Eating burgers and junk food as a teenager increases your risk of breast cancer later in life

Teenagers who gorge on a diet dripping with saturated fat are at greater risk of being diagnosed with breast cancer, evidence today suggests.

An abundance of junk food, cakes and biscuits, and lack of unsaturated fats from vegetable oils, nuts and seeds, is linked to higher breast density in young adulthood, scientists found.

Breast density is a key risk factor for breast cancer, past research has shown.

Dr Seungyoun Jung, at the University of Maryland School of Medicine, said: 'Overall, our results suggest possible long-term effects of fat intake during adolescence on young adult breast composition.

'If confirmed, the take-home message from our results is that diet consumed in early life is important and may confer chronic disease risk or protective benefits later in life.

'In particular, the timing of dietary exposures might be important and appropriate dietary modifications during adolescence may potentially contribute to lowering breast density and consequently breast cancer risk as well as preventing obesity, diabetes and cardiovascular disease.'

She explained that breast tissue is most sensitive to exposures during adolescence.

It is the time when breasts develop and undergo structural changes, she said.

As a result, her team set out to investigate whether fat intake during the teenage years was linked to breast density in early adulthood.

Dr Jung and her team analyzed data from the Dietary Intervention Study in Children (DISC).

It was a randomized clinical trial initiated in 1988 enrolling 663 children aged eight to 10 years old, and included 301 girls and assessed diet on multiple occasions during the teenage years.

Researchers then followed up with the study participants when they were between 25 and 29 years old.

At that point, they measured breast density by MRI scans in 177 participants.

Next the researchers took into account other variables, that could influence breast density, such as race, education, adult weight, number of live births, and total energy and protein intakes.

They found that higher teenage intake of saturated fat and lower intake of mono-and polyunsaturated fat were linked to higher per cent dense breast volume in early adulthood.

Those women who ate the most saturated fat in their teenage years had an average dense breast volume of 21.5 per cent, compared with 16.4 per cent for those who ate the least amount.

A similar difference in dense breast volume was noted for those who ate the lowest amount of monounsaturated fat, compared to those who ate the most. 

Dr Jung said: 'The five to six percentage point difference in per cent dense breast volume is relatively modest, compared to the overall distribution of per cent dense breast volume observed in our study participants - the 25th percentile and 75th percentile: 9.7 per cent to 41.2 per cent.

'There is no clinical cut-point to define high versus low per cent dense breast volume to indicate women at increased risk of breast cancer.

'However, because there is a gradient of increasing breast cancer risk with increasing breast density, the differences in per cent dense breast volume we observed across extreme quartiles in our study, if confirmed, could potentially be of interest with regards to later breast cancer risk.' 

Co-researcher Professor Joanne Dorgan said diet during adolescence is modifiable whereas most of the well-known risk factors for breast cancer such as age at puberty and number and timing of pregnancies 'offer little chance for intervention.'

She said: 'Adult alcohol consumption is the only adult dietary factor consistently associated with breast cancer risk.' 

The findings are published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.

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