What are vitamins?
Jul 23, 2025
Source: Cainiu Health
Dr. Yang Ziqi
Introduction
Under normal circumstances, vitamins are essential nutrients that maintain important bodily physiological functions. Common examples include vitamin A, vitamin B₁, vitamin C, vitamin D, and vitamin E. Different vitamins play unique roles in the human body, and most cannot be synthesized by the body itself, thus needing to be obtained through a balanced diet.
Generally speaking, vitamins are essential nutrients for maintaining normal physiological functions in the human body. Common types include vitamin A, vitamin B₁, vitamin C, vitamin D, and vitamin E. A detailed analysis is as follows:
1. Vitamin A
Vitamin A is important for visual function and helps maintain the ability of dark adaptation; deficiency can lead to night blindness. It also participates in epithelial tissue repair and helps protect the health of the skin and mucous membranes. It is abundant in animal livers, carrots, spinach, and similar foods. Excessive intake may cause poisoning, with symptoms such as dizziness and vomiting.
2. Vitamin B₁
Vitamin B₁ mainly participates in carbohydrate metabolism and helps maintain normal nervous system function. Its deficiency can cause beriberi, characterized by peripheral neuritis and muscle weakness. It is widely present in grains, legumes, and lean meats. It is easily destroyed by high-temperature cooking, so attention should be paid to appropriate food preparation methods.
3. Vitamin C
Vitamin C has antioxidant properties, promotes collagen synthesis, enhances immunity, and its deficiency can cause scurvy, with symptoms such as bleeding gums and delayed wound healing. Fresh fruits, such as citrus fruits and kiwifruit, and vegetables are the main sources. Vitamin C is water-soluble and can be significantly lost through excessive washing or prolonged cooking.
4. Vitamin D
Vitamin D regulates calcium and phosphorus metabolism, promotes intestinal calcium absorption, and maintains bone health. Deficiency in children can lead to rickets, while adults may develop osteomalacia. In addition to being obtained from foods such as cod liver oil and egg yolks, exposure to sunlight can stimulate vitamin D synthesis in the skin, and moderate sunlight exposure is beneficial for replenishment.
5. Vitamin E
Vitamin E is a potent antioxidant that protects cell membranes from free radical damage and is also related to reproductive function. It is abundant in nuts and plant oils and generally not easily deficient. However, excessive intake may affect blood clotting function.
Different vitamins play unique roles in the human body, and most cannot be synthesized by the body itself, so they must be obtained through a balanced diet. A varied diet should be ensured in daily life, avoiding picky eating habits and excessive food processing, to meet the body's vitamin requirements.
