A recent study published in the Journal of Dairy Science sheds light on the growing burden of colorectal cancer (CRC) in countries with low milk intake. The research examines the effects of inadequate milk consumption, a key source of calcium, vitamin D, protein, and phosphorus, on health outcomes such as cancer. While milk has long been associated with bone health, immunity, and overall well-being, a diet low in milk has been linked to an increased risk of several chronic diseases, including cancer, cardiovascular diseases (CVDs), and osteoporosis.
About the Study
The study evaluated the disease burden attributed to low milk consumption using data from the Global Burden of Diseases (GBD) 2021 study. This extensive analysis covers the burden of 371 diseases, impairments, injuries, and 88 risk factors across 204 countries and territories from 1990 to 2021. Researchers focused on the impact of low milk intake on two major cancers: prostate cancer and colorectal cancer (CRC).
The study found that CRC burden increased by 12% faster than the global average among adults under 50 in rapidly developing nations. This trend signals shifting dietary risks in urbanizing populations, where milk consumption may be lower than optimal levels. In contrast, areas with higher milk intake have generally seen improvements in cancer-related health outcomes.
Key Findings
The study found that replacing dairy milk with plant-based alternatives correlated with a 3-8% higher CRC risk in regions such as North America and Europe, where such dietary changes are common. The findings indicated that CRC-associated age-standardized mortality rates (ASMR) and disability-adjusted life years (DALYs) have fluctuated between 1990 and 2021. Although the global CRC-associated ASMR decreased slightly from 2.22 per 100,000 in 1990 to 1.87 in 2021, the global CRC-associated ASDR also decreased from 51.52 to 42.9 during the same period.
Interestingly, the prostate cancer ASMR and ASDR showed smaller changes. While the study reported a decline in CRC burden, the prostate cancer rates remained more stable.
One striking aspect of the study was the rise in global CRC deaths attributable to a low-milk diet, which increased from 81,405 deaths in 1990 to 157,563 deaths in 2021. Similarly, the total DALYs for CRC increased from 2.07 million to 3.7 million during the same time frame.
Regional Variations
The study highlighted significant regional differences in CRC burden. Southern Latin America had the highest CRC-associated ASMR and ASDR in 2021, followed by the Caribbean. On the other hand, Central Asia had the lowest CRC-associated ASMR, while Australasia recorded the lowest CRC-associated ASDR.
Prostate cancer also showed regional disparities. Western and Central Sub-Saharan Africa experienced the highest ASMRs and ASDRs for prostate cancer, while East Asia accounted for the majority of cancer deaths and DALYs.
At the country level, China, Japan, and India saw the highest CRC-related deaths and DALYs, with China showing the greatest change in prostate cancer deaths. The study also noted that Lesotho recorded the largest increase in CRC burden, while Germany showed the most significant reduction in the same period.
Projections and Future Trends
Projections for 2050 suggest a continued decline in the global CRC burden, particularly among women, who are expected to experience greater reductions in CRC-related rates than men. However, the study also highlighted that males are likely to continue to experience higher age-standardized rates of CRC than females, indicating sex-based disparities in the disease burden.
Socioeconomic and Cultural Context
The study also explored the relationship between socioeconomic factors and cancer burden trends. Countries with higher Human Development Index (HDI) scores generally experienced sharper declines in CRC burden. Conversely, CRC exhibited an S-shaped relationship with national development, while prostate cancer followed a U-shaped trend, indicating that both low- and high-income countries have high prostate cancer burdens.
Cultural dietary patterns significantly influence milk intake. In East Asia, where lactose intolerance is more common, milk consumption is traditionally lower, and soy-based beverages are favored instead. These dietary habits likely contribute to the increased cancer burden in regions with low milk intake.
Conclusions
The study concludes that increasing milk consumption to optimal levels could help reduce the global CRC burden. It suggests that improving milk intake, particularly in older adults and populations with historically low milk consumption, could prevent as many as 18,000 annual CRC deaths worldwide. Although prostate cancer showed smaller changes in relation to milk intake, the study underscores the importance of tailored public health strategies to address cancer risks, particularly through dietary modifications.
In sum, the research emphasizes the need for increased awareness of the potential health benefits of milk consumption, particularly in regions where low intake may be contributing to rising cancer rates. The study calls for more comprehensive public health initiatives to promote dairy milk consumption and reduce the global burden of CRC.
