Consuming
large amounts of milk may increase the risk of developing
ovarian cancer, research suggests.
A study of more than 60,000 women found drinking more than two
glasses of milk a day significantly upped the risk of the most
serious form of the disease.
Dairy products have previously been linked to cancers, including
those of the breast and prostate.
The research, by Sweden's Karolinska Institute, is published
in the American Journal of Clinical Nutrition.
"The
best advice is to emphasize a balanced diet which includes
plenty of fresh fruit and vegetables." --- Dr
Kate Law
The
researchers followed 61,084 women aged 38 to 76 for around
13 years.
During this time a total of 266 women were diagnosed with
ovarian cancer, of whom 125 had serious ovarian cancer.
The researchers found women who consumed more than four servings
of dairy products a day had twice the risk of serious ovarian
cancer than women who had fewer than two.
They found that milk had the strongest link with ovarian cancer
- those women who drank two or more glasses a day were at
double the risk of those who did not consume it at all, or
only in small amounts.
The reason why milk may increase the risk of ovarian cancer
is unclear, but one theory is that lactose, a type of sugar
found in milk, may overstimulate production of hormones which
encourage tumour growth.
Diet element unclear
Dr Kate Law, of Cancer Research UK, said it was not yet clear
how nutrients, or the amount and distribution of body fat
affected the risk of developing cancer.
She said: "Previous research has also suggested that a diet
rich in whole milk, yogurt and cheese may put women at higher
risk of ovarian cancer.
"But the picture is far from clear, as other evidence suggests
that women who drink skimmed or low-fat milk might have a
lower risk of ovarian cancer."
Dr Law a major study, involving 500,000 people, was currently
underway to try to assess the impact on diet on cancer.
"Until more is known about the specific components of diet
that influence cancer risk, the best advice is to emphasize
a balanced diet which includes plenty of fresh fruit and vegetables."
Around 6,700 women in the UK are diagnosed with ovarian cancer
each year.