TEENAGE girls are being encouraged to eat five portions of fruits and vegetables a day to cut their risk of developing breast cancer.
Researchers say the daily intake of fibre can cut the risk by as much as a quarter. And the earlier girls start eating healthy foods packed with dietary fibre, the more they are protected.
Harvard School of Public Health scientists analysed data from more than 90,000 women over a 25-year period. For each additional 10g of daily fibre intake – for example an apple, two slices of whole wheat bread or half a cup each of cooked kidney beans and cooked cauliflower or squash – during early adulthood, the risk dropped by more than an eighth (13 per cent).
Depending on how much dietary fibre they ate in early adulthood, the risk was reduced from between 12 and 19 per cent. But eating lots of fibre as a teenager was associated with a 16 per cent lower risk of overall breast cancer and a 24 per cent lower risk of breast cancer before menopause.
Researcher Maryam Farvid said: “Previous studies of fibre intake and breast cancer have almost all been non-significant, and none of them examined diet during adolescence or early adulthood, a period when breast cancer risk factors appear to be particularly important.
“This work on the role of nutrition in early life and breast cancer incidence suggests one of the very few potentially modifiable risk factors for pre-menopausal breast cancer.”
Dr. Walter Willett added: “From many other studies we know that breast tissue is particularly influenced by carcinogens and anticarcinogens during childhood and adolescence. We now have evidence that what we feed our children during this period of life is also an important factor in future cancer risk.”
The scientists said the greatest apparent benefit came from fruit and vegetable fibre and was one simple lifestyle choice women could take to reduce breast cancer risk before the menopause.
The study suggested eating more fibre-rich foods may lessen breast cancer risk partly by helping to reduce high oestrogen levels in the blood, which are strongly linked with the cancer development.
The study, published in the journal Pediatrics, analysed 90,534 women who participated in the Nurses’ Health Study II, a long-running investigation of factors that influence women’s health.
Meanwhile, a new study claims it can increase the risk of breast cancer and hasten spread of the disease to the lungs.
The new study suggests high sugar intake may raise the risk of breast cancer and metastasis.
Study coauthor Dr. Peiying Yang, assistant professor of palliative, rehabilitation and integrative medicine at the University of Texas MD Anderson Cancer Center, United States, and colleagues publish their findings in the journal Cancer Research.
According to the team, previous research has identified a link between dietary sugar intake and risk of breast cancer, with some studies suggesting inflammation may play an important role.
However, Yang notes that no studies had investigated the direct impact of sugar intake on breast cancer development in animal models or looked at the underlying mechanisms of the association in such models.
With this in mind, the team set out to assess how sugar intake influenced breast cancer development in mice that were randomized to various diets, including a sucrose-enriched diet, a fructose-enriched diet and a starch-control diet.
According to the researchers, the amount of sucrose and fructose the mice consumed was comparable to that found in a typical Western diet – characterized by high intake of refined sugars, saturated fat and red meat, and low intake of fresh fruits and vegetables and whole grains.
Compared with mice fed the starch-control diet, those fed the sucrose- and fructose-enriched diets were more likely to develop breast cancer.
At the age of six months, for example, the team found 30 per cent of the mice fed the starch-control diet had breast cancer tumors, compared with 50 to 58 per cent fed the sucrose-enriched diet.