The study was conducted by Hanyang University, with the findings published in Nutrients recently.
It assessed the relationship between micronutrient intake and breast cancer risk using a standardised semi-quantitative food frequency questionnaire (FFQ).
A total of 103 food items, excluding dietary supplements, were included in the FFQ to assess the women’s intake of micronutrients from their diets.
A total of 40,432 women without a history of cancer were included to take part in the survey. These women were selected to take part in the survey based on the Korean Genome and Epidemiology Study (KoGES).
After completing the survey, the researchers followed up on these women for an average of 4.9 years.
By the end of the follow-up, a total of 232 women reported that they had been diagnosed with breast cancer by a physician.
Breast cancer was the most common cancer in women, accounting for 23,647 (20.5%) cases of cancer, according to the 2018 cancer registration statistics in South Korea.
Risk factors include the lifestyle, the level of physical activity, alcohol consumption, as well as the age at which they gave birth, the number of births, breastfeeding experience and duration, and the use of hormone replacement therapy after menopause.
Findings showed that the intake of vitamin C and vitamin B6 above the daily recommended value – based on the 2020 Dietary Reference Intakes for Koreans (KDRIs) – was associated with a reduced risk in obese women.
However, no significant association was not observed in women with normal weight.
“Obesity is associated with higher estrogen levels in postmenopausal women due to the aromatase change of testosterone to estrogen in adipose tissue, as well as chronic inflammation status with increased oxidative stress permanently.
“Thus, the antioxidant effect of vitamin C may be more prominent in women with obesity,” the researchers explained.
As for the impact seen from vitamin B6, the researchers said this could be because the vitamin was involved in insulin resistance and could control adipogenesis-related genes, or fat-related genes.
“A protective association of high vitamin B6 intake was observed only in obese women. Studies have suggested that vitamin B6 is also involved in insulin resistance by controlling the expression of adipogenesis-related genes. Thus, the protective effect may be more prominent in women with obesity.”
The research was supported by a National Research Foundation of Korea grant funded by the South Korean government.
Association between Micronutrient Intake and Breast Cancer Risk According to Body Mass Index in South Korean Adult Women: A Cohort Study
Authors: Song, H.; Jeong, A.; Tran, T.X.M.; Lee, J.; Kim, M.; Park, B.