Mariette Gerber

Psycho-social influences on food choice in Southern France and Central England

This study used attitudinal scales to investigate the nature of attitudes to diet and health in a northern European country (Central England) and a southern European country (Mediterranean France). Cross-sectional studies were conducted using self-administered postal questionnaires that were distributed simultaneously in April 2001 in Montpellier, France and Nottingham, England. A stratified random sample of 1000 males and 1000 females aged 18-65 years was generated from the electoral roll in each country. The final sample comprised England: n = 826 (58% male and 42% female; mean age=44 years) and France: n = 766 (42% male and 58% female; mean age=42 years). This study has demonstrated that the pleasurable and social aspects of eating, certain food quality issues, as well as health as a value were regarded as priorities by French respondents. On the other hand, English respondents reported that organic and ethical issues and convenience were important factors influencing their food choices. In conclusion, the two populations can be differentiated overall in their attitudes and beliefs to food choice.

Dietary intakes of ω-6 and ω-3 polyunsaturated fatty acids and the risk of breast cancer

Experimental studies suggest detrimental effects of ω‐6 polyunsaturated fatty acids (PUFA), and beneficial effects of ω‐3 PUFAs on mammary carcinogenesis, possibly in interaction with antioxidants. However, PUFA food sources are diverse in human diets and few epidemiologic studies have examined whether associations between dietary PUFAs and breast cancer risk vary according to food sources or antioxidant intakes. The relationship between individual PUFA intakes estimated from diet history questionnaires and breast cancer risk was examined among 56,007 French women. During 8 years of follow‐up, 1,650 women developed invasive breast cancer. Breast cancer risk was not related to any dietary PUFA overall; however, opposite associations were seen according to food sources, suggesting other potential effects than PUFA per se. Breast cancer risk was inversely associated with α‐linolenic acid (ALA) intake from fruit and vegetables [highest vs. lowest quintile, hazard ratio (HR) 0.74; 95% confidence interval (CI) 0.63, 0.88; p trend < 0.0001], and from vegetable oils (HR 0.83; 95% CI 0.71, 0.97; p trend 0.017). Conversely, breast cancer risk was positively related to ALA intake from nut mixes (p trend 0.004) and processed foods (p trend 0.068), as was total ALA intake among women in the highest quintile of dietary vitamin E (p trend 0.036). A significant interaction was also found between ω‐6 and long‐chain ω‐3 PUFAs, with breast cancer risk inversely related to long‐chain ω‐3 PUFAs in women belonging to the highest quintile of ω‐6 PUFAs (p interaction 0.042). These results emphasize the need to consider food sources, as well as interactions between fatty acids and with antioxidants, when evaluating associations between PUFA intakes and breast cancer risk.

Reproductive factors and breast cancer risk. Do they differ according to age at diagnosis

Studies yielding results on risk factors stratified by age at diagnosis or menopausal status were reviewed to better understand the role of hormonal factors and to determine whether reproductive events influence breast cancer risk differently according to age at diagnosis of breast cancer. Through a Medline/Pubmed search, 26 articles providing risk estimates by age at diagnosis of breast cancer or by menopausal status were analysed. A decrease of about 9% of breast cancer risk was found for each additional year at menarche when breast cancer was diagnosed early or before the menopause, and of about 4% when diagnosed late or after. Breast cancer risk increased with increasing age at FFTP by 5% per year for breast cancer diagnosed early or before the menopause and by 3% for cancers diagnosed late or after the menopause. Each full term pregnancy (or child) led to a 3% reduction in the risk of breast cancer diagnosed early or before the menopause, whereas the reduction attained 12% for the breast cancers diagnosed later. No change in the effect of these three factors with time (date of diagnosis of the breast cancer before 1980 or after) was observed. These results support the hypothesis of an age-specific effect of the three breast cancer risk factors considered herein, based on the time of initiation of the carcinogenic process. These observations underline the importance of the time of initiation of the carcinogenic process in determining the effect of promoters such as reproductive factors. This largely unexplored aspect of breast carcinogenesis might open the way for new prevention approaches.

Profiles of a Healthful Diet and its Relationship to Biomarkers in a Population Sample from Mediterranean Southern France

OBJECTIVES The failure of single-nutrient supplementation to prevent disease in intervention studies underlines the necessity to develop a holistic view of food intake. The objectives of this study were to devise a diet quality index (DQI) and identify biomarkers of multidimensional dietary behavior. DESIGN A nutrition survey was conducted in Mediterranean southern France by means of a food frequency questionnaire. The DQI was based on current dietary recommendations for prevention of diet-related diseases such as cardiovascular disease and some cancers. A second DQI included tobacco use. STATISTICAL ANALYSES performed Spearman rank correlations, cross-classifications and intraclass correlations were computed between the DQI and biomarkers. RESULTS Of the 146 subjects, 10 had a healthful diet and 18 had a poor diet. Erythrocyte omega-3 fatty acids-eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)-beta carotene, and vitamin E concentrations were lower and cholesterol concentrations were higher in the poor diet; the difference was significant for EPA and DHA and borderline significant for vitamin E. Significant correlation was found between the DQI and vitamin E (-0.12), EPA (-0.30), and DHA (-0.28), and beta carotene (-0.17) when tobacco use was considered, but not between the DQI and cholesterol. The correlation coefficient reached 0.58 (P0.01) for a composite index based on all biomarkers except cholesterol. CONCLUSIONS Subjects with a beta carotene levels greater thanl micromol/L, vitamin E greater than 30 micromol/L and EPA greater than 0.65% and DHA greater than 4% of fatty acids in erythrocytes were likely to have a healthful diet. Each biomarker indicated the quality of diet, but correlation was higher with a composite index.

Diet profiles in a population sample from Mediterranean southern France

OBJECTIVE A Mediterranean diet quality index (MDQI) was devised to give an overall assessment of dietary habits and to identify groups at risk. DESIGN The MDQI was based on scores given for selected levels of consumption of selected nutrients and foods. SETTING Mediterranean southern France. SUBJECTS The sample included 473 men and 491 women in three age classes recruited at random. RESULTS Only 9.5% of men, 9.0% of women, 4.7% of 20-34 year old subjects, 6.6% of 35-54 year old subjects and 14.0% of 55-76 year old subjects were shown to have a healthy diet. However, 10.1% of men, 8.6% of women, 19.4% of 20-34 year old subjects, 10.2% of 35-54 year old subjects and 4.6% of 55-76 year old subjects were shown to have a poor diet. There were significantly fewer smokers among subjects with a good diet but the distribution of moderate wine drinkers was comparable between those with a good diet and those with a poor diet. Correspondence analysis associated a healthy diet with 55-76 year old men and women living in rural areas, who had received primary schooling only and who were manual workers. Both men and women with a poor MDQI score tended to be young and smokers. In addition, women with a poor MDQI tended to be heavy drinkers and obese. CONCLUSIONS This study showed that the Mediterranean model, which is generally recognized as a healthy diet, appears restricted to older people and to rural areas, whereas urbanized young people depart from it. A nutritional prevention policy targeted at young adults is required to encourage them to adhere to the Mediterranean model. Smoking and drinking showed different distribution patterns in the sample under study.

Genetic polymorphisms and lipoprotein responses to diets.

While human diets have markedly evolved since their origin, the human genome has only marginally changed. Nevertheless, polymorphisms of common genes are widespread. It has been substantiated that most major diseases (including cardiovascular disease, diabetes, obesity and cancers) result from the interaction between genetic susceptibility and environmental factors, including diet. In the field of lipoprotein metabolism and cardiovascular disease several gene polymorphisms for key proteins, such as apoproteins (apo) E, B, A-IV and C-III, LDL receptor, microsomal transfer protein (MTP), fatty acid-binding protein (FABP), cholesteryl ester transfer protein (CETP), lipoprotein lipase and hepatic lipase, have been identified and linked to variable responses to diets. We are carrying out an intervention study (RIVAGE) in Marseille dedicated to investigating the interactions between diets (Mediterranean or low-fat types v. standard Western type), risk factors for cardiovascular disease and gene polymorphisms in about 300 patients randomized into two groups over periods of 3 and 12 months. Some data obtained in about 100 patients after 3 months of dietary change are available. Among single nucleotide polymorphisms (SNP) already studied (apoE (epsilon2, epsilon3, epsilon4), apoB (-516C/T), apoC-III (SstI), apoA-IV (Ser347Thr), MTP (-493G/T), intestinal FABP (Ala54Thr), CETP (TaqIB) and hepatic lipase (-480C/T)), some SNP showed interactions with diets in relation to changes in particular variables after 3 months on the dietary regimens. This was the case for apoE and LDL-cholesterol and triacylglycerols, apoA-IV and LDL-cholesterol, MTP and LDL-cholesterol, intestinal FABP and triacylglycerols. These data provide evidence of the interaction between some SNP and the metabolic response to diets.

Interactions between genetic polymorphism of cytochrome P450-1B1, sulfotransferase 1A1, catechol-o-methyltransferase and tobacco exposure in breast cancer risk

Genetic polymorphisms of enzymes involved in the metabolism of xenobiotics and estrogens might play a role in breast carcinogenesis related to environmental exposures. In a case‐only study on 282 women with breast cancer, we studied the interaction effects (ORi) between smoking habits and the gene polymorphisms of Cytochrome P450 1B1 (Val432Leu CYP1B1), Phenol‐sulfotransferase 1A1 (Arg213His SULT1A1) and Catechol‐O‐methyltransferase (Val158Met COMT). The smokers carrying the Val CYP1B1 allele associated with a high hydroxylation activity had a higher risk of breast cancer than never smokers with the Leu/Leu genotype (ORi=2.32, 95%CI: 1.00–5.38). Also, the smokers carrying the His SULT1A1 allele associated with a low sulfation activity had a 2‐fold excess risk compared to never smokers carrying Arg/Arg SULT1A1 common genotype (ORi= 2.55, 95%CI: 1.21–5.36). The His SULT1A1 allele increased the risk only in premenopausal patients. The Met COMT allele with a lower methylation activity than Val COMT did not modify the risk among smokers. The excess risk due to joint effect could result from a higher exposure to activated tobacco‐compounds for women homo/heterozygous for the Val CYP1B1 allele. Also, a lower sulfation of the tobacco carcinogens among women with His SULT1A1 could increase exposure to genotoxic compounds. Alternatively, the Val CYP1B1 or His SULT1A1 allele with modified ability to metabolize estrogens could increase the level of genotoxic catechol estrogen (i.e., 4‐hydroxy‐estradiol) among smokers. Our study showed that gene polymorphisms of CYP1B1 and SULT1A1 induce an individual susceptibility to breast cancer among current smokers.

The comprehensive approach to diet: a critical review.

Recent disappointing results have challenged the earlier results of ecological studies that launched the hypothesis of a strong relationship between diet and cancer. The present state of knowledge regarding the relationship between cancer and diet is considered and discussed here. Steps for improving the understanding of the relationship and the content of recommendations for cancer prevention and survival are proposed, such as determining the possible food effect at each step of the carcinogenesis process, considering the dietary pattern instead of a single nutrient or food, introducing the diet quality index for evaluating cancer risk and developing more comprehensive statistical methods in nutritional epidemiology. In support of these propositions, previous, recent and on-going studies are reviewed and discussed. A holistic model of diet is described as a conclusion.

Relationship between vitamin E and polyunsaturated fatty acids in breast cancer. Nutritional and metabolic aspects

Intake of vitamin E, total lipids, total cholesterol, and fatty acids were analyzed with the blood levels of vitamin E, total cholesterol, triglycerides, and the serum distribution of fatty acids in a hospital‐based population of 120 patients and 109 controls. In regard to nutritional intake, the only significant differences involve saturated and monounsaturated fatty acid consumption, which is more elevated in postmenopausal patients than in postmenopausal controls. Vitamin E and total cholesterol blood levels are significantly higher in patients than in controls, where the difference is that vitamin E is independent from cholesterol level in premenopausal women only. Fatty acid serum distribution is comparable in both samples, with the exception of arachidonic acid, which is significantly lower in premenopausal patients than in premenopausal controls. Two multivariate regression analyses of the plasma vitamin E levels of patients and controls were done with menopausal status and nutrients as independent variables for the first analysis, and with menopausal status and all blood analytes for the second one. The regression coefficients for total cholesterol and triglycerides are statistically significant for both samples, whereas a positive association between vitamin E plasma level and sunflower oil consumption and between vitamin E plasma level and serum linoleic acid distribution is significant for patients only. Furthermore, the multiple regression shows that, when adjusted for analyte variables, plasma vitamin E levels are higher in premenopausal than in postmenopausal patients. In addition, plasma lipid peroxidation, evaluated by malondialdehyde measurement, is shown to be significantly lower in patients than in controls. Malondialdehyde level is associated with a significant lower odds ratio (OR) after multivariate tertile analysis (OR for the highest tertile: 0.51;95% CI:0.29–0.89). Together, these findings are consistent with a picture of lower lipid peroxidation in patients than in controls.

Evaluating and adapting the Mediterranean diet for non-Mediterranean populations: a critical appraisal.

This review outlines the limitations of current techniques for evaluating the Mediterranean diet in Mediterranean versus non-Mediterranean populations. Differences between the two populations with regard to the foods that are available, food processing and preparation techniques, and eating and lifestyle habits may influence the implementation and effects of a Mediterranean diet in non-Mediterranean regions. For example, the composition of food groups may vary significantly, due to differences in the specific foods within a food group and to differences in aspects of food production and preparation. Notable differences between the diets of Mediterranean versus non-Mediterranean populations include the source of monounsaturated fatty acids (olive oil versus meat), the amount of vegetables consumed and their manner of preparation, the source of alcohol (wine versus other) and the pattern of intake, and the types of meat and dairy products consumed. Lifestyle factors such as meal patterns and exposure to sunlight may also act as confounding factors when the overall benefits of a Mediterranean diet are assessed. Improving the calculation of Mediterranean diet scores and measuring plasma nutrient levels may help mitigate the effects of confounders. These considerations could have important health implications when a Mediterranean diet is implemented by non-Mediterranean populations.