Breast cancer: bad fats and dairy go tits up | Viva!

Breast cancer: bad fats and dairy go tits up

Bad fats and breast cancer

A wealth of evidence showing that diet impacts on breast cancer is accumulating. Common themes occur in the scientific literature; a diet rich in dairy and meat is linked to an increased risk of breast cancer while whole plant foods, vegetarian and vegan diets are linked to a lower risk. A major review of studies on diet and breast cancer published in the Journal of the National Cancer Institute found that women who ate the most saturated (mainly animal) fat had an increased risk. This study also showed that women who ate the most fruit and vegetables but low amounts of animal fats were less likely to have breast cancer. The landmark study on page 11 found that vegetables linked with stopping or slowing breast cancer cell growth in a petri dish include (most powerful first) garlic, leeks, green onions, Brussels sprouts, cauliflower, cabbage, broccoli, radish, kale, brown onions, green beans, red cabbage, asparagus, spinach, beetroot, potatoes, jalapeno peppers, raddichio, cucumber and orange bell peppers (Boivin, 2009). Southern California Medical School in Los Angeles published a review of studies looking at the effect of fat intake on oestrogen levels. It showed that lowering the intake of fat could reduce oestrogen levels and as high oestrogen levels are linked to a greater risk of breast cancer, reducing fat intake may help to prevent it. A study led by Dr Sheila Bingham of the Dunn Human Nutrition Unit in Cambridge revealed that women who ate the most saturated animal fat – found mainly in whole milk, butter, meat, cheese, cakes and biscuits – were almost twice as likely to develop breast cancer as those who ate the least (Bingham et al, 2003). In a subsequent study involving over 90,000 premenopausal women, researchers from Harvard Medical School confirmed that animal fat intake was associated with an increased risk of breast cancer. Red meat and high-fat dairy foods, such as whole milk, cream, ice-cream, butter, cream cheese and cheese, were the main sources of animal fat in this group of relatively young women (Cho et al, 2003). Importantly, not all fats are equal. This research did not find a link between vegetable fat and breast cancer, the increased risk being linked only with animal fat.

Oestrogen levels are a critical determinant of breast cancer risk and directly participate in the cancer process (Campbell et al, 2005). Oestrogens are found in meat and eggs but major sources are cows’ milk and dairy products, which account for 60 to 80 per cent of the oestrogens consumed (Butler, 2007).

The sad truth is that most women are not aware of the strong evidence showing that saturated fat and oestrogen in our diet can affect our risk of developing breast cancer. Nor are they aware that only five to 10 per cent of all breast cancers are linked to an inherited breast cancer gene. It follows that the vast majority of cancers (90-95 per cent) are not caused by abnormal genes (Butler, 2014). Nearly a third of all breast cancer cases are attributed to avoidable risk factors – alcohol, high meat and dairy consumption and lack of exercise – and a low intake of whole plant foods.