A large-scale study published in The BMJ this week that followed tens
of thousands of women over two decades has found that high consumption of fruit during adolescence could help lower the risk of breast cancer in later life.
Although many previous studies have hypothesised that fruit and vegetables could help protect against cancer, results have been mixed, and many previous studies have focused only on fruit intake during mid- and later life, which may be after the period when breast tissue is most vulnerable to cancer.
In this new study a team of US researchers looked at a possible association between fruit and vegetable consumption during teenage years and a future risk of breast cancer.
The team questioned 90,476 premenopausal women aged 27-44 on their diet in early adulthood every four years for a period of 22 years.
During the study 44,223 of these women also answered another questionnaire about their diet during adolescence between the ages of 13-18.
The results showed that a higher consumption of fruit during adolescence — 2.9 servings per day — was associated with around a 25 per cent lower risk of breast cancer in middle age than a low consumption of fruit — 0.5 servings per day.
In addition, the results also suggested that two servings per week of apples, bananas and grapes during adolescence was significantly associated with a reduced breast cancer risk, as was two servings per week of oranges and kale during early adulthood.
However there was no association between breast cancer risk and total vegetable intake in adolescence, or total fruit or vegetable intake in early adulthood.
Fruit juice intake in either adolescence or early adulthood was also not associated with a decreased risk.
As an observational study the researchers caution against drawing any firm cause and effect conclusions from the data as the results may be influenced by other factors, with University of Oxford researchers commenting in a linked editorial that “much more evidence is needed before we can draw conclusions on the reported protective association between adolescent fruit intake and breast cancer risk.” However, they also added that these foods “have well known beneficial effects on health, and efforts should continue to increase intake of both fruit and vegetables at all ages.”
The study’s researchers also pointed out that their findings are also in line with current cancer presentation advice on the benefits of eating more fruits and vegetables, and that the food choices made during adolescence could play a particularly important role in influencing health in later life.