Inverse associations between serum concentrations of zeaxanthin and other carotenoids and colorectal neoplasm in Japanese. Int J Clin Oncol. 2014;19:87-97. [PMID: 23380957 DOI: 10.1007/s10147-013-0520-2]

Neoxanthin alleviates the chronic renal failure-induced aging and fibrosis by regulating inflammatory process

Chronic renal failure (CRF) refers to progressive renal damage caused by chronic kidney diseases (CKD). Dialysis therapy and kidney transplantation are the important treatment for CRF. However, due to the limitation of conditions, they cannot be widely utilized. At present, the treatment of renal failure is a worldwide problem in clinic. Therefore, in the current study, we investigated the potential therapeutic effects of neoxanthin on CFR-caused aging and fibrosis. In this work, the effects of neoxanthin on CRF were studied using experimental techniques such as biochemistry, immunohistochemistry and molecular biology. In vitro, neoxanthin alleviated the aging and oxidative damage of kidney cells. In vivo, we found that Neoxanthin could alleviate adenine-induced CRF. Neoxanthin also inhibited CRF-caused renal aging, fibrosis, oxidative stress and inflammation. These findings indicate that neoxanthin could delay the progression of CRF and alleviate CRF-induced aging and fibrosis. Collectively, we found that neoxanthin shows good potential to inhibit CRF-caused kidney aging and fibrosis, suggesting that neoxanthin may be used as a drug (or a functional food) for the treatment of CRF-related diseases.

Effect Modification of Selenium Supplementation by Intake and Serum Concentrations of Antioxidants on the Development of Metachronous Colorectal Adenoma

BACKGROUND

Selenium (Se) is a trace element that has been investigated as a potential chemopreventive agent for colorectal cancer. Dietary intake of other antioxidant nutrients may modify the effect of Se.

OBJECTIVE

We examined the association between intake and serum concentrations of retinol, β-carotene, β-cryptoxanthin, lycopene, lutein/zeaxanthin, and α- and γ-tocopherol and the development of metachronous colorectal adenoma, and if these nutrients modified the effect of Se.

METHODS

We conducted a prospective study of 1874 participants from the Se Trial with data for antioxidant intake, as well as a subcohort of 508 participants with serum biomarker concentrations.

RESULTS

Statistically significantly lower odds for the development of metachronous adenoma were observed for those participants in the highest tertile of intake for lutein/zeaxanthin compared to the lowest, with an OR (95% CI) of 0.72 (0.56-0.94). No effect modification for intake of any nutrient was observed. However, circulating concentrations of lycopene exhibited statistically significant effect modification of selenium supplementation (p < 0.06).

CONCLUSION

These findings show that intake and circulating concentrations of antioxidant nutrients were not consistently associated with reduced odds for the development of metachronous lesions, although blood concentrations of lycopene may modify the effect of selenium supplementation.

The Relationship Between Colorectal Polyps and Serum Lipid Levels: A Systematic Review and Meta-analysis

Colorectal polyp has been considered as the precancerous lesion of colorectal cancer, to which serum lipid levels are closely related. At present, there is no consensus on the relationship between colorectal polyps and serum lipid levels. We performed a meta-analysis to explore the effects of lipid levels on colorectal polyps. Relevant articles published from 2000 to 2020 were searched in PubMed, Web of Science, EMBASE, and Cochrane Library databases. The mean value and SD of serum lipid indexes and body mass index in colorectal polyps groups and control groups were extracted from the included articles. Combined weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated to assess the effect size of serum lipid levels on colorectal polyps. The publication bias of the included studies were assessed based on the Egger test. Thirty-seven articles containing 19,464 cases and 63,979 controls were included. There were no significant publication bias. The levels of high-density lipoprotein cholesterol in the cases were lower than those in the controls (WMD: -2.589 mg/dL, 95% CI: -3.273, -1.906). While the levels of triglyceride (WMD: 16.933 mg/dL, 95% CI: 13.131, 20.736), total cholesterol (WMD: 5.561 mg/dL, 95% CI: 3.477, 7.645), low-density lipoprotein cholesterol (WMD: 3.109 mg/dL, 95% CI: 0.859, 5.359) and body mass index (WMD: 0.747 mg/dL, 95% CI: 0.588, 0.906) were higher in the cases. Colorectal polyps were associated with serum lipid levels and obesity. Hyperlipidemia and obesity may be the risk factors for colorectal polyps.

Association of Dietary Carrot/Carotene Intakes With Colorectal Cancer Incidence and Mortality in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

Background:

The evidence of dietary carrot/carotene intake's effect on the association with colorectal cancer (CRC) risk is conflicted. We sought to examine the association of carrot/carotene intake with CRC incidence and mortality in the Prostate, Lung, Colorectal, and Ovarian Cancer (PLCO) Screening cohort.

Methods

In all, 101,680 participants were enrolled between November 1993 and July 2001 from the PLCO cohort. We employed the multivariable Cox regression analyses to estimate the hazard ratios and 95% confidence interval. Subgroup analyses and interaction tests were performed to examine the potential effect modifiers. We further applied the generalized additive model to explore the non-linear trend of the exposure to cancer-related outcomes.

Results

A total of 1,100 CRC cases and 443 cancer-related deaths were documented. We noted that the 4th quintile of dietary carrot intakes was associated with a 21% lower risk of CRC incidence, compared with the lowest quintile group (full-adjusted HR_{quintile4vs.quintile1} = 0.79, 95%CI = 0.65–0.97, p for trend = 0.05), while the adjusted-HR was 0.95 (95%CI = 0.89–1.02) with per SD increment of carrot intakes, and no statistically significant associations were detected between dietary α-, and β-carotene intake and CRC incidence. There were no statistically significant associations observed between carrot/carotene intakes and CRC mortality. Furthermore, there were no non-linear dose-response relationships between dietary carrot, α-, and β-carotene intake and CRC incidence and mortality (all p_nonlinearity > 0.05). Of note, smoking status as a modifier on the association of dietary carrot intakes with CRC incidence but not mortality was observed.

Conclusions

In summary, this large U.S. prospective cohort study indicated that a moderate consumption of carrots was associated with a lower CRC incidence, which suggested that a certain dose-range of carrots consumed might contribute to a potential cancer-prevention effect, not the more the better.

Cruciferous Vegetables and Their Bioactive Metabolites: from Prevention to Novel Therapies of Colorectal Cancer

The Brassicaceae family, known as cruciferous vegetables, includes many economically important species, mainly edible oil plants, vegetable species, spice plants, and feed plants. Cruciferous vegetables are foods rich in nutritive composition and are also a good source of dietary fiber. Besides, cruciferous vegetables contain various bioactive chemicals known as glucosinolates and S-methyl cysteine sulfoxide, including sulphur-containing cancer-protective chemicals. Numerous studies have reported that daily intake of sulphurous vegetables helps prevent cancer formation and reduces cancer incidence, especially in colorectal cancer, through various mechanisms. The potential mechanisms of these compounds in preventing cancer in experimental studies are as follows: protecting cells against DNA damage, inactivating carcinogenic substances, showing antiviral and antibacterial effects, triggering apoptosis in cells with disrupted structure, inhibiting tumour cell migration causing metastasis and the development of tumour-feeding vessels (angiogenesis). These beneficial anticancer effects of cruciferous vegetables are generally associated with glucosinolates in their composition and some secondary metabolites, as well as other phenolic compounds, seed oils, and dietary fiber in the literature. This review aims to examine to the roles of cruciferous vegetables and their important bioactive metabolites in the prevention and treatment of colorectal cancer.

Antioxidant Phytochemicals in Pulses and their Relation to Human Health: A Review

Pulses are a staple food cultivated since ancient times, which play an important role in the human diet. From a nutritional point of view, pulses are very interesting foods as they are rich in proteins, carbohydrates and dietary fibre. Dietary antioxidants are a complex mixture of hydrophilic and lipophilic compounds usually present in foods of plant origin, including pulses. In the present study, the phytochemical composition of selected pulses (common beans, fava beans, lentils, chickpeas, peas and lupins) has been reviewed in terms of their content of antioxidant compounds. The content of hydrosoluble antioxidants (organic acids, phenolic compounds), liposoluble antioxidants (tocopherols, carotenoids) and other compounds which exert antioxidant properties, such as dietary fibre and minerals (zinc, selenium), has been studied, reporting that pulses are an interesting source of these compounds, which have important health benefits, including a preventing role in cardiovascular diseases, anticarcinogenic or neuroprotective properties. It is important to take into account that pulses are not usually consumed raw, but they must be processed before consumption in order to improve their nutritional quality and their palatability, therefore, the effect of different technological and heat treatments (germination, cooking, boiling, extrusion) on the antioxidant compounds present in pulses has been also reviewed. In this regard, it has been observed that as a consequence of processing, the content of phytochemicals with antioxidant properties is usually decreased, but processed pulses maintain relevant amounts of these compounds, preserving their beneficial health effect.

Dietary carotenoids in cancer chemoprevention and chemotherapy: A review of emerging evidence

In recent years, natural products have reemerged as biotherapeutic options, with several dietary carotenoids, viz. astaxanthin, fucoxanthin, siphonaxanthin, β-cryptoxanthin, α-carotene, β-carotene, and lycopene, developing as potential candidates for chemoprevention and chemotherapeutics of breast, colorectal, lung, and prostate cancers. The potent cytotoxic and antiproliferative effects of carotenoids against various cancer cells are mediated by a wide range of molecular mechanisms modulating oxidative stress and redox balance, mitogen-activated protein kinases (MAPK) and other cellular signaling proteins, transcription factors, caspase cascade pathways of apoptosis, cell cycle progression and proliferation, angiogenesis, metastasis, gap junction intercellular communication (GJIC), and multidrug resistance (MDR). This review discusses recent evidence demonstrating the crucial roles of carotenoids in these cellular and molecular events of cancer cell cytotoxicity. In addition, recent case-control and cohort studies are discussed to support the potential role of carotenoids in cancer prevention and therapy.

Fruits

Fruits come in a wide variety of colors, shapes, and flavors. This chapter will cover selected fruits that are known to be healthy and highly nutritious. These fruits were chosen due to their common usage and availability. Since it is not possible to cover all health benefits or essential nutrients and important phytochemicals of the fruit composition, this chapter will focus on the key valuable constituents and their potential health effects.

Carotenoids and their role in cancer prevention

Approximately two of every five people will develop cancer in their lifetime. Dietary modifications are one of the most promising lifestyle changes that can adjust the risk of developing cancer by nearly 40%. Carotenoids are a diverse group of natural pigments and are present in many fruits and vegetables. The data surrounding carotenoids and their potential roles in carcinogenesis have been rapidly growing over the past two decades. This review summarizes the literature surrounding the associations between the most six common carotenoids in the diet and ten of the most commonly diagnosed cancers. In this study, preclinical, epidemiological, and toxicology data were reviewed. Data from these studies suggest that several carotenoids might provide a beneficial impact on reducing carcinogenesis. Further studies are needed to determine the causal relationships between individual carotenoids and cancer incidence and progression. This article is part of a Special Issue entitled Carotenoids recent advances in cell and molecular biology edited by Johannes von Lintig and Loredana Quadro.

Dietary Lutein Plus Zeaxanthin Intake and DICER1 rs3742330 A > G Polymorphism Relative to Colorectal Cancer Risk

It is unclear whether dietary lutein/zeaxanthin intake in colorectal cancer is associated with microRNA processing involved in DICER1 cleavage for messenger RNA translation. We investigated whether dietary lutein/zeaxanthin intake affects colorectal cancer risk in patients with a DICER1 rs3742330 polymorphism. In this hospital-based case-control study, we recruited 923 colorectal cancer patients and 1,846 controls based on eligibility criteria, a semiquantitative food frequency questionnaire and the DICER1 rs3742330 genotype. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by unconditional logistic regression adjusted for confounders. The highest quartile of lutein/zeaxanthin consumption was inversely associated with a reduced colorectal cancer risk (OR, 95% CI = 0.25, 0.18-0.36). Carrying G allele (AG + GG) showed a significantly reduced colorectal cancer incidence compared with that of AA carriers (OR, 95% CI = 0.71, 0.55-0.91). Those carrying the G allele (AG + GG) along with high lutein/zeaxanthin consumption were markedly associated with a decreased colorectal cancer risk (OR, 95% CI = 0.32, 0.22-0.46, P for interaction = 0.018), particularly for rectal cancer (OR, 95% CI = 0.24, 0.15-0.39, P for interaction = 0.004), compared with that of AA carriers with low lutein/zeaxanthin intakes. In conclusion, colorectal cancer risk was related to an interactive effect between dietary lutein/zeaxanthin intake and the DICER1 rs3742330 polymorphism.

Serum carotenoids and colorectal cancer risk: A case-control study in Guangdong, China

SCOPE

Previous epidemiological studies on the association between circulating carotenoids and the risk of colorectal cancer drew inconclusive conclusions. This study aimed to examine serum carotenoids in relation to colorectal cancer risk in a Chinese population.

METHODS AND RESULTS

One case-control study beginning from July 2010, consecutively recruited 538 eligible colorectal cancer cases and 564 age (5-year interval) and sex frequency-matched controls. Serum levels of α-carotene, β-carotene, β-cryptoxanthin, lycopene and lutein/zeaxanthin were detected by HPLC. Unconditional logistic regression was used to estimate the odds ratio (OR) and 95% confidence internal (CI) after adjusting for various confounders. Serum levels of α-carotene, β-cryptoxanthin and lycopene were found to be inversely associated with colorectal cancer risk. The adjusted ORs of the highest quartile relative to the lowest quartile serum level were 0.49 (95% CIs 0.33-0.72) for α-carotene, 0.44 (95% CIs 0.29-0.66) for β-cryptoxanthin, and 0.36 (95% CIs 0.24-0.54) for lycopene, respectively. The association between serum β-carotene, lutein/zeaxanthin and colorectal cancer risk was not statistically significant.

CONCLUSION

The results indicated that the incidence of colorectal cancer was associated with lower serum levels of α-carotene, β-cryptoxanthin and lycopene among Chinese population residing in Guangdong.

Blood Lipid Concentrations and Colorectal Adenomas: A Systematic Review and Meta-Analysis of Colonoscopy Studies in Asia, 2000-2014

It is unclear whether dyslipidemia is associated with risk of colorectal neoplasia. The incidence of both conditions is increasing in Asia, motivating a number of new studies from this region. We performed a systematic literature search of Asian colonoscopy-based studies that collected blood lipid concentrations at the time of endoscopy. Persons found to have colorectal adenoma were considered cases, and those found to be adenoma-free were considered controls. Seventeen studies published between 2000 and 2014 met inclusion criteria, collectively enrolling 17,387 cases and 30,427 controls. Mean differences and adjusted odds ratios were summarized with random-effects meta-analyses. Compared with controls, cases had higher total cholesterol (mean difference (MD) = 2.4 mg/dL, 95% confidence interval (CI): 0.2, 4.6), higher low-density lipoprotein cholesterol (MD = 1.3 mg/dL, 95% CI: 0.1, 2.6), higher triglyceride (MD = 16.4 mg/dL, 95% CI: 11.2, 21.5), and lower high-density lipoprotein (HDL) cholesterol (MD = -2.1 mg/dL, 95% CI: -2.7, -1.6) concentrations. Based on adjusted odds ratios, associations for 40-mg/dL-higher triglyceride levels (odds ratio = 1.13, 95% CI: 1.05, 1.21) and 10-mg/dL-higher HDL cholesterol levels (odds ratio = 0.96, 95% CI: 0.92, 1.00) achieved statistical significance. Persons with adenoma were more likely to have unfavorable cholesterol profiles at the time of colonoscopy than those without adenoma. The most convincing evidence for an association between dyslipidemia and colorectal neoplasia was observed for hypertriglyceridemia.

Bioactive Compounds Isolated from Microalgae in Chronic Inflammation and Cancer

The risk of onset of cancer is influenced by poorly controlled chronic inflammatory processes. Inflammatory diseases related to cancer development include inflammatory bowel disease, which can lead to colon cancer, or actinic keratosis, associated with chronic exposure to ultraviolet light, which can progress to squamous cell carcinoma. Chronic inflammatory states expose these patients to a number of signals with tumorigenic effects, including nuclear factor kappa B (NF-κB) and mitogen-activated protein kinases (MAPK) activation, pro-inflammatory cytokines and prostaglandins release and ROS production. In addition, the participation of inflammasomes, autophagy and sirtuins has been demonstrated in pathological processes such as inflammation and cancer. Chemoprevention consists in the use of drugs, vitamins, or nutritional supplements to reduce the risk of developing or having a recurrence of cancer. Numerous in vitro and animal studies have established the potential colon and skin cancer chemopreventive properties of substances from marine environment, including microalgae species and their products (carotenoids, fatty acids, glycolipids, polysaccharides and proteins). This review summarizes the main mechanisms of actions of these compounds in the chemoprevention of these cancers. These actions include suppression of cell proliferation, induction of apoptosis, stimulation of antimetastatic and antiangiogenic responses and increased antioxidant and anti-inflammatory activity.

Vegetable consumption and colorectal cancer risk: an evaluation based on a systematic review and meta-analysis among the Japanese population

OBJECTIVE

The association between vegetable consumption and colorectal cancer risk remains unclear and may differ by region. We performed a systematic review and meta-analysis of epidemiologic studies on this issue among the Japanese population.

METHODS

A systematic review and meta-analysis was performed by searching MEDLINE through PubMed and the Ichushi database for cohort and case-control studies that were published by the end of December 2014. Associations were evaluated based on their magnitude and the strength of the evidence. Meta-analysis was performed by using the random effects model to estimate the summary relative risk with 95% confidence interval according to the study design. The final judgment was made based on a consensus of the research group members with consideration for both epidemiological evidence and biological plausibility.

RESULTS

We identified six cohort studies and 11 case-control studies on vegetable intake and colorectal cancer among the Japanese population. Of the cohort studies, one study showed a weak inverse association with colon cancer and another study showed a weak positive association with rectal cancer in men, but other studies found no associations between vegetable consumption and colon and rectal cancers. With regard to case-control studies, one study found a strong inverse association with colon cancer, and three studies showed a weak-to-strong inverse association with rectal cancer. In meta-analysis, the summary relative risk (95% confidence interval) for the highest vs. the lowest categories of vegetable consumption were 1.00 (0.92-1.10) and 0.75 (0.59-0.96) for cohort and case-control studies, respectively.

CONCLUSIONS

There was insufficient evidence to support an association between intake of vegetables and the risk of colorectal cancer among the Japanese population.

Potential ability of xanthophylls to prevent obesity-associated cancer

Obesity-associated cancers, including colon cancer and breast cancer, are increasing in Asian countries with Westernized lifestyles as exemplified by reduced physical activity and increased fat/sugar consumption. An excessive accumulation of visceral adipose tissue causes insulin resistance, dyslipidemia and adipocytokine imbalance, and these factors are suggested to be involved in cancer promotion. To prevent obesity-associated cancers, researcher attention is increasing on the so-called “functional foods”. In addition, new approaches to cancer control are in high demand, and using “functional foods” as supplemental or adjuvant agents in chemotherapy is thought to be a promising approach. One of these functional ingredients is xanthophylls, which are natural fat-soluble pigments found in fruits, vegetables, algae and other plants. Xanthophylls belong to the carotenoid class and have structures containing oxygen. Some studies have revealed that xanthophylls improve the inflammation status, serum triglyceride levels, blood pressure levels and liver function test values. Furthermore, recent studies show that xanthophylls possess high anti-cancer, anti-diabetic, anti-obesity and anti-oxidant properties. In this review, we highlight the recent findings for five xanthophylls, namely astaxanthin, β-cryptoxanthin, fucoxanthin, neoxanthin and zeaxanthin/lutein, and their relevance to cancer prevention.