Researchers suggest fathers who eat a diet high in animal fats may raise their daughter's risk for breast cancer.
The female offspring of male rats that consumed a diet high in vegetable fats, however, had a reduced breast cancer risk.
Study co-author Thomas Ong, of the University of Sao Paulo, Brazil, and colleagues recently reported their findings in the journal Breast Cancer Research.
The researchers note that if their results are confirmed in human trials, it may pave the way for new interventions to reduce the risk of breast cancer that involve modifying a father's diet prior to conception.
After skin cancer, breast cancer is the most common cancer among women in the United States; around 1 in 8 American women will develop the disease in their lifetime.
A woman's risk for breast cancer is known to be influenced by a number of factors, including a family history of the disease and inherited genetic mutations. Increasingly, researchers are uncovering how a father's health and lifestyle may affect the breast cancer risk of offspring.
Last month, for example, Medical News Today reported on a study that found obesity changes the gene expression of a man's sperm, which may increase breast cancer risk for their daughters.
The new study from Ong and colleagues builds on those findings, suggesting a woman's breast cancer risk may be influenced by their father's diet.
Modifying father's diet may reduce daughter's breast cancer risk
To reach their findings, the researchers fed 60 male rats either a lard- or corn oil-based, high-fat diet, from which around 60 percent of energy was derived from fat, or a control diet, from which around 16 percent of energy was fat-derived.
Next, the team mated the male rats with female rats that had been fed normal chow.
The female offspring of the rats were also fed a standard diet, and, when they were 50 days old, they underwent a procedure that initiates the growth of mammary tumors.
The team then assessed tumor incidence among the female rats, as well as how long it took for tumors to emerge, the number of tumors that arose, and the volume of each tumor. This information was used as indicators for the risk of breast cancer.
Compared with the female offspring of male rats that were fed the control diet, the female offspring of those fed the high-fat diets showed reduced death of tumor cells.
However, the team found that the female offspring of male rats that had been fed the corn oil-based, high-fat diet showed a reduction in tumor growth, had fewer tumors, and had longer tumor latency - that is, it took longer for tumor growth to initiate.
Based on their results, the researchers suggest that the type of fat a man consumes may have a significant impact on their daughter's risk for breast cancer, with the consumption of vegetable oil having a potentially preventive effect.
The researchers hypothesize that such effects may be down to altered microRNA and protein expressions; they found changes in such expressions in the sperm of fathers, as well as in the mammary gland tissue of their female offspring. What is more, these changes were associated with cell growth, survival, and death.
The team notes that previous research has shown that exercise and dietary changes can normalize the microRNA expression of male rodents.