The influence of dairy is far-reaching. In this installment we’ll look at some of its pervasive effects in multiple aspects affecting the health of human beings.
Dairy products can block absorption of antioxidants
The phenolic-type antioxidants in fruits such as blueberries are known to decrease blood pressure and stiffness in the arteries (1). This beneficial effect of blueberries can be blocked if they are eaten with milk (2).
Teas are rich in polyphenol antioxidants. Combining milk with tea results in inhibition of the absorption of these bioactive ingredients (3).
Dairy intake is associated with acne
There is now much evidence that components of Western diets, particularly dairy products, are associated with acne. Well-designed prospective studies have elucidated the mechanisms behind the effect of foods on acne development. These mechanisms include high levels of fats, high glycemic load, low intake of fiber and hormonal effects (4).
It is well-known that acne in teenagers closely follows their hormonal activity. Milk comes from an animal that is pregnant. Levels of estrogen in both the body of the dairy cow and her milk rise during pregnancy so that levels in mid-pregnancy can be ten times higher than at the beginning of the pregnancy (5).
The Harvard Nurses study of over 47,000 women found a direct association between increasing intake of both total milk and skim milk with worsening of acne. Researchers theorized that this relationship may be due to the “presence of hormones and bioactive molecules in the milk.” (6).
A research group compared the presence of acne in teenage boys and girls with their milk intake. Results showed that those consuming more than two servings of milk a day increased their acne risk by 20% compared to those drinking milk less than once a week (7,8).
Another study presented five case reports of male patients aged 14 to 18 years who experienced the onset of acne after starting supplements of whey protein. These patients did not respond to acne treatments however their lesions cleared fully in four out of five of them after the whey protein was discontinued. Multiple brands of whey protein were used among these patients. Researchers suggest that whey protein may be the portion of dairy products that promotes acne formation (9).
A 2012 paper examined more deeply the way in which the Western diet increases the development of acne. High amounts of animal-sourced foods such as dairy and meat result in high caloric intake and glycemic load; elevated fat intake; excessive levels of leucine; and overabundance of proteins that elevate insulin and IGF-1. These deleterious factors send metabolic signals through the endocrine system that affect the activity of mTOR and its consequences on energy and growth. (mTOR is a growth-promoting enzyme that fuels early aging.) Over-activated mTOR also increases the secretion of androgenic hormones such as testosterone with direct effects on the sebaceous follicles in the skin from which acne arises. Putting a stop to this escalating process can be achieved by increasing fruits and vegetables in the diet while decreasing meats and dairy (10).
Other investigations corroborate this mechanism. An international nutrition workshop presented acne as an indicator of the exaggerated insulin production caused by Western nutrition which is linked to the major factors of acne development – activation of sebaceous glands by androgenic hormones; increased production of sebum; formation of clogged pores and blackheads and inflammation of the follicles and pores (11).
Dairy allergy can cause constipation in children
Constipation in children is a common problem that is especially troublesome when it becomes chronic, lasting longer than a few days. Though fiber and laxatives may be administered to relieve the problem, the constipation often is not lessened. One possible cause of chronic constipation is allergy to milk.
Allergy to cow’s milk protein is one of the most common food allergies in infants (12).
A 1995 study examined the relationship between chronic constipation and milk protein allergy. It included 27 infants with chronic constipation. Researchers removed cow’s milk from the diet of these children and, within three days, 21 out of 27 of them had complete disappearance of their constipation. When cow’s milk was added back to the diet the constipation returned within 24 to 48 hours. Researchers concluded that chronic constipation in children may be due to an allergy to cow’s milk protein (13).
In 1998 the same research group recruited a larger group of 65 children suffering from long-term constipation for a double-blind crossover trial. Forty-nine of these children had endured constipation for so long that they had developed an anal fissure or tear, a very painful condition. For the study the children were given either cow’s milk or soy milk for two weeks and then were switched to the other milk for the next two weeks. In 44 of the children the constipation resolved while they were drinking soy milk. Additionally their anal fissures cleared up. None of the children receiving cow’s milk had a positive response (14).
More recently, a 2012 randomized clinical trial of 140 children between the ages of 1 and 13 with chronic constipation not responding to treatment were placed into two groups. The first group received a cow’s-milk-free diet for 4 weeks followed up by two weeks on a diet containing cow’s milk. The second group, the control, drank cow’s milk for the full six weeks. After four weeks, 80% of the children receiving the cow’s-milk-free diet had responded with significantly decreased symptoms compared to 47% of the control group. The constipation reappeared in 43% of the children during the succeeding 2 week change to cow’s milk (15).
Another study found that 99 out of 136 constipated children less than 3 years of age tested positive to allergy to cow’s milk protein. After cow’s milk was eliminated from their diet, all the children improved. Researchers concluded that an allergy to cow’s milk may be the most common cause of constipation in the first 3 years of life (16).
In 2013 a trial of young participants removed all cow’s milk protein from their diets. The children had all received a diagnosis of chronic constipation before the trial. All of them who completed the trial of soy milk experienced complete disappearance of their constipation.
This research suggests that all children with constipation that is not responding to treatment should be taken off cow’s milk for a period of 6 to 8 weeks to see if their symptoms resolve.
Detrimental effects of milk on health are ubiquitous but they need not occur. Of course, infant humans need human milk for their healthiest start in life but, after weaning, milk is not a necessary food. The nutrients it contains are readily available in foods that don’t bring with them potentially harmful substances such as animal protein, saturated fat, and cholesterol. Doesn’t it just make sense to steer away from a food specifically created to double the weight of a newborn calf in just one month?
1 Johnson, S.A., Figueroa, A., Navaei, N., et al. Daily blueberry consumption improves blood pressure and arterial stiffness in postmenopausal women with pre- and stage 1-hypertension: a randomized, double-blind, placebo-controlled clinical trial. J Acad Nutr Diet. 2015;115(3):369-377.
2 Serafini, M., Testa, M.F., Villaño, D., Pecorari, M., van Wieren, K., Azzini, E., Brambilla, A., Maiani, G. Antioxidant activity of blueberry fruit is impaired by association with milk. Free Radic Biol Med. 2009 Mar 15;46(6):769-774.
3 Serafini, M., Ghiselli, A., Ferro-Luzzi, A. In vivo antioxidant effect of green and black tea in man. Eur J Clin Nutr. 1996 Jan;50(1):28-32.
4 Spencer, E.H., Ferdowsian, H.R., Barnard, N.D. Diet and acne: a review of the evidence.
Int J Dermatol. 2009 Apr;48(4):339-347
5 Danby, F.W. Acne and milk, the diet myth, and beyond. J Am Acad Dermatol. 2005 Feb;52(2):360-362.
6 Adebamowo, C.A., Spiegelman, D., Danby, F.W., Frazier, A.L., Willett, W.C., Holmes, M.D. High school dietary dairy intake and teenage acne. J Am Acad Dermatol. 2005 Feb;52(2):207-214.
7 Adebamowo, C.A., Spiegelman, D., Berkey, C.S., Danby, F.W., Rockett, H.H., Colditz, G.A., Willett, W.C., Holmes, M.D. Milk consumption and acne in teenaged boys. J. Am. Acad. Dermatol. 2008; 58(5):787-793.
8 Adebamowo, C.A., Spiegelman, D., Berkey, C.S., Danby, F.W., Rockett, H.H., Colditz, G.A., Willett, W.C., Holmes, M.D., Milk consumption and acne in adincolescent girls. Dermatology Online 2006; 12(4):
9 Silverberg, N.B. Whey protein precipitating moderate to severe acne flares in 5 teenaged athletes. Cutis. 2012 Aug;90(2):70-72.
10 Melnik, B. Dietary intervention in acne: Attenuation of increased mTORC1 signaling promoted by Western diet. Dermatoendocrinol. 2012 Jan 1; 4(1):20-32.
11 Clemens, R.A., Hernell, O., Michaelsen, K.F. (eds): Milk and Milk Products in Human Nutrition. Nestlé Nutr Inst Workshop Ser Pediatr Program, vol 67, pp 131–145. Presented at the 67th Nestlé Nutrition Institute Workshop, Pediatric Program, Marakech, March 2010.
12 Koletzko, S., et al. Diagnostic Approach and Management of Cow’s-Milk Protein Allergy in Infants and Children: ESPGHAN Gl Committee Practical Guidelines. JPGN 2012 ;55:221–229
13 lacono, G., Carroccio, A., Cavataio, F., Montalto, G., Cantarero, M.D., Notarbartolo, A. Chronic constipation as a symptom of cow milk allergy. J Pediatr. Jan 1995 ;126(1) :34-39.
14 Iacono, G., Cavatiao, F., Montalto, G., Florena, A., Tumminello, M., Soresi, M., Notarbartolo, A., Carroccio, A. Intolerance of cow’s milk and chronic constipation in children. N Engl J Med. Oct 1998 ;339(16) :1100-1104.
15 Dehghani, S.M., Ahmadpour, B., Haghighat, M., Kashef, S., Imanieh, M.H., Soleimani, M. The Role of Cow’s Milk Allergy in Pediatric Chronic Constipation: A Randomized Clinical Trial. Iran J Pediatr. Dec 2012; 22(4): 468-744.
16 Kamer, B., Dółka, E., Pyziak, K., Blomberg, A. Food allergy as a cause of constipation in children in the first three years of life – own observations. Med Wieku Rozwoj. 2011 Apr-Jun; 15(2):157-161.
17 Crowley, E.T., Williams, L.T., Roberts, T.K., Dunstan, R.H., Jones, P.D. Does Milk Cause Constipation? A Crossover Dietary Trial. Nutrients 2013; 5(1): 253-266.