Overall, more than 55% of our country's population lacks Vitamin A, and over 50% lacks Vitamin D. The most commonly deficient vitamins are B1, B2, and C, with a particularly severe deficiency of Vitamin C among middle-aged and elderly people. These five vitamins are the ones that Chinese people currently lack the most.
Vitamin A is known as the "beautiful vitamin for bright eyes and healthy teeth." This is because its main function is to maintain the healthy growth of skin, hair, bones, and mucous membranes, and to enhance vision and reproductive function. Vitamin A is only found in animal foods; plant foods do not contain Vitamin A, but only its precursor substance—carotene, which can be converted into Vitamin A in the human body.
Vitamin D deficiency usually occurs in infants from 2 months after birth to 1 year old, as well as in pregnant and lactating women. Once children lack Vitamin D, they are very susceptible to rickets. The simplest way to supplement Vitamin D is by sunbathing. This is because the human skin contains a substance called "7-dehydrocholesterol," which, under ultraviolet light, can be converted into Vitamin D and utilized by the body. Of course, consuming more cod liver oil, egg yolks, and liver is also very beneficial.
Vitamin B1 is found in the highest amounts in grain products that contain the germ and bran. Today's flour products have been highly refined, which means that most of the Vitamin B1 is lost during processing—a great pity. It's no wonder that some nutritionists say, "In the past, the food of the poor was rich in Vitamin B1. Now that people's living conditions have improved, their nutritional level is actually not as high as that of the poor in the past."
The main sources of Vitamin B2 are animal liver, as well as eggs, milk, meat, fish, green vegetables, and legumes. In our country, the dietary intake of Vitamin B2 is relatively low, reaching only half of the standard, and this situation is particularly severe during the off-season for vegetables. Therefore, Vitamin B2 deficiency is quite common in China.
Vitamin C is a primary material for forming the intercellular substance. Its main function is to connect cells, maintain the normal function of teeth, blood vessels, bones, and muscles, promote wound healing, and enhance resistance to diseases. The most common symptoms of Vitamin C deficiency are bleeding gums and pinpoint bleeding under the skin.