Drinking dairy milk has been linked to an increased risk of breast cancer in women, a new study has concluded.
Scientists from Loma Linda University Health in California claim that daily dairy can increase the risk by up to a whopping 80% depending on the amount drunk.
Published in the International Journal of Epidemiology, they looked at what impact drinking cow’s milk compared to soy had on breast health, and they concluded that even drinking relatively small daily amounts of dairy was enough to increase breast cancer risk.
‘Consuming as little as 1/4 to 1/3 cup of dairy milk per day was associated with an increased risk of breast cancer of 30%,’ author of the study, Dr Gary Fraser said.
‘By drinking up to one cup per day, the associated risk went up to 50%, and for those drinking two to three cups per day, the risk increased further to 70% to 80%.’
Nearly 53,000 North American women were followed over an eight year period. Each filled in food frequency questionnaire as well as questionnaires about their family histories of breast cancer, medication use, alcohol consumption and other notable lifestyle factors.
None of them had cancer initially but by the end of the study, there were 1,057 new breast cancer cases. While soy seemed to play no role in the development of the disease, a higher intake of calories from dairy or dairy milk was linked to a greater risk when compared to low or no milk consumption.
It didn’t matter whether the women were drinking full-fat, low-fat or non-fat milks and interestingly, there were no associatiations noticed with yoghurt.
Why might dairy be scary?
Dr Fraser suggests that it might be something to do with the sex hormone content of dairy milk.
Milk comes from lactating cows and often, around 75% of dairy herds are pregnant. Breast cancer in women is a hormone-responsive cancer which suggests that some cases may be triggered by the introduction of foreign hormones such as insulin-like growth factor-1 (IGF-1).
It’s not the first time dairy has been linked to the disease.
A study in 2017 funded by the National Cancer Institute looked at 1,941 women diagnosed with breast cancer and found that those who ate the most cheddar, American and cream cheeses had had a 53% increased risk of developing the illness. That risk increased for those who drank the most milk.
This new study confirms the findings of a previous study published in the same journal which suggested that vegans have a lower risk of breast cancer compared to vegetarians who consume dairy and meat-eaters.
Drink in moderation
Dr Fraser concluded that women might be better off swapping their daily dairy milks for soy or other plant-based alternatives, but he also pointed out that diary milk does have some positive nutritional qualities.
Dairy milk contains calcium, phosphorus, B vitamins, protein and vitamin D. But soy milk, for example, contains protein and a less saturated fat than cow’s milk…and crucially doesn’t have the hormonal profile.
If you only have the odd splash in your tea, you probably have very little to worry about but if you are concerned and you do have a history of breast cancer in your family, why not give a plant-based alternative a try? Oat milk is fantastic in teas and coffees as it doesn’t separate like soy or coconut and can be easily frothed up for cappuccinos. It’s also delicious in cereal.
How to check your boobs
Self examination is the best way of ensuring that you keep a track of your breast health. Only you know how the usually look and feel, and regularly having a feel means that you can report any changes quickly to your GP.
Make sure you:
- Know what’s normal for you
- Look at your breasts and feel them
- Know what changes to look our for
- Report any changes ASAP
- Attend routine screenings if you’re 50+
Changes to look out for can include:
- Change to the size or shape of your breast
- Change to the look or feel of your breast skin (dimpling for eg)
- A lump in one breast or armpit
- Nipple discharge that isn’t milky
- Bleeding from the nipple
- Moist, red area on your nipple
- Change in nipple direction
- Rash around or on the nipple
- Pain or discomfort in one breast that doesn’t go away
Remember to look and feel around the collarbone, armpits, nipples and breast.
Keep forgetting to check? Sign up for one of Coppafeel’s regular reminders to check your boobs.