Food is medicine. It can either help us in our quest for optimal health, or massively detract from it. I therefore listen carefully, with interest, to anyone in the media who makes recommendations about what to eat to prevent, or reverse, any particular degenerative or life-limiting disease. I love life, and my aim is to be as healthy as possible for as long as possible.
As a health author myself, I am committed to ensuring that all the dietary recommendations I make in my books are backed up with legitimate science. There are a lot of opinions out there; many of them conflicting, which can often leave the reader more confused than before. Many new studies relating to food and health are published every month, and I pride myself on keeping up to date with as many of them as I can. In that way, I can ensure that my books present the most balanced view of currently available science on the subject I am writing about.
I recently listened to a radio interview with Professor Mohammed Keshtgar from the Royal Free Hospital, who, together with a dietitian and a home economist, has written a cookbook for patients with breast cancer. During the interview, I was surprised to hear him say that women with this diagnosis should not avoid consuming dairy products, since treatment for breast cancer often causes the bones to become thin, so patients therefore need the calcium present in dairy products to rebuild their bone density. This statement caused me considerable concern for the following main reasons:
- Dairy products, contrary to popular belief, do not actually create bone health.
- Many research studies are indicating that high dairy product consumption is a potential risk factor for the development of breast cancer.
This is probably news to many people, because we have always been told, most likely from a young age, that we need dairy products to give us strong bones, and the one mineral we need for bone health is calcium. Let’s start with point 1 above, and take a look at some scientific studies which I read whilst researching for my latest book, Love Your Bones.
Contrary to popular belief, dairy products are not a good food choice for osteoporosis prevention and bone-building. Interestingly, whilst the bones of women in the countries with the highest dairy product consumption may seem, on average, to be denser than those with low dairy consumption, this does not appear to protect them from fractures (1). It is also now being recognised that dairy products are of little value in promoting bone health and strength in children, and a re-evaluation of dietary recommendations was suggested by prominent researchers more than ten years ago (2).
More recently, in a study published in the American Journal of Clinical Nutrition, it was stated that “Osteoporotic bone fracture rates are highest in countries that consume the most dairy, calcium and animal protein. Most studies of fracture risk provide little or no evidence that milk or other dairy products benefit bone.” (3). Other studies indicate the positive correlation between dairy product consumption and hip fractures. Fundamentally, it appears that the more dairy products you consume, the more likely you are to have fragile hip bones that break later in life (4).
Regarding the calcium story, it’s increasingly being shown that calcium isn’t nearly as important as we have been led to believe. Indeed, recently published research has gone as far as to recommend that calcium supplements should be viewed as dangerous, since they increase heart attack risk, whilst doing nothing for bone health. The authors of a study published last week in the British Medical Journal summarised the situation as follows: “Dietary calcium intake is not associated with risk of fracture, and there is no clinical trial evidence that increasing calcium intake from dietary sources prevents fractures. Evidence that calcium supplements prevent fractures is weak and inconsistent.” (5).
In Love Your Bones, I put forward a comprehensive discussion on why concentrating only on calcium, or dairy products, is erroneous, and why this approach gives no benefit for bone health. I focus on the frequently overlooked minerals and vitamins which are essential for bone building, and without which bone will not grow strong, no matter how much calcium we consume. I explain why we need sunlight for vitamin D, why vitamin K2 is just as important as vitamin D, why we must control homocysteine levels if we want strong bones, and why magnesium, boron and manganese cannot be overlooked. Without these essential elements, we’ll suffer greatly. Importantly, I also discuss why dairy product consumption, past the natural weaning age of humans, is an erroneous choice, and the other health problems this habit can cause.
Within the scientific literature, studies into the effects of dairy product consumption and incidence of breast cancer are conflicting. More recent studies seem to show that it is the hormones present in commercially produced dairy products which are the most harmful aspect of dairy product consumption in regard to the formation of breast tumours. One of the main causative factors for the development of breast cancer is known to be lifetime cumulative exposure to oestrogen, and approximately 80 per cent of all exogenous (environmental) oestrogen derives from the consumption of dairy products (6). Researchers involved in a study published in 2005 have additionally stated:
“Increased consumption of animal-derived food may have adverse effects on the development of hormone-dependent cancers. Among dietary risk factors, we are most concerned with milk and dairy products, because the milk we drink today is produced from pregnant cows, in which oestrogen and progesterone levels are markedly elevated.” (7). Could it be possible that it is older studies involving dairy product consumption which indicate no correlation with breast cancer risk, and now that the type of milk consumed is changing, and has a higher hormonal content, we will start to see more positive correlations? Only time will tell. Is it a risk which we should be encouraged to take? I doubt it, since it isn’t just women who suffer from hormonally-linked cancers. It has already been shown that men are adversely affected by dairy product consumption in relation to prostate health, with the oestrogen content being particularly implicated (8). I did find other research publications on the subject of oestrogens in dairy products which seemed to play down any potential risks. However, the authors of these papers were in some way associated with the dairy industry, so cannot be considered to be independent.
Insulin-like Growth Factor-1 (IGF-1) is a compound which, under unhealthy conditions, promotes malignancy, metastasis and cell division, and it also interferes with cellular apoptosis (programmed cell death). The body makes small quantities of this hormone as required for its biological functions, but additionally it is present in dairy products and is considered to be one of the ways in which dairy product consumption stimulates the cancer process; particularly in relation to prostate cancer. Prostate cancer is now affecting one in six men in North America, and those who consume the most dairy products have twice the incidence of the disease, with four times the metastasis rate, compared with those whose consumption is minimal (9).
Despite mounting evidence, there may be some who remain unconvinced that dairy product consumption is potentially harmful when one is diagnosed with breast cancer, although consuming what is essentially bovine growth fluid is inherently an unnatural thing for the adult human to be doing. What is definite though, and supported by many scientific studies, is that eating and drinking dairy products is a highly inappropriate activity for people who want to promote bone health and strength, and should no longer be recommended.
- Ho SC. “Body measurements, bone mass and fractures: does the East differ from the West?” Journal of Clinical Orthopaedics and Related Research 323 (1996): 75-80.
- Lanou AJ, Berkow SE, Barnard ND. “Calcium, Dairy Products, and Bone Health in Children and Young Adults: A Reevaluation of the Evidence.” Pediatrics 115 No. 3 March 1, 2005 pp. 736 -743.
- Lanou AJ. “Should dairy be recommended as part of a healthy vegetarian diet? Counterpoint.” Am J Clin Nutr. 2009 May;89(5):16385-16425.
- Frassetto LA, Todd KM, Morris C, Jr et al. “Worldwide incidence of hip fracture in elderly women: relation to consumption of animal and vegetable foods”. Journal of Gerontology 55 (2000): M585-M592.
- Bolland MJ, Leung W, Tai V et al. “Calcium intake and risk of fracture: systematic review.” BMJ 2015;351:h4580
- Joseph Keon. The Real Truth about Health Conference, New York: January 2014.
- Ganmaa D, Sato A. “The possible role of female sex hormones in milk from pregnant cows in the development of breast, ovarian and corpus uteri cancers.” Med Hypotheses 2005;65(6):1028-37.
- Li XM, et al, Chinese publication, 2003 Jun;9(3) 186-190.
- Chan JM, Stampfer MJ, Ma J et al. “Insulin-like Growth Factor-1 (IGF-1) and IGF binding protein-3 as predictors of advanced-stage prostate cancer.” Journal of the National Cancer Institute 94 (2002): 1099-1109.