Dairy products are an essential source of nutrition in our daily diet, and a yogurt advertisement advertises: XXXX, the magical secret of longevity villages. So, are dairy products really effective in slowing down the aging process, or reducing certain diseases or cancers? Recent studies by Dr. Susan McCann and others have produced contrasting results in dairy products (cheese and yogurt).
Daily consumption of dairy products may have both advantages and disadvantages; while they are both a good source of calcium, they may also lead to a high fat bias. When it comes to the role of dairy products for breast cancer, a new study finds that they may also be at odds with each other.
Researchers found that high consumption of cheddar and cream cheese can increase a woman’s risk of breast cancer, but high intake of yogurt can reduce the risk of the disease. Susan McCann, PhD, of the Division of Cancer Prevention and Control at Roswell Park Cancer Institute in Buffalo, New York, recently published the findings of the study she led in the journal Current Developments in Nutrition.
Among U.S. women, breast cancer is the most common cancer, second only to skin cancer. Data indicate that in 2017, there were approximately 252,710 new cases of invasive breast cancer diagnosed in women, while more than 40,000 patients died from breast cancer.
Diet is known to play an important role in breast cancer risk, and a recent study reported in Medical News Today noted that poor diet during adolescence and early adulthood is associated with a higher risk of premenopausal breast cancer.
Although some dairy products may be classified as unhealthy, researchers have produced conflicting results by assessing the role of dairy products on breast cancer risk; one part of the study showed that dairy intake was associated with a higher risk of breast cancer, while another part of the study showed the opposite. may not be unexpected, as dairy products are a complex mixture of nutritional and non-nutritional substances that may influence cancer aetiology, thereby increasing or decreasing disease risk.”
Cheddar and cream cheeses increase breast cancer risk by 53 percent
For the study, McCann and team reviewed data from the Roswell Park Data Repository from 2003-2014, which included 1,941 female breast cancer patients and 1,237 healthy women. All women completed a food intake frequency questionnaire detailing the total amount of dairy products consumed each month, as well as the various specific types – including: cheese, yogurt and milk.
After correcting for a number of possible confounding factors, including: age, body mass index (BMI), menopausal status, and family history of breast cancer, the researchers found that a high intake of dairy products was associated with a 15 percent reduction in breast cancer risk. This reduction in breast cancer risk was primarily attributed to high yogurt intake; women who consumed large amounts of yogurt had a 39% lower risk of progressing to breast cancer.
However, high intake of cheese (especially cheddar and cream cheese) had the opposite effect, increasing the risk of breast cancer by 53%. Further research is still needed to better understand how dairy products affect breast cancer risk, but the researchers believe their current findings certainly shed some light.
This study of dairy consumption and breast cancer risk among women brings new and meaningful insights into the potential risk factors associated with breast cancer. While diet is thought to be associated with 30% of all cancers, we hope that further research will help us more fully understand which foods are more valuable in reducing the risk of these cancers. In addition to yogurt, let’s review what foods have a preventive effect on breast cancer and what foods are associated with an increased risk of developing it.
The “red” and “black” lists of breast cancer recipes
I. Red List
Fruits
A team led by researchers from the T.H. Chan School of Public Health at Harvard University conducted a prospective cohort study to assess the relationship between fruit and vegetable intake and breast cancer risk in adolescence and early adulthood.
1. total fruit consumption during adolescence was associated with a ‘low risk of breast cancer’, with the highest intake group having an approximately 25% lower risk than the lowest intake group
2. High consumption of α-carotene-rich fruits and vegetables in early adulthood was associated with a “low risk of premenopausal breast cancer”. The highest intake group had about 18% lower risk than the lowest intake group
3. a stronger association of pubertal fruit intake with ER-/PR- breast cancer compared to estrogen-positive
4. in terms of different foods, high consumption of apples, bananas and grapes during adolescence was associated with ‘low risk of breast cancer’, while in early adulthood it was oranges and kale that were associated with ‘low risk of breast cancer’
5. The study did not find an association between consumption of fruit juices and breast cancer risk.
Fibrous foods
Dr. Maryam Farvid and team members from the Harvard School of Public Health showed that women with higher fiber intake had a 12-19% lower risk of breast cancer compared to women with lower fiber intake in early adulthood; women with higher fiber intake during adolescence had a 16% lower risk of breast cancer and a 24% lower risk of breast cancer before menopause. In addition, researchers found that the more fiber consumed in early adulthood, the lower the risk of future breast cancer, with an additional 10g of fiber per day (equivalent to an apple and two slices of whole wheat bread) reducing a woman’s risk of breast cancer by 13%. If women get fiber from fruits and vegetables, the risk of breast cancer is reduced even more.
Omega-3 fatty acids
A study led by Professor Andrea Manni, Director of Endocrinology, Diabetes and Metabolism at Penn State University School of Medicine, suggests that Omega-3 fatty acids may reduce the risk of breast cancer in postmenopausal obese women. the protective effect of Omega-3 fatty acids may be due to their anti-inflammatory effects.
Vitamin D
Dr. Song Yao from Roswell Park Cancer Institute said, “Research has found that women diagnosed with breast cancer who have higher blood levels of vitamin D have a significantly better long-term prognosis. There is growing evidence that vitamin D, in addition to being an important nutrient, plays an important role in breast cancer.” In premenopausal women, the correlation between high 25OHD levels and OS is even stronger. For these patients, high levels of 25OHD were also associated with improved breast cancer-specific survival, as well as invasive disease-free survival, including recurrence, second primary invasive tumors and death. The 1/3 of women with the lowest premenopausal 25OHD concentrations had an increased risk of triple negative breast cancer compared to the 2/3 of women with higher concentrations.
Coffee
IARC has been organizing expert groups since 1971 to collect and evaluate information on the carcinogenic risks of chemicals to humans in countries around the world. Based on studies of the carcinogenicity of chemical substances in humans and in experimental animals, the relationship between chemical substances and human cancer was classified into the following five categories: Category 1, carcinogenic; Category 2A, likely to cause cancer; Category 2B, probably carcinogenic; Category 3, unclassifiable; and Category 4, probably not carcinogenic. In this reassessment coffee was released from the blacklist (2B –> 3). Results from more than 40 cohort or case-control studies and 1 meta-analysis that included a population of 1 million women agreed that coffee does not increase the risk of breast cancer, and some studies also found that coffee reduces the risk of breast cancer.
Second, the black list
Sweet tooth
High levels of sugar in the typical Western diet may increase the risk of breast cancer as well as its lung metastasis, according to a study reported by The University of Texas MD Anderson Cancer Center. The findings, published in the Jan. 1, 2016, issue of Cancer Research, suggest that dietary sugar has an effect on an enzyme signaling pathway called 12-LOX (12-lipoxygenase).
Carbohydrates
A case-control study based on a Mexican population was conducted by Amadou A et al. to investigate the relationship between dietary carbohydrates, glycemic index (GI), glycemic load (GL) and the risk of breast cancer development. After a thorough analysis of the data, the investigators found that total carbohydrate intake was associated with an increased risk of breast cancer in premenopausal women. Those with the highest total carbohydrate intake had an OR=1.3 (95% CI = 1.0, 1.7; P trend=0.03) for breast cancer occurrence compared to those with the lowest. Stratification of the study population according to BMI revealed a statistically significant association between carbohydrate intake and breast cancer risk in premenopausal women seen in overweight women: OR=1.9 (95% CI= 1.2, 3.0; P trend = 0.01) in the highest quartile compared to the lowest quartile in those with BMI ≥25 kg/m2; and not statistically significant in those with BMI <25 kg/m2.
What else can we do to reduce breast cancer risk?
Some lifestyle changes can be helpful in significantly reducing a woman’s risk of progressing to breast cancer.
Moderate alcohol consumption: Women who drink moderately or infrequently are less likely to progress to breast cancer than those who drink heavily on a regular basis. Moderate means no more than one drink per day.
Physical activity: There are data that show that exercising five days a week can reduce a woman’s risk of progressing to breast cancer. Researchers from the University of North Carolina at Chapel Hill, a global public health center, report that physical activity can reduce breast cancer risk, whether it is mild or severe, and is not associated with pre/post-menopause. However, significant weight gain may invalidate these benefits.
Diet: Some experts suggest that maintaining a healthy, balanced diet may reduce the risk of progression to breast cancer. A study published in the BMJ (June 2013) found that regular consumption of fish and marine n-3 polyunsaturated fatty acids reduced the risk of progression to breast cancer by 14% relative to other women. The authors, from Zhejiang University in China, explain that “regular consumption” means consuming at least 1-2 servings of deep-sea oily fish (tuna, salmon, sardines, etc.) per week.
Postmenopausal hormone therapy: Restrictive hormone therapy can help reduce the risk of progression to breast cancer. It is important for patients to thoroughly weigh the pros and cons of treatment with their supervising physician.
Weight: Women with a healthy weight have a fairly low chance of progressing to breast cancer compared to obese and overweight women.
Women at high risk for breast cancer: Your doctor may recommend estrogen-blocking drugs, including tamoxifen and raloxifene. Tamoxifen may increase the risk of uterine cancer. For women at very high risk, preventive surgery is a possible option.
Breast Cancer Screening: Patients should discuss with their physician when to begin breast cancer screening tests.
Breastfeeding: Women who breastfeed have a lower risk of progressing to breast cancer compared to other women. A team of researchers from the University of Granada, Spain, published a study in the Journal of Clinical Nursing that showed that breastfeeding for at least six months reduced the risk of early breast cancer. This result only applies to non-smoking women, the team added. Mothers who breastfed for at least six months, even if they progressed to breast cancer, did so on average 10 years later than other women.