Milk…good or bad, full fat or low fat?

I’m sure we have a been told by our parents to drink up our milk for our bones and teeth or been told skimmed milk is better for you. But does current scientific evidence support these claims?

A new scientific paper published in the prestigious New England Journal of Medicine looked at the available science in relation to dairy consumption, specifically milk, in relation to human health. The paper highlights some surprising findings which are summarised as follows:

• To increase milk production, cows have been bred to produce higher levels of insulin-like growth factor I (IGF-I), and they are pregnant for most of the time they are milked, which greatly increases levels of progestins, estrogens, and other hormones in milk consumed by humans.
• Pasteurization reduces transmission of brucellosis, tuberculosis, and other pathogens.
• Fermentation (to produce aged cheese, yoghurt, kefir, and other products) denatures peptide hormones, alters protein antigens, reduces lactose content, and affects bacterial composition.
• Although normal growth and development can be obtained in childhood without dairy products with a good quality diet, milk consumption appears to augment longitudinal growth and attained height.
• Evidence shows that paradoxically, countries with the highest intakes of milk tend to have the highest rates of hip fractures. This relationship is not fully understood.
• In relation to weight control, well-controlled studies reported no overall effects of milk or other dairy foods on body weight in adults.
• Some studies have shown that in children, intake of low-fat milk is positively associated with a gain in body-mass index (BMI, but intakes of full-fat milk and dairy fat were not. This weight gain associated with low-fat milk in children was accounted for in studies by higher energy intake.
• In prospective cohort studies, neither whole milk nor low-fat milk has been clearly associated with the incidence of, or mortality associated with, coronary heart disease or stroke.
• Large meta-analyses of studies to date suggest dairy consumption is not associated with or has only a weak weakly associated with a lower risk of type 2 diabetes.

The authors conclude that from research to date that an acceptable intake of dairy should be 0 to 2 servings per day for adults, whole milk is preferable to reduced-fat milk, and consumption of sugar-sweetened dairy foods should be discouraged.

Take away message: moderate amounts of full-fat milk do not appear to have detrimental health effects in adults or children and low fat, or sugar-sweetened milk drinks should be avoided, especially in children.

Reference: Willett WC, Ludwig DS: Milk and Health. N Engl J Med 2020, 382(7):644-654.

Full research paper