Milk intake in early life and risk of advanced prostate cancer

The Dairy and Cancer Controversy: Milking the Evidence

PURPOSE OF REVIEW

Cancer risk reduction remains a significant concern for both individuals with a cancer diagnosis and those aiming to prevent it. Dairy products, a source of beneficial dietary nutrients, have sparked controversy regarding their impact on cancer risk.

RECENT FINDINGS

Evidence indicates that dairy consumption, particularly milk, can decrease colorectal cancer risk. However, cow's milk, a key dairy product, exposes individuals to growth hormones, notably insulin-like growth factor-1, potentially elevating cancer risk. Extensive research supports the link between dairy intake and heightened prostate cancer risk. Nonetheless, investigations into dairy's association with breast, ovarian, and other cancers yield mixed results. The overall data on dairy and cancer remains inconclusive. Available data suggests that a diet emphasizing fiber-rich foods such as whole grains, fruits, and vegetables, while restricting milk and dairy intake-similar to the Mediterranean dietary pattern-might mitigate cancer incidence. However, further research is crucial to elucidate the precise role of dairy products in overall cancer risk.

Potential Pathogenic Impact of Cow’s Milk Consumption and Bovine Milk-Derived Exosomal MicroRNAs in Diffuse Large B-Cell Lymphoma

Epidemiological evidence supports an association between cow’s milk consumption and the risk of diffuse large B-cell lymphoma (DLBCL), the most common non-Hodgkin lymphoma worldwide. This narrative review intends to elucidate the potential impact of milk-related agents, predominantly milk-derived exosomes (MDEs) and their microRNAs (miRs) in lymphomagenesis. Upregulation of PI3K-AKT-mTORC1 signaling is a common feature of DLBCL. Increased expression of B cell lymphoma 6 (BCL6) and suppression of B lymphocyte-induced maturation protein 1 (BLIMP1)/PR domain-containing protein 1 (PRDM1) are crucial pathological deviations in DLBCL. Translational evidence indicates that during the breastfeeding period, human MDE miRs support B cell proliferation via epigenetic upregulation of BCL6 (via miR-148a-3p-mediated suppression of DNA methyltransferase 1 (DNMT1) and miR-155-5p/miR-29b-5p-mediated suppression of activation-induced cytidine deaminase (AICDA) and suppression of BLIMP1 (via MDE let-7-5p/miR-125b-5p-targeting of PRDM1). After weaning with the physiological termination of MDE miR signaling, the infant’s BCL6 expression and B cell proliferation declines, whereas BLIMP1-mediated B cell maturation for adequate own antibody production rises. Because human and bovine MDE miRs share identical nucleotide sequences, the consumption of pasteurized cow’s milk in adults with the continued transfer of bioactive bovine MDE miRs may de-differentiate B cells back to the neonatal “proliferation-dominated” B cell phenotype maintaining an increased BLC6/BLIMP1 ratio. Persistent milk-induced epigenetic dysregulation of BCL6 and BLIMP1 expression may thus represent a novel driving mechanism in B cell lymphomagenesis. Bovine MDEs and their miR cargo have to be considered potential pathogens that should be removed from the human food chain.

Milk Intake in Early Life and Later Cancer Risk: A Meta-Analysis

Dairy consumption in adulthood has been demonstrated to influence cancer risk. Although childhood and adolescence represent critical periods of rapid growth, the relationship between milk intake in early life and later cancer risk is unclear. Thus, we examined this relationship by conducting a meta-analysis of the observational studies. PubMed and Embase were searched for relevant articles that were published throughout December 2021. The summary relative risk (RR) and 95% confidence interval (CI) were estimated using the DerSimonian-Laird random-effects model. The summary RR for the highest vs. lowest milk intake was 0.83 (95% CI = 0.69–1.00; p = 0.05; I² = 60%; seven studies) for breast cancer, 0.98 (95% CI = 0.72–1.32; p = 0.88; I² = 51%; four studies) for prostate cancer, and 0.90 (95% CI = 0.42–1.93; p = 0.78; I² = 83%; three studies) for colorectal cancer. No evidence of an association emerged in subgroup analyses of menopausal status, cancer stage, fat content of milk, life stage of milk intake, or study design. Consistent results were observed in the meta-analyses using total dairy intake. In conclusion, milk intake during childhood and adolescence might not be associated with risks of breast, prostate, and colorectal cancer later in life. Given the small number of studies that were included in our meta-analysis, and the high heterogeneity, more studies are warranted for a definitive conclusion.

Growth Rate in Childhood and Adolescence and the Risk of Breast and Prostate Cancer: A Population-Based Study

Growth rate is regulated by hormonal pathways that might affect early cancer development. We explored the association between rate of growth in height from ages 8 to 13 years (childhood) and from age 13 to attainment of adult height (adolescence), as measured at study entry, and the risk of breast or prostate cancer. Participants were 2,037 Icelanders born during 1915-1935, who took part in the Reykjavik Study, established in 1967. Height measurements were obtained from school records and at study entry. We used multivariable Cox regression models to calculate hazard ratios with 95% confidence intervals of breast and prostate cancer by rates of growth in tertiles. During a mean follow-up of 66 years (women) and 64 years (men), 117 women were diagnosed with breast cancer and 118 men with prostate cancer (45 with advanced disease). Women in the highest growth-rate tertile in adolescence had a higher risk of breast cancer (hazard ratio = 2.4, 95% confidence interval: 1.3, 4.3) compared with women in the lowest tertile. A suggestive inverse association was observed for highest adolescent growth rate in men and advanced prostate cancer: hazard ratio = 0.4, 95% confidence interval: 0.2, 1.0. Rapid growth, particularly in adolescence may affect cancer risk later in life.

Short-term serum and urinary changes in sex hormones of healthy pre-pubertal children after the consumption of commercially available whole milk powder: a randomized, two-level, controlled-intervention trial in China

Progesterone was found in commercial milk. After consuming this milk, compared with the control, serum progesterone levels after 3 h and urinary pregnanediol levels within 4 h increased, but those in urine after 48 h had no significant change.

Dietary patterns in adolescence and risk of colorectal cancer: a population-based study

PURPOSE

To study whether dietary patterns in adolescence are associated with risk of colorectal cancer (CRC).

METHODS

Food frequency data were obtained from the AGES-Reykjavik study, conducted between 2002 and 2006, which included 5,078 (58% women) participants with mean age of 77 (± 5.8) years. Principal component analysis was used to identify dietary patterns. Participants were followed through linkage to the Icelandic Cancer Registry. Multivariable Cox models were used to calculate hazard ratios (HR) of CRC and 95% confidence interval (CI) by dietary patterns.

RESULTS

During the follow-up period (mean 8.2 years), 136 participants (75 women and 61 men) were diagnosed with CRC. The main dietary pattern in adolescence was characterized by high intake of traditional food items consumed in the earlier half of the twentieth century, namely, salted or smoked meat and fish, milk, offal, rye bread, and oatmeal. Compared to the lowest tertile, the middle tertile of this pattern was associated with increased risk of CRC (HR 1.63, 95% CI 1.04-2.57), while the highest tertile was not statistically associated with CRC (HR 1.48, 95% CI 0.93-2.37), except among women (HR 2.06, 95% CI 1.11-3.84).

CONCLUSION

These data suggest that strong adherence to a traditional Icelandic diet in adolescence might increase the risk of CRC, particularly among women. More research is need on the association between food items and dietary patterns of relevance to CRC at different points in the life cycle.

Dairy products and the risk of developing prostate cancer: A large-scale cohort study (JACC Study) in Japan

Dairy products have been indicated as a risk factor for prostate cancer. However, only a few epidemiological studies have reported dairy products as being a risk factor for prostate cancer in Japan, reporting contradictory results. We therefore investigated the association between the intake of dairy products and the occurrence of prostate cancer through a large‐scale cohort study. The Japan Collaborative Cohort study analyzed approximately 110,000 residents from various Japanese districts who participated in our questionnaire survey during 1988–1990. The subjects of the present study were 26,464 men (age range: 40–79 years) from 24 districts wherein cancer incidence was reported. Their clinical course was followed up until 2009. Hazard ratios (HRs) were calculated using Cox's proportional hazards model, adjusted for age, survey area, family history of prostate cancer, body mass index, and total energy intake. For diet, we calculated the HRs associated with intermediate and high consumption of dairy products and compared them with those associated with low consumption. There were 412 cases of prostate cancer in the survey population. As dairy products, milk, yogurt, cheese, and butter were evaluated. Among them, milk consumption was associated with a significant risk (HR = 1.37, p = 0.009) and a dose‐dependent response (p for trend = 0.009) adjusted for age and family history of prostate cancer, stratified by area. Milk and yogurt consumption showed a significantly positive risk and a dose–response relationship adjusted for age, family history of prostate cancer, body mass index, and total energy intake, stratified by area. In summary, a high intake of dairy products such as milk increased the risk of developing prostate cancer in Japanese men.

Cow's milk may be delivering potentially harmful undetected cargoes to humans. Is it time to reconsider dairy recommendations?

Mammalian evolution has shaped milk into a species-specific vehicle for post-natal development, continuing what began within the mother's womb. Increased consumption of the mother's breast milk is associated with the most adequate metabolic programming and lowers the incidence of the diseases of civilization during adulthood. An abundance of short sequences of RNA, known as microRNA, exists in mammalian breast milk, enclosed within robust small extracellular vesicles known as exosomes. These microRNAs can epigenetically regulate over 60% of human genes. When cow's milk is consumed by humans, the bovine exosomes are transported through the gastrointestinal tract, detected intact in the blood stream, and taken up by target cells, where they alter protein expression. The aim of this review was to highlight the role of dairy exosomes and microRNA, and of the type of dairy product consumed, in human diseases. Given that microRNAs are involved in a vast array of physiological processes and associated with several diseases, perhaps caution should be practiced with regard to human consumption of dairy, particularly for individuals within developmentally critical time frames, such as pregnant and lactating mothers, and young children.

Possible Biochemical Processes Underlying the Positive Health Effects of Plant-Based Diets-A Narrative Review

Plant-based diets are becoming more popular for many reasons, and epidemiological as well as clinical data also suggest that a well-balanced vegan diet can be adopted for the prevention, and in some cases, in the treatment of many diseases. In this narrative review, we provide an overview of the relationships between these diets and various conditions and their potential biochemical background. As whole plant foods are very rich in food-derived antioxidants and other phytochemicals, they have many positive physiological effects on different aspects of health. In the background of the beneficial health effects, several biochemical processes could stand, including the reduced formation of trimethylamine oxide (TMAO) or decreased serum insulin-like growth factor 1 (IGF-1) levels and altered signaling pathways such as mechanistic target of rapamycin (mTOR). In addition, the composition of plant-based diets may play a role in preventing lipotoxicity, avoiding N-glycolylneuraminic acid (Neu5Gc), and reducing foodborne endotoxin intake. In this article, we attempt to draw attention to the growing knowledge about these diets and provide starting points for further research.

Adolescent animal product intake in relation to later prostate cancer risk and mortality in the NIH-AARP Diet and Health Study

BACKGROUND

Adolescent intake of animal products has been proposed to contribute to prostate cancer (PCa) development because of its potentially carcinogenic constituents and influence on hormone levels during adolescence.

METHODS

We used data from 159,482 participants in the NIH-AARP Diet and Health Study to investigate associations for recalled adolescent intake of red meat (unprocessed beef and processed red meat), poultry, egg, canned tuna, animal fat and animal protein at ages 12-13 years with subsequent PCa risk and mortality over 14 years of follow-up. Cox proportional hazard regression was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) of total (n = 17,349), advanced (n = 2,297) and fatal (n = 804) PCa.

RESULTS

Suggestive inverse trends were observed for adolescent unprocessed beef intake with risks of total, advanced and fatal PCa (multivariable-adjusted P-trends = 0.01, 0.02 and 0.04, respectively). No consistent patterns of association were observed for other animal products by PCa outcome.

CONCLUSION

We found evidence to suggest that adolescent unprocessed beef intake, or possibly a correlate of beef intake, such as early-life socioeconomic status, may be associated with reduced risk and mortality from PCa. Additional studies with further early-life exposure information are warranted to better understand this association.

[Health risks related to milk consumption: a critical evaluation from the medical perspective]

BACKGROUND

Recent epidemiological studies associate the consumption of non-fermented cow's milk, but not fermented milk products, with an increased risk of diseases of civilization.

OBJECTIVES

Presentation of epidemiological and pathophysiological data on health risks associated with milk consumption.

METHOD

Selective PubMed surveys between 2005-2020 considering epidemiological studies which clearly differentiate between non-fermented versus fermented milk and its potential health risks.

RESULTS

Epidemiological studies confirm a correlation between milk consumption and birthweight, linear growth during puberty, acne vulgaris, type 2 diabetes mellitus, prostate cancer, breast cancer, hepatocellular carcinoma, non-Hodgkin lymphoma, Parkinson's disease and over-all mortality. In comparison to milk consumption, the intake of fermented milk/milk products exhibits neutral to beneficial health effects, which are explained by attenuated mTORC1 signaling due to bacterial fermentation of milk.

CONCLUSIONS

Long-term persistent consumption of non-fermented milk, but not fermented milk/milk products, might increase the risk of diseases of civilization. The avoidance of milk, especially pasteurized fresh milk, may enhance the prevention and reduce the recurrence of common Western diseases of civilization.

Lifetime Impact of Cow's Milk on Overactivation of mTORC1: From Fetal to Childhood Overgrowth, Acne, Diabetes, Cancers, and Neurodegeneration

The consumption of cow's milk is a part of the basic nutritional habits of Western industrialized countries. Recent epidemiological studies associate the intake of cow's milk with an increased risk of diseases, which are associated with overactivated mechanistic target of rapamycin complex 1 (mTORC1) signaling. This review presents current epidemiological and translational evidence linking milk consumption to the regulation of mTORC1, the master-switch for eukaryotic cell growth. Epidemiological studies confirm a correlation between cow's milk consumption and birthweight, body mass index, onset of menarche, linear growth during childhood, acne vulgaris, type 2 diabetes mellitus, prostate cancer, breast cancer, hepatocellular carcinoma, diffuse large B-cell lymphoma, neurodegenerative diseases, and all-cause mortality. Thus, long-term persistent consumption of cow's milk increases the risk of mTORC1-driven diseases of civilization. Milk is a highly conserved, lactation genome-controlled signaling system that functions as a maternal-neonatal relay for optimized species-specific activation of mTORC1, the nexus for regulation of eukaryotic cell growth, and control of autophagy. A deeper understanding of milk´s impact on mTORC1 signaling is of critical importance for the prevention of common diseases of civilization.

Dietary Factors and Prostate Cancer Development, Progression, and Reduction

Due to the constantly increasing number of cases, prostate cancer has become one of the most important health problems of modern societies. This review presents the current knowledge regarding the role of nutrients and foodstuff consumption in the etiology and development of prostate malignancies, including the potential mechanisms of action. The results of several in vivo and in vitro laboratory experiments as well as those reported by the clinical and epidemiological research studies carried out around the world were analyzed. The outcomes of these studies clearly show the influence of both nutrients and food products on the etiology and prevention of prostate cancer. Consumption of certain nutrients (saturated and trans fatty acids) and food products (e.g., processed meat products) leads to the disruption of prostate hormonal regulation, induction of oxidative stress and inflammation, and alteration of growth factor signaling and lipid metabolism, which all contribute to prostate carcinogenesis. On the other hand, a high consumption of vegetables, fruits, fish, and whole grain products exerts protective and/or therapeutic effects. Special bioactive functions are assigned to compounds such as flavonoids, stilbenes, and lycopene. Since the influence of nutrients and dietary pattern is a modifiable risk factor in the development and prevention of prostate cancer, awareness of the beneficial and harmful effects of individual food ingredients is of great importance in the global strategy against prostate cancer.

Milk consumption and multiple health outcomes: umbrella review of systematic reviews and meta-analyses in humans

In order to recapitulate the best available evidence of milk consumption and multiple health-related outcomes, we performed an umbrella review of meta-analyses and systematic reviews in humans. Totally, 41 meta-analyses with 45 unique health outcomes were included. Milk consumption was more often related to benefits than harm to a sequence of health-related outcomes. Dose–response analyses indicated that an increment of 200 ml (approximately 1 cup) milk intake per day was associated with a lower risk of cardiovascular disease, stroke, hypertension, colorectal cancer, metabolic syndrome, obesity and osteoporosis. Beneficial associations were also found for type 2 diabetes mellitus and Alzheimer's disease. Conversely, milk intake might be associated with higher risk of prostate cancer, Parkinson’s disease, acne and Fe-deficiency anaemia in infancy. Potential allergy or lactose intolerance need for caution. Milk consumption does more good than harm for human health in this umbrella review. Our results support milk consumption as part of a healthy diet. More well-designed randomized controlled trials are warranted.

Milk Consumption and Prostate Cancer: A Systematic Review

Prostate cancer is the third most common cancer in men globally, and the most common cancer among men in the United States. Dietary choices may play an important role in developing prostate cancer; in particular, a higher dairy product intake has been associated with an increased risk of developing prostate cancer. The overall positive association between milk consumption and the risk of prostate cancer development and prostate cancer mortality has been well documented in multiple epidemiological studies. However, there is limited literature on the association between types of milk, as classified by fat content (skim, low fat, and whole), and the risk of developing prostate cancer. When further examining current state of the literature on this topic, there is a number of epidemiologic studies assessing the relationship between prostate cancer and milk consumption. On the contrary, very few experimental studies explore this topic. Further experimental research may be necessary to examine the relationship between dairy and dairy products consumption and the increased risk of development of prostate cancer. At this time, there are no formal clinical recommendations regarding dairy products consumption for patients who are at risk of prostate cancer development or who have a history of prostate cancer. In this manuscript, we sought to systematically review the existing literature on the association between milk consumption classified by fat content, and the risk of developing prostate cancer. These findings may be useful for the clinicians who provide recommendations for the patients at risk of developing prostate cancer.

Adolescent dairy product and calcium intake in relation to later prostate cancer risk and mortality in the NIH-AARP Diet and Health Study

PURPOSE

Although a growing body of evidence supports an early-life contribution to prostate cancer (PCa) development, few studies have investigated early-life diet, and only three have examined early-life dairy product intake, a promising candidate risk factor because of its known/suspected influence on insulin-like growth factor levels and height.

METHODS

We used recalled dietary data from 162,816 participants in the NIH-AARP Diet and Health Study to investigate associations for milk, cheese, ice cream, total dairy, and calcium intake at ages 12-13 years with incident total (n = 17,729), advanced (n = 2,348), and fatal PCa (n = 827) over 14 years of follow-up. We calculated relative risks (RRs) and 95% confidence intervals (CIs) by Cox proportional hazards regression.

RESULTS

We observed suggestive positive trends for milk, dairy, and calcium intake with total and/or advanced PCa (p-trends = 0.016-0.148). These trends attenuated after adjustment for additional components of adolescent diet, particularly red meat and vegetables/potatoes. In contrast, suggestive inverse trends were observed for cheese and ice cream intake with total and/or advanced PCa (p-trends = 0.043-0.153), and for milk, dairy, and calcium intake with fatal PCa (p-trend = 0.045-0.117).

CONCLUSION

Although these findings provide some support for a role of adolescent diet in increasing PCa risk, particularly for correlates of milk intake or overall dietary patterns, our protective findings for cheese and ice cream intake with PCa risk and mortality, and for all dairy products with PCa mortality, suggest alternative explanations, such as the influence of early-life socioeconomic status, and increased PCa screening, earlier detection, and better PCa care.

Hormones in Food as a Potential Risk for Human Reproductive and Health Disorders

In the last 60 years, milk, meat, and egg worldwide consumption per capita increased 2-, 3-, and 5-fold, respectively. In the same period, several studies have reported a drop of semen quality and an increased incidence of cryptorchidism, hypospadias, and some hormone-related cancers (testicular, prostate, breast, endometrial cancer) in humans. A possible reason for these disruptions is increased exposure to exogenous hormones in food of animal origin. Hormones in food are considered to affect the endocrine system and cell signaling and thus disrupt homeostasis in the consumers. Since food safety assurance is a part of the veterinary service, the risk assessment of hormones in food as potential disruptive compounds is a significant challenge. Numerous cohort and epidemiologic studies and meta-analyses have been performed with respect to find an association between the consumption of food of animal origin and particular health disorders. Additionally, several studies in animal models have been performed to explain the mechanisms of disruptive effects of exogenous hormones. Since contradictory results have been reported, there is no general conclusion about the disruptive effects of exogenous hormones. Further experiments on animals in which long-term treatment with exogenous hormones is performed and further comprehensive endocrinological, toxicological, and human epidemiological studies are needed to confirm or deny the role of exogenous hormones in human health disorders. Moreover, long-term exposure to a combination of several exogenous compounds, such as environmental pollutants and dietary hormones and their additive effects, are also not well known and should be a topic for further studies.

Dairy Products: Is There an Impact on Promotion of Prostate Cancer? A Review of the Literature

This review of the literature aims to study potential associations between high consumption of milk and/or dairy products and prostate cancer (PC). Literature is scarce, yet there is a direct relationship between mTORC1 activation and PC; several ingredients in milk/dairy products, when in high concentrations, increase signaling of the mTORC1 pathway. However, there are no studies showing an unequivocal relationship between milk products PC initiation and/or progression. Three different reviews were conducted with articles published in the last 5 years: (M1) PC and intake of dairy products, taking into account the possible mTORC1signaling mechanism; (M2) Intake of milk products and incidence/promotion of PC; (M3) mTORC1 activation signaling pathway, levels of IGF-1 and PC; (M4) mTORC pathway and dairy products. Of the 32 reviews identified, only 21 met the inclusion criteria and were analyzed. There is little scientific evidence that directly link the three factors: incidence/promotion of PC, intake of dairy products and PC, and PC and increased mTORC1 signaling. Persistent hyper-activation of mTORC1 is associated with PC promotion. The activity of exosomal mRNA in cellular communication may lead to different impacts of different types of milk and whether or not mammalian milks will have their own characteristics within each species. Based on this review of the literature, it is possible to establish a relationship between the consumption of milk products and the progression of PC; we also found a possible association with PC initiation, hence it is likely that the intake of dairy products should be reduced or minimized in mens' diet.

Milk and Dairy Product Consumption and Prostate Cancer Risk and Mortality: An Overview of Systematic Reviews and Meta-analyses

Milk and dairy product consumption has been associated with an increase in prostate cancer risk; however, discrepancies have been observed in the literature. This first overview of systematic reviews and meta-analyses was carried out with the main objective of compiling and discussing the evidence generated to date related to milk and dairy product consumption and prostate cancer risk and mortality. A systematic search in MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, and the Web of Science (from inception to 30 April 2018) was conducted. The inclusion criteria were as follows: adult men, meta-analyses of longitudinal studies, dairy product consumption, and risk of prostate cancer or related outcomes. The AMSTAR2 checklist was used to evaluate methodological quality. The synthesis methods included dairy product exposure (high compared with low consumption or dose-response), dairy product type (total dairy products, milk, cheese, yogurt, and others), and prostate cancer outcomes (total, nonadvanced, and advanced prostate cancer and mortality) displayed in forest plots. Six meta-analyses were identified. These studies reported on the analysis of the 2 to 32 cohorts (up to 848,395 subjects/38,107 cases; 4-28 y of follow-up) and 2 case-control meta-analyses (12,435 subjects). The meta-analysis quality was valued as mostly "good" according to the AMSTAR2 criteria. All RRs of high compared with low consumption (dose-response) for total prostate cancer ranged from 1.68 to 1.09 (1.07 per 400 g/d) for total dairy products, 1.50 to 0.92 (1.06 to 0.98 per 200 g/d) for milk (whole, low-fat, and skim milk considered separately), and 1.18 to 0.74 (1.10 per 50 g/d) for cheese. RRs have decreased since the first meta-analysis. Statistical heterogeneity generates uncertainty in the observed results (up to I2 = 77.1%). In conclusion, although there are some data indicating that higher consumption of dairy products could increase the risk of prostate cancer, the evidence is not consistent. This review was registered with PROSPERO as CRD42018094737.

Diseases of Civilization - Cancer, Diabetes, Obesity and Acne - the Implication of Milk, IGF-1 and mTORC1

Nutrition and food are one of the most complex aspects of human lives, being influenced by biochemical, psychological, social and cultural factors. The Western diet is the prototype of modern dietary pattern and is mainly characterized by the intake of large amounts of red meat, dairy products, refined grains and sugar. Large amounts of scientific evidence positively correlate Western diet to acne, obesity, diabetes, heart disease and cancer, the so-called "diseases of civilization". The pathophysiological common ground of all these pathologies is the IGF-1 and mTORC pathways, which will be disscussed further in this paper.

MECHANISMS IN ENDOCRINOLOGY: Estrogens in consumer milk: is there a risk to human reproductive health?

Possible effects of xenoestrogens on human health, in particular on male reproductive health, have attracted considerable attention in recent years. Cow's milk was suggested in numerous publications as one of possible sources of xenoestrogens that could affect human health. Although milk has undoubtedly many beneficial health effects and could even have a role in reducing incidence of some cancers, concerns were raised about presumably high levels of estrogens in cow's milk. In intensive farming, concentrations of estrogens in milk are higher due to long milking periods that today extend long into the pregnancy, when concentrations of estrogens in the cow's body rise. Numerous studies examined potential effects of milk on reproductive health and endocrine-related cancers in both experimental studies with laboratory animals, and in human epidemiological studies. In the present review article, we compiled a review of recently published literature about the content of estrogens in cow's milk and potential health effects, in particular on reproductive system, in humans. Although results of published studies are not unequivocal, it seems that there is stronger evidence suggesting that amounts of estrogens in cow's milk are too low to cause health effects in humans.

Dietary intake is associated with risk of multiple myeloma and its precursor disease

The etiology of monoclonal gammopathy of undetermined significance (MGUS), the precursor state of multiple myeloma (MM), is mostly unknown and no studies have been conducted on the effect of diet on MGUS or progression from MGUS to MM. We aimed to explore the association between common foods and MGUS and progression to MM. Data from the population-based AGES Study (N = 5,764) were utilized. Food frequency questionnaire was used to assess dietary intake during adolescence, midlife, and late life. Serum protein electrophoresis and serum free light-chain assay was performed to identify MGUS (n = 300) and LC-MGUS cases (n = 275). We cross linked our data with the Icelandic Cancer Registry to find cases of MM in the study group. We found that intake of fruit at least three times per week during adolescence was associated with lower risk of MGUS when compared to lower fruit consumption (OR = 0.62, 95% CI 0.41–0.95). We additionally found that intake of fruit at least three times per week during the late life period was associated with decreased risk of progressing from MGUS to MM (HR = 0.34, 95% CI 0.13–0.89) when compared to lower intake. Adolescent intake of fruit may reduce risk of MGUS, whereas fruit intake after MGUS onset may reduce risk of progressing to MM. Our findings suggest that diet might alter the risk of developing MGUS and progression to MM.

DHA-enriched re-esterified triacylglycerol fish oil supplementation and oily fish consumption enhance red blood n-3 fatty acid index in Omani pre-adolescent schoolchildren

Dietary habits of Omani population particularly of children and young adults have changed significantly. Consumption of imported calorie-dense foods, vegetable oils, milled and polished grains and carbonated beverages have become the norm. Concomitantly, there has been an exponential increase in the prevalence of non-communicable diseases. The impact of the westernisation of eating habits on children has not been evaluated. We have investigated blood fatty acid profile of male (n = 125) and female (n = 160) children aged 9 and 10 (9.8 ± 0.4) years enrolled from three state-funded schools. The schools, which are homogenous with respect to socio-economic background of their pupils, were randomised into fish oil (n = 98), oily fish (n = 82) or control (n = 105) group. Subsequently, the children were given during morning tea break for 12 weeks: 1. DHA-enriched re-esterified triacylglycerol fish oil capsule with cheese/salad sandwich (fish oil group), 2. Lightly grilled oily fish with salad (fish group) or 3. Cheese/salad sandwich (control group). At baseline, the males had higher myristic, palmitic and oleic and lower adrenic acids than the females (p < 0.05). There was no difference in n-3 fatty acid index (4.86 ± 1.95 vs. 5.12 ± 1.67, p > 0.05) or AA (14.6 ± 1.9 vs. 14.9 ± 1.8, p > 0.05) between the genders. There was no difference in any of the fatty acids between the three groups at baseline. Post-intervention, the oily fish group had lower n-3 fatty acid index (EPA + DHA, 6.03 ± 1.39 vs. 6.60 ± 1.63, p < 0.05) and higher AA (15.2 ± 1.8 vs. 13.7 ± 2.0, p = 0.0001) and n-3 DPA (1.40 ± 0.27 vs. 1.07 ± 0.22, p = 0.0001) compared with those who received fish oil capsules. In both the fish oil and oily fish groups, fatty acid index correlated positively with AA (r = 0.394, p = 0.0001; r = 0.231, p = 0.038) and negatively with total saturated (r = - 0.816, p = 0.0001; r = - 0.439, p = 0.0001) and total mono-unsaturated (r = - 0.431, p = 0.0001; r = - 0.231, p = 0.037) fatty acids. Although seafood is an integral part of traditional Omani cuisine the children had a low level of n-3 fatty acids index. There is a need to address this nutritional insufficiency through school feeding programme, targeted intervention with n-3 fatty acid enriched food products and/or family education programme.

Dietary habits in adolescence and midlife and risk of breast cancer in older women

Recent studies indicate that lifestyle factors in early life affect breast cancer risk. We therefore explored the association of high consumption of meat, milk, and whole grain products in adolescence and midlife, on breast cancer risk. We used data from the population based AGES-Reykjavik cohort (2002–2006), where 3,326 women with a mean age of 77 years (SD 6.0) participated. For food items and principal component derived dietary patterns we used Cox proportional models to calculate multivariate hazard ratios (HR) with 95% confidence intervals (95% CI). During a mean follow-up of 8.8 years, 97 women were diagnosed with breast cancer. For both adolescence and midlife, daily consumption of rye bread was positively associated with breast cancer (HR 1.7, 95% CI 1.1–2.6 and HR 1.8, 95% CI 1.1–2.9, respectively). In contrast, persistent high consumption of oatmeal was negatively associated with breast cancer (0.4, 95% CI 0.2–0.9). No association was found for other food items or dietary patterns that included rye bread. High rye bread consumption in adolescence and midlife may increase risk of late-life breast cancer whilst persistent consumption of oatmeal may reduce the risk.

Milk disrupts p53 and DNMT1, the guardians of the genome: implications for acne vulgaris and prostate cancer

There is accumulating evidence that milk shapes the postnatal metabolic environment of the newborn infant. Based on translational research, this perspective article provides a novel mechanistic link between milk intake and milk miRNA-regulated gene expression of the transcription factor p53 and DNA methyltransferase 1 (DNMT1), two guardians of the human genome, that control transcriptional activity, cell survival, and apoptosis. Major miRNAs of milk, especially miRNA-125b, directly target TP53 and complex p53-dependent gene regulatory networks. TP53 regulates the expression of key genes involved in cell homeostasis such as FOXO1, PTEN, SESN1, SESN2, AR, IGF1R, BAK1, BIRC5, and TNFSF10. Nuclear interaction of p53 with DNMT1 controls gene silencing. The most abundant miRNA of milk and milk fat, miRNA-148a, directly targets DNMT1. Reduced DNMT1 expression further attenuates the activity of histone deacetylase 1 (HDAC1) involved in the regulation of chromatin structure and access to transcription. The presented milk-mediated miRNA-p53-DNMT1 pathway exemplified at the promoter regulation of survivin (BIRC5) provides a novel explanation for the epidemiological association between milk consumption and acne vulgaris and prostate cancer. Notably, p53- and DNMT1-targeting miRNAs of bovine and human milk survive pasteurization and share identical seed sequences, which theoretically allows the interaction of bovine miRNAs with the human genome. Persistent intake of milk-derived miRNAs that attenuate p53- and DNMT1 signaling of the human milk consumer may thus present an overlooked risk factor promoting acne vulgaris, prostate cancer, and other p53/DNMT1-related Western diseases. Therefore, bioactive miRNAs of commercial milk should be eliminated from the human food chain.

Early Life Residence, Fish Consumption, and Risk of Breast Cancer

Background: Little is known about fish intake throughout the life course and the risk of breast cancer.Methods: We used data on the first residence of 9,340 women born 1908 to 1935 in the Reykjavik Study as well as food frequency data for different periods of life from a subgroup of the cohort entering the Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study (n = 2,882).Results: During a mean follow-up of 27.3 years, 744 women were diagnosed with breast cancer in the Reykjavik Study. An inverse association of breast cancer was observed among women who lived through the puberty period in coastal villages, compared with women residing in the capital area [HR, 0.78; 95% confidence interval (CI), 0.61-0.99]. In the subgroup analysis of this Icelandic population, generally characterized by high fish intake, we found an indication of lower risk of breast cancer among women with high fish consumption (more than 4 portions per week) in adolescence (HR, 0.71; 95% CI, 0.44-1.13) and midlife (HR, 0.46; 95% CI, 0.22-0.97), compared with low consumers (2 portions per week or less). No association was found for fish liver oil consumption in any time period, which could be due to lack of a reference group with low omega-3 fatty acids intake in the study group.Conclusions: Our findings suggest that very high fish consumption in early to midlife may be associated with a reduced risk of breast cancer.Impact: Very high fish consumption in early adulthood to midlife may be associated with decreased risk of breast cancer. Cancer Epidemiol Biomarkers Prev; 26(3); 346-54. ©2016 AACR.

Milk: an epigenetic amplifier of FTO-mediated transcription? Implications for Western diseases

Single-nucleotide polymorphisms within intron 1 of the FTO (fat mass and obesity-associated) gene are associated with enhanced FTO expression, increased body weight, obesity and type 2 diabetes mellitus (T2DM). The N⁶-methyladenosine (m⁶A) demethylase FTO plays a pivotal regulatory role for postnatal growth and energy expenditure. The purpose of this review is to provide translational evidence that links milk signaling with FTO-activated transcription of the milk recipient. FTO-dependent demethylation of m⁶A regulates mRNA splicing required for adipogenesis, increases the stability of mRNAs, and affects microRNA (miRNA) expression and miRNA biosynthesis. FTO senses branched-chain amino acids (BCAAs) and activates the nutrient sensitive kinase mechanistic target of rapamycin complex 1 (mTORC1), which plays a key role in translation. Milk provides abundant BCAAs and glutamine, critical components increasing FTO expression. CpG hypomethylation in the first intron of FTO has recently been associated with T2DM. CpG methylation is generally associated with gene silencing. In contrast, CpG demethylation generally increases transcription. DNA de novo methylation of CpG sites is facilitated by DNA methyltransferases (DNMT) 3A and 3B, whereas DNA maintenance methylation is controlled by DNMT1. MiRNA-29s target all DNMTs and thus reduce DNA CpG methylation. Cow´s milk provides substantial amounts of exosomal miRNA-29s that reach the systemic circulation and target mRNAs of the milk recipient. Via DNMT suppression, milk exosomal miRNA-29s may reduce the magnitude of FTO methylation, thereby epigenetically increasing FTO expression in the milk consumer. High lactation performance with increased milk yield has recently been associated with excessive miRNA-29 expression of dairy cow mammary epithelial cells (DCMECs). Notably, the galactopoietic hormone prolactin upregulates the transcription factor STAT3, which induces miRNA-29 expression. In a retrovirus-like manner milk exosomes may transfer DCMEC-derived miRNA-29s and bovine FTO mRNA to the milk consumer amplifying FTO expression. There is compelling evidence that obesity, T2DM, prostate and breast cancer, and neurodegenerative diseases are all associated with increased FTO expression. Maximization of lactation performance by veterinary medicine with enhanced miRNA-29s and FTO expression associated with increased exosomal miRNA-29 and FTO mRNA transfer to the milk consumer may represent key epigenetic mechanisms promoting FTO/mTORC1-mediated diseases of civilization.

MicroRNAs in Breastmilk and the Lactating Breast: Potential Immunoprotectors and Developmental Regulators for the Infant and the Mother

Human milk (HM) is the optimal source of nutrition, protection and developmental programming for infants. It is species-specific and consists of various bioactive components, including microRNAs, small non-coding RNAs regulating gene expression at the post-transcriptional level. microRNAs are both intra- and extra-cellular and are present in body fluids of humans and animals. Of these body fluids, HM appears to be one of the richest sources of microRNA, which are highly conserved in its different fractions, with milk cells containing more microRNAs than milk lipids, followed by skim milk. Potential effects of exogenous food-derived microRNAs on gene expression have been demonstrated, together with the stability of milk-derived microRNAs in the gastrointestinal tract. Taken together, these strongly support the notion that milk microRNAs enter the systemic circulation of the HM fed infant and exert tissue-specific immunoprotective and developmental functions. This has initiated intensive research on the origin, fate and functional significance of milk microRNAs. Importantly, recent studies have provided evidence of endogenous synthesis of HM microRNA within the human lactating mammary epithelium. These findings will now form the basis for investigations of the role of microRNA in the epigenetic control of normal and aberrant mammary development, and particularly lactation performance.

Milk--A Nutrient System of Mammalian Evolution Promoting mTORC1-Dependent Translation

Based on own translational research of the biochemical and hormonal effects of cow's milk consumption in humans, this review presents milk as a signaling system of mammalian evolution that activates the nutrient-sensitive kinase mechanistic target of rapamycin complex 1 (mTORC1), the pivotal regulator of translation. Milk, a mammary gland-derived secretory product, is required for species-specific gene-nutrient interactions that promote appropriate growth and development of the newborn mammal. This signaling system is highly conserved and tightly controlled by the lactation genome. Milk is sufficient to activate mTORC1, the crucial regulator of protein, lipid, and nucleotide synthesis orchestrating anabolism, cell growth and proliferation. To fulfill its mTORC1-activating function, milk delivers four key metabolic messengers: (1) essential branched-chain amino acids (BCAAs); (2) glutamine; (3) palmitic acid; and (4) bioactive exosomal microRNAs, which in a synergistical fashion promote mTORC1-dependent translation. In all mammals except Neolithic humans, postnatal activation of mTORC1 by milk intake is restricted to the postnatal lactation period. It is of critical concern that persistent hyperactivation of mTORC1 is associated with aging and the development of age-related disorders such as obesity, type 2 diabetes mellitus, cancer, and neurodegenerative diseases. Persistent mTORC1 activation promotes endoplasmic reticulum (ER) stress and drives an aimless quasi-program, which promotes aging and age-related diseases.

A pilot study to investigate if New Zealand men with prostate cancer benefit from a Mediterranean-style diet

Carcinoma of the prostate is the most commonly diagnosed malignancy and the third leading cause of mortality in New Zealand men, making it a significant health issue in this country. Global distribution patterns suggest that diet and lifestyle factors may be linked to the development and progression of this cancer. Twenty men with diagnosed prostate cancer adhered to a Mediterranean diet, with specific adaptations, for three months. Prostate-specific antigen, C-reactive protein and DNA damage were evaluated at baseline and after three months of following the diet. Dietary data were collated from diet diaries and an adaptation of a validated Mediterranean diet questionnaire. A significant reduction in DNA damage compared to baseline was apparent, with particular benefit noted for overall adherence to the diet (p = 0.013), increased intake of folate (p = 0.023), vitamin C (p = 0.007), legumes (p = 0.004) and green tea (p = 0.002). Higher intakes of red meat and dairy products were inversely associated with DNA damage (p = 0.003 and p = 0.008 respectively). The results from this small feasibility study suggest that a high-antioxidant diet, modelled on Mediterranean traditions, may be of benefit for men with prostate cancer. Protection against DNA damage appears to be associated with the diet implemented, ostensibly due to reduction in reactive oxidant species. These findings warrant further exploration in a longer trial, with a larger cohort.

Adult lactose digestion status and effects on disease

BACKGROUND

Adult assimilation of lactose divides humans into dominant lactase-persistent and recessive nonpersistent phenotypes.

OBJECTIVES

To review three medical parameters of lactose digestion, namely: the changing concept of lactose intolerance; the possible impact on diseases of microbial adaptation in lactase-nonpersistent populations; and the possibility that the evolution of lactase has influenced some disease pattern distributions.

METHODS

A PubMed, Google Scholar and manual review of articles were used to provide a narrative review of the topic.

RESULTS

The concept of lactose intolerance is changing and merging with food intolerances. Microbial adaptation to regular lactose consumption in lactase-nonpersistent individuals is supported by limited evidence. There is evidence suggestive of a relationship among geographical distributions of latitude, sunhine exposure and lactase proportional distributions worldwide.

DISCUSSION

The definition of lactose intolerance has shifted away from association with lactose maldigestion. Lactose sensitivity is described equally in lactose digesters and maldigesters. The important medical consequence of withholding dairy foods could have a detrimental impact on several diseases; in addition, microbial adaptation in lactase-nonpersistent populations may alter risk for some diseases. There is suggestive evidence that the emergence of lactase persistence, together with human migrations before and after the emergence of lactase persistence, have impacted modern-day diseases.

CONCLUSIONS

Lactose maldigestion and lactose intolerance are not synonymous. Withholding dairy foods is a poor method to treat lactose intolerance. Further epidemiological work could shed light on the possible effects of microbial adaptation in lactose maldigesters. The evolutionary impact of lactase may be still ongoing.

An investigation into the association between DNA damage and dietary fatty acid in men with prostate cancer

Prostate cancer is a growing problem in New Zealand and worldwide, as populations adopt a Western style dietary pattern. In particular, dietary fat is believed to be associated with oxidative stress, which in turn may be associated with cancer risk and development. In addition, DNA damage is associated with the risk of various cancers, and is regarded as an ideal biomarker for the assessment of the influence of foods on cancer. In the study presented here, 20 men with prostate cancer adhered to a modified Mediterranean style diet for three months. Dietary records, blood fatty acid levels, prostate specific antigen, C-reactive protein and DNA damage were assessed pre- and post-intervention. DNA damage was inversely correlated with dietary adherence (p = 0.013) and whole blood monounsaturated fatty acids (p = 0.009) and oleic acid (p = 0.020). DNA damage was positively correlated with the intake of dairy products (p = 0.043), red meat (p = 0.007) and whole blood omega-6 polyunsaturated fatty acids (p = 0.015). Both the source and type of dietary fat changed significantly over the course of the dietary intervention. Levels of DNA damage were correlated with various dietary fat sources and types of dietary fat.

Dairy products, calcium, and prostate cancer risk: a systematic review and meta-analysis of cohort studies

BACKGROUND

Dairy product and calcium intakes have been associated with increased prostate cancer risk, but whether specific dairy products or calcium sources are associated with risk is unclear.

OBJECTIVE

In the Continuous Update Project, we conducted a meta-analysis of prospective studies on intakes of dairy products and calcium and prostate cancer risk.

DESIGN

PubMed and several other databases were searched up to April 2013. Summary RRs were estimated by using a random-effects model.

RESULTS

Thirty-two studies were included. Intakes of total dairy products [summary RR: 1.07 (95% CI: 1.02, 1.12; n = 15) per 400 g/d], total milk [summary RR: 1.03 (95% CI: 1.00, 1.07; n = 14) per 200 g/d], low-fat milk [summary RR: 1.06 (95% CI: 1.01, 1.11; n = 6) per 200 g/d], cheese [summary RR: 1.09 (95% CI: 1.02, 1.18; n = 11) per 50 g/d], and dietary calcium [summary RR: 1.05 (95% CI: 1.02, 1.09; n = 15) per 400 mg/d] were associated with increased total prostate cancer risk. Total calcium and dairy calcium intakes, but not nondairy calcium or supplemental calcium intakes, were also positively associated with total prostate cancer risk. Supplemental calcium was associated with increased risk of fatal prostate cancer.

CONCLUSIONS

High intakes of dairy products, milk, low-fat milk, cheese, and total, dietary, and dairy calcium, but not supplemental or nondairy calcium, may increase total prostate cancer risk. The diverging results for types of dairy products and sources of calcium suggest that other components of dairy rather than fat and calcium may increase prostate cancer risk. Any additional studies should report detailed results for subtypes of prostate cancer.

Prostate cancer and the influence of dietary factors and supplements: a systematic review

Background

Prostate cancer is the second most common cause of cancer worldwide after lung cancer. There is increasing evidence that diet and lifestyle plays a crucial role in prostate cancer biology and tumourigenesis. Prostate cancer itself represents a good model of cancer in which to look for chemopreventive agents due to the high disease prevalence, slowly progressive nature, and long latency period. Dietary agents have gained considerable attention, often receiving much publicity in the media.

Aim

To review the key evidence available for potential chemopreventive nutrients.

Methods

The methodology for this review involved a PubMed search from 1990 to 2013 using the key-words “diet and prostate cancer”, “nutrition and prostate cancer”, “dietary factors and prostate cancer”, “prostate cancer epidemiology”, “prostate cancer prevention”, “prostate cancer progression”.

Results

Red meat, dietary fat and milk intake should be minimised as they appear to increase the risk of prostate cancer. Fruit and vegetables and polyphenols may be preventive in prostate cancer, but further studies are needed to draw more solid conclusions and to clarify their role in patients with an established diagnosis of prostate cancer. Selenium and vitamin supplements cannot be advocated for the prevention of prostate cancer and indeed higher doses may be associated with a worse prognosis. There is no specific evidence regarding benefits of probiotics or prebiotics in prostate cancer.

Conclusions

From the wealth of evidence available, many recommendations can be made although more randomised control trials are required. These need to be carefully designed due to the many confounding factors and heterogeneity of the population.

Milk consumption throughout life and bone mineral content and density in elderly men and women

Association between bone mineral density and bone mineral content in old age and milk consumption in adolescence, midlife, and old age was assessed. The association was strongest for milk consumption in midlife: those drinking milk daily or more often had higher bone mineral density and content in old age than those drinking milk seldom or never.

INTRODUCTION

The role of lifelong milk consumption for bone mineral density (BMD) and bone mineral content (BMC) in old age is not clear. Here we assess the association between hip BMD and BMC in old age and milk consumption in adolescence, midlife, and current old age.

METHODS

Participants of the Age, Gene/Environment Susceptibility-Reykjavik Study, aged 66-96 years (N = 4,797), reported retrospective milk intake during adolescence and midlife as well as in current old age, using a validated food frequency questionnaire. BMC of femoral neck and trochanteric area was measured by volumetric quantitative computed tomography and BMD obtained. Association was assessed using linear regression models. Differences in BMC, bone volume, and BMD in relation to milk intake were portrayed as gender-specific Z-scores.

RESULTS

Men consuming milk ≥ once/day during midlife had 0.21 higher Z-scores for BMD and 0.18 for BMC in femoral neck (95 % confidence interval 0.05-0.39 and 0.01-0.35, respectively) compared with < once/week. Results were comparable for trochanter. For women the results were similar, with slightly lower differences according to midlife milk consumption. For current and adolescent milk consumption, differences in Z-scores were smaller and only reached statistical significance in the case of BMD for current consumption in men, while this association was less pronounced for BMC.

CONCLUSIONS

Our data suggest that regular milk consumption throughout life, from adolescence to old age, is associated with higher BMC and BMD in old age, with no differences seen in bone volume. The strongest associations are seen for midlife milk consumption in both genders.

Cancer incidence among population utilizing geothermal hot water: a census-based cohort study

The aim of the study was to assess whether utilization of geothermal hot-water is associated with risk of cancer. The cohort from census was followed from 1981 to 2010 in nation-wide death and cancer registries. The moving apart of American-Eurasian tectonic plates, observed in Iceland, results in high volcanic activity. The definition of the study populations was based on geological information. The target population was inhabitants of communities located on bedrock younger than 3.3 million years, utilizing hot-water supply generated from geothermal wells since 1972. The two reference populations were inhabitants of communities without this hot-water supply located on areas with less volcanic/geothermal activity, and bedrock older than 3.3 million years. Hazard ratio (HR), and 95% confidence intervals (CI) were adjusted for age, gender, education, housing, reproductive factors and smoking. HR in the geothermal hot-water supply areas for all cancer was 1.15 (95% CI 1.05-1.25) as compared with nongeothermal areas. The HR for breast cancer was 1.40 (1.12-1.75), prostate cancer 1.61 (1.29-2.00), kidney cancer 1.64 (1.11-2.41), lymphatic and haematopoietic tissue cancers 1.45 (1.08-1.95), and for basal cell carcinoma (BCC) of the skin 1.46 (1.16-1.82). Positive exposure-response relations were observed between the risk of these cancers and the degree of volcanic/geothermal activity in the reference areas. Increased incidence of all cancers, breast, prostate, kidney cancer and BCC of the skin was found among the population utilizing geothermal hot-water for decades. More precise information on exposure is needed in future studies.

Consumption of fish products across the lifespan and prostate cancer risk

Objective

To examine whether fish and fish oil consumption across the lifespan is associated with a lower risk of prostate cancer.

Design

The study was nested among 2268 men aged 67–96 years in the AGES-Reykjavik cohort study. In 2002 to 2006, dietary habits were assessed, for early life, midlife and later life using a validated food frequency questionnaire. Participants were followed for prostate cancer diagnosis and mortality through 2009 via linkage to nationwide cancer- and mortality registers. Adjusting for potential confounders, we used regression models to estimate odds ratios (ORs) and hazard ratios (HRs) for prostate cancer according to fish and fish oil consumption.

Results

Among the 2268 men, we ascertained 214 prevalent and 133 incident prostate cancer cases, of which 63 had advanced disease. High fish consumption in early- and midlife was not associated with overall or advanced prostate cancer. High intake of salted or smoked fish was associated with a 2-fold increased risk of advanced prostate cancer both in early life (95% CI: 1.08, 3.62) and in later life (95% CI: 1.04, 5.00). Men consuming fish oil in later life had a lower risk of advanced prostate cancer [HR (95%CI): 0.43 (0.19, 0.95)], no association was found for early life or midlife consumption.

Conclusions

Salted or smoked fish may increase risk of advanced prostate cancer, whereas fish oil consumption may be protective against progression of prostate cancer in elderly men. In a setting with very high fish consumption, no association was found between overall fish consumption in early or midlife and prostate cancer risk.

Prostate cancer: is it time to expand the research focus to early-life exposures?

Although the contribution of lifestyle and environment (non-genetic factors) to prostate carcinogenesis is indicated by international variation in prostate cancer occurrence and migration studies, no conclusive modifiable risk factors have yet been identified. One possible reason for this may be the dearth of epidemiological research on exposures experienced early in life, when the immature prostate may be more susceptible to carcinogenic exposures. In this Opinion article, we summarize the rationale for studying early-life exposures, describe the small body of early-life research and its associated challenges, and point to solutions for future research.

Whole milk intake is associated with prostate cancer-specific mortality among U.S. male physicians

Previous studies have associated higher milk intake with greater prostate cancer (PCa) incidence, but little data are available concerning milk types and the relation between milk intake and risk of fatal PCa. We investigated the association between intake of dairy products and the incidence and survival of PCa during a 28-y follow-up. We conducted a cohort study in the Physicians' Health Study (n = 21,660) and a survival analysis among the incident PCa cases (n = 2806). Information on dairy product consumption was collected at baseline. PCa cases and deaths (n = 305) were confirmed during follow-up. The intake of total dairy products was associated with increased PCa incidence [HR = 1.12 (95% CI: 0.93, 1.35); >2.5 servings/d vs. ≤0.5 servings/d]. Skim/low-fat milk intake was positively associated with risk of low-grade, early stage, and screen-detected cancers, whereas whole milk intake was associated only with fatal PCa [HR = 1.49 (95% CI: 0.97, 2.28); ≥237 mL/d (1 serving/d) vs. rarely consumed]. In the survival analysis, whole milk intake remained associated with risk of progression to fatal disease after diagnosis [HR = 2.17 (95% CI: 1.34, 3.51)]. In this prospective cohort, higher intake of skim/low-fat milk was associated with a greater risk of nonaggressive PCa. Most importantly, only whole milk was consistently associated with higher incidence of fatal PCa in the entire cohort and higher PCa-specific mortality among cases. These findings add further evidence to suggest the potential role of dairy products in the development and prognosis of PCa.

The impact of cow's milk-mediated mTORC1-signaling in the initiation and progression of prostate cancer

Prostate cancer (PCa) is dependent on androgen receptor signaling and aberrations of the PI3K-Akt-mTORC1 pathway mediating excessive and sustained growth signaling. The nutrient-sensitive kinase mTORC1 is upregulated in nearly 100% of advanced human PCas. Oncogenic mTORC1 signaling activates key subsets of mRNAs that cooperate in distinct steps of PCa initiation and progression. Epidemiological evidence points to increased dairy protein consumption as a major dietary risk factor for the development of PCa. mTORC1 is a master regulator of protein synthesis, lipid synthesis and autophagy pathways that couple nutrient sensing to cell growth and cancer. This review provides evidence that PCa initiation and progression are promoted by cow´s milk, but not human milk, stimulation of mTORC1 signaling. Mammalian milk is presented as an endocrine signaling system, which activates mTORC1, promotes cell growth and proliferation and suppresses autophagy. Naturally, milk-mediated mTORC1 signaling is restricted only to the postnatal growth phase of mammals. However, persistent consumption of cow´s milk proteins in humans provide highly insulinotropic branched-chain amino acids (BCAAs) provided by milk´s fast hydrolysable whey proteins, which elevate postprandial plasma insulin levels, and increase hepatic IGF-1 plasma concentrations by casein-derived amino acids. BCAAs, insulin and IGF-1 are pivotal activating signals of mTORC1. Increased cow´s milk protein-mediated mTORC1 signaling along with constant exposure to commercial cow´s milk estrogens derived from pregnant cows may explain the observed association between high dairy consumption and increased risk of PCa in Westernized societies. As well-balanced mTORC1-signaling plays an important role in appropriate prostate morphogenesis and differentiation, exaggerated mTORC1-signaling by high cow´s milk consumption predominantly during critical growth phases of prostate development and differentiation may exert long-term adverse effects on prostate health. Attenuation of mTORC1 signaling by contemporary Paleolithic diets and restriction of dairy protein intake, especially during mTORC1-dependent phases of prostate development and differentiation, may offer protection from the most common dairy-promoted cancer in men of Western societies.

Rye bread consumption in early life and reduced risk of advanced prostate cancer

OBJECTIVE

To determine whether consumption of whole-grain rye bread, oatmeal, and whole-wheat bread, during different periods of life, is associated with risk of prostate cancer (PCa).

METHODS

From 2002 to 2006, 2,268 men, aged 67-96 years, reported their dietary habits in the AGES-Reykjavik cohort study. Dietary habits were assessed for early life, midlife, and current life using a validated food frequency questionnaire. Through linkage to cancer and mortality registers, we retrieved information on PCa diagnosis and mortality through 2009. We used regression models to estimate odds ratios (ORs) and hazard ratios (HRs) for PCa according to whole-grain consumption, adjusted for possible confounding factors including fish, fish liver oil, meat, and milk intake.

RESULTS

Of the 2,268 men, 347 had or were diagnosed with PCa during follow-up, 63 with advanced disease (stage 3+ or died of PCa). Daily rye bread consumption in adolescence (vs. less than daily) was associated with a decreased risk of PCa diagnosis (OR = 0.76, 95 % confidence interval (CI): 0.59-0.98) and of advanced PCa (OR = 0.47, 95 % CI: 0.27-0.84). High intake of oatmeal in adolescence (≥5 vs. ≤4 times/week) was not significantly associated with risk of PCa diagnosis (OR = 0.99, 95 % CI: 0.77-1.27) nor advanced PCa (OR = 0.67, 95 % CI: 0.37-1.20). Midlife and late life consumption of rye bread, oatmeal, or whole-wheat bread was not associated with PCa risk.

CONCLUSION

Our results suggest that rye bread consumption in adolescence may be associated with reduced risk of PCa, particularly advanced disease.