Let's see what we can dig up about an optimal A intake. The RDA is more than covered by my vegetable intake, but I take 10,000 IU preformed A once per week because of that
genomic stability study. I'm not taking any more without a good reason, because all the vitamin A supplement studies I've found are depressing. I'm also not encouraged by the butter data. (Besides, olive oil was used by the 300, and look at how awesome they were.)
Br J Cancer. 2001 Mar 2;84(5):728-35.
Diet, smoking and lung cancer: a case-control study of 1000 cases and 1500 controls in South-West England.
Darby S, Whitley E, Doll R, Key T, Silcocks P.
ICRF/MRC/BHF Clinical Trial Service Unit & Epidemiological Studies Unit, Radcliffe Infirmary, Harkness Building, Oxford, OX2 6HE, UK.
We have examined the relationship between diet and lung cancer in a case-control study of 982 cases of lung cancer and 1486 population controls in south-west England in which subjects were interviewed personally about their smoking habits and their consumption of foods and supplements rich in retinol or carotene. Analyses were performed for 15 dietary variables, including intake of pre-formed retinol and carotene. There were significant associations (P< 0.01) with lung cancer risk for 13 of the variables, eight of which remained after adjustment for smoking. When the 15 variables were considered simultaneously, independent significant associations remained for 5:
pre-formed retinol (increased risk), and fish liver oil, vitamin pills, carrots and tomato sauce (decreased risk). It is unlikely that all five associations represent biological effects, or that they can all be explained by residual confounding by smoking, or by biases. We conclude that there is at least one as yet unidentified factor that is causally related to lung cancer risk and of considerable importance in terms of attributable risk in this population. Copyright 2001 Cancer Research Campaign.
PMID: 11237398
Int J Cancer. 2000 Jun 1;86(5):626-31.
Role of macronutrients, vitamins and minerals in the aetiology of squamous-cell carcinoma of the oesophagus.
Franceschi S, Bidoli E, Negri E, Zambon P, Talamini R, Ruol A, Parpinel M, Levi F, Simonato L, La Vecchia C.
Servizio di Epidemiologia, Centro di Riferimento Oncologico, Aviano, Italy. epidemiology@ets.it
Between 1992 and 1997 we conducted a case-control study of oesophageal cancer in 3 areas of northern Italy. Cases were 304 patients (29 women), ages 39-77 years (median age 60 years), with a first incident squamous-cell carcinoma (SCC) of the oesophagus. Controls were 743 patients (150 women), ages 35-77 years (median age 60 years), admitted for acute illnesses, unrelated to tobacco and alcohol, to major hospitals of the areas under surveillance. We derived estimates of daily dietary intake of 6 macronutrients, cholesterol, and 20 micronutrients or minerals from a validated food-frequency questionnaire, including 78 food groups and recipes and 15 questions on individual eating patterns. After allowance for age, gender, area of residence, education, body mass index, physical activity, smoking habit, alcohol consumption and energy intake, most micronutrients were inversely associated with oesophageal SCC risk. Highly significant associations emerged for monounsaturated fatty acids [odds ratio (OR) in highest vs. lowest intake quintile = 0.5]; carotene (OR = 0.3); lutein + zeaxanthin (OR = 0.4); vitamin C (OR = 0.4); and niacin (OR = 0.5).
Only retinol appeared to be positively related to risk (OR = 1.9). The effect of the above nutrients, expressed as ORs, appeared to be similar in non-smokers and smokers, and non/light drinkers and heavy drinkers. Copyright 2000 Wiley-Liss, Inc.
PMID: 10797282
Cochrane Database Syst Rev. 2008 Apr 16;(2):CD007176.
Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases.
Bjelakovic G, Nikolova D, Gluud LL, Simonetti RG, Gluud C.
Copenhagen University Hospital, Rigshospitalet, Department 3344,Copenhagen Trial Unit, Centre for Clinical Intervention Research, Blegdamsvej 9, Copenhagen, Denmark, DK-2100. goranb@junis.ni.ac.yu
BACKGROUND: Animal and physiological research as well as observational studies suggest that antioxidant supplements may improve survival. OBJECTIVES: To assess the effect of antioxidant supplements on mortality in primary or secondary prevention randomised clinical trials. SEARCH STRATEGY: We searched The Cochrane Library (Issue 3, 2005), MEDLINE (1966 to October 2005), EMBASE (1985 to October 2005), and the Science Citation Index Expanded (1945 to October 2005). We scanned bibliographies of relevant publications and wrote to pharmaceutical companies for additional trials. SELECTION CRITERIA: We included all primary and secondary prevention randomised clinical trials on antioxidant supplements (beta-carotene, vitamin A, vitamin C, vitamin E, and selenium) versus placebo or no intervention. Included participants were either healthy (primary prevention trials) or had any disease (secondary prevention trials). DATA COLLECTION AND ANALYSIS: Three authors extracted data. Trials with adequate randomisation, blinding, and follow-up were classified as having a low risk of bias. Random-effects and fixed-effect meta-analyses were performed. Random-effects meta-regression analyses were performed to assess sources of intertrial heterogeneity. MAIN RESULTS: Sixty-seven randomised trials with 232,550 participants were included. Forty-seven trials including 180,938 participants had low risk of bias. Twenty-one trials included 164,439 healthy participants. Forty-six trials included 68111 participants with various diseases (gastrointestinal, cardiovascular, neurological, ocular, dermatological, rheumatoid, renal, endocrinological, or unspecified). Overall, the antioxidant supplements had no significant effect on mortality in a random-effects meta-analysis (relative risk [RR] 1.02, 95% confidence interval [CI] 0.99 to 1.06), but significantly increased mortality in a fixed-effect model (RR 1.04, 95% CI 1.02 to 1.06). In meta-regression analysis, the risk of bias and type of antioxidant supplement were the only significant predictors of intertrial heterogeneity. In the trials with a low risk of bias, the antioxidant supplements significantly increased mortality (RR 1.05, 95% CI 1.02 to 1.08). When the different antioxidants were assessed separately, analyses including trials with a low risk of bias and excluding selenium trials found
significantly increased mortality by vitamin A (RR 1.16, 95% CI 1.10 to 1.24), beta-carotene (RR 1.07, 95% CI 1.02 to 1.11), and vitamin E (RR 1.04, 95% CI 1.01 to 1.07), but no significant detrimental effect of vitamin C (RR 1.06, 95% CI 0.94 to 1.20). Low-bias risk trials on selenium found no significant effect on mortality (RR 0.91, 95% CI 0.76 to 1.09). AUTHORS' CONCLUSIONS: We found no evidence to support antioxidant supplements for primary or secondary prevention. Vitamin A, beta-carotene, and vitamin E may increase mortality. Future randomised trials could evaluate the potential effects of vitamin C and selenium for primary and secondary prevention. Such trials should be closely monitored for potential harmful effects. Antioxidant supplements need to be considered medicinal products and should undergo sufficient evaluation before marketing.
PMID: 18425980
Int J Cancer. 2000 Jul 15;87(2):289-94.
Food groups and risk of squamous cell esophageal cancer in northern Italy.
Bosetti C, La Vecchia C, Talamini R, Simonato L, Zambon P, Negri E, Trichopoulos D, Lagiou P, Bardini R, Franceschi S.
Istituto di Ricerche Farmacologiche "Mario Negri", Milan, Italy. bosetti@irfmn.mnegri.it
To better understand the nutritional etiology of squamous cell esophageal cancer, we conducted a case-control study in 3 areas of northern Italy. A total of 304 incident, histologically confirmed cases of squamous cell carcinoma of the esophagus (275 men, 29 women) and 743 hospital controls (593 men, 150 women) with acute, non-neoplastic conditions, not related to smoking, alcohol consumption or long-term diet modification, were interviewed during 1992 to 1997. The validated food-frequency questionnaire included 78 questions on food items or recipes, which were then categorized into 19 main food groups, and 10 questions on fat intake pattern. After allowance for age, sex, education, area of residence, tobacco smoking, alcohol drinking and non-alcohol energy, a significant increased risk emerged for high consumption of soups (OR=2.1 for the highest vs. lowest quintile), whereas inverse associations with esophageal cancer risk were observed for pasta and rice (OR=0.7), poultry (OR=0.4), raw vegetables (OR=0.3), citrus fruit (OR=0.4) and other fruit (OR=0.5). The associations with dietary habits were consistent in different strata of tobacco smoking and alcohol drinking.
Among added lipids, olive oil intake showed a significant reduction of esophageal cancer risk, even after allowance for total vegetable consumption (OR=0.4), while butter consumption was directly associated with this risk (OR=2.2). Our results thus provide further support to the evidence that raw vegetables and citrus fruit are inversely related to the risk of squamous cell esophageal cancer and suggest that olive oil may also reduce this risk. Copyright 2000 Wiley-Liss, Inc.
PMID: 10861489
Int J Cancer. 1998 Mar 30;76(1):7-12.
Diet and squamous-cell cancer of the oesophagus: a French multicentre case-control study.
Launoy G, Milan C, Day NE, Pienkowski MP, Gignoux M, Faivre J.
Registre des cancers digestifs du Calvados (CJF INSERM 9603), Caen, France.
An increasing number of reports suggest that diet has an impact on oesophageal cancer risk in Western countries, where alcohol and tobacco are held to be the major determinants of the risk. The aim of our study was to identify dietary factors influencing the risk of oesophageal cancer in France and to determine whether certain of these could explain some of the geographical variations. We conducted a multicentre case-control study in 3 regions expected to have different diet and drinking habits (Normandy, Burgundy and Midi Pyrénées). Two hundred eight cases and 399 controls, all males, were interviewed about their eating, drinking and smoking habits. After proper adjustment for drinking and smoking, high consumption of butter and low consumption of fresh fish, vegetables and fruits were associated strongly and independently with an increase in oesophageal-cancer risk. Consistently, cholesterol appeared as a risk factor and vitamin E, vitamin D and phosphorus as independent protective factors. The protective effect of citrus and other fresh fruits (vitamin C) was confined strictly to heavy drinkers. Our findings suggest that more than one-third of the high incidence of oesophageal cancer in northwest France could be explained by the local excess in butter consumption, whereas geographical variations in consumption of dietary protective factors could explain no more than 10% of it.
Overall, a large proportion (57%) of the excess incidence of oesophageal cancer in northwest France could be explained by local dietary habits, e.g., drinking hot Calvados liquor and excessive consumption of butter.PMID: 9533754
Cancer Causes Control. 2007 Dec;18(10):1153-67.
Pancreatic cancer, animal protein and dietary fat in a population-based study, San Francisco Bay Area, California.
Chan JM, Wang F, Holly EA.
Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA 94118-1944, USA.
OBJECTIVE: The associations between animal protein or fat and risk of pancreatic cancer have been reported previously with inconsistent results. A population-based case-control study of pancreatic cancer was conducted in the San Francisco Bay Area to examine these associations. METHODS: A semi-quantitative food-frequency questionnaire was administered to 532 cases and 1,701 controls between 1995 and 1999. Odds ratios (OR) and 95% confidence intervals (CI) were computed as estimates of the relative risk of pancreatic cancer. RESULTS: When comparing highest versus lowest levels of intake in multivariable adjusted models, positive associations were observed for several beef/lamb and individual animal protein items, including beef/lamb as a main dish (OR = 2.2, 95% CI: 1.0-4.5), regular hamburger (OR = 1.7, 95% CI: 1.2-2.4), whole eggs (OR = 1.6, 95% CI: 1.0-2.4),
butter (OR = 2.4, 95% CI: 1.6-3.5), and total dairy not including butter (OR = 2.6, 95% CI: 1.8-3.7). Some high-fat/processed-meat products (i.e., sausage, salami, bacon), but not all (i.e., beef, pork, or poultry hot dogs), also were positively associated with risk. An inverse association was noted for greater chicken/turkey consumption (OR = 0.7, 95% CI: 0.5-1.0). The risk comparing the highest versus lowest quartiles for fats and cholesterol consumption were: total fat (OR = 1.6, 95% CI: 1.2-2.1); animal fat (OR = 1.9, 95% CI: 1.4-2.5); saturated fat (OR = 1.9, 95% CI: 1.4-2.6); monounsaturated fat (OR = 1.3, 95% CI: 1.0-1.8); and dietary cholesterol (OR = 1.5, 95% CI: 1.1-2.0, all p-trends < or = 0.02). CONCLUSIONS: These data provide some evidence that beef or lamb, eggs, dairy, fat, or cholesterol may increase the risk of pancreatic cancer.
PMID: 17805983
J Egypt Public Health Assoc. 2006;81(3-4):143-63.
Risk factors of Cancer Prostate A case control study.
Kamel NM, Tayel ES, El Abbady AA, Khashab SS.
Department of Community Medicine, Faculty of Medicine, Alexandria University, Alexandria, Egypt. nahidmkamel@yahoo.com.
The purpose of this study is to reveal the different risk factors related to this cancer particularly that there is no agreement about which factors affect the risk. A fishing expedition hospital based case control study was carried out. Cases and controls were identified from the Urology Department of Alexandria Main University Hospital, 2004. All cases diagnosed as having the tumor were included in the case series. For each case the second subject proved to have a negative pathological examination was included in the control group (50).Data collection was carried out blindly using a structured interview schedule. Analysis was applied using Chi-square test, Fisher exact and Student's t-test. Odds Ratios and 95% Confidence Intervals were calculated. Results indicated that regular consumption of sausages was greater among cases than controls (X(2)= 10.19, p= 0.001 and an odds ratio of 5.92 (CI: 1.69-25.99). Also more cases claimed consuming regularly butter and natural ghee than controls (X(2)= 5.47, p= 0.019). The estimate risk was as high as 2.79 (Cl: 1.07-7.33). However regular consumption of vegetables was more encountered among controls than cases (X(2) = 5.005, p= 0.025 where the odds ratio was 0.19 (Cl: 0.02-1.01). Moreover the multiple regression analysis confirmed the results obtained from univariate analysis.
The consistency of results of current work as regards sausages and butter with several other research works can support the identification of these specific possible risk factors. Also other research workers pointed out to the protective effect of vegetables. However further research is needed to address other risk factors.
PMID: 17382058