At some point, a strange saying emerged: milk and soy milk should not be consumed together. The reason cited is the "trypsin inhibitor" in soy milk. In fact, it is a type of protein, but it happens to hinder the human body's digestion of protein, making the protein digestibility of raw beans less than 40%. If consumed, it also interferes with the absorption of protein from other foods.
However, as long as soybeans are cooked, the trypsin inhibitor in them becomes mostly inactive. This is why people have been drinking soy milk with peace of mind for centuries. The key is the heating time for soy milk; it is best to simmer it for an additional 8 minutes after boiling to ensure the destruction rate of the trypsin inhibitor is over 90%. Since the trypsin inhibitor in soy milk is inactivated by heat, it will not hinder the absorption of protein in milk, so there should be no problem in drinking them together. The same, of course, goes for eating them with eggs.
Another claim comes from the "protein waste" theory. It suggests that people's absorption capacity in the morning is limited, and a glass of milk or a bowl of soy milk is already sufficient nutrition. Consuming both would result in unabsorbed nutrients, causing waste. This theory may seem reasonable, but it is actually baseless, and its flaws can be found with a careful analysis.
First, how much protein is in a carton of milk? According to the national standard of 2.9%, 250 grams of milk contains only a mere 7.3 grams of protein, equivalent to just 10% of the recommended daily protein intake for an adult male with light physical activity, and 11% for a female. The protein content of soy milk is typically 2%, so a large 300ml bowl contains only about 6 grams of protein. Combined, milk and soy milk only account for about 20% of the daily protein intake. How can this be considered excessive?
A carton of milk and a large bowl of soy milk, plus two slices of bread (equivalent to about 60g of flour), provide a total of 19 grams of protein. According to the principles of a balanced diet, breakfast should provide one-third of the day's high-quality protein, which should be 22-25 grams. Therefore, the claim that milk and soy milk lead to an excess of protein nutrition is simply unfounded.
So, let's look at the other components.
1. Milk is rich in calcium, while soy milk is relatively low in calcium but richer in potassium and magnesium.
2. Milk is abundant in Vitamin A, while soy milk does not contain this nutrient.
3. Soy milk contains more Vitamin E and Vitamin K, while milk has relatively low amounts of these two vitamins.
4. Milk does not contain dietary fiber, while soy milk has a large amount of soluble fiber.
5. Milk contains a small amount of saturated fat and cholesterol, while soy milk contains a small amount of unsaturated fat and phytosterols, which reduce cholesterol absorption.
6. Soy milk is rich in soy isoflavones, which can reduce calcium loss in menopausal women, while milk contains lactose and Vitamin D, which promote calcium absorption.
From the above comparison, it is clear that the nutrients in milk and soy milk not only do not cancel each other out but are actually enhanced by their complementary nature.
In terms of calcium supplementation, milk has a large amount of calcium, along with Vitamin D and lactose. With the help of Vitamin K, potassium, and magnesium from soy milk, calcium utilization can be made even more effective, which is beneficial for increasing bone density in adolescents. For menopausal women, the soy isoflavones in soy milk can help slow down calcium loss while supplementing calcium through milk, providing a dual benefit.
From a beauty perspective, the rich Vitamin B2 and Vitamin A in milk are beneficial for the renewal and metabolism of facial skin, while the soy isoflavones in soy milk can improve skin elasticity and moisture retention.
In terms of preventing cardiovascular disease, the abundant Vitamin B6 and Vitamin B12 in milk work synergistically with the folic acid, Vitamin E, soy isoflavones, and dietary fiber in soy milk to effectively lower homocysteine levels, increase the antioxidant capacity of LDL, and provide the best disease prevention effect.
Therefore, no matter how you look at it, milk and soy milk can be the best nutritional combination. If possible, you can drink both for breakfast. Alternatively, if you find the volume too much, you can substitute yogurt for milk, or have yogurt/milk as a mid-morning snack after drinking soy milk in the morning.