I. Milk and Cancer Risk: What Does the Research Say?
A widely circulated claim linking dairy consumption to increased risks of liver cancer (12%) and breast cancer (17%) per daily 50g intake originates from a 2022 study published in BMC Medicine. The China Kadoorie Biobank project (collaborating with Peking University, Chinese Academy of Medical Sciences, and Oxford University) tracked 510,000 participants over 11 years. Proposed mechanisms include:
- Insulin-like growth factor (IGF) stimulation of cancer cell proliferation.
- Lactose and branched-chain amino acids potentially promoting cellular growth.
- Saturated fats, trans fats, and lipid-soluble hormones in dairy possibly contributing to cancer progression.
Key limitations: Observational design, focus on two cancers only, and lack of causal proof. Current dietary guidelines (recommending 300–500 mL daily) still endorse milk as a nutrient-rich food.
II. Shelf-Stable Milk: Preservatives or Processing?
Contrary to popular belief, no preservatives are added to commercially available milk in China. Extended shelf life (up to 180 days) results from:
- Ultra-high temperature (UHT) processing: Kills bacteria at 135–150°C.
- Multilayer packaging: Blocks oxygen and contaminants.
Comparative Nutrition:
- Pasteurized milk (72–75°C, 15-day shelf life): Retains more flavor/nutrients but requires refrigeration.
- UHT milk: Comparable protein/calcium levels despite reduced heat-sensitive vitamins (e.g., B12, C).
III. “Fake Milks” to Avoid
- Plant-based “milks” (soy, almond, etc.): Low protein, no calcium/vitamin D.
- Flavored dairy drinks: High sugar, low protein (0.7–1%).
- Raw/unpasteurized milk: Risk of bacterial contamination (e.g., E. coli, Salmonella).
IV. Safe Milk Heating Practices
While heating doesn’t destroy calcium, improper methods can degrade nutrients or introduce toxins:
- Temperature control: Avoid exceeding 60°C to preserve lactoferrin and β-lactoglobulin.
- Packaging hazards:
- Microwaving cartons may release polyethylene toxins.
- Boiling packaged milk degrades nutrients.
- Pasteurized milk heating: Use water baths for gentle warming.
V. Key Takeaways
- Moderate dairy intake aligns with health guidelines.
- Shelf stability ≠ preservatives; UHT/packaging ensures safety.
- Avoid non-dairy “milk” alternatives for nutritional equivalence.
- Heat milk cautiously to preserve quality.