It's best to drink milk at night because it contains L-tryptophan, a biochemical substance that induces drowsiness, as well as trace amounts of morphine-like substances. These compounds have a certain sedative and hypnotic effect. L-tryptophan, in particular, is a primary raw material for the brain to synthesize serotonin, which plays a key role in sleep. It can temporarily inhibit the brain's thinking activities, making people want to sleep, and it has no side effects. Moreover, milk adheres well to the stomach wall for good absorption.
The calcium in milk can also relieve stress, making it even more beneficial for the sleep of the elderly. Therefore, drinking milk at night is good for people's rest and sleep. Drinking milk before bedtime allows the calcium in the milk to be slowly absorbed by the blood. Calcium levels are replenished and balanced throughout the night, preventing the need to dissolve calcium from the bones, thus preventing bone loss and osteoporosis. Therefore, drinking milk before bedtime is recommended. Milk should not be consumed raw. When heated, it should be removed just as it begins to boil. At 100°C, lactose begins to caramelize and break down into lactic acid and formic acid, reducing its nutritional value.
Long boiling of milk causes it to turn brown, reduces its milky aroma, denatures proteins causing precipitation, and also leads to a loss of vitamins. The rotavirus antibody in milk, which helps prevent infant diarrhea, is also destroyed. After boiling the milk and letting it cool slightly, do not add sugar. Lysine and fructose in milk form fructoselysine at high temperatures, which is harmful to the human body. Sugar is acidic, while the calcium in milk is alkaline; their combination causes a significant loss of calcium. It is best not to add sugar.
It is not advisable to drink milk on an empty stomach. When the body is in a hungry state and demanding energy, drinking milk will cause the protein to be consumed as heat energy like carbohydrates. It stays in the stomach for a short time and is quickly excreted into the intestines, which is not conducive to digestion and absorption. It should not be consumed with foods containing tannic acid or oxalic acid, such as strong tea, pomelo, lemon, bayberry, pomegranate, purslane, water bamboo, and spinach. The large amounts of oxalic acid and tannic acid in these foods will combine with calcium to form clots that are difficult to digest and absorb, destroying nutrients.