• United Kingdom
• Change

Bupa members

Support and offers for individual members and customers

Hot topic - Milk linked to ovarian cancer risk

07 December 2004 - written by Bupa's Health information team

Women who drink lots of milk have a higher risk of ovarian cancer, according to a new study in the November 2004 edition of The American Journal of Clinical Nutrition.¹

What did the study show?

The study showed that women who consumed four or more servings of dairy products (eg milk, cheese, yoghurt) a day had double the risk of developing ovarian cancer, compared with women who consumed less than two servings a day.

Were all dairy products equally linked to this increased risk?

Milk was the dairy product most strongly linked to the risk of ovarian cancer. Women who drank two or more glasses of milk a day had twice the risk of ovarian cancer compared with women who drank milk in small amounts or not at all.¹

How was the study carried out?

The researchers studied 61,084 Swedish women aged 38 to 76 years for about 13 years. During the first three years of the study, the women filled in questionnaires about their eating habits. This included keeping a record of how often they drank milk and ate other dairy products.¹

What are the ovaries?

The ovaries are part of the female reproductive system. They are two small oval-shaped organs that sit at the end of the Fallopian tubes. The Fallopian tubes lead to the womb.²

What do the ovaries do?

Each month, in women of childbearing age, the ovaries release an egg. This is called ovulation. The egg passes down the Fallopian tube to the womb. If the woman has sexual intercourse during ovulation, the egg may be fertilised by a sperm, resulting in pregnancy. If the egg isn't fertilised, it passes out of the womb and is shed during the monthly period.

The ovaries also produce the hormones oestrogen and progesterone. When a woman reaches the menopause, the ovaries make fewer hormones and stop producing eggs and periods gradually stop.²

What is ovarian cancer?

Ovarian cancer is a disease where the cells of the ovaries grow in an uncontrolled way. There are different types of ovarian cancer depending on the type of cell the cancer started in.³

Was this link shown for all types of ovarian cancer?

No. This link was only found for one type of cancer called serous ovarian cancer. There was no association found between drinking milk and developing other types of ovarian cancer.¹

How many women developed serous ovarian cancer?

During the 13 years of the study, 125 women developed serous ovarian cancer.¹

How common is ovarian cancer?

Ovarian cancer is the fourth most common cancer among women in the UK. Each year there are about 6,800 new cases. Serous ovarian cancers account for about 40 percent of ovarian cancers. Most ovarian cancers are found in women over 50.^3,4,5

What are the symptoms of ovarian cancer?

In the early stages of the disease, there are often no symptoms. Symptoms may only be noticed when the cancer has become quite large or has spread to other parts of the body.

These symptoms include:

• irregular periods
• pain or feeling of 'pressure' in the lower abdomen
• a feeling of bloating in the abdomen
• pain in the lower abdomen during sexual intercourse
• passing urine frequently
• change in bowel habit - constipation or diarrhoea³

What causes ovarian cancer?

It is not known what causes ovarian cancer. However there are factors that may slightly increase or decrease the risk of a woman developing ovarian cancer.²

What factors may slightly increase the risk of ovarian cancer?

• age - most cases occur in women over 50
• taking hormone replacement therapy (HRT)
• not having children
• late menopause³

According to this study, drinking milk may also increase a woman's risk of developing ovarian cancer.¹

What factors may slightly decrease the risk of ovarian cancer?

• sterilisation or a hysterectomy (removal of the womb)
• taking the contraceptive pill
• having children
• breast-feeding
• infertility³

Why is milk associated with an increased risk of ovarian cancer?

It is not certain why milk is associated with an increased risk of ovarian cancer. It may be due to a type of sugar found in milk called lactose. Lactose may cause the body to produce more hormones. These may encourage the cancer to grow. More research is needed.¹

What did the study conclude?

The researchers concluded that women who eat or drink a lot of dairy products, particularly milk, are at an increased risk of serous ovarian cancer, but not other subtypes of ovarian cancer.

More research is needed to show whether there is a definite link between drinking milk and an increased risk of ovarian cancer.¹

Should I stop drinking milk?

No. Milk and milk products are the best source of calcium. Calcium is important for keeping bones and teeth healthy. Milk also contains protein as well as important vitamins and minerals.⁶

How much calcium do I need?

One glass (200ml) of semi-skimmed milk, a pot (150g) of low-fat yoghurt and 40g of hard cheese would provide roughly the amount of calcium an adult needs in one day.

Calcium is very important for growing children. Two small glasses (300ml) of full-fat milk will provide enough calcium for children aged one to three.⁶

If I don't drink milk, how can I make sure I get enough calcium?

Good sources of calcium include:

• canned sardines and other fish where we eat the bones
• bread
• fortified (vitamin-rich) cereals
• dried figs
• low-fat rice pudding
• beans, lentils and chickpeas, nuts and seeds⁶

What can I do to reduce my risk of ovarian cancer?

The following factors may reduce a woman's risk of developing ovarian cancer. They can also make you feel better in many ways, regardless of cancer risk:

• eating a variety of foods to make sure you are getting a balance of all the key nutrients
• maintaining a healthy weight or losing weight if necessary
• physical activity - aim for at least 30 minutes of moderate intensity exercise on five or more days of the week²

How is ovarian cancer treated?

There are different types of treatment that are used for treating ovarian cancer:

• surgery - this is normally the first treatment for ovarian cancer. It is usually necessary to remove the ovaries, the Fallopian tubes and the womb during the operation
• chemotherapy - this is the use of special anti-cancer drugs to treat ovarian cancer. It is often given after surgery if it wasn't possible to remove all of the cancer during the operation
• radiotherapy - this uses high-energy rays to destroy cancer cells. It isn't usually used to treat ovarian cancer. However, it is sometimes used to treat individual areas of cancer if it comes back after surgery or chemotherapy²

Further information

Bupa resources:

• Factsheet: Ovarian cancer
• Factsheet: Chemotherapy
• Factsheet: Radiotherapy
• Factsheet: Healthy eating
• Factsheet: Healthy weight
• Factsheet: Physical activity

External resources:

• CancerBACUP
  Tel: 0808 800 1234
  www.cancerbacup.org.uk
• Ovacome - ovarian cancer support network
  www.ovacome.org.uk

References

1. Larsson SC, Bergkvist L, Wolk A. Milk and lactose intakes and ovarian cancer risk in the Swedish mammography cohort. Am J Clin Nutr 2004;80(5):1353-1357.
2. CancerBACUP.
   http://www.cancerbacup.org.uk
3. Patient UK. Ovarian cancer.
   http://www.patient.co.uk
4. Cancer Research UK: Ovarian cancer.
   http://www.cancerresearchuk.org
5. South West Cancer Intelligence Service. Factsheet No.8: Ovarian carcinoma in the South West ICD - 10:C56.
   http://www.theswcis.nhs.uk
6. Food Standards Agency. Milk and dairy.
   http://www.eatwell.gov.uk

All websites accessed on 2 December 2004