Dairy Consumption and Incidence of Breast Cancer in the 'Seguimiento Universidad de Navarra' (SUN) Project

Common Misconceptions about Diet and Breast Cancer: An Unclear Issue to Dispel

Breast cancer (BC) constitutes a prevalent health condition among women. Recent years have witnessed the identification of dietary proto-oncogenic factors that deserve attention. Besides the well-known role of alcohol and red and processed meat in BC development, the impact of other dietary components remains unclear. Our narrative review aims to explore the diet-BC relationship, focusing on sugar, dairy, and soy consumption. We conducted a PubMed literature search covering the last decade (2013-2023) and included 35 papers. We found limited evidence on the association between high sugar intake and BC incidence. On the other hand, dairy and soy consumption displayed a protective effect in the majority of the analyzed papers. However, a significant degree of heterogeneity was reported among the results. Menopausal status and the specific BC molecular subtypes were the main factors influencing the interpretation of the results. Exploring dietary factors and BC revealed inconsistencies: high glycemic index post-menopause may be a risk factor, while sugar-sweetened drinks and artificial sweeteners yielded conflicting results; fermented dairy showed potential benefits, non-fermented dairy presented inconsistent findings; soy impact on BC varied according to molecular subtype, with some studies suggesting a positive association in luminal-like BC. Hence, further investigation is crucial to obtain a uniform consensus on the diet-BC relationship.

Low-fat dairy consumption and the risk of lung cancer: A large prospective cohort study

BACKGROUND

Despite the possible contribution of dairy products to the development or prevention of cancers, there is a lack of epidemiological evidence linking low-fat dairy consumption to the risk of developing lung cancer. This research was conducted to fill this knowledge gap.

METHODS

The data for this research were collected from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. The Cox proportional risk model was employed to evaluate the link between low-fat dairy consumption and the risk of developing lung cancer. Hazard ratios (HRs) and 95% confidence intervals (CIs) were measured in both unadjusted and adjusted models. A series of predefined subgroup analyses were performed to identify potential effect modifiers, and several sensitivity analyses were conducted to assess the stability of the findings.

RESULTS

The study included data from 98,459 individuals. During a total of 869,807.9 follow-up person-years, 1642 cases of lung cancer were observed, with an incidence of 0.189 cases for every 100 person-years. In the fully adjusted model, participants in the highest quartile of low-fat dairy consumption had a significantly decreased risk of lung cancer compared to the ones in the lowest quartile (HRquartile 4 vs. 1 : 0.769, 95% CI: 0.664, 0.891, ptrend  = 0.005). The restricted cubic spline plot revealed an inverse nonlinear dose-response relationship between low-fat dairy consumption and lung cancer risk (pnonlinearity  = 0.008). Subgroup analyses demonstrated that the inverse association was stronger among participants with higher daily caloric intake (pinteraction  = 0.031). Various sensitivity analyses produced consistent results.

CONCLUSION

Consuming more low-fat dairy products is significantly linked to a reduced risk of developing lung cancer, indicating that an appropriate increase in the use of low-fat dairy products may help prevent lung cancer.

Inappropriate dietary habits in tobacco smokers as a potential risk factor for lung cancer: Pomeranian cohort study

OBJECTIVE

Little is known whether diet quality modulates lung cancer risk in smokers. The aim of the study was to assess the dietary habits of a large group of volunteers participating in the lung cancer screening program.

METHODS

The 62-item food frequency questionaire was completed by 5997 participants, 127 of whom (2.1%) were later diagnosed with lung cancer. Two approaches were applied to identify dietary habits. The non-healthy diet index was calculated, and a direct analysis of the frequency of consumption was used. A logistic regression analysis was performed to estimate the association between food product intake and the risk of lung cancer.

RESULTS

The study population did not follow the Polish nutritional recommendations. They consumed fruits and vegetables too rarely and far too often ate non-recommended foods, such as processed meat, refined products, sugar, sweets, and salty snacks. Participants diagnosed with lung cancer more often consumed low-quality processed meat, red meat, fats, and refined bread and less often whole-grain products, tropical fruits, milk, fermented unsweetened milk drinks, nuts, honey, and wine. The non-healthy diet index score was significantly higher in those with cancer diagnosis compared with those without lung cancer (11.9 ± 5.2 versus 10.9 ± 5.3; P < 0.001).

CONCLUSIONS

The surveyed population of smokers did not follow dietary recommendations; there was a particularly high index of an unhealthy diet in by people diagnosed with lung cancer. Prevention programs should be based on encouraging smoking cessation, lifestyle modification, and methods of early detection of lung cancer. Lifestyle modification should include changing eating habits based on a healthy diet, which may be an additional factor in reducing the risk of developing cancer.

Consumption of Dairy Products and the Risk of Developing Breast Cancer in Polish Women

Lack of consistency in the relationship between dairy products consumption and breast cancer (BC) risk motivated us to evaluate this association in a case-control study of BC among Polish women. The study includes 1699 women 26–79 years of age, 823 BC cases identified in Cancer Registries and 876 randomly selected controls from the national population registry. Using a validated, semiquantitative food frequency questionnaire (FFQ), the consumption of dairy products was collected for a time period of 10–15 years prior to BC diagnosis. We used logistic regression, adjusting for potential confounders, to assess the relationship between total dairy consumption as well as individual dairy groups of milk, cottage cheese and hard cheese and BC risk for premenopausal and postmenopausal women. For total consumption, a significant decrease in BC risk was observed with increased consumption of one serving/week, OR _trend = 0.98, 2% decrease in risk, for premenopausal women only. For milk, a significant decrease in BC risk was observed for an increase in consumption of one glass/week, OR _trend = 0.95, 5% decrease, in both strata of menopause. In contrast, for hard cheese, a significant increase in the risk of 10% was observed only in premenopausal women, OR _trend = 1.10. Cottage cheese consumption significantly reduced BC risk by 20%, OR _trend = 0.80, for an increase in one serving/week for postmenopausal women only. Our results show that individual dairy products have a statistically significant but bi-directional relationship with BC risk, which differs for premenopausal and postmenopausal women.