Relationship between calcium, lactose, vitamin D, and dairy products and ovarian cancer

Few prospective studies of the relationship between intake of dairy foods, calcium, vitamin D, and lactose and ovarian cancer have been conducted, and results have been largely inconsistent. Two recent studies found significant increased risk with frequent dairy consumption and perhaps with high intakes of calcium or lactose. The authors investigated the association between these foods and nutrients and ovarian cancer risk among 31,925 subjects in the Breast Cancer Detection Demonstration Project follow-up cohort. Multivariable (MV) relative risks (RRs) adjusted for age, parity, and other factors were estimated using Cox proportional hazards models. Over an average follow-up of 8.3 yr, 146 incident ovarian cancer cases were confirmed. Higher intakes of total dairy food (comparing four or more servings per day vs. less than one serving per day) were associated with a statistically significant decreased risk of ovarian cancer, although the trend was not significant (MV RR = 0.42; 95% confidence interval (CI) = 0.20-0.89; P for trend = 0.07). Comparing extreme quartiles, we observed a statistically nonsignificant inverse association between high dietary calcium intake and ovarian cancer (RR = 0.67; 95% CI = 0.43, 1.04; P for trend = 0.08). No statistically significant relations were found for consumption of specific dairy foods, lactose, or vitamin D and ovarian cancer risk. The possibility of a decreased risk of ovarian cancer for dietary calcium merits further evaluation.     

Milk and lactose intakes and ovarian cancer risk in the Swedish Mammography Cohort

BACKGROUND: High intakes of dairy products and of the milk sugar lactose have been hypothesized to increase ovarian cancer risk, but prospective data are scarce. OBJECTIVE: We examined the association between intakes of dairy products and lactose and the risk of total epithelial ovarian cancer and its subtypes. DESIGN: This was a prospective population-based cohort study of 61 084 women aged 38-76 y who were enrolled in the Swedish Mammography Cohort. Diet was assessed in 1987-1990 with the use of a self-administered food-frequency questionnaire. During an average follow-up of 13.5 y, 266 women were diagnosed with invasive epithelial ovarian cancer; 125 of those women had serous ovarian cancer. RESULTS: After adjustment for potential confounders, women who consumed >/=4 servings of total dairy products/d had a risk of serous ovarian cancer (rate ratio: 2.0; 95% CI: 1.1, 3.7; P for trend = 0.06) twice that of women who consumed <2 servings/d. No significant association was found for other subtypes of ovarian cancer. Milk was the dairy product with the strongest positive association with serous ovarian cancer (rate ratio comparing consuming >/=2 glasses milk/d with consuming milk never or seldom: 2.0; 95% CI: 1.1, 3.7; P for trend = 0.04). We observed a positive association between lactose intake and serous ovarian cancer risk (P for trend = 0.006). CONCLUSIONS: Our data indicate that high intakes of lactose and dairy products, particularly milk, are associated with an increased risk of serous ovarian cancer but not of other subtypes of ovarian cancer. Future studies should consider ovarian cancer subtypes separately.     

Association between soy products,fruits, vegetables,and dairy products and gastric cancer risk in Helicobacter pylori-infected subjects: a case-control study in Korea

BACKGROUND/OBJECTIVESConsumption of certain protective foods may help inhibit Helicobacter pylori (H. pylori) associated gastric pathologies. However, studies conducted to assess the efficacy of protective foods in H. pylori-infected subjects are either limited or inconsistent. This study evaluated the association of individual or a combination of protective foods on the incidence of gastric cancer (GC) in H. pylori-positive subjects through a case-control study.MATERIALS/METHODSSubjects aged 20–79 years were selected from 2 hospitals between December 2002 and September 2006. In total, 134 patients and 212 controls tested positive for H. pylori infection. Among these, we included 82 pairs of cases and controls matched by sex, age (± 5 years), enrollment period (± 1 years), and hospital.RESULTSA higher intake of soy products was associated with a significantly lower risk of GC than a lower intake of soy products (odds ratio [OR] = 0.37, 95% confidence interval [CI] = 0.14–0.96). Additionally, a higher fruit intake resulted in a significantly lower risk of GC than a lower fruit intake (OR = 0.35, 95% CI = 0.13–0.94). A combination of food groups was evaluated, and a lower risk of GC was observed with a high intake of both soy products and fruits (OR = 0.20, 95% CI = 0.06–0.67), high intake of soy and dairy products (OR = 0.28, 95% CI = 0.10–0.78) and high intake of fruits and dairy products (OR = 0.28, 95% CI = 0.09–0.83).CONCLUSIONSA high intake of soy products or fruits was associated with a lower risk of GC. A combination of soy products or fruits with dairy products was associated with a lower risk of GC. A balanced intake of soy products, fruits, and dairy products may help reduce GC risk.     

Dairy products, calcium, and prostate cancer risk in the Physicians' Health Study

BACKGROUND: A high calcium intake, mainly from dairy products, may increase prostate cancer risk by lowering concentrations of 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)], a hormone thought to protect against prostate cancer. The results of epidemiologic studies of this hypothesis are inconclusive. OBJECTIVE: We investigated the association between dairy product and calcium intakes and prostate cancer risk in the Physicians' Health Study, a cohort of male US physicians. DESIGN: At baseline, the men answered abbreviated dietary questionnaires. During 11 y of follow-up, we documented 1012 incident cases of prostate cancer among 20885 men. We estimated dairy calcium intake on the basis of consumption of 5 major dairy products and used logistic regression to estimate relative risk. RESULTS: At baseline, men who consumed >600 mg Ca/d from skim milk had lower plasma 1,25(OH)(2)D(3) concentrations than did those consuming < or =150 mg Ca/d [71 compared with 85 pmol/L (30.06 compared with 35.64 pg/mL); P = 0.005]. Compared with men consuming < or =0.5 daily servings of dairy products, those consuming >2.5 servings had a multivariate relative risk of prostate cancer of 1.34 (95% CI: 1.04, 1.71) after adjustment for baseline age, body mass index, smoking, exercise, and randomized treatment assignment in the original placebo-controlled trial. Compared with men consuming < or =150 mg Ca/d from dairy products, men consuming >600 mg/d had a 32% higher risk of prostate cancer (95% CI: 1.08, 1.63). CONCLUSIONS: These results support the hypothesis that dairy products and calcium are associated with a greater risk of prostate cancer.     

Association of oral contraceptive use, other contraceptive methods, and infertility with ovarian cancer risk

Although oral contraceptives are protective for ovarian cancer, it is unclear how long this protection persists. The authors prospectively assessed this question as well as associations of other, less studied contraceptive methods (tubal ligation, rhythm method, diaphragm, condoms, intrauterine device, foam, spousal vasectomy) and infertility with ovarian cancer risk among 107,900 participants in the US Nurses' Health Study. During 28 years of follow-up (1976-2004), 612 cases of invasive epithelial ovarian cancer were confirmed. Duration of oral contraceptive use was inversely associated with risk (p-trend = 0.02), but no clear trend was observed for years since last use. However, for women using oral contraceptives for >5 years, the rate ratio for ovarian cancer for 20 years since last use (rate ratio (RR) = 0.92, 95% CI: 0.61, 1.39). Tubal ligation (RR = 0.66, 95% CI: 0.50, 0.87) was associated with decreased ovarian cancer risk, whereas intrauterine device use (RR = 1.76, 95% CI: 1.08, 2.85) and infertility (RR = 1.36, 95% CI: 1.07, 1.75) were associated with an increased risk. Results suggest that the beneficial effect of oral contraceptives on ovarian cancer risk attenuates after 20 years since last use. Furthermore, tubal ligation, intrauterine device use, and infertility were associated with ovarian cancer risk.     

Calcium,dairy products,and colorectal cancer

The relation between calcium intake, estimated from frequency of use of 29 food items, and colorectal cancer risk was analyzed using data from a case‐control study conducted in Northern Italy. The study was conducted on 558 cases of colon cancer, 352 cases of rectal cancer, and 1,032 controls admitted to the hospital for acute, nonneoplastic, nondigestive tract disorders (39% with traumas, 17% nontraumatic orthopedic diseases, 25% acute surgical conditions, 19% other miscellaneous disorders). There was no appreciable trend in risk of colon or rectal cancer in relation to measures of calcium intake. The multivariate relative risk (adjusted for age, sex, education, area of residence, and consumption of selected indicator foods) for highest versus’ lowest quintile was 1.1 for colon and 1.0 for rectum. Likewise, there was no appreciable difference between cases and controls with reference to frequency of consumption of the two major calcium‐containing foods (milk and cheese), with relative risk for the highest level of intake between 0.9 and 1.2. This study indicates that little or no protection on large bowel cancer risk is provided by dairy products or calcium intake in a range of 0.5–1.5 g per day.     

Calcium, dairy products, and colorectal cancer

The relation between calcium intake, estimated from frequency of use of 29 food items, and colorectal cancer risk was analyzed using data from a case-control study conducted in Northern Italy. The study was conducted on 558 cases of colon cancer, 352 cases of rectal cancer, and 1,032 controls admitted to the hospital for acute, nonneoplastic, nondigestive tract disorders (39% with traumas, 17% nontraumatic orthopedic diseases, 25% acute surgical conditions, 19% other miscellaneous disorders). There was no appreciable trend in risk of colon or rectal cancer in relation to measures of calcium intake. The multivariate relative risk (adjusted for age, sex, education, area of residence, and consumption of selected indicator foods) for highest versus lowest quintile was 1.1 for colon and 1.0 for rectum. Likewise, there was no appreciable difference between cases and controls with reference to frequency of consumption of the two major calcium-containing foods (milk and cheese), with relative risk for the highest level of intake between 0.9 and 1.2. This study indicates that little or no protection on large bowel cancer risk is provided by dairy products or calcium intake in a range of 0.5-1.5 g per day.     

The influence of lactose consumption on the association of oral contraceptive use and ovarian cancer risk

The authors investigated the joint effects of diet and oral contraceptive use on ovarian cancer risk in 194 white women aged 65 years or less with epithelial ovarian cancer and 193 age- and residence-matched controls in Boston between 1984 and 1987 by using in-person interviews and self-administered food frequency questionnaires. Use of oral contraceptives for 3 months or more was associated with a modest protective effect for ovarian cancer (odds ratio (OR) = 0.7, 95 percent confidence interval (CI) 0.5-1.1). In women who consumed 11 g or less per day of lactose, use of oral contraceptives for 3 months or more was associated with a nonsignificant increased risk (OR = 1.6, 95 percent CI 0.8-3.2). In women who consumed more than 11 g per day of lactose, use of oral contraceptives for 3 months or more was associated with a substantially decreased risk of ovarian cancer (OR = 0.3, 95 percent CI 0.1-0.7). Within this group, the strongest association occurred with more than 4 years of total oral contraceptive use (OR = 0.2, 95 percent CI 0.1-0.6) and in those who had more than 2 years of oral contraceptive use after age 30 years (OR = 0.1, 95 percent CI 0.03-0.4). These results suggest that, with respect to ovarian cancer, lactose users may be the most likely to benefit from oral contraceptive use and that the benefit may be strongest when oral contraceptive use occurs after age 30 years.     

Dietary meat,dairy products,fat, and cholesterol and pancreatic cancer risk in a prospective study

Case-control studies suggest that meat and cholesterol intakes may be related to elevated risks of pancreatic cancer. Few prospective studies have examined associations between diet and pancreatic cancer, although in one recent study saturated fat consumption was related to higher risk. In a cohort of US women, the authors confirmed 178 pancreatic cancer cases over 18 years of follow-up. A mailed 61-item food frequency questionnaire was self-administered at baseline, and health and lifestyle variables were updated biennially. Analyses were performed using Cox proportional hazards models to adjust for potential confounders. Intakes of total fat, different types of fats, and cholesterol were not associated with pancreatic cancer risk. Similarly, total meat, red meat, and dairy products were not related to risk. Individual food items contributing to intakes of total meat and dairy products, as well as fish and eggs, did not reveal any specific association. Updating dietary exposures by using questionnaires from 1980, 1984, 1986, and 1990 produced similar findings. The authors' data do not support previous findings that meat or saturated fat intakes are related to pancreatic cancer risk. Future prospective studies should examine the influence of cooking practices as well as other dietary habits on the risk of pancreatic cancer.     

Consumption of dairy products and the risk of breast cancer: a review of the literature

Differences in eating patterns and breast cancer rates across countries suggest that several dietary components, including dairy products, could affect breast cancer risk. However, dairy products are a diverse food group in terms of the factors that could potentially influence risk. Some dairy products, such as whole milk and many types of cheese, have a relatively high saturated fat content, which may increase risk. Moreover, milk products may contain contaminants such as pesticides, which have carcinogenic potential, and growth factors such as insulin-like growth factor I, which have been shown to promote breast cancer cell growth. In contrast, the calcium and vitamin D contents of dairy products have been hypothesized to reduce breast cancer risk. We reviewed the current epidemiologic literature on the relation between dairy product intakes and breast cancer risk, focusing primarily on the results of cohort and case-control studies. Most of the studies reviewed showed no consistent pattern of increased or decreased breast cancer risk with a high consumption of dairy products as a whole or when broken down into high-fat and low-fat dairy products, milk, cheese, or butter. Measurement error may have attenuated any modest association with dairy products. The available epidemiologic evidence does not support a strong association between the consumption of milk or other dairy products and breast cancer risk.     

Dairy products, calcium intake, and breast cancer risk: a case-control study in China

The results of dairy food consumption and breast cancer risk are conflicting, and their relationship has not previously been studied in China. The objective of this study is to examine the association between dairy products, calcium intake, and breast cancer risk among Chinese women. A hospital-based case-control study was conducted among Chinese women in the Guangdong province from June 2007 to August 2008. Four hundred and thirty-eight consecutively recruited cases with primary breast cancer were frequency-matched to 438 controls on age and residence. Dietary intake information was collected by interviewers using a validated food frequency questionnaire. Odds ratios (ORs) and 95% confidence interval (CI) were estimated using unconditional multiple logistic regression adjusted for various potential confounders. We observed a statistically significant inverse association of dietary calcium intake with breast cancer risk, with the adjusted OR (95% CI) of 0.35 (0.22-0.56) comparing the highest with the lowest quartile. No significant association was found between dairy products measured either by dry weight of dairy product or dairy product protein intake and breast cancer risk. Our study supports a protective effect of high intake of dietary calcium on breast cancer risk, and no association with dairy product intake.     

Consumption of dairy products and cancer risks

BACKGROUND: Relationships between consumption of dairy products and death from various types of cancer are largely unknown. METHODS: Between April 1992 and July 1995, a baseline survey was conducted for 11,349 residents in 12 communities in Japan, which included collection of demographic data and a self-administered food-frequency questionnaire inquiring about three dairy products: milk, butter and yogurt. The subjects were followed prospectively until 2002. Causes of death were identified using death certificates. Hazard ratios (HRs) and their 95% confidence intervals (CIs) for each dairy product were calculated using Cox's proportional hazard models. RESULTS: Among eight common cancers, only deaths from hematopoietic neoplasm (n=14) were significantly associated with consumption of butter (HR=5.11, 95% CI: 1.40-18.62), though they exhibited a nearly-significant association with milk consumption (HR=3.17, 95% CI: 0.99-10.17), independent of age and sex. Consumption of milk and butter was significantly associated with non-lymphoma deaths (n=9) when adjusted for age and sex (HR=9.86, 95% CI: 1.23-79.19 for milk; and HR=10.04, 95% CI: 2.39-42.18 for butter). CONCLUSION: The frequencies of butter consumption, and probably that of milk, were correlated with death from hematopoietic neoplasm, particularly from non-lymphomas.     

Intake of dairy fat and dairy products, and risk of myocardial infarction: a case-control study

The role of dairy fat in the aetiology of myocardial infarction (MI) is controversial. The aim of this study was to evaluate the association between intake of dairy fat and dairy products, and risk of a first acute MI. A total of 111 MI patients with a first acute MI and 107 population controls (men and women, age 45 75 years) were studied. Diet was assessed using a 180-item food frequency questionnaire. The MI cases had higher intake of total fat, but lower intake of saturated fat and dairy fat than the control persons. No effect of dairy fat or saturated fat on the odds ratio for MI was observed, however. A significant inverse trend in odds of MI for intake of cheese was observed, but the trend was no longer significant after adjustment for smoking. The results suggest that intake of fat from dairy products may not be associated with increased risk of having a first MI. The healthy control persons had a diet that differed from the diet of the MI patients in many aspects, and dairy products were a part of this diet. This may have protected them from having a first MI.     

Consumption of dairy products and risk of Parkinson's disease

The authors prospectively investigated the association between intake of dairy products and risk of Parkinson's disease among 57,689 men and 73,175 women from the American Cancer Society's Cancer Prevention Study II Nutrition Cohort. A total of 250 men and 138 women with Parkinson's disease were identified during follow-up (1992-2001). Dairy product consumption was positively associated with risk of Parkinson's disease: Compared with the lowest intake quintile, the corresponding relative risks for quintiles 2-5 were 1.4, 1.4, 1.4, and 1.6 (95 percent confidence interval (CI): 1.1, 2.2; p for trend = 0.05). A higher risk among dairy product consumers was found in both men and women, although the association in women appeared nonlinear. Meta-analysis of all prospective studies confirmed a moderately elevated risk of Parkinson's disease among persons with high dairy product consumption: For extreme intake categories, relative risks were 1.6 (95 percent CI: 1.3, 2.0) for both sexes, 1.8 for men (95 percent CI: 1.4, 2.4), and 1.3 for women (95 percent CI: 0.8, 2.1). These data suggest that dairy consumption may increase the risk of Parkinson's disease, particularly in men. More studies are needed to further examine these findings and to explore underlying mechanisms.     

Association of galactose-1-phosphate uridyltransferase activity and N314D genotype with the risk of ovarian cancer

Deficiency in the galactose-1-phosphate uridyltransferase (GALT) enzyme results in accumulation of galactose and its metabolites in the ovary (Am J Epidemiol 1989;130:904-10). Galactose may raise gonadotropin levels, resulting in proliferation of ovarian epithelium. In 1993-1999, the authors conducted a population-based case-control study of ovarian cancer in Hawaii and Los Angeles, California, to examine the hypothesis that reduced GALT activity is associated with an increased risk of ovarian cancer. A total of 239 ovarian cancer cases and 244 population controls were interviewed. A blood sample was collected to measure levels of GALT and to assay for the N314D (A940G) polymorphism of the GALT gene. Covariate-adjusted mean GALT activity was similar between cases (23.8 micro mol per hour/g hemoglobin (Hb)) and controls (23.7 micro mol per hour/g Hb) (p = 0.83). No evidence was found for a dose-response relation between the odds ratios for ovarian cancer and GALT activity or the ratio of lactose intake to GALT activity. The risk associated with the presence of at least one variant Asp314 allele was 0.77 (95% confidence interval: 0.42, 1.41). This study did not support the hypothesis that reduced galactose metabolism is a risk factor for ovarian cancer, although increased GALT activity attenuated the inverse association of oral contraceptive pill use with risk.     

Interactions of lactose with calcium, magnesium and zinc in rats

The effects of lactose on utilization of calcium, magnesium and zinc were examined in two studies. In study 1, weanling male rats were fed either nonfat dry milk or CaHPO4, dolomite or a calcium chelate with supplemental lactose or sucrose for 27 d. In study 2, weanling male rats were fed diets based on milk or lactose-hydrolyzed milk for 28 d or in one meal labeled with 45Ca. Rats fed the lactose-hydrolyzed milk rather than the untreated milk digested their diet more completely, apparently absorbed total calcium and 45Ca less efficiently, and lost more calcium in urine but retained similar amounts of total calcium and 45Ca in bone. The effect of lactose hydrolysis on the absorption of 45Ca was similar whether rats were fed only one meal of the milk-based diets or were fed the diets chronically. The rats fed supplemental lactose (study 1) or unhydrolyzed milk (study 2) retained more magnesium and zinc in bone.