Current understanding and future directions of cruciferous vegetables and their phytochemicals to combat neurological diseases

Neurological disorders incidences are increasing drastically due to complex pathophysiology, and the nonavailability of disease-modifying agents. Several attempts have been made to identify new potential chemicals to combat these neurological abnormalities. At present, complete abolishment of neurological diseases is not attainable except for symptomatic relief. However, dietary recommendations to help brain development or improvement have increased over the years. In recent times, cruciferous vegetables and their phytochemicals have been identified from preclinical and clinical investigations as potential neuroprotective agents. The present review highlights the beneficial effects and molecular mechanisms of phytochemicals such as indole-3-carbinol, diindolylmethane, sulforaphane, kaempferol, selenium, lutein, zeaxanthin, and vitamins of cruciferous vegetables against neurological diseases including Parkinson's disease, Alzheimer's disease, stroke, Huntington's disease, autism spectra disorders, anxiety, depression, and pain. Most of these cruciferous phytochemicals protect the brain by eliciting antioxidant, anti-inflammatory, and antiapoptotic properties. Regular dietary intake of cruciferous vegetables may benefit the prevention and treatment of neurological diseases. The present review suggests that there is a lacuna in identifying the clinical efficacy of these phytochemicals. Therefore, high-quality future studies should firmly establish the efficacy of the above-mentioned cruciferous phytochemicals in clinical settings.

Association between carotenoid intake and periodontitis in diabetic patients

This study aimed to evaluate the association between dietary carotenoid intake and periodontitis in diabetic patients. Data on diabetic patients were collected from the National Health and Nutrition Examination Survey (NHANES) 2009-2014 for this cross-sectional study. Dietary intake of carotenoids was assessed through the first 24-hour dietary recall interview. Full-mouth periodontal examinations were conducted by trained dental examiners. Subgroup analysis was conducted in terms of age, gender, the number of missing teeth, cardiovascular disease, smoking, and anti-diabetic drugs. Totally 1914 diabetic patients were included, with 1281 (66.93%) in the periodontitis group. After adjusting for age, gender, race, education, smoking, dental implants, hepatitis, and the number of missing teeth, α-carotene intake ≥55.82 mcg was associated with lower odds of periodontitis than α-carotene intake <55.82 mcg [OR = 0.70, 95% CI: 0.53-0.91, P = 0.010]; lutein and zeaxanthin intake ≥795.95 mcg was associated with decreased odds of periodontitis than lutein and zeaxanthin intake <795.95 mcg (OR = 0.75, 95%CI: 0.57-0.98, P = 0.039). The association between carotenoid intake and periodontitis varied across different subpopulations. In diabetes, dietary intake of α-carotene and lutein and zeaxanthin was inversely associated with the odds of periodontitis, which may facilitate clinical periodontitis management.

Associations Between Serum Polar Oxygenated Carotenoids Level and Erectile Dysfunction in Men Older Than 40 Years

Lutein, zeaxanthin, and β-cryptoxanthin are polar oxygenated carotenoids found to be detectable in more than 95% of the population in the United States. Research has linked these carotenoids with lower coronary heart disease prevalence. This study investigates the association of serum lutein/zeaxanthin and β-cryptoxanthin with erectile dysfunction (ED) among middle-aged and older men in the United States. Serum lutein/zeaxanthin and β-cryptoxanthin were independent variables. The outcome variable was ED. Analyzed data from 1,302 men (≥40 years old) who participated in the National Health and Nutrition Examination Survey 2001-2002 cross-sectional study were included. After adjusting for all covariates, serum lutein/zeaxanthin negatively correlated with ED (odds ratio [OR]: 0.972, 95% confidence interval [CI]: [0.951, 0.994], p = .011). However, a U-shaped association between serum lutein/zeaxanthin and ED was detected in men with diabetes or prevalent cardiovascular disease. A U-shaped non-linear association was observed between β-cryptoxanthin levels and ED. These findings suggest that while both lutein/zeaxanthin and β-cryptoxanthin are recognized as essential antioxidants, maintaining lower serum lutein/zeaxanthin levels and appropriate serum β-cryptoxanthin levels may offer potential benefits for individuals with ED. Further investigations, particularly prospective studies, are warranted to determine the role of serum lutein/zeaxanthin and β-cryptoxanthin in the biological mechanism associated with ED.

Early Childhood Lutein and Zeaxanthin Intake Is Positively Associated with Early Childhood Receptive Vocabulary and Mid-Childhood Executive Function But No Other Cognitive or Behavioral Outcomes in Project Viva

BACKGROUND

Lutein and zeaxanthin are carotenoids associated with better cognition in older adults. Recent evidence suggests that their dietary intake may also have cognitive implications in childhood.

OBJECTIVE

The aim was to examine associations of early childhood lutein and zeaxanthin (L/Z) intake with cognition in early and mid-childhood.

METHODS

Among 1378 children in Project Viva, a prospective cohort, mothers reported their child's dietary intake in early childhood (median: 3.2 y) using a food-frequency questionnaire. Child cognition and behavior were assessed at the same time point using the Peabody Picture Vocabulary Test (PPVT-III) and the Wide Range Assessment of Visual Motor Abilities (WRAVMA) and at mid-childhood (median: 7.7 y) using the Kaufman Brief Intelligence Test, the WRAVMA drawing subtest, the Wide Range Assessment of Memory and Learning, the Behavior Rating Inventory of Executive Function (BRIEF), and the Strengths and Difficulties Questionnaire.

RESULTS

Children consumed a daily mean (SD) of 1.0 (0.4) mg L/Z in early childhood. Children in the third-quartile category of L/Z intake had a mean PPVT-III score 2.40 (95% CI: 0.27, 4.53) points higher than children in the lowest quartile category in early childhood, suggesting better receptive vocabulary. Children in the highest quartile category of L/Z intake had a parent-reported mean BRIEF Global Executive Composite score 1.65 (95% CI: -3.27, -0.03) points lower than children in the lowest quartile category in mid-childhood, indicating better executive function. We did not observe associations between L/Z intake and any of the other cognitive or behavioral outcomes assessed.

CONCLUSIONS

The overall findings do not provide strong evidence of an association between child L/Z intake and cognition and behavior. However, the positive associations found between early childhood L/Z intake and early childhood receptive vocabulary and mid-childhood executive function, in addition to previous evidence of neurodevelopmental benefit of L/Z intake, suggest that this relation deserves further investigation.

The Mediation Role of the Risk of Non-Alcoholic Fatty Liver Disease in Relationship between Lutein and Zeaxanthin and Cognitive Functions among Older Adults in the United States

Background: Previous studies showed lutein and zeaxanthin (L and Z) may influence cognitive function by different mechanisms. Our study aimed to be the first to examine whether the risk of non-alcoholic fatty liver disease (NAFLD) mediated the possible association between the dietary intake of L and Z and cognitive function. Methods: We conducted a cross-sectional analysis of participants aged 60 years or over in the National Health and Nutrition Examination Survey (NHANES) 2011–2014. Multivariable linear regression was used to investigate the association between the dietary intake of L and Z and cognitive function, and structural equation modeling tested the mediation effect. Results: The fatty liver index for the United States population (US FLI) acted as a mediator in the association between the higher intake of L and Z and the Animal Fluency Test, the Digit Symbol Substitution Test (DSST), and composite score and mediated 13.89%, 17.87%, and 13.79% of the total association in dietary L and Z intake (14.29%, 13.68%, and 10.34% of the total association in total L and Z intake), respectively. Conclusion: Our study indicated the potential role of the risk of NAFLD as a mediator of associations between the dietary intake of L and Z and cognitive function in the geriatric American population.

Maternal Intake of Lutein and Zeaxanthin during Pregnancy Is Positively Associated with Offspring Verbal Intelligence and Behavior Regulation in Mid-Childhood in the Project Viva Cohort

BACKGROUND

Lutein and zeaxanthin are carotenoids associated with better cognition at older age. To our knowledge, no previous study has evaluated their cognitive implications in the prenatal period, when the brain undergoes its most rapid development.

OBJECTIVE

The objective of this study was to examine associations of maternal lutein and zeaxanthin (L/Z) intake during pregnancy with child cognition.

DESIGN

Among 1580 mother-child pairs in Project Viva, a prospective cohort, we assessed maternal intake of L/Z during pregnancy using food frequency questionnaires and offspring cognition by the Visual Recognition Memory paradigm in infancy, the Peabody Picture Vocabulary Test and the Wide Range Assessment of Visual Motor Abilities (WRAVMA) in early childhood, and the Kaufman Brief Intelligence Test (KBIT-II), the WRAVMA drawing subtest, and the Wide Range Assessment of Memory and Learning in mid-childhood. Parents completed the Behavior Rating Inventory of Executive Function (BRIEF) and Strengths and Difficulties Questionnaire.

RESULTS

Mothers consumed a daily mean (SD) of 2.6 (2.0) mg L/Z in the first and second trimesters of pregnancy. Mean mid-childhood KBIT-II verbal scores were higher with greater maternal L/Z intake [difference of Q4-Q1 means for first trimester: 2.67 (95% CI: 0.13, 5.20) and for second trimester: 3.55 (95% CI: 0.81, 6.28)], indicating better verbal intelligence. Secondary analyses on cognitive subtests showed that mean mid-childhood BRIEF Behavioral Regulation Index scores were lower with greater maternal L/Z intake [difference of Q4-Q1 means for first trimester: -1.63 (95% CI: -3.22, -0.04) and for second trimester: -1.89 (95% CI: -3.58, -0.21)], indicating better behavior regulation ability.

CONCLUSIONS

Higher maternal L/Z intake during pregnancy was associated with better offspring verbal intelligence and behavior regulation ability in mid-childhood, suggesting a potential benefit during prenatal development. We did not find a benefit of higher maternal L/Z intake on other child cognitive or behavioral outcomes. Project Viva is registered at clinicaltrials.gov as NCT02820402.

Association between Dietary Xanthophyll (Lutein and Zeaxanthin) Intake and Early Age-Related Macular Degeneration: The Atherosclerosis Risk in Communities Study

PURPOSE

To examine the association between xanthophyll intake and prevalent early age-related macular degeneration (AMD) using data from the Atherosclerosis Risk in Communities Study (n = 10,295). Potential effect modification by genetic polymorphisms and biomarkers of high-density lipoprotein (HDL) metabolism was explored.

METHODS

Xanthophyll intake was assessed at visit 1 (1987-1989) using food frequency questionnaires. Prevalent early AMD was assessed at visit 3 (1993-1995) via retinal photographs. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for AMD by quintiles of xanthophyll intake, adjusted for age, sex, race, field center, and pack-years of smoking. To evaluate effect modification, the association between tertiles (T) of xanthophyll intake and AMD was stratified by complement factor H (CFH) rs1061170 and age-related maculopathy susceptibility 2 (ARMS2) rs10490924 genotypes, as well as by median cutpoints of HDL biomarkers.

RESULTS

Xanthophyll intake was not associated with AMD in the overall sample, Caucasians (n = 8257), or African-Americans (n = 2038). Exploratory analyses observed that the association between xanthophyll intake and AMD varied statistically significantly by CFH rs1061170 genotype among Caucasians (p for interaction = 0.045) but not African Americans. No interactions were observed between xanthophyll intake and ARMS2 rs10490924. Moreover, higher xanthophyll intake was associated with decreased odds of AMD among participants with lower HDL (OR = 0.79, 95% CI 0.57-1.09) but not higher HDL (p for interaction = 0.048).

CONCLUSION

Xanthophyll intake was not associated with early AMD. Further studies to investigate this association by genetic susceptibility or variations in HDL metabolism are needed.

Lycopene, Lutein and Zeaxanthin May Reduce Faecal Blood, Mucus and Pus but not Abdominal Pain in Individuals with Ulcerative Colitis

BACKGROUND

The main symptom of ulcerative colitis is diarrhoea, which is often accompanied by painful tenesmus and faecal blood and mucus. It sometimes co-occurs with abdominal pain, fever, feeling of fatigue, loss of appetite and weight loss. Some dietary factors have been indicated as important in the treatment of ulcerative colitis. The aim of the study was to analyse the association between retinoid intake (total vitamin A, retinol, β-carotene, α-carotene, β-cryptoxanthin, lycopene, lutein and zeaxanthin) and ulcerative colitis symptoms (abdominal pain, faecal blood, faecal mucus, faecal pus) in individuals with ulcerative colitis in remission.

METHODS

Assessment of diet was based on self-reported data from each patient's dietary records taken over a period of three typical, random days (2 weekdays and 1 day of the weekend).

RESULTS

A total of 56 individuals with ulcerative colitis in remission (19 males and 37 females) were recruited for the study. One in every four individuals with ulcerative colitis in remission was characterised as having inadequate vitamin A intake. Higher lycopene, lutein and zeaxanthin intakes in individuals with ulcerative colitis in remission were associated with lower faecal blood, mucus and pus but not with lower incidence of abdominal pain. Higher carotene intake in individuals with ulcerative colitis in remission may contribute to higher incidence of faecal mucus.

CONCLUSIONS

Optimising intake of specific retinoids may enhance disease control in individuals with ulcerative colitis. Prospective studies, including patient reported and objective outcomes, are required to confirm this.

Candidate gene study of macular response to supplemental lutein and zeaxanthin

Supplementation with carotenoids is proposed to protect against age-related macular degeneration. There is, however, considerable variability in retinal macular pigment response, which may be due to underlying genetic variation. The purpose of this study was to determine whether genetic factors, which have been previously associated with cross-sectional macular pigment levels in the retina or serum lutein, also influence response to supplementation.

To this end we conducted an association study in 310 subjects from the TwinsUK cohort between variants in 8 candidate genes and serum lutein and retinal macular pigment optical density (MPOD) levels before and after supplementation. Four variants were associated with MPOD response to supplementation (p < 0.05): rs11057841 (SCARB1), rs4926339 (RPE65), rs1929841 (ABCA1) and rs174534 (FADS1). We also confirmed previous associations between rs6564851 near BMCO1 (p < 0.001) and rs11057841 within SCARB1 (p = 0.01) and baseline measures of serum lutein; while the latter was also associated with MPOD response, none of the BMCO1 variants were. Finally, there was evidence for association between variants near RPE65 and ELOVL2 and changes in lutein concentration after supplementation.

This study is the first to show association between genetic variants and response to carotenoids supplementation. Our findings suggest an important link between MP response and the biological processes of carotenoids transport and fatty acid metabolism.

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Four variants were associated with macular pigment response to supplementation.

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We replicated associations between BMCO1 variants and lutein at baseline.

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Carotenoids transport may affect macular response to supplementation.

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Lipid metabolism may affect macular response to supplementation.

Possible influences of lutein and zeaxanthin on the developing retina

The carotenoids lutein and zeaxanthin (LZ) are found throughout the central nervous system but reach their highest concentration within the macular region of the primate retina where they are commonly referred to as the macular pigments. Although LZ are a major integral feature of the central fovea, no information currently exists regarding the effects of variability in the concentration of these pigments on the developing retina. In particular, the long-term effects of very low levels of macular pigment are not known and potentially meaningful. Macular pigment levels depend upon dietary intake since LZ cannot be synthesized de novo. Infants with low intake of LZ (eg, infants receiving unfortified infant formula or breast milk from mothers with low carotenoid diets) would be expected to have considerably lower macular pigment compared with infants with high LZ intake (eg, breast-fed infants with mothers on carotenoid-rich diets). In this paper we discuss possible implications of this difference and the available evidence suggesting that LZ could influence the developing visual system.