Smoking attenuates the negative association between carotenoids consumption and colorectal cancer risk

Cigarette smoking and cardiovascular disease incidence and all-cause mortality: the modifying role of diet quality

BACKGROUND

This study examines the potential long-term joint association between smoking and diet quality as modifiable risk factors concerning cardiovascular diseases (CVDs) incidence and all-cause mortality among current and former smokers.

METHODS

The study followed 955 smokers from the third and fourth examinations of the Tehran Lipid and Glucose Study to March 2018. Dietary data was collected using a food frequency questionnaire. Three diet quality indices (DQIs) were computed at baseline: DQI-international (DQI-I), DQI-revised (DQI-R), and Mediterranean-DQI (Med-DQI). Cox proportional hazards regression models were used to determine the HR (95% CI) of the joint association between smoking and diet quality among heavy and light smokers, based on the number of cigarettes per day and pack-years, as well as between current and former smokers based on smoking habits.

RESULTS

Over a follow-up period of almost eight years, 94 cases of CVDs (9.80%) and 40 cases of mortality (4.20%) were documented. The lower diet quality based on the Med-DQI was associated with a higher risk of mortality among current smokers (HR:3.45; 95%CI:1.12, 10.57). Light smokers with good diet quality, compared to heavy smokers with poor diet quality, had a lower risk of CVDs incident (HR:0.35; 95%CI: 0.15, 0.83) and all-cause mortality (HR:0.20; 95%CI:0.05, 0.77). Current smokers with good DQI had a lower risk of mortality compared to current smokers with poor DQI (HR:0.26; 95%CI:0.08, 0.80). However, this lower risk was more significant in former smokers with good DQI (HR:0.10; 95%CI:0.02, 0.45).

CONCLUSIONS

Light and former smokers had a lower risk of developing CVDs and experiencing mortality. However, when coupled with a high-quality diet, this protective effect is even more pronounced.

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.

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.

Carotenoid intake from natural sources and colorectal cancer: a systematic review and meta-analysis of epidemiological studies

Carotenoid intake from natural sources has been hypothesized to reduce the risk of colorectal cancer (CRC). The aim of this study was to systematically review the epidemiological evidence for the association between carotenoid intake from natural sources and CRC development. We carried out a systematic review and meta-analysis of epidemiological studies to investigate whether the intake of specific carotenoids from natural sources, as well as combined carotenoids, is associated with the risk of CRC overall and by anatomic subsite. A comprehensive literature search of MEDLINE and Scopus databases was performed. Twenty-two articles were identified from the literature search, of which 16 were case-control studies and 6 were cohort studies. In the random-effects meta-analysis of case-control and cohort studies, we found no association between the intake of individual and total carotenoids and the risk of CRC overall and by anatomic subsite. Overall, our findings do not support a significant association between intake of specific carotenoids from dietary sources, as well as combined carotenoids, and the risk of CRC overall and by anatomic subsite.

Carotenoids from Marine Organisms: Biological Functions and Industrial Applications

As is the case for terrestrial organisms, carotenoids represent the most common group of pigments in marine environments. They are generally biosynthesized by all autotrophic marine organisms, such as bacteria and archaea, algae and fungi. Some heterotrophic organisms also contain carotenoids probably accumulated from food or partly modified through metabolic reactions. These natural pigments are divided into two chemical classes: carotenes (such as lycopene and α- and β-carotene) that are composed of hydrogen and carbon; xanthophylls (such as astaxanthin, fucoxanthin and lutein), which are constituted by hydrogen, carbon and oxygen. Carotenoids, as antioxidant compounds, assume a key role in the protection of cells. In fact, quenching of singlet oxygen, light capture and photosynthesis protection are the most relevant biological functions of carotenoids. The present review aims at describing (i) the biological functions of carotenoids and their benefits for human health, (ii) the most common carotenoids from marine organisms and (iii) carotenoids having large success in pharmaceutical, nutraceutical and cosmeceutical industries, highlighting the scientific progress in marine species cultivation for natural pigments production.

A Possible Indicator of Oxidative Damage in Smokers: (13Z)-Lycopene?

In vitro, the gaseous phase of cigarette smoke is known to induce both isomerization and degradation of dietary carotenoids, such as β-carotene and lycopene. However, the effects of cigarette smoke on the composition of circulating lycopene in vivo are not well understood. In this study, we examined the lycopene profiles of plasma from non-smokers and smokers. No oxidative intermediates of lycopene that have been observed previously in vitro were detected in the plasma, but evidence of isomerization of the carotenoid was seen. Four geometric forms of lycopene were detected in the plasma of both smokers and non-smokers, namely the (5Z), (9Z), (13Z) and (all-E) forms. The relative amounts of these isomers differed between the two cohorts and there was a significant difference (p < 0.05) between smokers and non-smokers for the ratio of total-Z:all-E lycopene, and in the relative amounts of (13Z) and (all-E)-lycopene. The ratio of (all-E):(13Z)-lycopene was 0.84:1.00 in smokers compared to 1.04:1.00 in non-smokers. In smokers, the (13Z)-isomer was generated in preference to the more thermodynamically stable (5Z) and (9Z)-isomers. This mirrors the scenario seen in vitro, in which the formation of (13Z)-lycopene was the main isomer that accompanied the depletion of (all-E) lycopene, when exposed to cigarette smoke. The results suggest that the relative amount of (13Z)-lycopene could be used as an indicator of oxidative damage to lycopene in vivo.

Modification of additive effect between vitamins and ETS on childhood asthma risk according to GSTP1 polymorphism: a cross -sectional study

Background

Asthma is characterized by airway inflammation, and bronchial airways are particularly susceptible to oxidant-induced tissue damage.

Objective

To investigate the effect of dietary antioxidant intake and environmental tobacco smoke (ETS) on the risk of childhood asthma according to genotypes susceptible to airway diseases.

Methods

This cross-sectional study included 1124 elementary school children aged 7–12 years old. Asthma symptoms and smoking history were measured using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Intake of vitamin A (including retinol and β-carotene), C, and E was measured by a semi-quantitative food frequency questionnaire (FFQ). GSTP1 polymorphisms were genotyped from peripheral blood samples.

Results

ETS was significantly associated with presence of asthma symptoms (adjusted odds ratio [aOR], 2.48; 95 % confidence interval [CI], 1.29–4.76) and diagnosis (aOR, 1.91; 95 % CI, 1.19–3.06). Dietary antioxidant intake was not associated with asthma symptoms, although ETS plus low vitamin A intake showed a significant positive association with asthma diagnosis (aOR, 2.23; 95 % CI, 1.10–4.54). Children with AA at nucleotide 1695 in GSTP1 who had been exposed to ETS and a low vitamin A intake have an increased risk of asthma diagnosis (aOR, 4.44; 95 % CI,1.58–12.52) compared with children who had not been exposed to the two risk factors. However, ETS exposure and low vitamin A intake did not significantly increase odds of asthma diagnosis in children with AG or GG genotypes.

Conclusion

Low vitamin A intake and ETS exposure may increase oxidative stress and thereby risk for childhood asthma. These relationships may be modified by gene susceptibility alleles of GSTP1.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-015-0093-0) contains supplementary material, which is available to authorized users.

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.

Plasma carotenoids and retinol and overall and breast cancer risk: a nested case-control study

Experimental studies suggest that carotenoids and retinol may play a role in carcinogenesis, but epidemiological evidence is lacking. We investigated the prospective associations between plasma concentrations of major carotenoids and retinol, and overall and breast cancer risk. A nested case-control study included all first incident cancer cases diagnosed in the SU.VI.MAX cohort between 1994 and 2002 (n = 159 cases, 1 matched control/case). Baseline plasma concentrations of carotenoids and retinol were measured by high-performance liquid chromatography. Conditional logistic regression was used to assess odds ratios for an increase of 0.1 μmol/L [odds ratio (OR)] and 95% confidence intervals (CI). Plasma β-carotene (OR = 0.95, 95% CI = 0.90-0.99, Ptrend = 0.04) and β-cryptoxanthin concentrations (OR = 0.89, 95% CI = 0.81-0.99, Ptrend = 0.03) were inversely associated with overall cancer risk. Plasma β-cryptoxanthin concentration was inversely associated with breast cancer risk (OR = 0.83, 95% CI = 0.71-0.96, Ptrend = 0.02). The OR between plasma lycopene concentration and overall cancer risk was 1.07 (0.99-1.15), Ptrend = 0.06. This association turned significant (Ptrend = 0.01) when excluding cancer cases diagnosed during the first year of follow-up. This prospective study suggests an inverse association between plasma concentrations of β-cryptoxanthin and both overall and breast cancer risk, and an inverse association between β-carotene and overall cancer risk. The direct association between lycopene concentration and cancer risk deserves further investigation.

Fruit and vegetable intake and the risk of colorectal cancer: results from the Shanghai Men's Health Study

PURPOSE

The observed associations of fruit and vegetable consumption with the risk of colorectal cancer have been inconsistent. Therefore, we aimed to evaluate the association of fruit and vegetable consumption with the risk of colorectal cancer among Chinese men.

METHODS

61,274 male participants aged 40-74 years were included. A validated food frequency questionnaire was administered to collect information on usual dietary intake, including 8 fruits and 38 vegetables commonly consumed by residents of Shanghai. Follow-up for diagnoses of colon or rectal cancer was available through 31 December 2010. Dietary intakes were analyzed both as categorical and continuous variables. Multivariable-adjusted hazard ratios (HRs) and 95 % confidence intervals (95 % CIs) were calculated for colorectal, colon, and rectal cancers using Cox proportional hazards models.

RESULTS

After 390,688 person-years of follow-up, 398 cases of colorectal cancer (236 colon and 162 rectal) were observed in the cohort. Fruit consumption was inversely associated with the risk of colorectal cancer (fifth vs. first quintile HR 0.67; 95 % CI 0.48, 0.95; p trend = 0.03), whereas vegetable intake was not significantly associated with risk. The associations for subgroups of fruits and legumes, but not other vegetable categories, were generally inversely associated with the risk of colon and rectal cancers.

CONCLUSIONS

Fruit intake was generally inversely associated with the risk of colorectal cancer, whereas vegetable consumption was largely unrelated to risk among middle-aged and older Chinese men.

Effects of smoking and antioxidant micronutrients on risk of colorectal cancer

BACKGROUND & AIMS

Antioxidant intake has been reported to increase the risk of colorectal cancer (CRC) for smokers, yet reduce the risk for nonsmokers. We investigated the association between tobacco smoking and risk of colon or rectal cancer, and whether dietary and supplemental intake of the antioxidant vitamins A, C, E, β-carotene, selenium, zinc, and manganese affects the risk of CRC among smokers.

METHODS

Data on smoking habits and antioxidant intake were analyzed for 54,208 participants in the Danish Prospective Diet, Cancer and Health Study. Of these participants, 642 were diagnosed with colon cancer and 348 were diagnosed with rectal cancer. Hazard ratios and 95% confidence intervals were estimated using Cox proportional hazard models. Principal components were used to analyze intake of combinations of antioxidants.

RESULTS

Ever smoking increased the risk for CRC (hazard ratio, 1.19; 95% confidence interval, 1.03-1.37), especially for rectal cancer. Smoking for at least 20 years was associated with a 26% increase in risk of CRC, compared with never smokers, and smoking 20 g tobacco or more each day was associated with a 30% increase in risk. Smoking for more than 30 years, or more than 20 g tobacco each day, was associated with a 48% increase in risk of rectal cancer. We did not observe an interaction between smoking and antioxidant consumption on risk of CRC.

CONCLUSIONS

Tobacco smoking increases the risk for CRC. We did not observe that consumption of antioxidant micronutrients modulates the effects of smoking on CRC risk.

Adherence to a healthy Nordic food index is associated with a lower incidence of colorectal cancer in women: the Diet, Cancer and Health cohort study

Colorectal cancer (CRC) is a multi-factorial disease in which diet is believed to play a role. Little is known about the health effects of specific regional diets. The Nordic diet is high in fat and sugar but also includes a range of traditional products with anticipated health-promoting effects. The aim of this cohort study was to determine whether a healthy Nordic food index consisting of fish, cabbage, rye bread, oatmeal, apples, pears and root vegetables was related to CRC incidence. Data were obtained from a prospective cohort study of 57,053 Danish men and women aged 50-64 years, of whom 1025 developed CRC (13 years' follow-up). Incidence rate ratios (IRR) with 95 % CI were calculated from Cox proportional hazard models. Women who strongly adhered to a healthy Nordic food index had a 35 % lower incidence of CRC than women with poor adherence (adjusted IRR, 0·65; 95 % CI 0·46, 0·94); a similar tendency was found for men. Women had a 9 % lower incidence of CRC per point adherence to the healthy Nordic food index, but no significant effect was found for men. A regional diet based on healthy Nordic food items was therefore associated with a lower incidence of CRC in women. The protective effect was of the same magnitude as previously found for the Mediterranean diet, suggesting that healthy regional diets should be promoted in order to ensure health; this will also preserve cultural heredity and the environment.

Effects of organic and conventional growth systems on the content of carotenoids in carrot roots, and on intake and plasma status of carotenoids in humans

BACKGROUND

The demand for organic food products has increased during the last decades due to their probable health effects, among others. A higher content of secondary metabolites such as carotenoids in organic food products has been claimed, though not documented, to contribute to increased health effects of organic foods. The aim was to study the impact of organic and conventional agricultural systems on the content of carotenoids in carrots and human diets. In addition, a human cross-over study was performed, measuring the plasma status of carotenoids in humans consuming diets made from crops from these agricultural systems.

RESULTS

The content of carotenoids in carrot roots and human diets was not significantly affected by the agricultural production system or year, despite differences in fertilisation strategy and levels. The plasma status of carotenoids increased significantly after consumption of the organic and conventional diets, but no systematic differences between the agricultural production systems were observed.

CONCLUSION

The expected higher content of presumed health-promoting carotenoids in organic food products was not documented in this study.

Colorectal cancer: what should patients and families be told to lower the risk of colorectal cancer?

Colorectal cancer (CRC) is the second most common cause of cancer-related death in the United States. CRC, however, is potentially preventable, and several strategies may be employed to decrease the incidence of and mortality from CRC. Understanding of individual risk and adherence to screening and surveillance recommendations undoubtedly will reduce CRC-associated deaths. Several natural and synthetic chemopreventive agents may prove effective for both primary and secondary CRC chemoprevention. Finally, dietary modifications (ie, increased dietary fiber, fruits and vegetables, and decreased red meat) and other lifestyle changes (i.e., increased physical activity, weight maintenance, avoidance of smoking, and moderation of alcohol intake) also may lower the risk of developing CRC.

Comparison of polyacetylene content in organically and conventionally grown carrots using a fast ultrasonic liquid extraction method

A rapid and sensitive analytical method for quantification of polyacetylenes in carrot roots was developed. The traditional extraction method (stirring) was compared to a new ultrasonic liquid processor (ULP)-based methodology using high-performance liquid chromatography-ultraviolet (HPLC-UV) and mass spectrometry (MS) for identification and quantification of three polyacetylenes. ULP was superior because a significant reduction in extraction time and improved extraction efficiencies were obtained. After optimization, the ULP method showed good selectivity, precision [relative standard deviations (RSDs) of 2.3-3.6%], and recovery (93% of falcarindiol) of the polyacetylenes. The applicability of the method was documented by comparative analyses of carrots grown organically or conventionally in a 2 year field trial study. The average concentrations of falcarindiol, falcarindiol-3-acetate, and falcarinol in year 1 were 222, 30, and 94 mug of falcarindiol equiv/g of dry weight, respectively, and 3-15% lower in year 2. The concentrations were not significantly influenced by the growth system, but a significant year-year variation was observed for falcarindiol-3-acetate.