Signs of supplementation: weakness, poor appetite, weight loss, irritability, joint pain, swollen, red, painful and bleeding gums, etc. Applicable people: smokers, people who often stay up late, salesmen and so on. Expert analysis: smoking will consume a lot of vitamins in the body; and stay up late when adrenaline secretion increases, the synthesis of adrenaline also need vitamin C. Salesmen are often on the go, water-soluble vitamin C will be with the sweat from the body of the loss of a lot of vitamins, so the above groups should be possible to supplement more vitamin C. Signal of overdose: a large dose of vitamin C can lead to an increase in intestinal peristalsis, causing abdominal pain and diarrhea. Vitamin C and food containing vitamin B12 at the same time intake, can destroy the effectiveness of vitamin B12, resulting in anemia. Foods rich in vitamin A: Fresh dates, kiwi, hawthorn, citrus, strawberries, grapefruit and other fruits, mung bean sprouts, tomatoes, kale, etc.