplements alone or in combination with other vitamins/minerals, versus placebo. Primary outcomes were incident fracture at any site and bone mineral density (BMD) in g/cm2. Secondary outcomes included bone formation or resorption markers and bone turnover regulators. A total of 10 RCTs met inclusion criteria. Effect sizes with 95 % confidence intervals were estimated to compare studies across various treatments and outcome measures. No pooled analysis was completed due to heterogeneity of studies and small sample sizes. No RCTs included fracture as an outcome. Four studies reported significant favorable effects of n-3 FA on BMD or bone turnover markers. Of these, three delivered n-3 FA in combination with high calcium foods or supplements. Five studies reported no differences in outcomes between n-3 FA intervention and control groups; one study included insufficient data for effect size estimation. Strong conclusions regarding n-3 FAs and bone disease are limited due to the small number and modest sample sizes of RCTs, however, it appears that any potential benefit of n-3 FA on skeletal health may be enhanced by concurrent administration of calcium.

Dietary sources of omega 3 fatty acids: public health risks and benefits

Omega 3 fatty acids can be obtained from several sources, and should be added to the daily diet to enjoy a good health and to prevent many diseases. Worldwide, general population use omega-3 fatty acid supplements and enriched foods to get and maintain adequate amounts of these fatty acids. The aim of this paper was to review main scientific evidence regarding the public health risks and benefits of the dietary sources of omega-3 fatty acids. A systematic literature search was performed, and one hundred and forty-five articles were included in the results for their methodological quality. The literature described benefits and risks of algal, fish oil, plant, enriched dairy products, animal-derived food, krill oil, and seal oil omega-3 fatty acids.

Perinatal maternal dietary supplementation of ω3-fatty acids transiently affects bone marrow microenvironment, osteoblast and osteoclast formation, and bone mass in male offspring

It is increasingly evident that micronutrient environment experienced before birth and in infancy is important for achieving optimal bone mass by adolescence and maintaining bone health. This study determined whether maternal supplementation with ω3-polyunsaturated fatty acids (n3FA) improved offspring bone growth and adult bone mass. Female rats were fed a diet containing 0.1% (control, n = 10) or 1% (n3FA, n = 11) docosahexanoic acid (DHA) during pregnancy and lactation. Offspring were weaned onto a control rat chow diet. Tibial growth plate and metaphysis structure, osteoblast/osteoclast density and differentiation, and gene expression were assessed in offspring at 3 wk (weaning), 6 wk (adolescent), and 3 months (adult). Maternal n3FA supplementation elevated offspring plasma n3FA levels at 3 and 6 wk. Although total growth plate heights were unaffected at any age, the resting zone thickness was increased in both male and female offspring at 3 wk. In n3FA males, but not females, bone trabecular number and thickness were increased at 3 wk but not other ages. The wk 3 n3FA males also exhibited an increased bone volume, an increased osteoblast but decreased osteoclast density, and lower expression of osteoclastogenic cytokines receptor activator of nuclear factor-κB ligand, TNF-α, and IL-6. No effects were seen at 6 wk or 3 months in either sex. Thus, perinatal n3FA supplementation is associated with increased bone formation, decreased resorption, and a higher bone mass in males, but not in females, at weaning; these effects do not persist into adolescence and adulthood and are unlikely to produce lasting improvements in bone health.

Plasma phosphatidylcholine concentrations of polyunsaturated fatty acids are differentially associated with hip bone mineral density and hip fracture in older adults: the Framingham Osteoporosis Study

Polyunsaturated fatty acids (PUFAs) may influence bone health. The objective of this work was to examine associations between plasma phosphatidylcholine (PC) PUFA concentrations and hip measures: (1) femoral neck bone mineral density (FN-BMD) (n = 765); (2) 4-year change in FN-BMD (n = 556); and (3) hip fracture risk (n = 765) over 17-year follow-up among older adults in the Framingham Osteoporosis Study. BMD measures were regressed on quintile of plasma PC PUFAs (docosahexaenoic acid [DHA], linoleic acid [LA], and arachidonic acid [AA]), adjusted for covariates. Hazard ratios (HR) and 95% confidence interval (CI) for hip fracture were estimated by quintile of plasma PC PUFAs, adjusted for covariates. Higher concentrations of PC DHA were associated with loss of FN-BMD over 4 years in women (p-trend = 0.04), but was protective in men in the uppermost quintile compared to men grouped in the lower four quintiles, in post hoc analysis (p = 0.01). PC LA concentrations were inversely associated with baseline FN-BMD in women (p-trend = 0.02), and increased hip fracture risk in women and men (p-trend = 0.05), but body mass index (BMI) adjustment attenuated these associations (p-trend = 0.12 and p-trend = 0.14, respectively). A trend toward a protective association was observed between PC AA and baseline FN-BMD in men (p-trend = 0.06). Women and men with the highest PC AA concentrations had 51% lower hip fracture risk than those with the lowest (HR = 0.49, 95% CI = 0.24-1.00). Opposing effects of PC DHA on FN-BMD loss observed in women and men need further clarification. Bone loss associated with PC LA may be confounded by BMI. High PC AA concentrations may be associated with reduced hip fracture risk.

The effects of n-3 fatty acids on inflammatory cytokines in osteoporotic spinal cord injured patients: A randomized clinical trial

BACKGROUND

Clinical studies have reported that osteoporosis after spinal cord injury (SCI) can be the inflammation-induced base condition and n-3 polyunsaturated fatty acids (PUFAs) suppress the production of pro-inflammatory cytokines. This study documents the effects of n-3 PUFAs on cytokines in a group of patients after chronic SCI.

METHODS

This double-blind, placebo- controlled trial was designed in 82 (69 males and 13 females) osteoporotic patients with SCI for 4 months. All participants received 1000 mg calcium and 400 IU vitamin D daily. The patients received two MorDHA capsules (435 g of DHA and 65 mg of EPA per day) or two placebo capsules (one with lunch, and the other with dinner) in the treatment and control groups, respectively. Serum interleukins and Dietary intakes were assessed in the beginning and end of the study. Mean difference for each group was compared by using Student's t test.

RESULTS

A total of 75 (13 females, 62 males) participants completed the study over 4 months. The supplemented and control groups did not show any difference in their baseline characteristics. There were significant difference neither between two groups at the end of the study nor in each group between beginning and end of the study.

CONCLUSINS

MorDHA supplementation for 4 months had no significant effect on inflammatory markers. Although mean difference in all pro-inflammatory cytokines were not significant in both treatment and control groups during the study (P>0.05), the decrease in treatment group was weakly higher that it may be important in point of clinical view.

Alternative therapies for the prevention and treatment of osteoporosis

Osteoporosis is a medical condition that affects millions of men and women. People with this condition have low bone mass, which places them at increased risk for bone fracture after minor trauma. The surgeries and treatments required to repair and heal bone fractures involve long recovery periods and can be expensive. Because osteoporosis occurs frequently in the elderly, the financial burden it places on society is likely to be large. In the United States, the Food and Drug Administration has approved several drugs for use in the prevention and treatment of osteoporosis. However, all of the currently available agents have severe side effects that limit their efficacy and underscore the urgent need for new treatment options. One promising approach is the development of alternative (nonpharmaceutical) strategies for bone maintenance, as well as for the prevention and treatment of osteoporosis. This review examines the currently available nonpharmaceutical alternatives that have been evaluated in in vitro and in vivo studies. Certain plants from the following families have shown the greatest benefits on bone: Alliceae, Asteraceae, Thecaceae, Fabaceae, Oleaceae, Rosaceae, Ranunculaceae, Vitaceae, Zingiberaceae. The present review discusses the most promising findings from studies of these plant families.

Maternal supplementation with dietary arachidonic and docosahexaenoic acids during lactation elevates bone mass in weanling rat and guinea pig offspring even if born small sized

Whether post-natal long chain polyunsaturated fatty acids (LCPUFA) elevates bone mineral content (BMC) of small and normal neonates was studied using pregnant rats and guinea pigs fed a control (C) diet or low protein (LP) diet to induce small neonates followed by C or LCPUFA diets during lactation. Measurements (days 3 and 21 post-partum) included BMC and density (BMD) plus bone metabolism. In rats LP reduced birth weight but at day 21 elevated weight and whole body BMC; LCPUFA enhanced spine BMC, tibia BMC and BMD and whole body BMD. In guinea pig pups, at days 3 and 21, LP reduced weight, whole body and regional BMC and BMD whereas LCPUFA reduced day 3 osteocalcin and elevated day 21 spine BMD. LCPUFA minimized loss of whole body BMC in dams and elevated osteocalcin in sows. LCPUFA during lactation enhances bone in normal and small neonates without compromising maternal bone.

Associations of dietary polyunsaturated fatty acids with bone mineral density in elderly women

BACKGROUND/OBJECTIVES

Significance of dietary fatty acids on bone health is not clear, and the evidence is controversial. This study aimed to investigate the relationship between dietary polyunsaturated fatty acids (PUFAs) and bone mineral density (BMD) among elderly women.

SUBJECTS/METHODS

Subjects (n=554) were drawn from the Kuopio OSTPRE Fracture Prevention Study. At baseline they filled a 3-day food record and a questionnaire on lifestyle factors, diseases and medications. BMD was measured at lumbar spine (L2-L4), femoral neck and total body by dual energy X-ray absorptiometry at baseline and after 3 years. The associations between dietary fatty acids and BMD were analyzed by a linear mixed model adjusting for potential dietary and non-dietary confounders.

RESULTS

Our findings suggested a positive relationship between the dietary PUFAs and BMD at lumbar spine and in total body but not at femoral neck. Further analyses revealed that these results were due to associations among the women without hormone therapy (HT) at baseline. Among them, the intake of total PUFAs as well the intakes of linoleic and linolenic acids and total n-3 and n-6 fatty acids were significantly associated with BMD at lumbar spine; P for trend over the quartiles ranged between 0.013 and 0.001. Similarly, significant associations were demonstrated for total body BMD and fatty acids with an exception of total PUFA. No significant associations were found among women with HT at baseline.

CONCLUSIONS

Our findings among elderly women without HT support the suggested beneficial effect of dietary PUFAs on bone health.

Long-term aerobic exercise and omega-3 supplementation modulate osteoporosis through inflammatory mechanisms in post-menopausal women: a randomized, repeated measures study

BACKGROUND

Evidence indicates that dietary fats and physical activity influence bone health. The purpose of this study was to examine the effects of long-term aerobic exercise and omega-3 (N-3) supplementation on serum inflammatory markers, bone mineral density (BMD), and bone biomarkers in post-menopausal women.

METHODS

Seventy-nine healthy sedentary post-menopausal women aged 58-78 years participated in this study. Subjects were randomized to one of 4 groups: exercise + supplement (E+S, n = 21), exercise (E, n = 20), supplement (S, n = 20), and control (Con, n = 18) groups. The subjects in the E+S and E groups performed aerobic exercise training (walking and jogging) up to 65% of HRmax, three times a week for 24 weeks. Subjects in the E+S and S groups consumed 1000 mg/d N-3 for 24 weeks. The lumbar spine (L2-L4) and femoral neck BMD, serum tumor necrosis factor (TNF) α, interleukin (IL) 6, prostaglandin (PG) E2, estrogen, osteocalcin, 1, 25-dihydroxyvitamin D3 (1, 25 Vit D), C-telopeptide (CTX), parathyroid hormone (PTH) and calcitonin (CT) were measured at baseline, the end of week 12 and 24.

RESULTS

Serum estrogen, osteocalcin, 1, 25 Vit D, CT, L2-L4 and femoral neck BMD measures increased (P < 0.05) and the serum CTX, PTH, TNF-α, IL-6, and PGE2 decreased (P < 0.05) in E + S group after the 24 wk intervention but not in the E or S intervention groups. L2-L4 and femoral neck BMD, estrogen, osteocalcin, and CT were negatively (P < 0.05) correlated with TNF-α and PGE2. PTH and CT were correlated positively and negatively with IL-6, respectively (P < 0.05).

CONCLUSIONS

The present study demonstrates that long-term aerobic exercise training plus N-3 supplementation have a synergistic effect in attenuating inflammation and augmenting BMD in post-menopausal osteoporosis.

Dietary intakes of arachidonic acid and alpha-linolenic acid are associated with reduced risk of hip fracture in older adults

PUFA are hypothesized to influence bone health, but longitudinal studies on hip fracture risk are lacking. We examined associations between intakes of PUFA and fish, and hip fracture risk among older adults (n = 904) in the Framingham Osteoporosis Study. Participants (mean age ~75 y at baseline) were followed for incident hip fracture from the time they completed the baseline exam (1988-1989) until December 31, 2005. HR and 95% CI were estimated for energy-adjusted dietary fatty acid exposure variables [(n-3) fatty acids: α-linolenic acid (ALA), EPA, DHA, EPA+DHA; (n-6) fatty acids: linoleic acid, arachidonic acid (AA); and the (n-6):(n-3) ratio] and fish intake categories, adjusting for potential confounders and covariates. Protective associations were observed between intakes of ALA (P-trend = 0.02) and hip fracture risk in a combined sample of women and men and between intakes of AA (P-trend = 0.05) and hip fracture risk in men only. Participants in the highest quartile of ALA intake had a 54% lower risk of hip fracture than those in the lowest quartile (Q4 vs. Q1: HR = 0.46; 95% CI = 0.26-0.83). Men in the highest quartile of AA intake had an 80% lower risk of hip fracture than those in the lowest quartile (Q4 vs. Q1: HR = 0.20; 95% CI = 0.04-0.96). No significant associations were observed among intakes of EPA, DHA, EPA+DHA, or fish. These findings suggest dietary ALA may reduce hip fracture risk in women and men and dietary AA may reduce hip fracture risk in men.

Protective effects of fish intake and interactive effects of long-chain polyunsaturated fatty acid intakes on hip bone mineral density in older adults: the Framingham Osteoporosis Study

BACKGROUND

Polyunsaturated fatty acids and fish may influence bone health.

OBJECTIVE

We aimed to examine associations between dietary polyunsaturated fatty acid and fish intakes and hip bone mineral density (BMD) at baseline (1988-1989; n = 854) and changes 4 y later in adults (n = 623) with a mean age of 75 y in the Framingham Osteoporosis Study.

DESIGN

BMD measures were regressed on energy-adjusted quartiles of fatty acid intakes [n-3 (omega-3): α-linolenic acid, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and EPA+ DHA; n-6 (omega-6): linoleic acid (LA) and arachidonic acid (AA); and n-6:n-3 ratio] and on categorized fish intakes, with adjustment for covariates. Effect modification by EPA+DHA intake was tested for n-6 exposures.

RESULTS

High intakes (≥3 servings/wk) of fish relative to lower intakes were associated with maintenance of femoral neck BMD (FN-BMD) in men (dark fish + tuna, dark fish, and tuna) and in women (dark fish) (P < 0.05). Significant interactions between AA and EPA+DHA intakes were observed cross-sectionally in women and longitudinally in men. In women with EPA+DHA intakes at or above the median, those with the highest AA intakes had a higher mean baseline FN-BMD than did those with the lowest intakes (quartile 4 compared with quartile 1: P = 0.03, P for trend = 0.02). In men with the lowest EPA+DHA intakes (quartile 1), those with the highest intakes of AA (quartile 4) lost more FN-BMD than did men with the lowest intakes of AA (quartile 1; P = 0.04). LA intake tended to be associated with FN-BMD loss in women (P for trend < 0.06).

CONCLUSIONS

Fish consumption may protect against bone loss. The protective effects of a high AA intake may be dependent on the amount of EPA+DHA intake.

The effect of polyunsaturated fatty acids on bone health

The essential polyunsaturated fatty acids (PUFAs) are divided into two classes, n-3 (ω-3) and n-6 (ω-6) and their dietary precursors are α-linolenic (ALA) and linoleic acid (LA), respectively. PUFAs are precursors of a wide range of metabolites, for example eicosanoids like prostaglandins and leukotrienes, which play critical roles in the regulation of a variety of biological processes, including bone metabolism.

A large body of evidence supports an effect of PUFA on bone metabolism which may be mediated by regulation of osteoblastogenesis and osteoclast activity, change of membrane function, decrease in inflammatory cytokines, such as interleukin-1 (IL-1), interleukin-6 (IL-6), and tumour necrosis factor alpha (TNF-α), modulation of peroxisome proliferators-activated receptor γ (PPARγ) and influence in NO secretion and NO synthase.

Animal studies have shown that a higher dietary omega-3/omega-6 fatty acids ratio is associated with beneficial effects on bone health. Human studies conducted in elderly subjects suggest that omega-3 instead of omega-6 has a positive effect on bone metabolism. In spite of increasing evidence, studies conducted in humans do not allow us to draw a definitive conclusion on the usefulness of PUFAs in clinical practice.

Supplementation with a low–moderate dose ofn-3 long-chain PUFA has no short-term effect on bone resorption in human adults

Previous research suggests thatn-3 PUFA may play a role in bone health. The present analysis aimed to investigate the impact ofn-3 PUFA supplementation on bone resorption in adult men and women. Serum samples from 113 mild–moderately depressed individuals (twenty-six males and eighty-seven females, aged 18–67 years) randomised to receive 1·48 g EPA+DHA/d (n53) or placebo (n60) for 12 weeks as part of a large recent randomised controlled trial were assayed forn-3 PUFA status and a bone resorption marker, C-terminal cross-linking telopeptide of type 1 collagen (β-CTX). Regression analyses revealed thatn-3 PUFA status following supplementation was associated with randomisation (placebo/n-3 PUFA) (B = 3·25, 95 % CI 2·60, 3·91,P < 0·01). However, β-CTX status following supplementation was not associated with randomisation (B = − 0·01, 95 % CI − 0·03, 0·04). Change in β-CTX status was also not associated with change inn-3 PUFA status (B = − 0·002, 95 % CI − 0·01, 0·01). These findings provide no evidence for an association betweenn-3 PUFA supplementation (1·48 g EPA+DHA/d) for 12 weeks and bone resorption in humans assessed by β-CTX, and suggest thatn-3 PUFA supplementation may be unlikely to be of benefit in preventing bone loss.

Fatty acid consumption and risk of fracture in the Women's Health Initiative

BACKGROUND

Fatty acids (FAs) may be important dietary components that modulate osteoporotic fracture risk.

OBJECTIVE

The objective was to examine FA intake in relation to osteoporotic fractures.

DESIGN

The participants were postmenopausal women enrolled in the Women's Health Initiative (n = 137,486). Total fractures were identified by self-report; hip fractures were confirmed by medical record review. FA intake was estimated from baseline food-frequency questionnaires and standardized to total caloric intake. No data on omega-3 (n-3) FA supplements were available. Cox proportional hazard models were constructed to estimate risk of fracture.

RESULTS

Higher saturated FA consumption was associated with higher hip fracture risk [quartile 4 multivariate-adjusted hazard ratio (HR): 1.31; 95% CI: 1.11, 1.55; P for trend = 0.001]. Lower total fracture risk was associated with a higher monounsaturated FA intake (quartile 3 HR: 0.94; 95% CI: 0.89, 0.98; P for trend = 0.050) and polyunsaturated FA intake (quartile 4 HR: 0.95; 95% CI: 0.90, 0.99; P for trend = 0.019). Unexpectedly, higher consumption of marine n-3 FAs was associated with greater total fracture risk (quartile 4 HR: 1.07; 95% CI: 1.02, 1.12; P for trend = 0.010), whereas a higher n-6 FA intake was associated with a lower total fracture risk (quartile 4 HR: 0.94; 95% CI: 0.89, 0.98; P for trend 0.009).

CONCLUSIONS

These results suggest that saturated FA intake may significantly increase hip fracture risk, whereas monounsaturated and polyunsaturated FA intakes may decrease total fracture risk. In postmenopausal women with a low intake of marine n-3 FAs, a higher intake of n-6 FAs may modestly decrease total fracture risk. This trial was registered at clinicaltrials.gov as NCT00000611.

Improvement of bone formation biomarkers after 1-year consumption with milk fortified with eicosapentaenoic acid, docosahexaenoic acid, oleic acid, and selected vitamins

The hypothesis of this study was that the replacement of regular milk with fortified milk in hyperlipidemic adults for 1 year would improve bone biomarkers. The fortified milk contained eicosapentaenoic acid and docosahexaenoic acid from fish oils, oleic acid, vitamins A, B(6), and E, as well as folic acid. We believe that the fortified milk will improve the blood fatty acid profile and vitamin status in subjects to benefit bone health biomarkers. From the 84 patients who accepted to participate, 11 of these were excluded for the presence of metabolic diseases and 1 was excluded for noncompliance with the protocol. Seventy-two hyperlipidemic patients (35-65 years) were randomly divided between 2 study groups. The supplement group (E; n = 39) consumed 0.5 L/d of fortified milk that contained fish oil, oleic acid, and vitamins. The control group (C; n = 33) consumed 0.5 L/d of semiskimmed milk containing the same amount of total fat. Blood samples were taken at T(0), T(3), T(6), and T(12) months to determine plasma fatty acids, vitamins B(6), E, and 25-hydroxyvitamin D and serum folate, calcium, soluble osteoprotegerin (OPG), soluble receptor activator of NF-kappaB ligand (RANKL), osteocalcin, parathormone, type I collagen carboxy-terminal telopeptide, and malondialdehyde. After 1 year, the E group showed a significant increase in plasma eicosapentaenoic acid (42%), docosahexaenoic acid (60%), vitamin B6 (38%), OPG (18%), RANKL (7%), OPG/RANKL (10%), red blood cell folate (21%), serum folate (53%), calcium (4%), vitamin D (11%), and osteocalcin (22%). Dietary supplementation with the fortified milk drink improved nutritional status and bone formation markers in adult hyperlipidemic patients.

The calciotropic hormone response to omega-3 supple-mentation during long-term weight-bearing exercise training in post menopausal women

The purpose of this study was to examine the effects of ingestion of omega-3 (n-3) and aerobic exercise intervention on the calcium regulating hormones in healthy postmenopausal women. To this end, 56 healthy sedentary postmenopausal women with mean age 57.7 ± 3.5 yrs participated in this study. Participants were randomly divided into exercise plus supple-ment (E+S; n = 14), exercise (E; n = 14), supplement (S; n = 14) and control (Con, n = 14) groups. The subjects in E+S and E groups performed aerobic exercise training (walking and jog-ging) up to 65% of exercise HRmax, three times a week for 16 weeks. Subjects in E+S and S groups were asked to consume 1000 mg/d omega-3 for 16 weeks. The blood ionized Calcium (Ca(+2)), Parathyroid hormone (PTH), estrogen and Calcitonin (CT) were measured before and after 16 weeks of exercise training. Results indicated that consuming 1000 mg·day(-1) omega-3 during 16 weeks and or the aerobic exercise, significantly increased CT (p = 0.001) in E+S, E and S groups and significantly decreased PTH (p = 0.001) levels in E+S and E groups, also significantly increased estrogen (p = 0.024) levels in E+S and E groups, but had no significant effects on blood Ca(+2) (p = 0.619) levels. The results of present study demonstrate that omega-3 in combination with regular aerobic exercise training have significant effects on serum CT, estrogen and PTH in non-athletic post-menopausal women, suggesting that participating in moderate intensity weight-bearing exercise and incorporating sources of omega-3 in the diet a possible intervention to help slow the loss of bone that occurs following menopause. Key pointsLong-term weight-bearing exercise was shown to prove positive effects on bone metabolism.Serum calciotropic hormone levels and Ca(+2) can be affected by exercise intensity as well as dura-tion.There is a good relationship between dietary omega-3 (n-3) and bone metabolism in post-menopausal women.Omega-3 in combination with long-term weight-bearing exercise training has significant effects on serum calciotropic hormone levels in non-athlete post-menopausal women.

The effect of n-3 fatty acids on bone biomarkers in Iranian postmenopausal osteoporotic women: a randomized clinical trial

Recently, n-3 fatty acids are in the center of attention for their potent anti-inflammatory effects. Osteoporosis as a chronic senile disease is associated with inflammation, and the role of inflammatory mediators has been demonstrated in recent years. The beneficial effects of n-3 fatty acids on bone were proven in many animal studies, while to date, no conclusive data is available in human. The aim of this study was to evaluate the impact of n-3 fatty acids on bone biomarkers in osteoporotic postmenopausal women. Twenty-five osteoporotic postmenopausal women were recruited in the study and randomized in treatment and control groups. The patients received 900 mg n-3 fatty acid capsules or placebo per day for 6 months. Serum levels of osteocalcin, bone alkaline phosphatase (BALP), calcium, vitamin D, and parathormone and urine concentration of pyridinoline (Pyd) were measured at baseline, second month, and sixth month in both groups. In the treatment group, compared with baseline, at the second month, osteocalcin increased slightly; thereafter, it showed decrement trend until the end of the study. In the control group, it decreased all over the study. None of these changes was significant. BALP showed nonsignificant decrease from baseline over the time in both groups. Urine level of Pyd decreased significantly (P < 0.05) in the treatment group, while no significant change was seen in the control group. Serum calcium and vitamin D increased in both groups; however, changes were not significant. No significant changes were seen in calcium clearance and parathormone. In conclusion, n-3 fatty acids can decrease bone resorption; however, it could not affect bone formation significantly after 6 months treatment. Further investigations are recommended.

Self-reported dietary intake of omega-3 fatty acids and association with bone and lower extremity function

OBJECTIVES

To assess the relationship between self-reported omega-3 fatty acid (O3FA) intake and bone mineral density (BMD) and lower extremity function in older adults.

DESIGN

Cross-sectional analysis of baseline information from three separate ongoing studies of older adults, pooled for this analysis.

SETTING

Academic health center.

PARTICIPANTS

Two hundred forty-seven men (n=118) and women (n=129) residing in the community or an assisted living facility.

MEASUREMENTS

Self-reported dietary intake (O3FA, omega-6 fatty acids (O6FA), protein, and total calorie); BMD of the hip or heel; and lower extremity function including leg strength, chair rise time, walking speed, Timed Up and Go, and frailty.

RESULTS

The mean reported intake of O3FA was 1.27 g/day. Correlation coefficients (r) between O3FA and T-scores from total femur (n=167) were 0.210 and 0.147 for combined femur and heel T scores. Similar correlations were found for leg strength (r=0.205) and chair rise time (r=-0.178), but the significance was lost when corrected for protein intake. Subjects with lower reported O3FA intake (<1.27 g/day) had lower BMD than those with higher reported O3FA intake. In a multiple regression analysis with femoral neck BMD as the dependent variable and reported intake of O3FA, O6FA, protein, and vitamin D as independent variables, reported O3FA intake was the only significant variable, accounting for 6% of the variance in BMD.

CONCLUSION

Older adults had low reported intakes of O3FA. There was an association between greater reported O3FA intake and higher BMD. There was no independent association between reported O3FA intake and lower extremity function. Results from this preliminary report are promising and suggest further investigation.

Are all n-3 polyunsaturated fatty acids created equal?

N-3 Polyunsaturated fatty acids have been shown to have potential beneficial effects for chronic diseases including cancer, insulin resistance and cardiovascular disease. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in particular have been studied extensively, whereas substantive evidence for a biological role for the precursor, alpha-linolenic acid (ALA), is lacking. It is not enough to assume that ALA exerts effects through conversion to EPA and DHA, as the process is highly inefficient in humans. Thus, clarification of ALA's involvement in health and disease is essential, as it is the principle n-3 polyunsaturated fatty acid consumed in the North American diet and intakes of EPA and DHA are typically very low. There is evidence suggesting that ALA, EPA and DHA have specific and potentially independent effects on chronic disease. Therefore, this review will assess our current understanding of the differential effects of ALA, EPA and DHA on cancer, insulin resistance, and cardiovascular disease. Potential mechanisms of action will also be reviewed. Overall, a better understanding of the individual role for ALA, EPA and DHA is needed in order to make appropriate dietary recommendations regarding n-3 polyunsaturated fatty acid consumption.

Ingredients for Functional Drinks in Neurodegenerative Diseases: A Review

Several studies have indicated that oxidative stress is a major risk factor for the initiation and progression of neurological disorders like Parkinson's disease (PD) and Alzheimer's (AD). Therefore, reducing oxidative stress appears to be a rational choice for the prevention and reduction in the rate of progression of these neurological disorders. The brain utilizes about 25% of respired oxygen even though it represents only 5% of the body weight. Free radicals are generated during the normal intake of oxygen, during infection, and during normal oxidative metabolism of certain substrates. Although experimental data are consistent in demonstrating the neuroprotective effects of antioxidants in vitro and in animal models, the clinical evidence that antioxidant agents may prevent or slow the course of these diseases is still relatively unsatisfactory, and insufficient to strongly modify clinical practice.

In this paper, natural possible substances that could be added to a beverage to prevent or decrease the developing of neurodegenerative diseases are reviewed.

Mastication of almonds: effects of lipid bioaccessibility, appetite, and hormone response

BACKGROUND

Epidemiologic and clinical data indicate that nuts can be incorporated into the diet without compromising body weight. This has been attributed to strong satiety properties, increased resting energy expenditure, and limited lipid bioaccessibility.

OBJECTIVE

The role of mastication was explored because of evidence that the availability of nut lipids is largely dependent on the mechanical fracture of their cell walls.

DESIGN

In a randomized, 3-arm, crossover study, 13 healthy adults (body mass index, in kg/m(2): 23.1 +/- 0.4) chewed 55 g almonds 10, 25, or 40 times. Blood was collected and appetite was monitored during the following 3 h. Over the next 4 d, all foods were provided, including 55 g almonds, which were consumed under the same chewing conditions. Complete fecal samples were collected.

RESULTS

Hunger was acutely suppressed below baseline (P < 0.05), and fullness was elevated above baseline longer (P < 0.05) after 40 chews than after 25 chews. Two hours after consumption, fullness levels were significantly lower and hunger levels were significantly higher after 25 chews than after 10 and 40 chews (P < 0.05). Initial postingestive glucagon-like peptide-1 concentrations were significantly lower after 25 chews than after 40 chews (P < 0.05), and insulin concentrations declined more rapidly after 25 and 40 chews than after 10 chews (both P < 0.05). Fecal fat excretion was significantly higher after 10 chews than after 25 and 40 chews (both P < 0.05). All participants had higher fecal energy losses after 10 and 25 chews than after 40 chews (P < 0.005).

CONCLUSION

The results indicate important differences in appetitive and physiologic responses to masticating nuts and likely other foods and nutrients. This trial was registered at clinicaltrials.gov as NCT00768417.

Flaxseed does not antagonize the effect of ultra-low-dose estrogen therapy on bone mineral density and biomechanical bone strength in ovariectomized rats

A previous study showed that flaxseed (FS) combined with low-dose (LD) estrogen therapy, resembling LD transdermal estrogen therapy in postmenopaual women, inhibited loss of bone mineral density (BMD), bone mineral content (BMC), and strength in lumbar vertebrae in ovariectomized rats. Whether FS combined with an even lower dose of estrogen is effective at preserving bone or whether FS interferes with the effect of this lower dose of estrogen is unknown. Thus, this study determined whether an ultra-low-dose (ULD) estrogen therapy, half the dose previously studied, in combination with FS preserved bone mass and strength in the lumbar vertebrae in ovariectomized rats. Rats were treated for 12 wk with (1) basal diet (BD) (ovariectomized control), (2) BD + ULD estrogen implant, or (3) BD containing 10% FS + ULD estrogen implant. A sham-operated control group was fed BD. Unlike ULD, FS + ULD attenuated loss of BMD and strength at the lumbar vertebrae and BMD in femurs and tibias. FS + ULD resulted in higher percentages of n-3 fatty acids including alpha-linolenic acid and eicosapentaenoic acid and lower percentages of n-6 fatty acids including linoleic acid compared to all other groups. Differences in fatty acid composition at the lumbar vertebrae and tibia were significantly related to BMD, BMC, and strength. No treatment-induced effects on uterus weight were observed, but histological analyses are needed to confirm safety. In conclusion, FS did not antagonize the activity of ULD, and their combination attenuated the loss of BMD and strength at the lumbar vertebrae, which was associated with differences in bone fatty acid composition.

Femur EPA and DHA are correlated with femur biomechanical strength in young fat-1 mice

Evidence suggests that n-3 polyunsaturated fatty acids (PUFA) are beneficial for maintenance of bone health and possibly bone development. This study used the fat-1 mouse, a transgenic model that synthesizes n-3 PUFA from n-6 PUFA, to determine if outcomes of bone health were correlated with n-3 PUFA in femurs. Control and fat-1 mice were fed an AIN-93G diet containing 10% safflower oil from weaning through 12 weeks of age. Femur bone mineral content (BMC) and density were determined by dual-energy X-ray absorptiometry, and biomechanical strength properties, surrogate measures of fracture risk, were measured by a materials testing system. Femur fatty acid composition was determined by gas chromatography. At 12 weeks of age, femur n-3 PUFA were higher among fat-1 mice compared to control mice. The n-6/n-3 PUFA ratio in the femur was negatively correlated with BMC (r=-.57, P=.01) and peak load at femur midpoint (r=-.53, P=.02) and femur neck (r=-.52, P=.02). Moreover, long-chain n-3 PUFA, eicosapentaenoic acid, and docosahexaenoic acid were significantly and positively correlated or displayed a trend suggesting positive correlations, with BMC and peak load. In conclusion, the results of the present study suggest that n-3 PUFA have a favorable effect on mineral accumulation and functional measures of bone in fat-1 mice at young adulthood.

Effect of long-chain n-3 polyunsaturated fatty acid on inflammation mediators during osteoblastogenesis

This study examined the effects of eicosapentaenoic acid (EPA) and arachidonic acid (AA) on inflammation mediators during osteoblastogenesis, in terms of modulation of the cyclooxygenase (COX)-2 and the inducible nitric oxide (NO) synthase (iNOS) pathways. We hypothesized that n-3 polyunsaturated fatty acid (PUFA) would reduce the production of inflammation mediators, including prostaglandin E(2) (PGE(2)) and NO, and related mRNA gene expression during osteoblastogenesis. Mouse bone marrow stromal cells (ST-2) were treated with 40 microM ethanol (as a control), 40 microM AA, or 40 microM EPA in osteogenic medium for 7, 14, 21, or 28 days. Prior to harvest, cells were treated with respective treatments along with cytokine mixtures for an additional 24 hours, and then cells were harvested for mRNA expression. In addition, cells were also treated with respective treatments along with the same cytokine mixtures for an additional 48 hours for experiment measuring PGE(2) and NO production using conditioned culture medium and protein expression using cells. Except for 7 days of culture, AA treatment resulted in the highest value for PGE(2) production throughout 28 days of culture. AA treatment also enhanced COX-2 mRNA expression up to 21 days. AA treatment resulted in a higher value for NO production after 7 days, while EPA treatment yielded a higher value for NO production relative to those receiving AA treatment after 14 and 21 days. Our investigation has corroborated that the protective action of EPA on osteoblastogenesis was mediated by the modulation of PGE(2) and the NO pathway.

Preventive effects of flaxseed and sesame oil on bone loss in ovariectomized rats

A study was designed to examine the effects of dietary flaxseed oil (FO) and sesame oil (SO) which are rich successively in n-3 and (n-9 and n-6) on biochemical parameters and histological status of bone. Sixty-four 90-day-old female wistar rats were randomly assigned to 6 groups: sham-operated rat (sham)+ control diets, ovariectomized rat (OVX) + control diets, OVX + 7% FO, OVX + 7% SO, OVX + 10% FO, OVX + 10% SO. After 4 weeks of treatments, rats were euthanized; blood and tissues were collected for analyses. Markers of bone formation which is alkaline phosphatase activity and markers of bone resorption which is tartrate resistant acid phosphatase activity were measured. Present results showed that OVX increased significantly ALP and TRAP activity and the examination of bone tissue showed disruptive and lytic bone trabeculae. Animals fed 10% FO and 10% SO of fat reduced these parameters and improved bone microarchitecture. Whereas, there was no improvement in biochemical and histological states in OVX rats that received 7% of PUFAs successively provided from FO and SO diets. In conclusion, our results are encouraging because they suggest that PUFAs intake may help to prevent osteoporosis associated with estrogens deficiency. However, further studies are needed to determine the mechanism by which a diet rich in n-3 or lignans modulate bone tissue.

The amino- and carboxyterminal cross-linked telopeptides of collagen type I, NTX-I and CTX-I: a comparative review

Bone diseases such as osteoporosis or bone metastases are a continuously growing problem in the ageing populations across the world. In recent years, great efforts have been made to develop specific and sensitive biochemical markers of bone turnover that could help in the assessment and monitoring of bone turnover. The amino- and carboxyterminal cross-linked telopeptides of type I collagen (NTX-I and CTX-I, respectively) are two widely used bone resorption markers that attracted great attention due to their relatively high sensitivity and specificity for the degradation of type I collagen, and their rapid adaptation to automated analyzers. However, the clinical performance of both markers differs significantly depending on the clinical situation. These differences have caused considerable confusion and uncertainty. If used correctly, both markers have great potential to improve the management of many bone diseases. We here review the biochemistry, analytical background and clinical performance of NTX-I and CTX-I, as documented in the accessible literature until March 2008.

Walnut extract (Juglans regia L.) and its component ellagic acid exhibit anti-inflammatory activity in human aorta endothelial cells and osteoblastic activity in the cell line KS483

Epidemiological studies suggest that the incidence of CVD and postmenopausal osteoporosis is low in the Mediterranean area, where herbs and nuts, among others, play an important role in nutrition. In the present study, we sought a role of walnuts (Juglans regia L.) in endothelial and bone-cell function. As the endothelial cell expression of adhesion molecules has been recognised as an early step in inflammation and atherogenesis, we examined the effect of walnut methanolic extract and ellagic acid, one of its major polyphenolic components (as shown by HPLC analysis), on the expression of vascular cell adhesion molecule (VCAM)-1 and intracellular adhesion molecule (ICAM)-1 in human aortic endothelial cells. After incubating the cells with TNF-α (1 ng/ml) in the absence and in the presence of walnut extract (10–200 μg/ml) or ellagic acid (10− 7–10− 5m), the VCAM-1 and ICAM-1 expression was quantified by cell-ELISA. We further evaluated the effect of walnut extract (10–50 μg/ml), in comparison with ellagic acid (10− 9–10− 6m), on nodule formation in the osteoblastic cell line KS483.Walnut extract and ellagic acid decreased significantly the TNF-α-induced endothelial expression of both VCAM-1 and ICAM-1 (P < 0·01; P < 0·001). Both walnut extract (at 10–25 μg/ml) and ellagic acid (at 10− 9–10− 8m) induced nodule formation in KS483 osteoblasts. The present results suggest that the walnut extract has a high anti-atherogenic potential and a remarkable osteoblastic activity, an effect mediated, at least in part, by its major component ellagic acid. Such findings implicate the beneficial effect of a walnut-enriched diet on cardioprotection and bone loss.