Prospective Studies of Dairy Product and Calcium Intakes and Prostate Cancer Risk: A Meta-Analysis

Boston University, Boston, Massachusetts, United States
Journal of the National Cancer Institute (Impact Factor: 12.58). 12/2005; 97(23):1768-77. DOI: 10.1093/jnci/dji402
Source: PubMed


The Dietary Guidelines for Americans 2005 recommends that Americans increase their intake of dairy products. However, some studies have reported that increasing dairy product intake is associated with an increased risk of prostate cancer. We conducted a meta-analysis to examine associations between intakes of calcium and dairy products and the risk of prostate cancer.
We searched Medline for prospective studies published in English-language journals from 1966 through May 2005. We identified 12 publications that used total, advanced, or fatal prostate cancer as end points and reported associations as relative risks (RRs) with 95% confidence intervals (CIs) by category of dairy product or calcium intake. Data were extracted using standardized data forms. Random-effects models were used to pool study results and to assess dose-response relationships between dairy product or calcium intakes and the risk of prostate cancer. We conducted sensitivity analyses by changing criteria for inclusion of studies or by using fixed-effects models. All statistical tests were two-sided.
Men with the highest intake of dairy products (RR =1.11 [95% CI = 1.00 to 1.22], P = .047) and calcium (RR = 1.39 [95% CI = 1.09 to 1.77], P = .018) were more likely to develop prostate cancer than men with the lowest intake. Dose-response analyses suggested that dairy product and calcium intakes were each positively associated with the risk of prostate cancer (Ptrend = .029 and .014, respectively). Sensitivity analyses generally supported these associations, although the statistical significance was attenuated. The pooled relative risks of advanced prostate cancer were 1.33 (95% CI = 1.00 to 1.78; P = .055) for the highest versus lowest intake categories of dairy products and 1.46 (95% CI = 0.65 to 3.25; P > .2) for the highest versus lowest intake categories of calcium.
High intake of dairy products and calcium may be associated with an increased risk of prostate cancer, although the increase appears to be small.

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    • "Among individual food groups/nutrients a high consumption of dairy are related to an increased risk in several studies, including the European Prospective Investigation into Cancer and Nutrition (2014) and studies in Canada (Raimondi et al., 2010) and Japan (Kurahashi et al., 2008). However, the results of two meta-analyses of the relation between dairy product intake and PC provided conflicting conclusions: one showed a significantly positive association (Gao et al., 2005) and the other (supported by the National Dairy Council) showed an overall null association (Huncharek et al., 2008). High consumption of meat has been also associated with PC risk (John et al., 2011; Punnen et al., 2011). "
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    ABSTRACT: The aim of the present study was to determine the association between the socio-demographic, lifestyle factors, and dietary habits with the risk of prostate cancer (PC) in a case-control study of Spanish men. None of the socio-demographic, lifestyle or dietetic variables was found predictors of PC risk. Body mass index was associated with an increased risk for aggressive PC and fruit consumption with lower Gleason scores, thus less aggressive cancers. Nonetheless, after applying Bonferroni correction, these variables were not still associated with PC aggressiveness. More adequately, powered epidemiological studies that measure the effect of lifestyle and dietary intake in PC risk and aggressiveness are warranted to further elucidate the role of these modifiable factors on PC etiology.
    International Journal of Food Sciences and Nutrition 09/2015; 66(7):1-6. DOI:10.3109/09637486.2015.1077786 · 1.21 Impact Factor
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    • "Therefore , various studies (Park and others 2008; Davoodi and others 2013) have elucidated the role of dairy food consumption in the development of various malignancies. An increased consumption of dairy foods and calcium has been linked with increased prostate cancer risks (Gao and others 2005). Larsson and others (2004) also reported that high intakes of dairy products, particularly milk, are associated with increased risk of serous ovarian cancer . "
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    ABSTRACT: Cancer is the most widely recognized reason for human deaths globally. Conventional anticancer therapies, including chemotherapy and radiation, are very costly and induce severe side effects on the individual. The discovery of natural anticancer compounds like peptides may thus be a better alternative for cancer prevention and management. The anticancer peptides also exist in the amino acid chain of milk proteins and can be generated during proteolytic activities such as gastrointestinal digestion or food processing including fermentation. This paper presents an exhaustive overview of the contemporary literature on antitumor activities of peptides released from milk proteins. In addition, caseins and whey proteins have been evaluated for anticancer potential using the AntiCP database, a web-based prediction server. Proline and lysine, respectively, dominate at various positions in anticancer peptides obtained from caseins and whey proteins. The remarkable number of potential anticancer peptides revealed milk proteins as favorable candidates for the development of anticancer agents or milk and milk products for reduction of cancer risks. Moreover, anticancer peptides liberated from milk proteins can be identified from fermented dairy products. Although current findings of correlation between dairy food intakes and cancer risks lack consistency, dairy-derived peptides show promise as candidates for cancer therapy. This critical review supports the notion that milk proteins are not only a nutritious part of a normal daily diet but also have potential for prevention and/or management of cancer.
    Comprehensive Reviews in Food Science and Food Safety 03/2015; 14(2). DOI:10.1111/1541-4337.12126 · 4.18 Impact Factor
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    • "Most epidemiologic studies [1,2,3,4,5,6], but not all [7,8], have reported an increase in prostate cancer risk with an increased milk intake. To elucidate the effect of milk on prostate cancer, numerous experimental studies have tried to identify hazardous ingredients in milk, such as calcium [6,9], estrogen [10], and insulin-like growth factor-1 (IGF-1) [11]. However, among the components of milk, protein has been enigmatic. "
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    ABSTRACT: Purpose Despite most epidemiologic studies reporting that an increase in milk intake affects the growth of prostate cancer, the results of experimental studies are not consistent. In this study, we investigated the proliferation of prostate cancer cells treated with casein, the main protein in milk. Materials and Methods Prostate cancer cells (LNCaP and PC3), lung cancer cells (A459), stomach cancer cells (SNU484), breast cancer cells (MCF7), immortalized human embryonic kidney cells (HEK293), and immortalized normal prostate cells (RWPE1) were treated with either 0.1 or 1 mg/mL of α-casein and total casein extracted from bovine milk. Treatments were carried out in serum-free media for 72 hours. The proliferation of each cell line was evaluated by an 3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Results α-Casein and total casein did not affect the proliferations of RWPE1, HEK293, A459, SNU484, MCF7, HEK293, or RWPE1 cells. However, PC3 cells treated with 1 mg/mL of α-casein and casein showed increased proliferation (228% and 166%, respectively), and the proliferation of LNCaP cells was also enhanced by 134% and 142%, respectively. The proliferation mechanism of α-casein in PC3 and LNCaP cells did not appear to be related to the induction of Insulin-like growth factor-1 (IGF-1), since the level of IGF-1 did not change upon the supplementation of casein. Conclusions The milk protein, casein, promotes the proliferation of prostate cancer cells such as PC3 and LNCaP.
    08/2014; 32(2):76-82. DOI:10.5534/wjmh.2014.32.2.76
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