Women-who as adolescents or young adults-ate few vegetables while regularly consuming foods associated with chronic inflammation, like those high in sugar-sweetened and diet soft drinks, refined sugars, carbohydrates, margarine, and red and processed meats, are considerably more likely to develop premenopausal breast cancer than those who didn't (Cancer Research 2017; doi:10.1158/0008-5472.CAN-16-2273).
According to http://cdc.gov, only 39 percent of children ages 2-17 meet the USDA's dietary recommendation for fiber; found primarily in dried beans and peas, fruits, vegetables, and whole grains. Almost 80 percent of adolescent females do not consume enough calcium while, during the past 25 years, consumption of milk, the largest source of calcium, has decreased 36 percent among adolescent females, the site reported. Additionally, from 1978 to 1998, average daily soft drink consumption almost doubled among adolescent females, increasing from six ounces to 11 ounces, and almost tripled among adolescent males, from seven ounces to 19 ounces.
As for the report, a prime takeaway is that it analyzed the diet of girls rather than adult women, noted Karin Michels, ScD, PhD, senior author of the study and Professor and Chair of the Department of Epidemiology at the UCLA Fielding School of Public Health, Los Angeles. Additionally, the report explored inflammatory dietary patterns, also previously rarely done.
Study Specifics
For the study, Michels and colleagues used data from 45,204 women enrolled in the Nurses' Health Study II who had completed a food frequency questionnaire in 1998, when they were ages 33-52, about their diet during high school. Adult diet was assessed first using a food frequency questionnaire in 1991, when participants were ages 27-44, and then every 4 years after that. Each woman's diet was given an inflammatory score using a method previously developed that links diet with inflammatory markers in the blood.
During 22 years of follow-up, 870 of the women who completed the high school food frequency questionnaire were diagnosed with premenopausal breast cancer and 490 were diagnosed with postmenopausal breast cancer.
When women were divided into five groups based on the inflammatory score of their adolescent diet, those in the highest score group had a 35 percent higher risk for premenopausal breast cancer relative to those in the lowest score group. When the same analysis was done based on early adulthood diet, those in the highest inflammatory score group had a 41 percent higher risk for premenopausal breast cancer relative to those in the lowest score group. Diet inflammatory score was not associated with overall breast cancer incidence or postmenopausal breast cancer, the report observed.
Importance of Dietary Patterns
Melina Jampolis, MD, Immediate Past President of the National Board of Physician Nutrition Specialist, believes the fact that the study looked at dietary patterns rather than specific foods or nutrients is critical "since people don't eat individual foods or nutrients in isolation." As such, in her opinion, "looking at dietary patterns and the impact on inflammation and disease risks is more realistic and relevant than looking at single foods or nutrients."
Jampolis also thought the study was valuable because it focused on what young girls should consume rather than on what they shouldn't. "I talk about that all the time in my practice." She also was intrigued by the findings because she's always considered premenopausal breast cancer more strongly related to genetics. "So, it's encouraging to think improving adolescent dietary choices could make a difference."
On another front, the study showed that during adolescence and early adulthood; when the mammary glands are rapidly developing and, therefore, particularly susceptible to lifestyle factors, it's important to consume a diet rich in vegetables, fruit, whole grains, nuts, seeds, and legumes, said Michels. However, the latter can be a relatively difficult factor to conquer since many adolescent and young teens believe they're invulnerable to chronic disease, continued Michels, who added that, while about 12 percent of women in the U.S. develop breast cancer in their lifetimes, each woman's breast cancer risk varies based on numerous factors, including genetic predisposition, demographics, and lifestyle. "They're still in good health and say, maybe when they become adults, they'll eat healthier. As children, they believe they can do whatever they want; it can't hurt them. But that's just not true."
Nutrition consultant Sarah Krieger, MPH, RDN, LDN, registered and licensed dietitian nutritionist in St. Petersburg, Fla., said teens "are thinking about today and not 20 years from now. Physicians and other health care providers can track a child's weight and growth pattern and make small, achievable suggestions that the teen agrees with." For example, if a teen's gained 20 pounds in a year without gaining height, it should be discussed without being critical, she explained. "Ask the teen if there's anything that could be improved and provide realistic suggestions along with local resources for teens. Then follow up."
According to Jampolis, the focus should be on improving the quality of the overall diet, not just cutting sugar. "I don't think most kids or, especially teenagers, think about long-term health. In most cases, I think teenager girls are a lot more focused on weight than health," she noted. As a result, while Jampolis is unsure how to change the conversation, she called education and promoting health dietary patterns "a great start."
Educating Young Women
To help set them get started on the right path, Sandhya Pruthi, MD, described what she characterized as a "modifiable lifestyle factor." She explained that, conceivably, it could reduce premenopausal breast cancer. Pruthi, Professor of Medicine and Associate Medical Director in the Department of Development at Mayo Clinic, said many of her patients diagnosed with breast cancer "want to know if there was something in their lifestyle or diet that may have contributed to the development of breast cancer." And, if so, how could they help educate and inform their daughters or nieces about modifiable factors to prevent breast cancer.
The educational process, for starters, should include parents consulting with a registered dietitian nutritionist for a full assessment of their child, as well as establishing and, just as importantly, sticking to a healthy diet, said Krieger.
That effort takes on added importance considering more than 23 million Americans-including 6.5 million children-live in food deserts, which are areas that are more than a mile away from a supermarket, according to the U.S. Department of Agriculture's (USDA) Creating Access to Healthy, Affordable Food. In 2008, an estimated 49.1 million people, including 16.7 million children, experienced food insecurity or limited availability to safe and nutritionally adequate foods multiple times throughout the year, reported USDA. Furthermore, empty calories from added sugars and solid fats contribute to 40 percent of total daily calories for 2- to 18-year-olds. Half of these empty calories come from six sources: soda, fruit drinks, dairy desserts, grain desserts, pizza, and whole milk, the site stated.
In the meantime, despite their relatively lax attitude toward their diet, in a http://breastcancer.org survey of 2,500 girls ages 8-18, nearly 30 percent believed they might currently have breast cancer. More than 20 percent of the girls surveyed believe that breast cancer is caused by infection, tanning, drug use, stress, and breast injury or bruising. Furthermore, few girls surveyed knew how to reduce their risk of developing breast cancer in their lifetime.
For Krieger, that was unexpected. "With the exception of tanning and drug use, the answers they share aren't really self-controlled." She recommended physicians suggest that food choices and fitness are in your control.
Pruthi added that health care providers and educators within school systems and communities should promote healthy eating and lifestyle behaviors during the adolescent years. Tools like social media and health education websites can pitch in, too, by hyping lifestyle behaviors to reduce lung, breast, gastrointestinal, and skin cancers, observed Pruthi, also Chief Medical Editor of Mayo Clinic's Global Business Solution.
Researchers did note the report had limitations as well. For instance, Michels said women were recollecting their adolescence about 15-20 years later after the fact and researchers lacked adolescent or early adulthood measurements of blood markers of inflammation in the study. "We couldn't measure the inflammation markers at the time they ate the diet."
Pruthi also pointed out the lack of information about hormonal and other lifestyle factors, such as physical exercise and alcohol use of the participants. Additionally, the actual mechanism by which diets high in sugar and processed meats contribute to breast cancer risk is not well-defined, she concluded.
Chuck Green is a contributing writer.
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