Does milk really do a body good?

Those milk mustaches may look really cool, but it may be time to look more closely at the long term health effects of milk. A recent Scandinavian study showed that drinking milk may be damaging for your bones and your health overall. This is only one of a number of studies indicating that milk may need to be reconsidered when it comes to preventing osteoporosis and bone fractures.

Bottle and glass of milkFor example, in the large Harvard study which looked at male and female health professionals, individuals that drank one glass or less of calcium per week were at no greater risk of bone fractures than those that drank two or more glasses per week.[i][ii] More recent studies were more concerning, demonstrating not only a lack of benefits but potential damaging effects associated with milk. For instance, the results of a 2014 study where patients were followed for 22 years showed that greater milk consumption during teenage years leads to an increase in the risk of bone fractures in men while women saw no benefits for fracture prevention.[iii]

The latest study was probably the most damming. Scandinavian researchers used two large patient groups comprised of more than one hundred thousand patients and evaluated their milk intake based on food frequency questionnaires.[iv] The questionnaires were repeated after roughly twenty years for women and about eleven years for men. The results showed that higher milk consumption (more than three glasses of milk per day) increased the risk of mortality in men and women and also increases the incidence of bone fractures in women. The researchers then looked at potential causes for these ill-effects.

Animal studies had previously showed that one of the main sugars in milk, galactose, can increase inflammation and oxidative stress or free radical damage.[v][vi][vii] Essentially, research showed that galactose, which comes from the breakdown of lactose is very “sticky”, forming permanent bonds with proteins in the body, leading to accelerated aging, memory deficits, damage to tissues, inflammation and free radical damage. It is therefore not surprising that in this latest human study milk consumption was associated with increased levels of oxidative stress and increased inflammatory markers in men.

This association was not found for cheese intake or other fermented dairy products. The likely explanation for this is that fermented dairy products have much lower sugar content. As any lactose intolerant person can tell you, milk is very high in lactose containing 9-14% of this milk sugar while hard cheeses contain far less at roughly 2%.

Although more studies are needed to confirm these findings and exclude potential confounding factors, the evidence so far seems to indicate that the health benefits of milk, especially when it comes to the prevention of fractures need to be re-evaluated.

 

Ludovic Brunel ND 

Ludovic BrunelDr. Ludovic Brunel graduated with a degree in Human Nutrition from McGill University in Montreal and pursued his studies in Naturopathic Medicine at the Canadian College of Naturopathic Medicine in Toronto.

 

 

 


 

References

[i] Owusu W, Willett WC, Feskanich D, Ascherio A, Spiegelman D, Colditz GA. Calcium intake and the incidence of forearm and hip fractures among men. J Nutr. 1997; 127:1782–87.

[ii] Feskanich D, Willett WC, Stampfer MJ, Colditz GA. Milk, dietary calcium, and bone fractures in women: a 12-year prospective study. Am J Public Health. 1997; 87:992–97.

[iii] Feskanich D, Bischoff-Ferrari HA, Frazier AL, Willett WC. Milk consumption during teenage years and risk of hip fractures in older adults. JAMA Pediatr. 2014 Jan;168(1):54-60.

[iv] Michaëlsson K, Wolk A, Langenskiöld S, Basu S, Warensjö Lemming E, Melhus H, Byberg L. Milk intake and risk of mortality and fractures in women and men: cohort studies. BMJ. 2014 Oct 28;349:g6015.

[v] Song X, Bao M, Li D, Li YM. Advanced glycation in D-galactose induced mouse aging model. Mech Ageing Dev. 1999 May 17;108(3):239-51.

[vi] Cui X, Zuo P, Zhang Q, Li X, Hu Y, Long J, Packer L, Liu J. Chronic systemic D-galactose exposure induces memory loss, neurodegeneration, and oxidative damage in mice: protective effects of R-alpha-lipoic acid. J Neurosci Res. 2006 Aug 15;84(3):647-54.

[vii] Hao L, Huang H, Gao J, Marshall C, Chen Y, Xiao M. The influence of gender, age and treatment time on brain oxidative stress and memory impairment induced by d-galactose in mice. Neurosci Lett2014;571C:45-9.

 


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