Is drinking milk before bedtime beneficial or harmful?

Drinking Milk Before Bedtime: Benefits and Considerations

Drinking milk before bedtime can be beneficial for most healthy adults, as it provides valuable nutrients and may promote sleep through its content of tryptophan and melatonin, particularly when consumed as part of a balanced diet. 1

Nutritional Benefits

Milk consumed at any time, including before bed, provides essential nutrients that support overall health:

• High-quality protein, calcium, phosphorus, vitamin A, vitamin D, riboflavin, vitamin B-12, potassium, zinc, choline, magnesium, and selenium are all present in milk 1
• The Dietary Guidelines for Americans recommend 3 cup-equivalents per day (710 mL) of fat-free or low-fat dairy for adults, which can be distributed throughout the day including evening consumption 1
• Milk intake has been linked to decreased risk of diabetes (low-fat milk), colon cancer, cognitive disorders, and stroke, with no increased risk of coronary artery disease or mortality 1

Sleep-Promoting Properties

Emerging research suggests specific benefits of nighttime milk consumption:

• Night-harvested milk contains exceptionally high amounts of tryptophan and melatonin, which are sleep-promoting constituents 2
• In animal studies, night milk demonstrated sedative effects, shortened sleep onset, prolonged sleep duration, and showed anxiolytic (anti-anxiety) properties comparable to diazepam 2
• A study in elderly institutionalized subjects found that melatonin-rich night-time milk (containing 10-40 ng/L melatonin) increased daytime activity, suggesting improved sleep quality 3
• A systematic review of 14 studies concluded that a well-balanced diet including milk and dairy products is effective in improving sleep quality 4

Important Caveats and Considerations

Timing and Gastric Emptying

• Milk is classified similarly to solid foods for gastric emptying purposes, taking approximately 6 hours to clear from the stomach 1
• This slower gastric emptying is generally not problematic for bedtime consumption in healthy individuals, but should be considered if planning procedures requiring anesthesia 1

Sleep Hygiene Context

When incorporating milk into your bedtime routine, follow evidence-based sleep hygiene practices:

• Avoid consuming excessive food and liquids at night, as these may disrupt sleep through reflux and increased bathroom trips 1
• Establish a regular bedtime routine that can include a moderate serving of milk 1
• Avoid spicy foods and alcohol before bedtime, while milk can be part of a sleep-promoting routine 1

Lactose Intolerance Concerns

For individuals concerned about lactose intolerance:

• People who report severe lactose intolerance often mistakenly attribute various abdominal symptoms to lactose 5, 6
• When lactose intake is limited to 240 mL (8 oz) of milk or less daily, symptoms are likely to be negligible, with mean symptom scores remaining between 0.1-1.2 (trivial to mild) 5, 6
• The use of lactose-digestive aids is generally unnecessary for this amount 6

Practical Recommendations

• Choose fat-free or low-fat (1%) milk to align with dietary guidelines and cardiovascular health recommendations 1
• A reasonable bedtime serving is 240 mL (8 oz) or less, which provides nutrients without excessive fluid intake that might disrupt sleep 1, 5
• For individuals with diabetes, milk consumption should be incorporated into overall carbohydrate management, though it provides beneficial nutrients 1
• Avoid adding excessive amounts of milk to caffeinated beverages (coffee, tea) within 6 hours of bedtime, as caffeine is a stimulant that should be avoided before sleep 1

When to Avoid or Modify

• Individuals with gastroesophageal reflux disease should be cautious with any food or beverage consumption close to bedtime 1
• Those with significant sleep difficulties should consult sleep specialists, as milk alone may not address underlying sleep disorders 1
• If gastrointestinal symptoms persist despite moderate milk consumption, consider lactose-hydrolyzed milk or plant-based alternatives, though evidence for superior health benefits of plant-based substitutes over cow's milk is currently insufficient 1