Is cow’s milk good for muscles?

A buddy of mine made a casual comment the other day about how ‘milk makes your muscles huge’. As a soy-milk drinker for many years (personal choice – not due to lactose intolerance, cow activism, etc… more due to the fact that as human milk is for human babies, I feel cow’s milk should be for cow babies) I was incredulous and slightly pompous in my internal laughing.

Anyway, I’ve always thought this ‘milk helps muscle growth’ was a bit of a myth. So, let’s look at the evidence. Quite frankly I don’t think there are even going to be any papers on the topic…

As search on PubMed revealed, er, more than 1 study. My look of incredulousness is fading to one of relaxed surprisedness (a bit like when you’re drunk and someone walks in on you at the pub loo). A good proportion of these studies dealt with how if we pump lactating bovines full of crap, we can increase their milk output. Poor Bessie.

There were however some relevant findings:

There is epidemiological (population-based) evidence that consumption of dairy products is associated with a lower prevalence of metabolic disorders. Dairy protein helps loss of body fat and fat mass through enhanced satiety (feeling full) and also promotes skeletal muscle growth and function through the anabolic effects of dairy protein-derived branch chain amino acids (BCAAs). BCAAs improve muscle protein synthesis, lean body mass, and skeletal muscle metabolic function.

Milk proteins (especially casein and whey) are the highest quality proteins and whey protein is able to support muscle protein synthesis the bestest (well, better than soy protein) – which is why whey protein supports greater net muscle mass gains with resistance exercise. (FYI milk is approximately 20% whey protein).

On the topic of soy, another study looked at cow vs soy-milk and their effect on sex hormones following a bout of heavy resistance exercise in ‘trained’ men. It found that there were lower testosterone responses following supplementation with soy protein. Not what dudes want.

Milk is not just good for dudes, but also for chicks. There are many studies showing that female athletes have improved performance and decreased body fat composition when ingesting protein with daily resistance training and conditioning. One of these also showed improved bone metabolic status (in this case it is most likely that the evil effects of milk on bone – see my rant later – were overcome by the beneficial effects of resistance exercise). Some of this papers however had study design faults – for instance in one, there was no control group; they just compared two different types of proteins.

OK, so epic fail on the ‘milk does not cause muscle growth’ front… except for old dudes.

The benefits of milk on muscles do not exist for old dudes (sorry, like the prostate issue wasn’t enough…) – milk has no effect on muscle size, strength or function in healthy middle-aged and older men.

There you have it – milk does appear to be pretty awesome for muscles.

Before you go, here are some other studies in the general domain of milk/ protein/ muscle/ anything I want (I know… very poor segway).

(Interestingly, the ‘segway’ that everyone is dropping when transitioning from one topic to another, should actually be segue, which comes from Italian seguire, meaning ‘to follow’. There’s an unimportant irrelevant fact you didn’t know you didn’t need to know!).

One study (bravely) investigated the optimal timing for protein supplementation when working out. Those of you who know will NEVER get in the way of a man and his protein shake, because that delay of 30 seconds could cost him at least 20 muscle fibres which would mean instant muscle (and therefore ego) death. Fat-free milk post-workout was effective at increasing lean body mass, strength, muscle hypertrophy and decreases in body fat. The consumption of 3-4g of leucine is needed to promote maximum protein synthesis (pause to do massive flex and inspect own biceps). The optimal post-workout replacement should include whey protein with at least 3g leucine per serving, as well as maltodextrin or glucose (to stimulate insulin, which transports the leucine). There was no mention of exactly what length of time post workout you should allow before ingesting the hallowed nectar of protein… And I did laugh at the final study conclusion “to enhance muscle growth and strength, a weight-training programme should be followed for at least 12 weeks with movements for both upper and lower body”. No shit.

Oh, and for the dudes trying to bulk up on soy-protein shakes… Milk is better at promoting muscle growth and retention than soy-based proteins. The same buddy advised that “soy protein is made from oestrogen and romance novels, and synthesised in the tear ducts of depressed vegan mice”. Nicely worded.

Other studies have found milk to be a better rehydration beverage than commercially available sports drinks (most of which are essentially sugar and colourings, blegh). Another awesome conclusion in this study… “bovine low-fat fluid milk is a safe and effective post exercise beverage for most individuals, except for those who are lactose intolerant”. Yeah, bummer for them. Awesome loosely associated pun there.

And why only discuss cow’s milk – what about the benefits of boobie? They harp on about stronger immune systems, mother’s weight loss, blah blah, BUT midwives are failing to mention the most important benefit of all – a study from the UK found that men who were breastfed as infants had a higher grip strength as an adult. Which begs the question – who dropped a tab and thought up this study? The same relationship between breast milk and grip strength did not exist for women. This information I’m sure has men worldwide berating their mothers as the reason for their failed grip after doing 1,000,000,000kg deadlifts.

Are there any reasons NOT to drink cow’s milk? I say yes, but read the following and decide for yourself…

Osteoporotic fracture risk: milk intake has been pushed for ages as a method for reducing osteoporosis BUT studies have shown that increased intake of calcium from dairy products does not protect against osteoporosis and in fact results in increased fracture risk. (Dairy – as well as other animal proteins – leaches calcium from the bones, and it goes bye-bye in your pee-pee.)

Cancer risk: some cancers have been linked to the consumption of dairy products (eg. Ovarian, breast, prostate). This is thought to be in part due to increased levels of IGF-I (insulin-like growth factor) found in cow’s milk.

Insulin dependent diabetes risk: dairy proteins can trigger an autoimmune reaction (which destroys the pancreatic cells that make insulin).

Contaminants: valid concern unless you’re getting the milk straight from the udder. It would be so great to have one stationed in the lunchroom, but these days management are all about coffee machines instead.

Risks specific to youngsters: constipation, abnormal body weight, iron deficiency anaemia.

There are other risks too, but I’ll stop here. Don’t want the milk-lovers to go all boo-hoo on me…

Wang P, Drackley JK, Stamey-Lanier JA, Keisler D, Loor JJ. Effects of level of nutrient intake and age on mammalian target of rapamycin, insulin, and insulin-like growth factor-1 gene network expression in skeletal muscle of young Holstein calves. J Dairy Sci. 2014 Jan;97(1):383-91. doi: 10.3168/jds.2013-7042. Epub 2013 Nov 7.
McGregor RA, Poppitt SD. Milk protein for improved metabolic health: a review of the evidence. Nutr Metab (Lond). 2013 Jul 3;10(1):46. doi: 10.1186/1743-7075-10-46.
Robinson SM, Simmonds SJ, Jameson KA, Syddall HE, Dennison EM, Cooper C, Sayer AA; Hertfordshire Cohort Study Group. Muscle strength in older community-dwelling men is related to type of milk feeding in infancy. J Gerontol A Biol Sci Med Sci. 2012 Sep;67(9):990-6. doi: 10.1093/gerona/gls061. Epub 2012 Mar 15.
Phillips SM, Tang JE, Moore DR. The role of milk- and soy-based protein in support of muscle protein synthesis and muscle protein accretion in young and elderly persons. J Am Coll Nutr. 2009 Aug;28(4):343-54.
Feskanich D, Willet WC, Stampfer MJ, Colditz GA. Milk, dietary calcium, and bone fractures in women: a 12-year prospective study. Am J Public Health 1997;87:992-7.
Cumming RG, Klineberg RJ. Case-control study of risk factors for hip fractures in the elderly. Am J Epidemiol 1994;139:493-505.
Huang Z, Himes JH, McGovern PG. Nutrition and subsequent hip fracture risk among a national cohort of white women. Am J Epidemiol 1996;144:124-34.
Cummings SR, Nevitt MC, Browner WS, et al. Risk factors for hip fracture in white women. N Engl J Med 1995;332:767-73.
Outwater JL, Nicholson A, Barnard N. Dairy products and breast cancer: the IGF-1, estrogen, and bGH hypothesis. Medical Hypothesis 1997;48:453-61.
Chan JM, Stampfer MJ, Giovannucci E, et al. Plasma insulin-like growth factor-1 and prostate cancer risk: a prospective study. Science 1998;279:563-5.
Wilborn CD, Taylor LW, Outlaw J, Williams L, Campbell B, Foster CA, Smith-Ryan A, Urbina S, Hayward S. The Effects of Pre- and Post-Exercise Whey vs. Casein ProteinConsumption on Body Composition and Performance Measures in Collegiate Female Athletes. J Sports Sci Med. 2013 Mar 1;12(1):74-9. eCollection 2013.
Kraemer WJ, Solomon-Hill G, Volk BM, Kupchak BR, Looney DP, Dunn-Lewis C, Comstock BA, Szivak TK, Hooper DR, Flanagan SD, Maresh CM, Volek JS. The effects of soy and whey protein supplementation on acute hormonal reponses to resistance exercise in men. J Am Coll Nutr. 2013;32(1):66-74. doi: 10.1080/07315724.2013.770648.
Stark M, Lukaszuk J, Prawitz A, Salacinski A. Protein timing and its effects on muscular hypertrophy and strength in individuals engaged in weight-training. J Int Soc Sports Nutr. 2012 Dec 14;9(1):54. doi: 10.1186/1550-2783-9-54.
Josse AR, Phillips SM. Impact of milk consumption and resistance training on body composition of female athletes. Med Sport Sci. 2012;59:94-103. doi: 10.1159/000341968. Epub 2012 Oct 15. Review.
Josse AR, Tang JE, Tarnopolsky MA, Phillips SM. Body composition and strength changes in women with milk andresistance exercise. Med Sci Sports Exerc. 2010 Jun;42(6):1122-30.
Kukuljan S, Nowson CA, Sanders K, Daly RM. Effects of resistance exercise and fortified milk on skeletal muscle mass, muscle size, and functional performance in middle-aged and older men: an 18-mo randomized controlled trial. J Appl Physiol (1985). 2009 Dec;107(6):1864-73.
Roy BD. Milk: the new sports drink? A Review. J Int Soc Sports Nutr. 2008 Oct 2;5:15. doi: 10.1186/1550-2783-5-15.
Wilkinson SB, Tarnopolsky MA, Macdonald MJ, Macdonald JR, Armstrong D, Phillips SM. Consumption of fluid skim milk promotes greater muscle protein accretion after resistance exercise than does consumption of an isonitrogenous and isoenergetic soy-protein beverage. Am J Clin Nutr. 2007 Apr;85(4):1031-40. Erratum in: Am J Clin Nutr. 2013 Aug;98(2):512.

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