Milk — what the science says

In a nutshell

Most adults in the world digest lactose poorly, yet most of them can usually handle a glass of milk.^1,2
According to the studies so far, drinking milk does not prevent hip fractures.³
Dairy products probably lower the risk of colorectal cancer — mainly thanks to calcium.⁴

1Lactose: most of the world can't digest it

Strong evidence 68% of adults worldwide have a reduced ability to digest the milk sugar lactose. It varies with ancestry: in northern and western Europe the share is much lower than in Asia or Africa.¹

In most people, lactase — the enzyme that breaks down lactose — weakens after childhood. In some people, mainly those with northern European ancestors, it stays active for life.¹

Strong evidence 12 g of lactose at once — roughly a glass of milk — causes no or only minor symptoms in the vast majority of people who digest lactose poorly. Spread over the day, even more is fine.²

2Bones: less simple than it seems

Moderate evidence An analysis of cohort studies with almost 200,000 women found no link between how much milk they drank and their risk of hip fracture. For men there were too few data for a clear conclusion.³

Bones do need calcium, but according to these data milk alone is no miracle protection against fractures.

3Calcium and the colon

Strong evidence According to the World Cancer Research Fund, dairy products probably reduce the risk of colorectal cancer. The main explanation is calcium.⁴

Fact ~300 mg of calcium in a glass of milk (250 ml).⁶ The European Food Safety Authority recommends 950 mg of calcium a day for adults aged 25 and over.⁵

4Protein for muscles

Strong evidence Milk contains high-quality proteins — whey and casein — with all the essential amino acids. Experts recommend 1.4–2.0 g of protein per kilogram of body weight a day for people who exercise.⁷

What to take from this

You like milk and it agrees with you? It is a good source of calcium and protein.
Milk upsets your stomach? Try smaller portions spread over the day, or lactose-free milk.²
Calcium doesn't have to come only from milk — ForkRep counts it from everything you eat.

Sources

Written on 7 Oct 2026, based on studies available at that date. Newer research may change the conclusions.

Storhaug C. L., Fosse S. K., Fadnes L. T. (2017). Country, regional, and global estimates for lactose malabsorption in adults: a systematic review and meta-analysis. Lancet Gastroenterology & Hepatology 2(10):738–746. pubmed.ncbi.nlm.nih.gov/28690131
EFSA NDA Panel (2010). Scientific Opinion on lactose thresholds in lactose intolerance and galactosaemia. EFSA Journal 8(9):1777. doi.org/10.2903/j.efsa.2010.1777
Bischoff-Ferrari H. A. et al. (2011). Milk intake and risk of hip fracture in men and women: a meta-analysis of prospective cohort studies. Journal of Bone and Mineral Research 26(4):833–839. pubmed.ncbi.nlm.nih.gov/20949604
World Cancer Research Fund / American Institute for Cancer Research (2018). Diet, nutrition, physical activity and colorectal cancer — Continuous Update Project. wcrf.org
EFSA NDA Panel (2015). Scientific Opinion on Dietary Reference Values for calcium. EFSA Journal 13(5):4101. doi.org/10.2903/j.efsa.2015.4101
USDA ARS. FoodData Central — whole milk (calcium about 113–120 mg per 100 g). fdc.nal.usda.gov
Jäger R. et al. (2017). International Society of Sports Nutrition Position Stand: protein and exercise. JISSN 14:20. doi.org/10.1186/s12970-017-0177-8

This is general information and does not replace a doctor or dietitian. If you are allergic to cow's milk protein (which is something else than lactose intolerance), avoid dairy as your doctor advises.