An increasing amount of scientific evidence now shows that cow’s milk is not the wonder food the dairy industry would have us believe. … The aim of this report is to redress the balance by presenting and reviewing the research on the health effects of cow’s milk and dairy products.
This report combines the findings of over 400 scientific papers from reputable peer-reviewed journals such as the British Medical Journal and the Lancet. The research is clear – the consumption of cow’s milk and dairy products is linked to the development of teenage acne, allergies, arthritis, some cancers, colic, constipation, coronary heart disease, Crohn’s disease, diabetes, dementia, ear infection, food poisoning, gallstones, kidney disease, migraine, autoimmune conditions, including multiple sclerosis, overweight, obesity and osteoporosis.
Dr. Butler makes a lot of claims, but she includes a lot of peer-reviewed evidence to back them up. I was interested in the cancer link. That was covered on pages 31-50. Some highlights:
- After smoking, a poor diet is the second largest preventable risk factor for cancer.
- Vegetarian diets are sometimes associated with reduced cancer risk. However, vegetarian diets that include eggs, cheese, cream, butter, milk, yogurt, and other dairy products often show no difference in cancer mortality when compared to non-vegetarian diets.
- Vegan diets that exclude eggs and dairy products are consistently associated with lower cancer risk when compared to vegetarian diets that include eggs and dairy products.
- Migrant studies show that when people move from a low cancer risk area to a high cancer risk area, they assume an increased cancer risk within one to two generations.
- Today’s milk is different from milk produced 100 years ago. Modern milk often comes from a pregnant cow (the cow is artificially inseminated while still producing milk from a prior insemination). That means the milk contains higher levels of hormones (e.g. estrogen, progesterone, androgen) than the milk our parents and grandparents consumed. High levels of these hormones have been linked to breast, ovarian, and prostate cancer, among others.
- The growth factor IGF-1 is present in all milk and is not destroyed by pasteurization. Some can pass into our circulation and along with other small peptides in milk can raise IGF-1 levels in our body, partly by driving up IGF-1 production in the liver. High IGF-1 levels are a risk factor for several cancers, notably breast, colon, and prostate.
- Dietary calcium has been consistently associated with an increased risk of prostate cancer. Within EPIC, a 300 mg per day intake of dietary calcium (a cup of yogurt, a cup of milk, a square inch of cheddar cheese) was associated with a 9% increased risk of prostate cancer. The WCRF/AICR report judged it a probable cause of the disease. “It would seem clear that recommending dairy to men would not be sensible.” (One mechanism: calcium suppresses circulating vitamin D.)
- It is now well documented that diets high in calcium and dairy foods (may be the proteins, fat, calcium, hormones, IGF-1) can increase the risk of prostate cancer.
- Studies indicate that yogurt, milk, the milk sugar lactose, and/or its component galactose, are risk factors for ovarian cancer.
There’s a lot here I didn’t know, like the high hormone content of today’s milk compared to milk from decades ago. Or that compounds in milk can drive up our own production of IGF-1.
There are any number of compounds in milk that could be responsible for its link to cancer, including but not limited to: its total fat and saturated fat, proteins and amino acids, IGF-1, estrogen, progesterone, androgen, and other hormones, its sugar lactose, its calcium. One they didn’t mention is environmental pollutants – pesticides and other fat-soluble chemicals that act as endocrine disruptors and that bioaccumulate in animal fat.
There really is a lot here. If you’re still eating dairy by the end of it, I’ll eat my hat.