You can certainly have cold buttermilk in the late evenings if you enjoy it, as it is a refreshing and nutritious beverage. Buttermilk is a good source of calcium, protein, and probiotics, which can support bone health, digestive health, and immune function.
However, it is important to keep in mind that sweetened or flavoured buttermilk can be high in saturated fat and calories. Women who are watching their calorie or fat intake may want to opt for low-fat or fat-free buttermilk, or consume it in moderation as part of a balanced diet.
Consulting with a healthcare professional or registered dietitian can help to determine the appropriate buttermilk intake for individual needs.