Nutrition and carcinogenesis

Relevance of apple consumption for protection against oxidative damage induced by hydrogen peroxide in human lymphocytes

In a single-dosing crossover study, we investigated the ability of apple fruit consumption to protect human lymphocytes against peroxide-induced damage to DNA. Six healthy, non-smoking male volunteers were placed for 2 d on an antioxidant-poor (AP) diet. After 48 h of AP diet, the volunteers were required to consume a homogenate obtained from 600 g of red delicious unpeeled apples or water (500 ml); blood samples were collected 0, 3, 6 and 24 h post-consumption. To evaluate whether the apple intake was sufficient to restore resistance of DNA to oxidative damage, for each subject at any time point the plasma total antioxidant activity, reactive oxygen species (ROS) formation and induction of micronuclei (MN) in isolated lymphocytes following hydrogen peroxide (H2O2) treatment were measured. Results indicated a significant inhibition (58 %, P < 0·05) of H2O2-induced MN frequency in the plasma samples collected at 3 h after apple consumption, as compared with plasma samples collected at 0 h (4·17 (sd 1·83) v. 9·85 (sd 1·87) MN/1000 binucleated (BN) cells, respectively). A gradual return towards the value observed at 0 h was recorded starting from 6 to 24 h. MN frequency induced by H2O2 was significantly influenced by plasma total antioxidant activity (r = –0·95, P < 0·05) and by the increase of intracellular ROS formation (r = 0·88, P < 0·05). These findings suggest that the consumption of whole apple provides a useful dietary source of active scavengers to protect cells and tissue from oxidative stress and related DNA injury.

Effect of nickel exposure on peripheral tissues: role of oxidative stress in toxicity and possible protection by ascorbic acid

The vast industrial use of nickel has led to environmental pollution by the metal and its by-products during production, recycling, and disposal. Nickel is a known hematotoxic, immunotoxic, hepatotoxic, pulmotoxic, and nephrotoxic agent. Allergic skin reactions are common in individuals who are sensitive to nickel. This article presents a selective review on nickel and its effect on certain metabolically active peripheral tissues of human and animals. The subtopics include nickel sources and uses, exposure pathways, transport, excretion, general health effects, and specific acute and chronic nickel toxicities in peripheral tissues like liver, lungs, and kidneys. The review particularly addresses the nickel-induced generation of reactive oxygen species and increased lipid peroxidation in various metabolically active tissues in humans and animals, and the possible role of vitamin c as a protective antioxidant.

Food groups and risk of non-Hodgkin lymphoma: a multicenter, case-control study in Italy

Incidence of non-Hodgkin lymphoma (NHL) has been rising worldwide, but the reasons are undefined. Dietary habits may play a role in the etiology of NHL by influencing the metabolic pathways of several cells of the immune system. This case-control study investigated the relation between food consumption and NHL risk. Between 1999 and 2002, we conducted a hospital-based case-control study on NHL in 2 areas of Italy. Cases were 190 patients (median age 58 years) with incident NHL admitted to specialized and general hospitals. Controls were 484 patients (median age 63 years) with acute non-neoplastic conditions admitted to the same hospitals network of cases. A validated food-frequency questionnaire was used to assess habitual diet 2 years before interview. Unconditional multiple logistic regression was used to estimate the odds ratios (OR) and the corresponding 95% confidence intervals (CI), with allowance for energy intake, according to the residual model. Consumption of highest versus lowest quartile of pasta/rice (OR = 1.87, 95% CI: 1.04-3.36) and cheese (OR = 1.66, 95% CI: 0.98-2.83) were associated with a significantly increased NHL risk. Inverse association was found for vegetables (OR = 0.49, 95% CI: 0.28-0.87), fruits (OR = 0.51, 95% CI: 0.30-0.85), and egg consumption (OR = 0.59, 95% CI: 0.36-0.97). The association of pasta/rice was also supported by an increased risk of high glycemic load levels (OR = 1.86, 95% CI: 1.04-3.32). In conclusion, our results suggested that diet could affect NHL risk.

Genetic instability in human tumors

Genetic, or genomic, instability refers to a series of observed spontaneous genetic changes occurring at an accelerated rate in cell populations derived from the same ancestral precursor. This is far from a new finding, but is one that has increasingly gained more attention in the last decade due to its plausible role(s) in tumorigenesis. The majority of genetic alterations contributing to the malignant transformation are seen in growth regulatory genes, and in genes involved in cell cycle progression and arrest. Genomic instability may present itself through alterations in the length of short repeat stretches of coding and non-coding DNA, resulting in microsatellite instability. Tumors with such profiles are referred to as exhibiting a mutator phenotype, which is largely a consequence of inactivating mutations in DNA damage repair genes. Genomic instability may also, and most commonly, results from gross chromosomal changes, such as translocations or amplifications, which lead to chromosomal instability. Telomere length and telomerase activity, important in maintaining chromosomal structure and in regulating a normal cell's lifespan, have been shown to have a function in both suppressing and facilitating malignant transformation. In addition to such direct sequence and structural changes, gene silencing through the hypermethylation of promoter regions, or increased gene expression through the hypomethylation of such regions, together, form an alternative, epigenetic mechanism leading to instability. Emerging evidence also suggests that dietary and environmental agents can further modulate the contribution of genetic instability to tumorigenesis. Currently, there is still much debate over the distinct classes of genomic instability and their specific roles in the initiation of tumor formation, as well as in the progressive transition to a cancerous state. This review examines the various molecular mechanisms that result in this genomic instability and the potential contribution of the latter to human carcinogenesis.

The Protective Role of Fruits and Vegetables against Radiation-Induced Cancer

The role of fruits and vegetables in protecting against radiation-induced cancer and the positive evidence from epidemiology and ancillary investigations are discussed in this review. The recently reported Hiroshima and Nagasaki atomic bomb survivor studies provide strong evidence for the protective role of fruits and vegetables against radiation-induced cancer. The anticarcinogenic substances contained in, and the anticarcinogenic mechanisms proposed for, fruits and vegetables are reviewed. The anticarcinogenic effectiveness of fruits and vegetables are compared with that of dietary supplements. The reasons for the observed superiority of fruits and vegetables are advanced.

Dietary factors and risk of non-hodgkin lymphoma in men and women

BACKGROUND

The incidence of non-Hodgkin lymphoma (NHL) has increased worldwide in recent decades. Diet could influence NHL risk by modulating the immune system, although evidence is limited. We did a population-based case-control study to determine whether differences in diet were associated with NHL risk.

METHODS

A total of 597 NHL cases and 467 population controls in Sweden completed a semiquantitative food frequency questionnaire evaluating their dietary habits 2 years before the interview. Unconditional logistic regression was used to estimate the odds ratios (OR) and corresponding 95% confidence intervals (95% CI) for associations between food intake and risk of NHL.

RESULTS

High consumption of dairy products and fried red meat was associated with increased risk of NHL. The OR of NHL for individuals in the highest quartile compared with the lowest quartile of dairy intake was 1.5 (95% CI, 1.1-2.2; P(trend) = 0.003). The OR for the highest versus lowest quartile of fried red meat intake was 1.5 (95% CI, 1.0-2.1; P(trend) = 0.02). In contrast, high consumption of fruits and vegetables was associated with reduced risk of NHL, particularly follicular lymphoma, among women but not men. Compared with the lowest quartile of vegetable intake, the OR of follicular lymphoma among women in the highest quartile of vegetable intake was 0.3 (95% CI, 0.1-0.7; P(trend) = 0.002).

CONCLUSIONS

The positive associations of NHL risk with dairy products and fried red meat and the inverse association with fruits and vegetables suggest that diet affects NHL risk and could explain the increase of some histopathogic subtypes.