Which milk is safer for your heart? Decades of Norwegian data provide the answer

By Hugo Francisco de SouzaReviewed by Susha Cheriyedath, M.Sc.Aug 5 2025

Fascinating research from Norway reveals that choosing low-fat milk over whole milk could lower your risk of dying from heart disease or any cause, reshaping decades of dietary advice.

Study: Low-fat and Whole Milk Consumption in relation to Cardiovascular and All-Cause Mortality: A prospective cohort study in three Norwegian counties. Image Credit: Hitra / Shutterstock

In a recent study published in The American Journal of Clinical Nutrition, researchers leveraged data from an extensive long-term Norwegian cohort to investigate associations between milk consumption (specifically whole versus low-fat milk) and cardiovascular disease (CVD) or mortality outcomes.

Study findings reveal that high overall milk consumption is associated with increased all-cause and cardiovascular mortality. Whole milk was linked to statistically increased mortality risk compared to low-fat milk, reinforcing current public health recommendations.

Background

One of nutrition science's most enduring and heated debates is that of dietary fats. In particular, saturated fatty acids (SFA) from dairy products have remained at the center of nutritional discourse. While public health recommendations have favored the consumption of low-fat (or fat-free) dairy for decades, critics cite a persistent lack of evidence in challenging these conventions.

Public health agencies claim that low- or fat-free dairy lowers consumers' risk of cardiovascular disease (CVD). This advice is based on the known effect of SFA on raising low-density lipoprotein (LDL; "bad") cholesterol. However, the evidence directly linking full-fat dairy to adverse health outcomes has been inconsistent, with some studies even suggesting that dairy fat may be less harmful than SFA from other sources.

To robustly describe the effects of different milk types on CVDs, a long-term study of a large cohort of participants is required. Understanding these effects would help resolve this debate and inform future public health policy, especially relevant in today's growing CVD burden.

About the study

The present study leverages the unique historical context of the Norwegian population. In the 1970s, whole milk consumption dominated in the country, but was replaced by low-fat milk in the 1980s. This context provides a powerful natural experiment to investigate the long-term health consequences of these different milk choices.

Specifically, the study utilized data from the Norwegian Counties Study conducted by the National Health Screening Service. The study encompassed individuals from three counties: Finnmark, Sogn and Fjordane, and Oppland. Data comprised three cardiovascular health screenings conducted between 1974 and 1988, with high attendance rates in each wave.

Additionally, dietary intake data (milk consumption, including frequency and subtype) were assessed using a semi-quantitative food frequency questionnaire (FFQ). This repeated measures approach allowed the researchers to calculate a "cumulative mean intake," which proved crucial for detecting associations, as baseline-only analyses showed attenuated results.

The study's primary outcomes of interest included mortality from CVD, ischemic heart disease (IHD), acute myocardial infarction (AMI), and all causes. Mortality data were tracked through linkage with the national Cause of Death Registry.

Statistical analyses incorporated Cox proportional hazards regression models to estimate the hazard ratios (HRs) for mortality, carefully adjusting for a wide range of potential confounders, including participants' age, sex, body mass index (BMI), smoking status, physical activity levels, educational qualifications, and intake of other dietary sources of saturated fat.

Study findings

The final sample cohort comprised 73,860 individuals (mean age = 41.2 years at baseline). Over the median follow-up of 33 years, the study recorded 26,393 deaths, including 8,590 from CVD. Regression models revealed a clear positive association between high milk consumption and mortality.

Individuals in the highest quintile of milk intake had a 22% higher risk of all-cause mortality (HR = 1.22; 95% CI 1.16–1.28) and a 12% higher risk of CVD mortality (HR 1.12; 95% CI 1.03–1.21) compared to those in the lowest consumption quintile.

Subgroup analyses of milk consumption by type, however, revealed that the harmful associations were primarily driven by whole milk, which was significantly associated with increased risk of death from all causes (HR 1.15; 95% CI 1.10–1.21), ischemic heart disease (HR 1.13; 95% CI 1.01–1.27), and cardiovascular disease, though the CVD association was borderline significant (HR 1.07; 95% CI 0.99–1.16 for highest consumers). In contrast, compared to non-consumers, low-fat milk consumption was not associated with increased mortality risk.

Most importantly, when directly comparing the two among consumers while adjusting for total milk quantity, consuming low-fat milk was associated with a 7–11% lower mortality risk than consuming whole milk. Low-fat milk drinkers had an 11% lower risk of all-cause mortality (HR 0.89; 95% CI 0.87–0.92) and a 7% lower risk of CVD mortality (HR 0.93; 95% CI 0.88–0.98) compared to whole milk drinkers. These associations were stronger in women and normal-weight individuals.

Conclusions

The present study presents robust, long-term (33 years) and extensive cohort (n = 73,860) evidence addressing the decades-long debate on the health associations between milk consumption and CVD or mortality outcomes.

While restricted to a Norwegian sample cohort and hence not globally generalizable without further investigation, and relying on self-reported dietary data, it highlights that whole milk is associated with a greater risk of cardiovascular and all-cause mortality in a population with high milk consumption, while low-fat milk is not. The findings remained consistent even after excluding early deaths or participants with pre-existing conditions.