Spinach cultigen variation for tissue carotenoid concentrations influences human serum carotenoid levels and macular pigment optical density following a 12-week dietary intervention

Ecdysterone and Turkesterone-Compounds with Prominent Potential in Sport and Healthy Nutrition

The naturally occurring compounds ecdysterone and turkesterone, which are present in plants, including Rhaponticum carthamoides Willd. (Iljin), Spinacia oleracea L., Chenopodium quinoa Willd., and Ajuga turkestanica (Regel) Briq, are widely recognized due to their possible advantages for both general health and athletic performance. The current review investigates the beneficial biological effects of ecdysterone and turkesterone in nutrition, highlighting their roles not only in enhancing athletic performance but also in the management of various health problems. Plant-based diets, associated with various health benefits and environmental sustainability, often include sources rich in phytoecdysteroids. However, the therapeutic potential of phytoecdysteroid-rich extracts extends beyond sports nutrition, with promising applications in treating chronic fatigue, cardiovascular diseases, and neurodegenerative disorders.

Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration

BACKGROUND

Age-related macular degeneration (AMD) is a degenerative condition of the back of the eye that occurs in people over the age of 50 years. Antioxidants may prevent cellular damage in the retina by reacting with free radicals that are produced in the process of light absorption. Higher dietary levels of antioxidant vitamins and minerals may reduce the risk of progression of AMD. This is the third update of the review.

OBJECTIVES

To assess the effects of antioxidant vitamin and mineral supplements on the progression of AMD in people with AMD.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, one other database, and three trials registers, most recently on 29 November 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared antioxidant vitamin or mineral supplementation to placebo or no intervention, in people with AMD.

DATA COLLECTION AND ANALYSIS

We used standard methods expected by Cochrane.

MAIN RESULTS

We included 26 studies conducted in the USA, Europe, China, and Australia. These studies enroled 11,952 people aged 65 to 75 years and included slightly more women (on average 56% women). We judged the studies that contributed data to the review to be at low or unclear risk of bias. Thirteen studies compared multivitamins with control in people with early and intermediate AMD. Most evidence came from the Age-Related Eye Disease Study (AREDS) in the USA. People taking antioxidant vitamins were less likely to progress to late AMD (odds ratio (OR) 0.72, 95% confidence interval (CI) 0.58 to 0.90; 3 studies, 2445 participants; moderate-certainty evidence). In people with early AMD, who are at low risk of progression, this means there would be approximately four fewer cases of progression to late AMD for every 1000 people taking vitamins (one fewer to six fewer cases). In people with intermediate AMD at higher risk of progression, this corresponds to approximately 78 fewer cases of progression for every 1000 people taking vitamins (26 fewer to 126 fewer). AREDS also provided evidence of a lower risk of progression for both neovascular AMD (OR 0.62, 95% CI 0.47 to 0.82; moderate-certainty evidence) and geographic atrophy (OR 0.75, 95% CI 0.51 to 1.10; moderate-certainty evidence), and a lower risk of losing 3 or more lines of visual acuity (OR 0.77, 95% CI 0.62 to 0.96; moderate-certainty evidence). Low-certainty evidence from one study of 110 people suggested higher quality of life scores (measured with the Visual Function Questionnaire) in treated compared with non-treated people after 24 months (mean difference (MD) 12.30, 95% CI 4.24 to 20.36). In exploratory subgroup analyses in the follow-on study to AREDS (AREDS2), replacing beta-carotene with lutein/zeaxanthin gave hazard ratios (HR) of 0.82 (95% CI 0.69 to 0.96), 0.78 (95% CI 0.64 to 0.94), 0.94 (95% CI 0.70 to 1.26), and 0.88 (95% CI 0.75 to 1.03) for progression to late AMD, neovascular AMD, geographic atrophy, and vision loss, respectively. Six studies compared lutein (with or without zeaxanthin) with placebo and one study compared a multivitamin including lutein/zeaxanthin with multivitamin alone. The duration of supplementation and follow-up ranged from six months to five years. Most evidence came from the AREDS2 study in the USA; almost all participants in AREDS2 also took the original AREDS supplementation formula. People taking lutein/zeaxanthin may have similar or slightly reduced risk of progression to late AMD (RR 0.94, 95% CI 0.87 to 1.01), neovascular AMD (RR 0.92, 95% CI 0.84 to 1.02), and geographic atrophy (RR 0.92, 95% CI 0.80 to 1.05) compared with control (1 study, 4176 participants, 6891 eyes; low-certainty evidence). A similar risk of progression to visual loss of 15 or more letters was seen in the lutein/zeaxanthin and control groups (RR 0.98, 95% CI 0.91 to 1.05; 6656 eyes; low-certainty evidence). Quality of life (Visual Function Questionnaire) was similar between groups (MD 1.21, 95% CI -2.59 to 5.01; 2 studies, 308 participants; moderate-certainty evidence). One study in Australia randomised 1204 people to vitamin E or placebo with four years of follow-up; 19% of participants had AMD. The number of late AMD events was low (N = 7) and the estimate of effect was uncertain (RR 1.36, 95% CI 0.31 to 6.05; very low-certainty evidence). There was no evidence of any effect of treatment on visual loss (RR 1.04, 95% CI 0.74 to 1.47; low-certainty evidence). There were no data on neovascular AMD, geographic atrophy, or quality of life. Five studies compared zinc with placebo. Evidence largely drawn from the largest study (AREDS) found a lower progression to late AMD over six years (OR 0.83, 95% CI 0.70 to 0.98; 3 studies, 3790 participants; moderate-certainty evidence), neovascular AMD (OR 0.76, 95% CI 0.62 to 0.93; moderate-certainty evidence), geographic atrophy (OR 0.84, 95% CI 0.64 to 1.10; moderate-certainty evidence), or visual loss (OR 0.87, 95% CI 0.75 to 1.00; 2 studies, 3791 participants; moderate-certainty evidence). There were no data on quality of life. Gastrointestinal symptoms were the main reported adverse effect. In AREDS, zinc was associated with a higher risk of genitourinary problems in men, but no difference was seen between high- and low-dose zinc groups in AREDS2. Most studies were too small to detect rare adverse effects. Data from larger studies (AREDS/AREDS2) suggested there may be little or no effect on mortality with multivitamin (HR 0.87, 95% CI 0.60 to 1.25; low-certainty evidence) or lutein/zeaxanthin supplementation (HR 1.06, 95% CI 0.87 to 1.31; very low-certainty evidence), but confirmed the increased risk of lung cancer with beta-carotene, mostly in former smokers.

AUTHORS' CONCLUSIONS

Moderate-certainty evidence suggests that antioxidant vitamin and mineral supplementation (AREDS: vitamin C, E, beta-carotene, and zinc) probably slows down progression to late AMD. People with intermediate AMD have a higher chance of benefiting from antioxidant supplements because their risk of progression is higher than people with early AMD. Although low-certainty evidence suggested little effect with lutein/zeaxanthin alone compared with placebo, exploratory subgroup analyses from one large American study support the view that lutein/zeaxanthin may be a suitable replacement for the beta-carotene used in the original AREDS formula.

An appraisal of trials investigating the effects on macular pigment optical density of lutein and zeaxanthin dietary interventions: a narrative review

Lutein and zeaxanthin (L/Z), xanthophylls obtained from the diet, are deposited in the macula of the eye. The macular concentration of L/Z is quantifiable as macular pigment optical density (MPOD). The aim of this review was to critically appraise the effect on MPOD of increasing L/Z intake by dietary intervention in adults. Pubmed, Cochrane Library, Web of Science, and Cinahl were searched up to April 2020. Ten studies investigating populations with and without age-related macular degeneration were included. MPOD increased significantly in 2 of the 8 controlled studies. Studies varied largely in the prescribed dietary L/Z dosage, duration, and participant characteristics. No relationships between types of dietary L/Z interventions and MPOD response could be determined. Limited monitoring of habitual dietary L/Z intake was identified as a major limitation of all 10 studies. Habitual dietary L/Z intake should be closely monitored in future studies to account for their effects on MPOD response to dietary L/Z interventions.

The Effect of Lutein/Zeaxanthin Intake on Human Macular Pigment Optical Density: A Systematic Review and Meta-Analysis

Lutein, zeaxanthin, and meso-zeaxanthin are the only carotenoids found in the human macula and may have a role in visual function. These carotenoids are reported to protect the retina, and thus vision, as antioxidants and by acting as a blue light filter. Our objective was to determine a minimum concentration of lutein/zeaxanthin intake that is associated with a statistically significant and/or clinically important change in macular pigment optical density (MPOD) among adults with healthy eyes. We searched Ovid MEDLINE, CENTRAL, and the Commonwealth of Agriculture Bureau for English-language studies through to July 2020. Two reviewers screened results to identify studies that evaluated supplements or dietary sources of lutein/zeaxanthin on MPOD among adults with healthy eyes. One reviewer extracted data and assessed strength of evidence, which was confirmed by a second reviewer. Two independent reviewers assessed the risk of bias. Meta-analyses were stratified by total lutein/zeaxanthin dose. We included 46 studies (N = 3189 participants; mean age = 43 y; 42% male). There was no statistically significant change in MPOD among studies evaluating <5 mg/d of total lutein/zeaxanthin intake which primarily assessed dietary interventions for 3-6 mo (pooled mean difference, 0.02; 95% CI: -0.01 to 0.05). The pooled mean increase in MPOD was 0.04 units (95% CI: 0.02 to 0.07) among studies evaluating 5 to <20 mg/d of lutein/zeaxanthin and was 0.11 units (95% CI: 0.06 to 0.16) among studies evaluating ≥20 mg/d of lutein/zeaxanthin for 3-12 mo. MPOD increased with lutein/zeaxanthin intake, particularly at higher doses, among adults with healthy eyes. The effects of lutein/zeaxanthin intake at doses <5 mg/d or from dietary sources is less clear. Increased lutein/zeaxanthin intake can help with maintaining ocular health. Future research is needed to determine the minimum dose and duration of lutein/zeaxanthin intake that is associated with a clinically important change in MPOD or visual function.

European ferns as rich sources of antioxidants in the human diet

Wild edible plants have become an attractive variation of the human diet, especially in East Asia, North America, and Oceania. However, their potential in nutrition is only rarely considered in Europe. This study aims to reveal the nutritional and antioxidant potential of mature fern leaves from 13 families grown in Europe. We found that most of the examined fern species displayed a high antioxidant capacity, exceeding 0.5 g Trolox equivalent per gram of extract dry weight in ORAC assay and reaching IC₅₀ values lower than 30 µg·mL^-1 in DPPH assay (with the value for Trolox 7 µg·mL^-1). Most of the species also appeared to be a good source of carotenoids, especially of lutein (205 µg·g^-1 DW on average) and β-carotene (161 µg·g^-1 DW on average) when compared to the reference leafy vegetables spinach and rocket. A cytotoxicity test using ovine hepatocytes showed a non-toxicity effect of fern leaf extracts.

Nutritional and Antioxidant Potential of Fiddleheads from European Ferns

Ferns are part of the diet and traditional medicine in East Asia, North America, and Oceania, however, their importance has been forgotten in Europe. Here, the nutritional and antioxidant potential of young fern fronds (fiddleheads) of eight families were studied. Most of the tested fern species excelled in high antioxidant capacity when compared to the reference leafy vegetables spinach and rocket. On average, the total phenol content reached 220 mg·g-1 of extract dry weight for all fiddleheads, and 15 out of 24 tested species exceeded 1 g Trolox equivalent per gram of extract dry weight in Oxygen Radical Absorbance Capacity (ORAC) assay. On the other hand, fiddleheads contained a comparable amount of carotenoids and ascorbic acid with the reference vegetables. In the case of fatty acid composition, fiddleheads contained especially high amounts of essential omega-3 (n3) and omega-6 (n6) polyunsaturated fatty acids with a beneficial n6/n3 ratio. The n6/n3 ratio in all tested species was between 2 and 6.4, whereas the ratio in the reference vegetables was below 0.4. All in all, fiddleheads from European ferns are a rich source of valuable antioxidants and essential fatty acids with a desirable n-6/n-3 ratio and may thus form an alternative source of these compounds, especially for those people not consuming fish and fish products.

Validation of a Method for Quantification of Lutein in Spinach Using High-Performance Liquid Chromatography: Interlaboratory Study

BACKGROUND

Lutein is gaining attention as a strong antioxidant contained in foods. It accumulates in the human blood and retina, and is considered to play an important role in the body, especially in the eyes.

OBJECTIVE

A method to determine the lutein content of raw spinach (Spinacia oleracea L.) was developed with the aim of its enactment as a Japanese agricultural standard (JAS) measurement method for components beneficial to human health.

METHODS

An interlaboratory study was conducted to evaluate an analytical method for the determination of lutein in spinach. The detection limit and quantification limit of lutein for this method were 0.2 and 0.7 mg/kg, respectively. Twelve participating laboratories independently analyzed test samples (five pairs of blind duplicates) using high-performance liquid chromatography (HPLC).

RESULTS

After removal of a few outliers, the repeatability relative standard deviation (RSDr), reproducibility (RSDR), and predicted RSDR of the evaluated method were 3.4-7.5, 4.6-13, and 7.5-8.5%, respectively, in a concentration range from 64.9-150 mg/kg.

CONCLUSIONS

The HorRat values (RSDR/predicted RSDR) of the lutein concentration were calculated to be 0.61-1.6.

HIGHLIGHTS

The study results indicate the acceptable precision of this method.

Food intake biomarkers for green leafy vegetables, bulb vegetables, and stem vegetables: a review

BACKGROUND

Numerous studies acknowledged the importance of an adequate vegetable consumption for human health. However, current methods to estimate vegetable intake are often prone to measurement errors due to self-reporting and/or insufficient detail. More objective intake biomarkers for vegetables, using biological specimens, are preferred. The only concentration biomarkers currently available are blood carotenoids and vitamin C, covering total fruit and vegetable intake. Identification of biomarkers for specific vegetables is needed for a better understanding of their relative importance for human health. Within the FoodBAll Project under the Joint Programming Initiative "A Healthy Diet for a Healthy Life", an ambitious action was undertaken to identify candidate intake biomarkers for all major food groups consumed in Europe by systematically reviewing the existent literature. This study describes the review on candidate biomarkers of food intake (BFIs) for leafy, bulb, and stem vegetables, which was conducted within PubMed, Scopus and Web of Science for studies published through March 2019.

RESULTS

In total, 65 full-text articles were assessed for eligibility for leafy vegetables, and 6 full-text articles were screened for bulb and stem vegetables. Putative BFIs were identified for spinach, lettuce, endive, asparagus, artichoke, and celery, but not for rocket salad. However, after critical evaluation through a validation scheme developed by the FoodBAll consortium, none of the putative biomarkers appeared to be a promising BFI. The food chemistry data indicate that some candidate BFIs may be revealed by further studies.

CONCLUSION

Future randomized controlled feeding studies combined with observational studies, applying a non-targeted metabolomics approach, are needed in order to identify valuable BFIs for the intake of leafy, bulb, and stem vegetables.

Potential of Microalgae Carotenoids for Industrial Application

Microalgae cultivation, when compared to the growth of higher plants, presents many advantages such as faster growth, higher biomass productivity, and smaller land area requirement for cultivation. For this reason, microalgae are an alternative platform for carotenoid production when compared to the traditional sources. Currently, commercial microalgae production is not well developed but, fortunately, there are several studies aiming to make the large-scale production feasible by, for example, employing different cultivation systems. This review focuses on the main carotenoids from microalgae, comparing them to the traditional sources, as well as a critical analysis about different microalgae cultivation regimes that are currently available and applicable for carotenoid accumulation. Throughout this review paper, we present relevant information about the main commercial microalgae carotenoid producers; the comparison between carotenoid content from food, vegetables, fruits, and microalgae; and the great importance and impact of these molecule applications, such as in food (nutraceuticals and functional foods), cosmetics and pharmaceutical industries, feed (colorants and additives), and healthcare area. Lastly, the different operating systems applied to these photosynthetic cultivations are critically discussed, and conclusions and perspectives are made concerning the best operating system for acquiring high cell densities and, consequently, high carotenoid accumulation.

Inclusion complexes of yellow bell pepper pigments with β-cyclodextrin: preparation, characterisation and application as food natural colorant

BACKGROUND

This work aimed to prepare inclusion complexes using yellow bell pepper pigments and β-cyclodextrin by two different procedures (method A, ultrasonic homogenisation; method B, kneading), to characterise them and evaluate their colour stability in an isotonic beverage model. The extract/β-cyclodextrin ratio was 1:2 for both inclusion methodologies evaluated. The formed extract-β-cyclodextrin complexes and a physical mixture of extract and β-cyclodextrin were evaluated by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR).

RESULTS

Both methodologies resulted in good complex yield and inclusion efficiency. The colour indices L* (lightness), a* (green/red) and b* (blue/yellow) of isotonic drinks added with the complexes were measured during storage under irradiance (1400 lx) and in the absence of light at temperatures between 25 and 31 °C for 21 days.

CONCLUSION

The complex obtained by inclusion method B promoted better colour protection for the beverage compared with the use of the crude extract, showing that the molecular inclusion of yellow bell pepper carotenoids can provide good results for that purpose. © 2017 Society of Chemical Industry.

Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration

BACKGROUND

It has been proposed that antioxidants may prevent cellular damage in the retina by reacting with free radicals that are produced in the process of light absorption. Higher dietary levels of antioxidant vitamins and minerals may reduce the risk of progression of age-related macular degeneration (AMD).

OBJECTIVES

The objective of this review was to assess the effects of antioxidant vitamin or mineral supplementation on the progression of AMD in people with AMD.

SEARCH METHODS

We searched CENTRAL (2017, Issue 2), MEDLINE Ovid (1946 to March 2017), Embase Ovid (1947 to March 2017), AMED (1985 to March 2017), OpenGrey (System for Information on Grey Literature in Europe, the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 29 March 2017.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared antioxidant vitamin or mineral supplementation (alone or in combination) to placebo or no intervention, in people with AMD.

DATA COLLECTION AND ANALYSIS

Both review authors independently assessed risk of bias in the included studies and extracted data. One author entered data into RevMan 5; the other author checked the data entry. We graded the certainty of the evidence using GRADE.

MAIN RESULTS

We included 19 studies conducted in USA, Europe, China, and Australia. We judged the trials that contributed data to the review to be at low or unclear risk of bias.Nine studies compared multivitamins with placebo (7 studies) or no treatment (2 studies) in people with early and moderate AMD. The duration of supplementation and follow-up ranged from nine months to six years; one trial followed up beyond two years. Most evidence came from the Age-Related Eye Disease Study (AREDS) in the USA. People taking antioxidant vitamins were less likely to progress to late AMD (odds ratio (OR) 0.72, 95% confidence interval (CI) 0.58 to 0.90; 2445 participants; 3 RCTs; moderate-certainty evidence). In people with very early signs of AMD, who are at low risk of progression, this would mean that there would be approximately 4 fewer cases of progression to late AMD for every 1000 people taking vitamins (1 fewer to 6 fewer cases). In people at high risk of progression (i.e. people with moderate AMD) this would correspond to approximately 8 fewer cases of progression for every 100 people taking vitamins (3 fewer to 13 fewer). In one study of 1206 people, there was a lower risk of progression for both neovascular AMD (OR 0.62, 95% CI 0.47 to 0.82; moderate-certainty evidence) and geographic atrophy (OR 0.75, 95% CI 0.51 to 1.10; moderate-certainty evidence) and a lower risk of losing 3 or more lines of visual acuity (OR 0.77, 95% CI 0.62 to 0.96; 1791 participants; moderate-certainty evidence). Low-certainty evidence from one study of 110 people suggested higher quality of life scores (National Eye Institute Visual Function Questionnaire) in treated compared with the non-treated people after 24 months (mean difference (MD) 12.30, 95% CI 4.24 to 20.36). Six studies compared lutein (with or without zeaxanthin) with placebo. The duration of supplementation and follow-up ranged from six months to five years. Most evidence came from the AREDS2 study in the USA. People taking lutein or zeaxanthin may have similar or slightly reduced risk of progression to late AMD (RR 0.94, 95% CI 0.87 to 1.01; 6891 eyes; low-certainty evidence), neovascular AMD (RR 0.92, 95% CI 0.84 to 1.02; 6891 eyes; low-certainty evidence), and geographic atrophy (RR 0.92, 95% CI 0.80 to 1.05; 6891 eyes; low-certainty evidence). A similar risk of progression to visual loss of 15 or more letters was seen in the lutein and control groups (RR 0.98, 95% CI 0.91 to 1.05; 6656 eyes; low-certainty evidence). Quality of life (measured with Visual Function Questionnaire) was similar between groups in one study of 108 participants (MD 1.48, 95% -5.53 to 8.49, moderate-certainty evidence). One study, conducted in Australia, compared vitamin E with placebo. This study randomised 1204 people to vitamin E or placebo, and followed up for four years. Participants were enrolled from the general population; 19% had AMD. The number of late AMD events was low (N = 7) and the estimate of effect was uncertain (RR 1.36, 95% CI 0.31 to 6.05, very low-certainty evidence). There were no data on neovascular AMD or geographic atrophy.There was no evidence of any effect of treatment on visual loss (RR 1.04, 95% CI 0.74 to 1.47, low-certainty evidence). There were no data on quality of life. Five studies compared zinc with placebo. The duration of supplementation and follow-up ranged from six months to seven years. People taking zinc supplements may be less likely to progress to late AMD (OR 0.83, 95% CI 0.70 to 0.98; 3790 participants; 3 RCTs; low-certainty evidence), neovascular AMD (OR 0.76, 95% CI 0.62 to 0.93; 2442 participants; 1 RCT; moderate-certainty evidence), geographic atrophy (OR 0.84, 95% CI 0.64 to 1.10; 2442 participants; 1 RCT; moderate-certainty evidence), or visual loss (OR 0.87, 95% CI 0.75 to 1.00; 3791 participants; 2 RCTs; moderate-certainty evidence). There were no data reported on quality of life.Very low-certainty evidence was available on adverse effects because the included studies were underpowered and adverse effects inconsistently reported.

AUTHORS' CONCLUSIONS

People with AMD may experience some delay in progression of the disease with multivitamin antioxidant vitamin and mineral supplementation. This finding was largely drawn from one large trial, conducted in a relatively well-nourished American population. We do not know the generalisability of these findings to other populations. Although generally regarded as safe, vitamin supplements may have harmful effects. A systematic review of the evidence on harms of vitamin supplements is needed. Supplements containing lutein and zeaxanthin are heavily marketed for people with age-related macular degeneration but our review shows they may have little or no effect on the progression of AMD.

Dietary fruits and vegetables and cardiovascular diseases risk

Diet is likely to be an important determinant of cardiovascular disease (CVD) risk. In this article, we will review the evidence linking the consumption of fruit and vegetables and CVD risk. The initial evidence that fruit and vegetable consumption has a protective effect against CVD came from observational studies. However, uncertainty remains about the magnitude of the benefit of fruit and vegetable intake on the occurrence of CVD and whether the optimal intake is five portions or greater. Results from randomized controlled trials do not show conclusively that fruit and vegetable intake protects against CVD, in part because the dietary interventions have been of limited intensity to enable optimal analysis of their putative effects. The protective mechanisms of fruit and vegetables may not only include some of the known bioactive nutrient effects dependent on their antioxidant, anti-inflammatory, and electrolyte properties, but also include their functional properties, such as low glycemic load and energy density. Taken together, the totality of the evidence accumulated so far does appear to support the notion that increased intake of fruits and vegetables may reduce cardiovascular risk. It is clear that fruit and vegetables should be eaten as part of a balanced diet, as a source of vitamins, fiber, minerals, and phytochemicals. The evidence now suggests that a complicated set of several nutrients may interact with genetic factors to influence CVD risk. Therefore, it may be more important to focus on whole foods and dietary patterns rather than individual nutrients to successfully impact on CVD risk reduction. A clearer understanding of the relationship between fruit and vegetable intake and cardiovascular risk would provide health professionals with significant information in terms of public health and clinical practice.

Chlorophyll enhances oxidative stress tolerance inCaenorhabditis elegansand extends its lifespan

Green vegetables are thought to be responsible for several beneficial properties such as antioxidant, anti-mutagenic, and detoxification activities. It is not known whether these effects are due to chlorophyll which exists in large amounts in many foods or result from other secondary metabolites. In this study, we used the model systemCaenorhabditis elegansto investigate the anti-oxidative and anti-aging effects of chlorophyllin vivo. We found that chlorophyll significantly improves resistance to oxidative stress. It also enhances the lifespan ofC. elegansby up to 25% via activation of the DAF-16/FOXO-dependent pathway. The results indicate that chlorophyll is absorbed by the worms and is thus bioavailable, constituting an important prerequisite for antioxidant and longevity-promoting activities inside the body. Our study thereby supports the view that green vegetables may also be beneficial for humans.

Variation in Carotenoid Content of Kale and Other Vegetables: A Review of Pre- and Post-harvest Effects

Lutein and zeaxanthin are carotenoids that are selectively taken up into the macula of the eye, where they are thought to protect against the development of age-related macular degeneration. They are obtained from dietary sources, with the highest concentrations found in dark green leafy vegetables, such as kale and spinach. In this Review, compositional variations due to variety/cultivar, stage of maturity, climate or season, farming practice, storage, and processing effects are highlighted. Only data from studies which report on lutein and zeaxanthin content in foods are reported. The main focus is kale; however, other predominantly xanthophyll containing vegetables such as spinach and broccoli are included. A small amount of data about exotic fruits is also referenced for comparison. The qualitative and quantitative composition of carotenoids in fruits and vegetables is known to vary with multiple factors. In kale, lutein and zeaxanthin levels are affected by pre-harvest effects such as maturity, climate, and farming practice. Further research is needed to determine the post-harvest processing and storage effects of lutein and zeaxanthin in kale; this will enable precise suggestions for increasing retinal levels of these nutrients.

An Evidence-Based Systematic Review of Lutein by the Natural Standard Research Collaboration

An evidence-based systematic review of lutein by the Natural Standard Research Collaboration consolidates the safety and efficacy data available in the scientific literature using a validated, reproducible grading rationale. This article includes written and statistical analysis of clinical trials, plus a compilation of expert opinion, folkloric precedent, history, pharmacology, kinetics/dynamics, interactions, adverse effects, toxicology, and dosing.

Macular xanthophylls, lipoprotein-related genes, and age-related macular degeneration

Plant-based macular xanthophylls (MXs; lutein and zeaxanthin) and the lutein metabolite meso-zeaxanthin are the major constituents of macular pigment, a compound concentrated in retinal areas that are responsible for fine-feature visual sensation. There is an unmet need to examine the genetics of factors influencing regulatory mechanisms and metabolic fates of these 3 MXs because they are linked to processes implicated in the pathogenesis of age-related macular degeneration (AMD). In this work we provide an overview of evidence supporting a molecular basis for AMD-MX associations as they may relate to DNA sequence variation in AMD- and lipoprotein-related genes. We recognize a number of emerging research opportunities, barriers, knowledge gaps, and tools offering promise for meaningful investigation and inference in the field. Overviews on AMD- and high-density lipoprotein (HDL)-related genes encoding receptors, transporters, and enzymes affecting or affected by MXs are followed with information on localization of products from these genes to retinal cell types manifesting AMD-related pathophysiology. Evidence on the relation of each gene or gene product with retinal MX response to nutrient intake is discussed. This information is followed by a review of results from mechanistic studies testing gene-disease relations. We then present findings on relations of AMD with DNA sequence variants in MX-associated genes. Our conclusion is that AMD-associated DNA variants that influence the actions and metabolic fates of HDL system constituents should be examined further for concomitant influence on MX absorption, retinal tissue responses to MX intake, and the capacity to modify MX-associated factors and processes implicated in AMD pathogenesis.

Effects of extraction and high-performance liquid chromatographic conditions on the determination of lutein in spinach

A major factor in the direct determination of lutein in spinach extracts proved to be obtaining reproducible and stable chromatography of lutein. This was achieved on a C30 column with the mobile phase acetone-0.1M triethylammonium acetate (TEAA) buffer (pH 7) 9:1 (v/v). Extraction of 10mg of lyophilized spinach with 10 mL of extraction solvent (ethanol, acetone, ethanol-ethyl acetate 1:1 (v/v), methanol-THF 1:1 (v/v)) for 15 min with magnetic stirring under nitrogen resulted in equal yields of lutein. The yields were enhanced by addition of 15% of 1M TEAA buffer pH 7 to all four extraction solvents. As confirmed by recovery experiments, no loss of lutein occurred during the extraction. The relative standard deviation from triplicate extractions was less than 5%. The addition of 15% TEAA pH 7 to acetone enhanced the extraction yield of lutein also from unlyophilized spinach. The content of lutein in different spinach samples ranged from 5 to 15 mg/100g of fresh weight. The first separation is reported of all the carotenoids and chlorophylls on a C18 core-shell column and the addition of 15% of 1M TEAA buffer pH 7 to acetone also enhanced the extraction yield of β-carotene compared to the yield produced by pure acetone.

Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration

BACKGROUND

It has been proposed that antioxidants may prevent cellular damage in the retina by reacting with free radicals that are produced in the process of light absorption. Higher dietary levels of antioxidant vitamins and minerals may reduce the risk of progression of age-related macular degeneration (AMD).

OBJECTIVES

The objective of this review was to assess the effects of antioxidant vitamin or mineral supplementation on the progression of AMD in people with AMD.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 8), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to August 2012), EMBASE (January 1980 to August 2012), Allied and Complementary Medicine Database (AMED) (January 1985 to August 2012), OpenGrey (System for Information on Grey Literature in Europe) (www.opengrey.eu/), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 20 August 2012. We searched the reference lists of identified reports and the Science Citation Index. We contacted investigators and experts in the field for details of unpublished studies. We also searched for systematic reviews of harms of vitamin supplements.

SELECTION CRITERIA

We included randomised trials comparing antioxidant vitamin or mineral supplementation (alone or in combination) to placebo or no intervention in people with AMD.

DATA COLLECTION AND ANALYSIS

Two authors assessed risk of bias and extracted data from the included trials. Where appropriate, we pooled data using a random-effects model unless three or fewer trials were available in which case we used a fixed-effect model.

MAIN RESULTS

Thirteen trials (6150 participants) were included in this review. Over half the participants (3640) were randomised in one trial (AREDS in the USA), which found a beneficial effect of antioxidant (beta-carotene, vitamin C and vitamin E) and zinc supplementation on progression to advanced AMD (adjusted odds ratio (OR) 0.68, 95% confidence interval (CI) 0.53 to 0.87) over an average of 6.3 years. People taking supplements were less likely to lose 15 or more letters of visual acuity (adjusted OR 0.77, 95% CI 0.62 to 0.96). The other trials, in general, had shorter follow-up (less than two years). No evidence for an effect of supplementation was seen in these smaller trials of shorter duration. Overall we considered the strength of the evidence to be moderate. We did not consider included trials, in general, to be at risk of bias, although we found it difficult to assess reporting biases. The main reason for downgrading the strength of the evidence was because, for several analyses, only one trial was included and therefore consistency of the findings could not be assessed. The included trials reported the following adverse effects: hospitalisation for genito-urinary problems was more common in people taking zinc and yellowing of skin was more common in people taking antioxidants. Systematic searching of the literature identified other potential harms of vitamin supplementation, in particular an increased risk of lung cancer in smokers associated with beta-carotene supplements, but we were unable to identify a good systematic review of the evidence for harms of nutritional supplementation.

AUTHORS' CONCLUSIONS

People with AMD may experience delay in progression of the disease with antioxidant vitamin and mineral supplementation. This finding is drawn from one large trial conducted in a relatively well-nourished American population. The generalisability of these findings to other populations is not known. Although generally regarded as safe, vitamin supplements may have harmful effects. A systematic review of the evidence on harms of vitamin supplements is needed.

Effect of sulfur and nitrogen fertilization on the content of nutritionally relevant carotenoids in spinach ( Spinacia oleracea )

Spinach is an important dietary source of lutein and β-carotene. Their synthesis is closely linked to chlorophyll synthesis and dependent upon an adequate supply of sulfur and nitrogen. Soils may become sulfur-deficient during winter because microorganisms convert atmospheric SO2 less efficiently to sulfate. The influence of sulfur and nitrogen fertilization on the carotenoid and chlorophyll contents of spinach grown in summer or winter was investigated. Carotenoid and chlorophyll levels were positively correlated. Lutein and β-carotene were 25% higher in summer than in winter. Winter levels were increased by 35-40% by sulfur fertilization in one location but not in the other, with the impact depending upon soil type, growing location, and atmospheric conditions. Carotenoids were little or not affected by nitrogen addition in winter or sulfur addition in summer. It is concluded that sulfur fertilization of spinach in winter may modestly increase carotenoids but high carotenoid levels are best assured with carotenoid-rich cultivars grown in summer.

The value of measurement of macular carotenoid pigment optical densities and distributions in age-related macular degeneration and other retinal disorders

There is increasing recognition that the optical and antioxidant properties of the xanthophyll carotenoids lutein and zeaxanthin play an important role in maintaining the health and function of the human macula. In this review article, we assess the value of non-invasive quantification of macular pigment levels and distributions to identify individuals potentially at risk for visual disability or catastrophic vision loss from age-related macular degeneration, and we consider the strengths and weaknesses of the diverse measurement methods currently available.

Increase in nutritionally important sweet corn kernel carotenoids following Mesotrione and atrazine applications

The herbicide mesotrione inhibits a critical enzyme, phytoene desaturase, in plant carotenoid biosynthesis. Mesotrione is currently labeled for selective weed control in sweet corn ( Zea mays var. rugosa). Mesotrione applied alone, or in mixtures with the photosystem II inhibitor atrazine, acted to increase concentrations of kernel antheraxanthin, lutein, and zeaxanthin carotenoids in several sweet corn genotypes. Kernel lutein and zeaxanthin levels significantly increased 15.6% after mesotrione + atrazine early postemergence applications, as compared to the control treatment. It appears that mesotrione applications resulted in greater pools of kernel carotenoids once the sweet corn genotypes expressing moderate injury overcame the initial herbicidal photo-oxidative stress. This is the first report of herbicides directly up-regulating the carotenoid biosynthetic pathway in corn kernels, which is associated with the nutritional quality of sweet corn. Enhanced accumulation of lutein and zeaxanthin is important because dietary carotenoids function in suppressing aging eye diseases such as macular degeneration, now affecting 1.75 million older Americans.

Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration

BACKGROUND

It has been proposed that antioxidants may prevent cellular damage in the retina by reacting with free radicals that are produced in the process of light absorption.

OBJECTIVES

The objective of this review was to assess the effects of antioxidant vitamin or mineral supplementation, or both, on the progression of age-related macular degeneration (AMD).

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2005, Issue 4); MEDLINE (1966 to January 2006); SIGLE (1980 to March 2005); EMBASE (1980 to January 2005); NRR (2005, Issue 4); AMED (1985 to January 2006); and PubMed (24 January 2006 covering last 60 days), reference lists of identified reports and the Science Citation Index. We contacted investigators and experts in the field for details of unpublished studies.

SELECTION CRITERIA

We included randomised trials comparing antioxidant vitamin or mineral supplemention (alone or in combination) to a control intervention in people with AMD.

DATA COLLECTION AND ANALYSIS

The author extracted data and assessed trial quality. Where appropriate, data were pooled using a random-effects model unless three or fewer trials were available in which case a fixed-effects model was used.

MAIN RESULTS

Eight trials were included in this review. The majority of people were randomised in one trial (AREDS in the USA) that found a beneficial effect of antioxidant (beta-carotene, vitamin C and vitamin E) and zinc supplementation on progression to advanced AMD (adjusted odds ratio 0.68, 99% confidence interval 0.49 to 0.93). People taking supplements were less likely to lose 15 or more letters of visual acuity (adjusted odds ratio 0.77, 99% confidence interval 0.58 to 1.03). Hospitalisation for genito-urinary problems was more common in people taking zinc and yellowing of skin was more common in people taking antioxidants. The other trials were, in general, small and the results were inconsistent.

AUTHORS' CONCLUSIONS

The evidence as to the effectiveness of antioxidant vitamin and mineral supplementation in halting the progression of AMD comes mainly from one large trial in the USA. The generalisability of these findings to other populations with different nutritional status is not known. Further large, well-conducted randomised controlled trials in other populations are required. Long-term harm from supplementation cannot be ruled out. Beta-carotene has been found to increase the risk of lung cancer in smokers; vitamin E has been associated with an increased risk of heart failure in people with vascular disease or diabetes.