Evidence has been steadily mounting during the past few decades of the potential negative effects of dairy on human health from colic and gut disorders to cancer. Milk is associated with many digestive disorders, poor gut health, food intolerances and allergies. Many children develop food intolerances to milk which, at the very least, cause overproduction of mucous and lots of phlegm and runny noses. Worse, these intolerances can cause severe allergic symptoms. This is often related to the negative impact dairy products have on the gut. Associated with this I have seen colic clear up in many infants once they are taken off dairy.
Lactose intolerance is a “condition” in which the body cannot digest the sugar efficiently (or at all), leading to poor gut health and excess mucous, acid and gas production and varying degrees of abdominal discomfort 1. People with lactose intolerance also experience reduced absorption in the gastrointestinal system 2. Approximately 75% of the world’s population (particularly in Eastern countries such as China, India, Africa and in minority populations such as Australian Aboriginals and Native Americans) has a level of lactose intolerance 1, and it is now generally accepted that this “condition” is actually the norm for the human species. It is more prevalent in Asians (about 85%) and African Americans (about 50%) than Caucasians (about 10%). It should be highlighted that the inability to digest lactose is exacerbated by pasteurisation destroying all the enzymes naturally found in milk that would normally help with digestion of the milk.
A food allergy is an abnormal immunological response due to a sensitisation to a food or food component. It represents an important health problem, especially in industrialised countries where it has been estimated to affect about 1% to 2% of the adult population and up to 8% of children below the age of three 3. As far as statistics go, cow’s milk allergy can be considered one of the most common food allergies, especially in early childhood with an incidence of 2% to 3% in the first years of life 4.
If an allergic reaction develops it is not always due to the dietary habits of the infant. A baby can be exposed to the proteins that cause an allergic response. Breast milk from mothers who have consumed products containing cow’s milk might be another threat for the development of cow’s milk allergy due to the absorption of cow proteins, their passage through the gut mucosa and their release in human milk 4. Antibody reactivity to bovine casein as well as to casein and lactoglobulin is detectable only in bottle-fed infants and not in infants who are exclusively breast-fed5.
Hormones and growth factors
Many of the bioactive components of milk contain hormones and growth factors. Milk contains more than 50 hormones and growth factors 6. The consumption of cow’s milk can result in significant hormonal changes and disrupt the balance of insulin, growth hormones and insulin-like growth factors (IGF) 7. Insulin Growth Factor One (IGF-1) is intended to assist suckling calves to grow and produce new tissue through the prolific reproduction of cells 8. However, when this hormone is introduced to the adult human body, which is no longer growing, cells may be encouraged to reproduce at the wrong time or place, providing the basis for cancerous growth 9. Cow’s milk and human’s milk share the same amino acid sequence of IGF and therefore the cow form is capable of binding to human IGF 10. Numerous studies have shown a link between these hormone levels and levels of IGF in prepubertal boys and girls 11 and as a result such levels have been positively correlated with increased height 12,13. The levels of IGF-1 in dairy milk may have increased significantly with the increase in milk production per cow since the beginning of the agricultural revolution. This problem is compounded in the US where they can add IGFs to milking cows to increase milk production. There is some scientific debate whether homogenisation allows the hormone to be digested and consequently reach the bloodstream 14.
Insulin Growth Factor One (IGF-1) has been linked with numerous types of cancer, including prostate and breast cancer 15,16 and cow’s milk consumption has been strongly associated with an increase in hormone-dependent cancers 17. A large study, a meta-analysis, found that high intake of dairy products and calcium was associated with an increased risk of prostate cancer. Researchers found men with the highest intake of dairy products were more likely to develop prostate cancer than men with the lowest intake 18. Dose-response analyses suggested that dairy product and calcium intakes were each positively associated with the risk of prostate cancer. That is, the more dairy consumed, the higher the rates of prostate cancer 19,20,21. One study found a 5.1 times higher risk of advanced stage prostate cancer 22 while another found that milk consumption was most strongly associated with mortality rates of prostate cancer 19. A strong link has also been found between dairy consumption and testicular cancer 24,25,26.
A study of 3,300 cancer patients and 1,300 control subjects 27 comparing milk and dairy intake between the two groups found a significant association between the exclusive consumption of whole milk and increased risk of certain cancers (e.g., oral, stomach, rectum, lung, breast, etc.). Most of the subjects in the control group were drinkers of reduced fat milk or non-fat milk, linking the reduction in saturated fat to a reduction in oral and cervical cancers. A number of other studies have linked dairy consumption with breast cancer 28-32 as well as ovarian cancer 33.
Diabetes mellitus (type 1)
Cow’s milk-based infant formulas and cow’s milk consumption in childhood have been found to promote the development of type 1 diabetes mellitus and other immune-mediated or neurological diseases. The introduction of cow’s milk-based infant formula within the first three months of life is associated with increased risk of type 1 diabetes mellitus 34-38 and there are more than 100 studies linking early exposure to dairy milk to the onset of diabetes mellitus (type 1) in children who are genetically prone to the disease 37-43. The evidence for this association is overwhelming. Furthermore, in animal models of type 1 diabetes mellitus, cow’s milk proteins have been proven to lead to the development of diabetes.
In a study on newly diagnosed type 1 diabetes, researchers found that the children in the study had antibodies that were primed to attack cow’s milk proteins. These antibodies had apparently risen in response to cow proteins in their infant formula, but the antibodies were also capable of attacking the body’s insulin-producing cells. The antibodies that arose to destroy the cow’s milk protein ended up attacking the children’s insulin-producing cells. The infant’s immune system recognises these bovine proteins as foreign and forms antibodies to attack them. Unfortunately, these antibodies attack not only the cow proteins but also the insulin-producing cells in the pancreas.
There is so much concern about this that a worldwide study has begun in which children are being kept off all cow’s milk to see whether diabetes can be prevented 7.
Evidence dating back to 1976 44 shows that cow’s milk consumption is linked with the development of multiple sclerosis (MS) 45-48. One study of dairy consumption in 27 countries and 29 populations around the world found a strong correlation between liquid cow’s milk and MS prevalence; interestingly no such correlation was found with cream, butter or cheese 42.
A number of cow’s milk proteins have now been shown to be targeted by the immune cells of people with MS 7. Further, injecting the proteins into experimental animals has caused lesions to appear in the central nervous systems of the animals. Other researchers have demonstrated how certain proteins in cow’s milk mimic part of myelin oligodendrocyte glycoprotein, the part of myelin thought to initiate the autoimmune reaction in MS49.
Milk has also been linked to Parkinson’s disease (PD). Researchers found that among more than 130,000 U.S. adults followed for nine years, those who consumed the largest amount of dairy foods had an increased risk of developing Parkinson’s disease 50. Men with the highest levels of dairy consumption were 60% more likely to develop the disease than those who consumed the least amounts of dairy, particularly milk 50-54. This supports earlier findings about dairy intake and the development of PD: the same authors studied men with high dairy consumption and found that those men had an 80% higher risk. Women with moderate dairy intake were also found to be in the high-risk range for PD.
A study found that Japanese-American men in Honolulu, Hawaii who consumed more than 0.5 litres of milk per day had a 130% higher risk of PD than men who did not drink milk 52. In a study in which a total of 128 participants developed Parkinson’s disease, the risk of Parkinson’s disease increased as the amount of milk consumed each day rose. Heavy milk drinkers—those who consumed more than 16 ounces (454g) per day—were more than twice as likely to develop Parkinson’s disease than non-milk drinkers 52.
Epidemiological evidence suggests that per capita consumption of milk proteins and milk is associated with national mortality rates from heart attack or stroke 55-58. Although it does not appear to be associated with the saturated fat consumption.
Milk consumption results in significantly elevated blood levels of IGF-1 in prepubertal and pubertal individuals as well as young adults which is associated with acne 59-62.
Not a great food
Cow’s milk is not a great food for humans. What I have presented here is just a small fraction of the scientific literature highlighting the problems with milk. Perhaps in the future we will see health warnings on milk containers. Unfortunately, we have been sold a deceptive message for more than 50 years so everyone believes that “milk does a body good.”
No other animal on this planet consumes milk beyond infancy or another animals milk. Despite this humans are the only animal that suffer form such high rates of chronic illness. To complicate this equation even further we destroy many of the healthful qualities of milk by pasteurisation including enzymes and antioxidants, we then mix the fat and liquid together through homeginastion and we still call it a natural food. What beneficial qualities milk might have in very small quantities, they no longer exist when we process them out. Then add sugar and chemical colours to make flavoured milk and I could not think of a more toxic compound.
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