A food composition database for assessing nitrate intake from plant-based foods

Nitrate and nitrite food composition database: an update and extensive deep dive

BACKGROUND

Growing evidence suggests that health outcomes of dietary nitrate and nitrite intake are food source dependent. Robust evaluations in dietary studies necessitate a comprehensive and current food composition database of nitrate/nitrite content, along with variation based on country or region of origin, calendar year, growing season, and cooking method.

OBJECTIVES

The objectives of this study were to update the previous animal- and plant-based food nitrate/nitrite databases and investigate effects of cooking methods, seasonal and geographic variations, and longitudinal changes on nitrate and nitrite content to guide application of the database in observational and clinical studies.

METHODS

Food nitrate/nitrite composition data was acquired from an extensive worldwide data collation. The animal- and plant-based food nitrate/nitrite databases were combined and substantially expanded. An in-depth data stratification and comparison were performed to explore retention factors of nitrate/nitrite, seasonal differences in vegetable nitrate, geographic variations, and the temporal change in food nitrate/nitrite content over 30 years.

RESULTS

The aggregated database has >150,000 nitrate and nitrite values for 823 foods, being 5+ times their original size. Nitrite content in plant foods is presented for the first time, being ≤12.27 mg/kg of fresh weight. Retention factors of 55.00 (39.59-65.56) % (median (interquartile range)) and 279.53 (179.53-386.89) % are now suggested for boiled and fried plant foods, respectively, with a factor of 1.0 for other cooking methods. Significant seasonal variations in plant nitrate and geographic differences in both plant- and animal-based foods are identified, whereas several leafy vegetables show declining nitrate content over 30 years, and longitudinal changes in nitrate and nitrite in animal foods are minor. An objective language-model-assisted data extraction pipeline was established that accommodates regional differences in nitrate/nitrite data reporting.

CONCLUSIONS

The newly developed database and automated nitrate/nitrite calculator will facilitate future nutritional health studies to estimate dietary nitrate/nitrite exposure more accurately and efficiently and determine the resulting health implications.

Baseline habitual dietary nitrate intake and Alzheimer's Disease related neuroimaging biomarkers in the Australian Imaging, Biomarkers and Lifestyle study of ageing

BACKGROUND

Dietary nitrate, as a nitric oxide (NO) precursor, may support brain health and protect against dementia.

OBJECTIVE

Our primary aim was to investigate whether dietary nitrate is associated with neuroimaging markers of brain health linked with Alzheimer's disease (AD).

PARTICIPANTS

Study participants were cognitively unimpaired individuals from the Australian Imaging, Biomarkers and Lifestyle Study of Ageing (AIBL) who had β-amyloid positron emission tomography (PET) scans (n = 554) and magnetic resonance imaging (MRI) scans (n = 335) and had completed a Food Frequency Questionnaire at baseline.

METHODS

Source-specific nitrate intakes were estimated using comprehensive nitrate food composition databases. Rates of cerebral β-amyloid (Aβ) deposition, measured using PET, and rates of brain atrophy, measured using MRI, were assessed between baseline and 126-months follow-up, at intervals of 18 months. Multivariable-adjusted linear mixed effect models were used to examine associations between baseline source-specific nitrate intake and rates of (i) cerebral Aβ deposition and (ii) brain atrophy, over the 126 months of follow-up. Analyses were carried out following stratification of the sample by established dementia Alzheimer's disease (AD) risk factors including sex and presence or absence of the apolipoprotein E (APOE) ε4 allele.

RESULTS

In women carriers of the APOE ε4 allele, higher plant sourced nitrate intake (median intake 121 mg/day), was associated with a slower rate of cerebral Aβ deposition [β: 4.47 versus 8.99 Centiloid (CL) /18 months, p < 0.05] and right hippocampal atrophy [-0.01 versus -0.03 mm3 /18 months, p < 0.01], after multivariable adjustments. Moderate intake showed protective associations in men carriers and in both men and women non-carriers of APOE ε4.

CONCLUSIONS

Associations were observed between plant-derived nitrate intake and cerebral Aβ deposition, particularly in high-risk populations (women and APOE ε4 carriers). Associations were also observed for brain volume atrophy, however these exhibited subgroup variability without clear patterns relative to sex and APOE ε4 allele carriage. These findings suggest a potential link between plant-sourced nitrate and AD related neuroimaging markers of brain health improved brain health, but further validation in larger studies is required.

Higher dietary nitrate intake is associated with lower likelihood of first clinical diagnosis of central nervous system demyelination in Australian women

Dietary nitrate is a precursor to nitric oxide, for which plausible mechanisms exist for both beneficial and detrimental influences in first clinical diagnosis of central nervous system demyelination (FCD), a common precursor to the diagnosis of multiple sclerosis (MS). Whether dietary nitrate has any role in FCD onset is unclear. We tested associations between nitrate intake from food sources (plant, vegetable, animal, processed meat, and unprocessed meat) and likelihood of FCD. We used data from the Ausimmune Study (264 cases, 474 controls) and logistic regression with full propensity score matching. In females, higher nitrate intake from plant-based foods (odds ratio [OR] per 60 mg/day = 0.50; 95 % confidence interval [CI] 0.31, 0.81; p = <0.01) and vegetables (OR per 60 mg/day = 0.39; 95 % CI 0.22, 0.70; p = <0.01), but not other sources, was statistically significantly associated with lower likelihood of FCD. In males, no associations were found between any source of nitrate intake and likelihood of FCD. Our results support further research to explore a possible beneficial role for plant-derived nitrate in people at higher risk of MS.

Combination of inorganic nitrate and vitamin C prevents collagen-induced arthritis in rats by inhibiting pyroptosis

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease characterized by synovial inflammation, cartilage damage, and bone loss. Although effective treatments are currently lacking, early interventions hold promise for alleviating RA symptoms. Inorganic nitrates and vitamin C (VC) are essential bioactive substances abundant in fruits and vegetables. Notably, nitrates and VC exhibit synergistic effects in a series of physiological and pathological conditions. In this study, we aim to examine the combination of nitrate and VC for preventing RA in a collagen-induced arthritis (CIA) rat model. Nitrate partly reduced foot swelling and arthritis scores and was more effective when combined with VC. Histopathological and radiological analyses revealed that nitrate + VC treatment alleviated synovial hyperplasia and bone loss. Additionally, nitrate + VC lowered the levels of TNF-α and IL-1β in serum as well as synovial tissue, decreased the expression of NF-κB and reduced the number of macrophages in synovial tissue. Compared to the CIA group, nitrate + VC decreased the levels of NLRP3 and GSDMD in macrophages, thus inhibiting pyroptosis. According to in vitro experiments, nitrate inhibited the activation of the NLRP3/caspase-1/GSDMD pathway in macrophages by conversion into nitrite. VC reduced the expression and phosphorylation of NF-κB in macrophages and thus reduced the expression levels of TNF-α and IL-1β. Therefore, nitrate/nitrite and VC may exert synergistic effects by blocking the interaction between NF-κB and NLRP3, further alleviating the inflammation and pyroptosis of macrophages, which provides a new strategy for RA prevention.

The Health Effects of Dietary Nitrate on Sarcopenia Development: Prospective Evidence from the UK Biobank

Nitrate is abundant in natural foods, especially plant-based foods, having the potential to enhance muscle function. However, its relationship with sarcopenia in the context of daily diet remains unexplored. This cohort study investigated the associations between dietary nitrate intake and sarcopenia, as well as related symptoms, using data including 28,229 participants with a mean follow-up of 9.37 years from the UK Biobank. Dietary nitrate intake was estimated using a comprehensive nitrate food database. Adjusted logistic regression models suggested potential inverse associations between total nitrate intake and risks of sarcopenia plus pre-sarcopenia (Sarc-Presarc), low hand grip strength (HGS), and low walking pace. Similar results were primarily observed for nitrate from plant-based foods. With higher intake, females appeared to have higher HGS and a decreased risk of Sarc-Presarc, while males exhibited a reduced risk of low walking pace. The inverse association between nitrate intake and low skeletal muscle mass index was more evident in individuals aged 65 and above. These associations seemed independent of antioxidants, though higher antioxidants might augment the protective effect against low walking pace. Mediation analyses indicated that protein homeostasis and blood pressure might mediate these associations. These findings suggested that a higher dietary nitrate intake from plant-based foods could contribute to sarcopenia prevention, though further research is needed to confirm these observations.

Optimizing vertical farm cultivation of Cichorium spinosum L.: White Light's influence and nutrition management

The objective of this study was to examine the integration of a wild leafy vegetable, Cichorium spinosum L., in vertical farms. This research comprises two experiments focusing on different "white" light products and nutrient solutions. During both experiments, the temperature varied between 25 and 28 °C, relative humidity ranged from 50 to 70 %, carbon dioxide was at 450 ppm, and light intensity was set at 300 μmol m-2 s-1 respectively. In the lighting experiment, the three spectra used had the commercial names Neutral, Full and a SunLike™, and their spectral composition (blue:green:red:far-red) were 14:32:43:10, 16:36:40:8, and 21:34:36:7 respectively. The photoperiod was set to 12 h and the plant density was 50 plants m-2. Results showed no significant impact on agronomical parameters and leaf anatomy. The stomatal length and width decreased as the red:blue ratio of the light sources decreased, being greater in the Neutral treatment (red:blue ratio of 3.1) compared to the Full and SunLike™ (red:blue ratios of 2.5 and 1.7 respectively). Based on these results the preferable "white light" product was the one with the highest efficiency and lowest market price at the time of the experiment. In the nutrient solution experiment, the agronomical and nutritional attributes of stamnagathi plants supplied with a control nutrient solution, "N10-Fe15" were compared to plants cultivated under limited nitrogen, "N4-Fe15" and elevated iron, "N10-Fe48", EC was 1.5 ds m-1, and pH was 5.6-6.5. The experiment simulated commercial practices by increasing the photoperiod to 15 h and plant density to 100 plants per square meter. The results did not demonstrate significant effect of the nutrient solution differences on the agronomical characteristics except from a decrease in total Kjeldahl nitrogen under limited nitrogen conditions. Notably, leaf tissue phosphorus content increased under elevated iron conditions. The nitrate content remained within safe for consumption thresholds for all treatments. Based on these results, stamnagathi can be integrated in vertical farms under limited nitrogen conditions. Stamnagathi's resilience to elevated iron in the nutrient solution demonstrated its potential for future biofortification experiments.

Higher plant-derived nitrate intake is associated with lower odds of frailty in a cross-sectional study of community-dwelling older women

PURPOSE

Dietary nitrate intake is inversely related to numerous contributors towards frailty, including cardiovascular disease and poor physical function. Whether these findings extend to frailty remain unknown. We investigated if habitual nitrate intake, derived from plants or animal-based foods, was cross-sectionally associated with frailty in women.

METHODS

Community-dwelling older Australian women (n = 1390, mean age 75.1 ± 2.7 years) completed a validated semi-quantitative food frequency questionnaire (FFQ). Nitrate concentrations in food were obtained from international nitrate databases. We adopted the Rockwood frailty index (FI) of cumulative deficits comprising 33 variables across multiple health domains (scored 0 to 1), which predicts increased hospitalisation and mortality risk. A FI ≥ 0.25 indicated frailty. Cross-sectional associations between nitrate intake (total plant and animal nitrate, separately) and frailty were analysed using multivariable-adjusted logistic regression models (including lifestyle factors), as part of restricted cubic splines.

RESULTS

A non-linear inverse relationship was observed between total plant nitrate intake and frailty. Compared to women with the lowest plant nitrate intake (Quartile [Q]1), women with greater intakes in Q2 (OR 0.69 95%CI 0.56-0.84), Q3 (OR 0.67 95%CI 0.50-0.90) and Q4 (OR 0.66 95%CI 0.45-0.98) had lower odds for frailty. A nadir in the inverse association was observed once intakes reached ~ 64 mg/d (median Q2). No relationship was observed between total animal nitrate and frailty.

CONCLUSION

Community-dwelling older women consuming low amounts of plant-derived nitrate were more likely to present with frailty. Consuming at least one daily serving (~ 75 g) of nitrate-rich green leafy vegetables may be beneficial in preventing frailty.

Plant but not animal sourced nitrate intake is associated with lower dementia-related mortality in the Australian Diabetes, Obesity, and Lifestyle Study

Introduction

Dietary nitrate is potentially beneficial for cardiovascular, cerebrovascular, and nervous systems due to its role as a nitric oxide (NO) precursor. Increased nitrate intake improves cardiovascular health and therefore could protect against dementia, given the cardiovascular-dementia link.

Objective

To investigate the association between source-dependent nitrate intake and dementia-related mortality. As individuals with diabetes are at higher risk of dementia, a secondary aim was to investigate if the associations between nitrate and dementia varied by diabetes mellitus (DM) and pre-diabetes status.

Methods

This study involved 9,149 participants aged ≥25 years from the well-characterised Australian Diabetes, Obesity, and Lifestyle (AusDiab) Study followed over a period of 17 years. Intakes of plant-sourced, vegetable-sourced, naturally occurring animal-sourced nitrate, and processed meat (where nitrate is an allowed additive)-sourced nitrate were assessed from a 74-item food frequency questionnaire completed by participants at baseline and nitrate databases were used to estimate nitrate from these different dietary sources. Associations between source-dependent nitrate intake and dementia-related mortality were assessed using multivariable-adjusted Cox proportional hazards models adjusted for demographics, lifestyle, and dietary factors.

Results

Over 17 years of follow-up, 93 (1.0%) dementia-related deaths occurred of 1,237 (13.5%) total deaths. In multivariable-adjusted models, participants with the highest intakes of plant-sourced nitrate (median intake 98 mg/day) had a 57% lower risk of dementia-related mortality [HR (95% CI): 0.43 (0.22, 0.87)] compared to participants with lowest intakes of plant-sourced nitrate (median intake 35 mg/day). A 66% lower risk was also seen for higher intakes of vegetable-sourced nitrate [HR (95% CI): 0.34 (0.17, 0.66)]. No association was observed for animal-sourced nitrate, but the risk was two times higher amongst those who consumed the most processed meat-sourced nitrate intake [HR (95%): 2.10 (1.07, 4.12)]. The highest intake of vegetable-sourced nitrate was associated with a lower risk of dementia-related mortality for those with and without DM and pre-diabetes.

Conclusion

Encouraging the intake of nitrate-rich vegetables, such as green leafy vegetables and beetroot, may lower the risk of dementia-related mortality, particularly in individuals with (pre-) diabetes who are at a higher dementia risk.

Nitrate, Nitrite, and Iodine Concentrations in Commercial Edible Algae: An Observational Study

Edible algae are a natural source of nutrients, including iodine, and can also contain nitrogen in the form of nitrate (NO3-) and nitrite (NO2-) as they can fix nitrogen from seawater. This study aimed to analyse the NO3-, NO2-, and iodine concentrations in eighteen macroalgae and five microalgae species commercially available in the United Kingdom. NO3- and NO2- concentrations were measured using high-performance liquid chromatography (HPLC), and iodine was determined using inductively coupled plasma mass spectrometry (ICP-MS). NO3- and iodine concentrations in macroalgae (NO3-: 4050.13 ± 1925.01 mg/kg; iodine: 1925.01 ± 1455.80 mg/kg) were significantly higher than in microalgae species (NO3-: 55.73 ± 93.69 mg/kg; iodine: 17.61 ± 34.87 mg/kg; p < 0.001 for both). In the macroalgae group, nori had the highest NO3- (17,191.33 ± 980.89 mg/kg) and NO2- (3.64 ± 2.38 mg/kg) content, as well as the highest iodine content. Among microalgae, Dunaliella salina had the highest concentration of NO3- (223.00 ± 21.93 mg/kg) and iodine (79.97 ± 0.76 mg/kg), while Spirulina had the highest concentration of NO2- (7.02 ± 0.13 mg/kg). These results indicate that commercially available edible algae, particularly macroalgae species, could be a relevant dietary source of NO3- and iodine.

Source-specific nitrate intake and all-cause mortality in the Danish Diet, Cancer, and Health Study

INTRODUCTION

Nitrate and nitrite are naturally occurring in both plant- and animal-sourced foods, are used as additives in the processing of meat, and are found in water. There is growing evidence that they exhibit a spectrum of health effects, depending on the dietary source. The aim of the study was to examine source-dependent associations between dietary intakes of nitrate/nitrite and both all-cause and cause-specific mortality.

METHODS

In 52,247 participants of the Danish Diet, Cancer and Health Study, associations between source-dependent nitrate and nitrite intakes--calculated using comprehensive food composition and national drinking water quality monitoring databases--and all-cause, cardiovascular disease (CVD)-related, and cancer-related mortality over 27 years were examined using restricted cubic splines within Cox proportional hazards models adjusting for demographic, lifestyle, and dietary confounders. Analyses were stratified by factors hypothesised to influence the formation of carcinogenic N-nitroso compounds (namely, smoking and dietary intakes of vitamin C, vitamin E, folate, and polyphenols).

RESULTS

Plant-sourced nitrate intake was inversely associated with all-cause mortality [HRQ5vsQ1: 0.83 (0.80, 0.87)] while higher risks of all-cause mortality were seen for higher intakes of naturally occurring animal-sourced nitrate [1.09 (1.04, 1.14)], additive permitted meat-sourced nitrate [1.19 (1.14, 1.25)], and tap water-sourced nitrate [1.19 (1.14, 1.25)]. Similar source-dependent associations were seen for nitrite and for CVD-related and cancer-related mortality except that naturally occurring animal-sourced nitrate and tap water-sourced nitrate were not associated with cancer-related mortality and additive permitted meat-sourced nitrate was not associated with CVD-related mortality. No clear patterns emerged in stratified analyses.

CONCLUSION

Nitrate/nitrite from plant sources are inversely associated while those from naturally occurring animal-sources, additive-permitted meat sources, and tap water-sources are positively associated with mortality.

Seven-day dietary nitrate supplementation clinically significantly improves basal macrovascular function in postmenopausal women: a randomized, placebo-controlled, double-blind, crossover clinical trial

Introduction

Cardiovascular disease (CVD) is the leading cause of death in women, with increased risk following menopause. Dietary intake of beetroot juice and other plant-based nitrate-rich foods is a promising non-pharmacological strategy for increasing systemic nitric oxide and improving endothelial function in elderly populations. The purpose of this randomized, placebo-controlled, double-blind, crossover clinical trial was to determine the effects of short-term dietary nitrate (NO3 -) supplementation, in the form of beetroot juice, on resting macrovascular endothelial function and endothelial resistance to whole-arm ischemia-reperfusion (IR) injury in postmenopausal women at two distinct stages of menopause.

Methods

Early-postmenopausal [1-6 years following their final menstrual period (FMP), n = 12] and late-postmenopausal (6+ years FMP, n = 12) women consumed nitrate-rich (400 mg NO3 -/70 mL) and nitrate-depleted beetroot juice (approximately 40 mg NO3 -/70 mL, placebo) daily for 7 days. Brachial artery flow-mediated dilation (FMD) was measured pre-supplementation (Day 0), and approximately 24 h after the last beetroot juice (BR) dose (Day 8, post-7-day BR). Consequently, FMD was measured immediately post-IR injury and 15 min later (recovery).

Results

Results of the linear mixed-effects model revealed a significantly greater increase in resting FMD with 7 days of BRnitrate compared to BRplacebo (mean difference of 2.21, 95% CI [0.082, 4.34], p = 0.042); however, neither treatment blunted the decline in post-IR injury FMD in either postmenopausal group. Our results suggest that 7-day BRnitrate-mediated endothelial protection is lost within the 24-h period following the final dose of BRnitrate.

Conclusion

Our findings demonstrate that nitrate-mediated postmenopausal endothelial protection is dependent on the timing of supplementation in relation to IR injury and chronobiological variations in dietary nitrate metabolism.

Clinical trial registration

https://classic.clinicaltrials.gov/ct2/show/NCT03644472.

Increased nitrate intake from beetroot juice over 4 weeks affects nitrate metabolism, but not vascular function or blood pressure in older adults with hypertension

The decline in vascular function and increase in blood pressure with aging contribute to an increased cardiovascular disease risk. In this randomized placebo-controlled crossover study, we evaluated whether previously reported cardiovascular benefits of plant-derived inorganic nitrate via nitric oxide (NO) translate into improved vascular function and blood pressure-lowering in 15 men and women (age range: 56-71 years) with treated hypertension. We investigated the effects of a single ∼400 mg-dose at 3 hours post-ingestion (3H POST) and the daily consumption of 2 × ∼400 mg of nitrate through nitrate-rich compared with nitrate-depleted (placebo) beetroot juice over 4 weeks (4WK POST). Measurements included nitrate and nitrite in plasma and saliva; endothelial-dependent and -independent forearm blood flow (FBF) responses to acetylcholine (FBFACh) and glyceryltrinitrate (FBFGTN); and clinic-, home- and 24-hour ambulatory blood pressure. Compared to placebo, plasma and salivary nitrate and nitrite increased at 3H and 4WK POST following nitrate treatment (P < 0.01), suggesting a functioning nitrate-nitrite-NO pathway in the participants of this study. There were no differences between treatments in FBFACh and FBFGTN-area under the curve (AUC) ratios [AUC ratios after (3H POST, 4WK POST) compared with before (PRE) the intervention], or 24-hour ambulatory blood pressure or home blood pressure measures (P > 0.05). These findings do not support the hypothesis that an increased intake of dietary nitrate exerts sustained beneficial effects on FBF or blood pressure in hypertensive older adults, providing important information on the efficacy of nitrate-based interventions for healthy vascular aging. This study was registered under ClinicialTrials.gov (NCT04584372).

Source-specific nitrate and nitrite intakes and associations with sociodemographic factors in the Danish Diet Cancer and Health cohort

Background

The dietary source and intake levels of nitrate and nitrite may govern its deleterious versus beneficial effects on human health. Existing evidence on detailed source-specific intake is limited. The objectives of this study were to assess nitrate and nitrite intakes from different dietary sources (plant-based foods, animal-based foods, and water), characterize the background diets of participants with low and high intakes, and investigate how sociodemographic and lifestyle factors associate with intake levels.

Methods

In the Danish Diet, Cancer and Health Cohort, sociodemographic and lifestyle information was obtained from participants at enrolment (1993-1997). Source-dependent nitrate and nitrite intakes were calculated using comprehensive food composition databases, with tap water nitrate intakes estimated via the national drinking water quality monitoring database linked with participants' residential addresses from 1978 to 2016. Underlying dietary patterns were examined using radar plots comparing high to low consumers while sociodemographic predictors of source-dependent nitrate intakes were investigated using linear regression models.

Results

In a Danish cohort of 55,754 participants aged 50-65 at enrolment, the median [IQR] intakes of dietary nitrate and nitrite were 58.13 [44.27-74.90] mg/d and 1.79 [1.43-2.21] mg/d, respectively. Plant-based foods accounted for ~76% of nitrate intake, animal-based foods ~10%, and water ~5%. Nitrite intake was sourced roughly equally from plants and animals. Higher plant-sourced nitrate intake was associated with healthier lifestyles, better dietary patterns, more physical activity, higher education, lower age and lower BMI. Females and participants who had never smoked also had significantly higher plant-sourced nitrate intakes. Higher water-sourced nitrate intake was linked to sociodemographic risk factors (smoking, obesity, lower education). Patterns for animal-sourced nitrate were less clear.

Conclusion

Participants with higher plant-sourced nitrate intakes tend to be healthier while participants with higher water-sourced nitrate intakes tended to be unhealthier than their low consuming counterparts. Future research in this cohort should account for the sociodemographic and dietary predictors of source-specific nitrate intake we have identified.

Dietary Nitrate from Plant Foods: A Conditionally Essential Nutrient for Cardiovascular Health

Under specific conditions, such as catabolic stress or systemic inflammation, endogenous nutrient production becomes insufficient and exogenous supplementation (for example, through dietary intake) is required. Herein, we propose consideration of a dietary nitrate from plant foods as a conditionally essential nutrient for cardiovascular health based on its role in nitric oxide homeostasis. Nitrate derived from plant foods may function as a conditionally essential nutrient, whereas nitrate obtained from other dietary sources, such as drinking water and cured/processed meats, warrants separate consideration because of the associated health risks. We have surveyed the literature and summarized epidemiological evidence regarding the effect of dietary nitrate on cardiovascular disease and risk factors. Meta-analyses and population-based observational studies have consistently demonstrated an inverse association of dietary nitrate with blood pressure and cardiovascular disease outcomes. Considering the available evidence, we suggest 2 different approaches to providing dietary guidance on nitrate from plant-based dietary sources as a nutrient: the Dietary Reference Intakes developed by the National Academies of Sciences, Engineering, and Medicine, and the dietary guidelines evaluated by the Academy of Nutrition and Dietetics. Ultimately, this proposal underscores the need for food-based dietary guidelines to capture the complex and context-dependent relationships between nutrients, particularly dietary nitrate, and health.

Nutritional strategies to optimise musculoskeletal health for fall and fracture prevention: Looking beyond calcium, vitamin D and protein

Falls and osteoporotic fractures are a major public health problem, particularly among older adults. A third of individuals aged 65 years and over fall at least once each year, with up to 20 % of these resulting in serious injury, including fracture. In conjunction with regular exercise, the importance of diet for musculoskeletal health has largely focused upon calcium, vitamin D, and protein, particularly in the context of preventing falls and fractures. Whilst there is evidence for the benefits of these nutrients for musculoskeletal health, other aspects of the diet remain largely underexplored. For example, vegetables are rich sources of macro- and micronutrients that are essential for muscle function and bone health, which are key factors in the prevention of falls and fractures. Recent work has highlighted the importance of nutrients such as vegetable-derived nitrate and vitamin K1 in optimising muscle strength, physical function, and bone quality. In the context of dietary patterns, vegan/plant-based diets have recently gained popularity due to perceived health benefits, animal welfare, or to tackle climate change. The elimination and/or substitution of animal-based products for plant foods (without careful planning and/or expert dietary guidance) could, however, have long-term negative musculoskeletal consequences; a trend uncovered by recent evidence. Within the overarching theme of nutrition for fall and fracture prevention in older populations, the aim of this review is to (i) summarise the current evidence for calcium, vitamin D and protein; (ii) describe the importance of vegetables and selected nutrients, such as nitrate and vitamin K1, for muscle function and bone structural integrity; and (iii) highlight current evidence around different dietary patterns (e.g., plant-based, diet quality, data driven approaches) and their impact on musculoskeletal health.

Are Chokeberry Products Safe for Health? Evaluation of the Content of Contaminants and Health Risk

The health-promoting properties of chokeberry fruit have been confirmed in numerous scientific studies. It has been shown that the consumption of these fruits, due to the high content of bioactive compounds, has beneficial effects in neurodegenerative diseases, in addition to having hypolipemic, hypotensive, hypoglycemic, and anti-inflammatory properties. However, different conditions and methods of fruit cultivation, as well as methods of juice and fiber production, may result in a high content of toxic substances, which reduce the health value of chokeberry products. Many substances are environmental pollutants. In this study, for the first time, we examined the content of toxic elements (As, Hg, Cd, Pb), nitrates, and nitrites in all chokeberry juices (organic, conventional, from concentrate, and not from fruit concentrate) without additives and in all chokeberry fibers available in Poland. In addition, risk indicators of adverse health effects were calculated. The median content of the contaminants tested in juices was 0.461 µg/kg for As, 1.170 µg/kg for Cd, 0.427 µg/kg for Hg, 1.404 µg/kg for Pb, 4.892 mg/kg for NO2-, and 41.788 mg/kg for NO3-. These values did not exceed the permissible standards for the calculated indicators. There were also no statistically significant differences in the content of Cd, Hg, and Pb, as well as nitrates (III) and nitrates (V), in the tested juices depending on the method of cultivation and juice production. However, statistically significant differences in As content were found between juices from conventional and organic cultivation (1.032 µg/kg vs. 0.458 µg/kg) and juices from concentrate and not from concentrate (1.164 µg/kg vs. 0.460 µg/kg). There were no statistically significant differences with respect to impurities in fibers. It is shown that the consumption of chokeberry juice and fiber in the amount normally consumed does not pose a health risk associated with the intake of toxic substances; in the case of long-term fiber consumption, the Pb content should be monitored. In particular, organic juices and those not from fruit concentrate are recommended due to the lower As content.

Habitual dietary nitrate intake and cognition in the Australian Imaging, Biomarkers and Lifestyle Study of ageing: A prospective cohort study

BACKGROUND & AIMS

Dietary nitrate improves cardiovascular health via a nitric oxide (NO) pathway. NO is key to both cardiovascular and brain health. There is also a strong association between vascular risk factors and brain health. Dietary nitrate intake could therefore be associated with better cognitive function and reduced risk of cognitive decline. This is yet to be investigated. The aim of this study was to investigate the association between habitual intake of dietary nitrate from sources where nitrate is naturally present, and cognitive function, and cognitive decline, in the presence or absence of the apolipoprotein E (APOE) ε4 allele.

METHODS

The study included 1254 older adult participants of the Australian Imaging, Biomarkers and Lifestyle Study of Ageing who were cognitively normal at baseline. Plant-derived, vegetable-derived, animal derived nitrate (not including meat where nitrate is an allowed additive), and total nitrate intakes were calculated from baseline food frequency questionnaires using comprehensive nitrate databases. Cognition was assessed at baseline and every 18 months over a follow-up period of 126 months using a comprehensive neuropsychological test battery. Multivariable-adjusted linear mixed effect models were used to examine the association between baseline nitrate intake and cognition over the 126 months (median [IQR] follow-up time of 36 [18-72] months), stratified by APOE ε4 carrier status.

RESULTS

In non APOE ε4 carriers, for every 60 mg/day higher intake of plant-derived nitrate at baseline there was an associated higher language score [β (95% CI): 0.10 (0.01, 0.19)] over 126 months, after multivariable adjustments. In APOE ε4 carriers, there was an associated better episodic recall memory [0.24 (0.08, 0.41)] and recognition memory [0.15 (0.01, 0.30)] scores. Similar associations were seen for the intakes of vegetable-derived and total nitrate. Additionally, in APOE ε4 carriers, for every 6 mg/day higher intake of animal-derived nitrate (excluding meat with nitrate as an allowed additive) at baseline there was an associated higher executive function score [β (95% CI): 1.41 (0.42, 2.39)]. We did not find any evidence of an association between dietary nitrate intake and rate of cognitive decline.

CONCLUSION

Our results suggest that habitual intake of dietary nitrate from sources where nitrate is naturally present impacts cognitive performance in an APOE genotype contingent manner. Further work is needed to validate our findings and understand potential mechanisms underlying the observed effects.

Nitrate Quantification in Fresh Vegetables in Shanghai: Its Dietary Risks and Preventive Measures

To investigate nitrate and nitrite content in fresh vegetables, 264 samples were randomly collected in the farmers' markets in Shanghai, Southeast China. The results indicate that 25.0% of the fresh vegetables were critically or more contaminated by nitrate [>1440 mg/kg FW (Fresh weight)]. Generally, leafy vegetables were more highly enriched in nitrate than root-tuber and fruit vegetables. About 22.6% of the leafy vegetables had a nitrate content exceeding the limit for edible permission (>3000 mg/kg FW). Nitrite content in the fresh vegetables was all within the safe level (<1 mg/kg FW). It was estimated that the daily nitrate intake through eating vegetables in Shanghai exceeded the WHO/FAO allowable limit. The field experiment indicated that the hyper-accumulation of nitrate and nitrite in the vegetables was mainly attributed to the excessive application of chemical fertilizers. The maxima of nitrate and nitrite in the vegetables were attained one week after applying chemical fertilizer, and thus they cannot be picked for dietary use. Applying organic manure can effectively lower the risk of nitrate and nitrite contamination in vegetables. The old leaves and leaf petioles were more easily enriched in nitrate due to their weaker metabolic activity. Vegetables with high nitrate content had a high risk of nitrite toxicity during storage due to the biological conversion of nitrate into nitrite, which is easily triggered by suitable temperature and mechanical damage processing. Therefore, fresh vegetables should be stored by rapid cooling and in undamaged forms to prevent nitrite accumulation.