Cow’s milk friend or foe

Recently cow’s milk has gotten a bad rap and with many inconsistent information regarding cow’s milk and health. Is milk really that bad, we have been drinking milk for centuries? If you suffer from specific conditions such as a milk protein allergy or lactose intolerance milk will not be your friend. But milk has many benefits and especially in the sporting world. Let’s unpack this further.  

The composition of milk

About 80% of full cream cow’s milk consists out of water, while 20% consist out of solids. The solids consist of 27% protein, 37% lactose, 30% fat and 6% vitamins and minerals. Full cream milk contains > 3.5% fat, low fat 1.5-1.8% and skimmed milk less than 1.5% fat. About 60% of the fatty acids found in milk are saturated fatty acids, but it also contains essential fatty acids, omega-6 and omega-3. The protein we find in milk consist of 20% Whey and 80% Casein. These are both high quality, complete proteins. Meaning it contains all 20 amino acids and both are high in leucine.  Milk is also an excellent source of calcium. The mineral that plays an important role in bone health. This is especially important in children who are still growing and in older individuals it will reduce the risk of osteoporosis. Calcium is also present in other plant-based foods, but when we consider the energy value per serving and the relative cost of each food item, cow’s milk still remains the more advantageous calcium dietary source, supplying energy, high-quality protein, calcium, and essential fatty acids at a fairly low cost. Some research has also shown that dairy products are more effective than calcium supplements at increasing bone mineral density. Other minerals include phosphorus, potassium, magnesium, zinc and selenium. Vitamins in milk include Vitamin B2 and B12 and fat-soluble vitamins A & E, which may be better absorbed in full-cream milk. Many milks are also fortified with Vitamin D.  

Milk in sport 

After a hard training session there are 3 important recovery goals: rehydrate, refuel and repair. Milk can address all three those goals. As mentioned earlier milk consist out of a lot of water, but it also contains many electrolytes which are effective in promoting rehydration. Combined with the carbohydrate and protein it helps with fluid retention. The rehydration capacity of milk is comparable to that of sports drinks and may even be better. The carbohydrate source in milk is called lactose, which helps to refuel our carbohydrate stores. Chocolate milk is a popular recovery milk, with the added sucrose it further helps to refill both our liver and muscle carbohydrate stores. While the high-quality protein found in milk is used to rebuild our muscles. Milk will give a better bang for your buck compared to protein supplements and comes without the risk of consuming contaminated substances. Therefore consuming 250 – 500 ml of milk 1 hour exercise will promote hydration, muscle recovery and refill carbohydrate stores.  

Milk as foe 

Lactose intolerance and milk allergy are often confused by the general public and considered as the same thing. A milk allergy is usually triggered by one of more of the cow’s milk proteins (casein or serum albumin) and are especially common in infancy, but about 80-90% of children outgrow the allergy by adulthood. The allergic reactions are mediated by immunoglobulin E (IgE) and symptoms varies from skin reactions to more severe anaphylactic shock, or non-IgE mediated which usually cause gastrointestinal disorders. Depending on the severity of reaction, people with milk allergies should rather avoid dairy products or only eat very same amounts. Lactose intolerance on the other hand is caused by the absence or reduction of the enzyme lactase, needed to digest lactose. If the lactose is not digested is stays in the lower intestines and result in stomach cramps, abdominal pain, bloating and diarrhea. People with lactose intolerance can generally consume up to 12 g of lactose in a single dose without experiencing any symptoms. By adding small amounts of lactose to your diet it is possible to increase your tolerance.  Milk contains about 5 grams of lactose per 100ml, while other dairy products such as ripened cheese and certain yoghurts can very little amounts of lactose.  

Milk myths 

Does cow’s milk increase your risk of developing heart disease?  

This is probably due to the high portion of saturated fatty acids in milk, known to increase LDL cholesterol levels, which is a recognized risk factor for coronary heart disease. However, based on current research the risk of coronary heart disease is generally unchanged or not significantly increased by milk consumption and the risk for strokes is reduced. 

Does cow’s milk cause cancer? 

There are some theories that cow’s milk consumption is associated with the incidents of specific cancers. However, the results of epidemiological studies including 8000 cases did not observe any significant associations between milk consumption and total tumor incidence.  

Does cow’s milk increase risk of developing type 2 diabetes? 

Dairy consumption has been linked to type 2 diabetes incidence. But based on the current available studies total diary consumption is associated with a lower risk of type 2 diabetes, especially when consuming yoghurt and low-fat milk. The relative risk was reduced by 11% in subjects consuming 200 g per day of low-fat milk.

Conclusion

Cow’s milk is a great source of both macro- and micronutrients needed for health and sport performance. Based on scientific literature most of the associates between milk consumption and health are beneficial.  

References 

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Guo J, Astrup A, Lovegrove JA, Gijsbers L, Givens DI, Soedamah-Muthu SS. Milk and dairy consumption and risk of cardiovascular diseases and all-cause mortality: Dose–response meta-analysis of prospective cohort studies. Eur J Epidemiol. 32(4):269–287, 2017. 

Gallus S, Bravi F, Talamini R, Negri E, Montella M, Ramazzotti V, Franceschi S, Giacosa A, La Vecchia C. Milk, dairy products and cancer risk (Italy). Cancer Causes Control. 17(4):429–437, 2006. 

Manios Y, Moschonis G, Trovas G, Lyritis GP. Changes in biochemical indexes of bone metabolism and bone mineral density after a 12-mo dietary intervention program: the Postmenopausal Health Study. The American Journal of Clinical Nutrition. 86(3):781-9, 2007. 

Marangoi et al. Cow’s milk consumption and health: A health professional’s guide. Journal of the American College of Nutrition. 38 (3), 197-208, 2019. 

Misselwitz B, Pohl D, Fruhauf H, Fried M, Vavricka SR, Fox M. Lactose malabsorption and intolerance: pathogenesis, diagnosis and treatment. United European Gastroenterol J. 1(3):151-9, 2013 

Seery S & Jakeman P. A metered intake of milk following exercise and thermal dehydration restores whole-body net fluid balance better than a carbohydrate-electrolyte solution or water in healthy young men. BJN. 116(6): 1013-1021, 2016. 

Shirreffs, MS, Watson P, Maughan RJ. Milk as an effective post-exercise rehydration drink. BJN. 98: 173-180, 2007.