Too Much Milk Could Disrupt Sleep, Nutritionist Says

Milk may help sleep, but drinking more is not necessarily better. A meta-analysis covering 29 studies and 712,379 participants found that people who drank two 240-milliliter cups a day had the lowest risk of poor sleep quality.

The analysis also found that consuming at least 0.7 cups of milk a day was associated with a lower risk of short sleep. Nutritionist Curtis said milk contains tryptophan, a precursor to serotonin and melatonin, as well as zinc and magnesium. These nutrients may help regulate circadian rhythms, relax muscles and influence neurotransmitters such as GABA.

The pattern changed among people drinking more than three cups daily, whose risk of poor sleep quality increased. Curtis suggested that saturated fat could play a role, citing links between higher saturated-fat intake, lighter sleep and sleep that provides less physical recovery. Another meta-analysis of observational studies in young adults found a significant negative association between saturated-fat intake and sleep duration.

Curtis cautioned that most of the research was observational, limiting conclusions about cause and effect. Some studies recorded only how often participants consumed milk, rather than how much, so the evidence does not establish a precise clinical recommendation. Based on dietary guidelines, he suggested one to two cups a day for calcium and protein, and said people with poor sleep could consider drinking a cup one to two hours before bed.