Vitamin C: Recommended doses (recommended) and limited doses

The article was consulted professionally by Master, Dr. Nguyen Thi Nhat – Infectious Diseases Specialist – Department of Medical Examination and Internal Medicine – Share99 Hai Phong International Health Hub

As everyone knows Vitamin C is a substance that has a lot of benefits for human health. However, it is not necessary to take vitamin C as much as possible. Vitamin C should be used in accordance with the recommended dose and the limited dose of doctors.

Vitamin C plays an important role for the body and is present in many processes of transformation:

• Vitamin C is involved in collagen generation and some other ingredients with the role of creating connective tissue in teeth, bones, blood vessels. Therefore, people who lack vitamin C often have swelling of the gums, bleeding root, teeth easily fall out.
• Participates in the metabolism of protid, lipids, glucid,…
• Participate in the synthesis of substances such as an renal cori secretion hormone, catecholamin,…
• It is a reaction catalyst that converts Fe+++ into Fe++ so that iron can be absorbed in the duodenum. That is why vitamin C deficiency also leads to iron deficiency anemia.
• Helps increase the body's resistance, immune system by creating interferons and reducing the body's sensitivity to histamine.
• In combination with vitamin A and vitamin E involved in antioxidant processes, neutralizing free radicals is produced from chemical reactions, thereby preserving cell membranes.

In addition, vitamin C has many other uses. For clarity, you can ask your doctor for the most detailed and accurate information.

According to nutritionists, the maximum limit of vitamin C that the body can accept is 2,000mg for people over 19 years of age. The limits for pregnant and breastfeeding women are similar.

For young children and babies, the daily limit of vitamin C is specifically:

• Children 1 – 3 years old: 400mg
• Children 4 – 8 years old: 650mg
• Children 9 – 13 years old: 1,200mg
• Minors 14 – 18 years old: 1,800mg

Besides, there is also a dose limiting vitamin C for some specific exceptions. However, limited dose exceptions are usually applied only with the consent of medical professionals.

The recommended dosage of vitamin C per day for people in each specific age group is as follows:

• Children from 1 to 3 years old: 15mg
• Children from 4 to 8 years old: 25mg
• Children from 9 to 13 years old: 45mg
• Minors 14 – 18 years old: 75mg (for men) and 65mg (for females)
• Adults over 19 years old: 90mg (for men) and 75mg (for women)

Some special cases require additional vitamin C supplements such as:

• Smokers should add 35mg/day compared to recommended doses
• Women during pregnancy should take 85mg of vitamin C per day
• Breastfeeding women should take 120mg of vitamin C a day

So far, there has been no research on vitamin C dosages for children under 1 year old. Experts have given estimates:

• Children under 6 months: 40mg
• Child 7 – 12 months: 50mg

However, the body does not absorb all the vitamin C loaded into the body. If the amount of vitamin C taken per day is 30 – 180mg, only 70 – 80% of that vitamin C is absorbed by the body. The absorption rate of vitamin C is only about 50% if a person takes more than 1g of vitamin C per day. The remaining amount of vitamin C that is not absorbed will be eliminated by urine.

Users should use vitamins in accordance with the instructions of their doctor, absolutely do not voluntarily increase or decrease the dosage compared to the recommendation.

Depending on which form vitamin C is prepared, there is an appropriate use:

• Vitamin C gum: can be chewed as long as you like, be aware of throwing away after chewing, not swallowing.
• Vitamin C in the form of chewing tablets: before swallowing it is necessary to completely chew vitamin C tablets, combined with drinking plenty of water.
• Vitamin C tablets release prolonged: swallow completely and do not chew, crush or smash tablets.
• Liquid vitamin C: use a measuring spoon or measuring glass to measure a sufficient dose of vitamin C.
• Vitamin C tablets disintegrate quickly: open the packaging only when ready to drink. It is necessary to keep your hands dry when taking vitamin C tablets out of the packaging and putting them in your mouth. Do not swallow immediately but suck so that the vitamin disintegrates in the mouth. When the drug dissolves should swallow several times.

You absolutely must not abruptly stop using vitamin C if you are in a vitamin C deficiency or have been taking vitamin C for a long time. You should strictly follow the doctor's instructions to avoid leading to undesirable effects.

In addition to the main effects of treating the disease, Vitamin C can also cause some undesirable effects such as:

• Shortness of breath
• Rash
• Swelling of the lips, tongue, throat or face
• Diarrhea, stomach shrinkage
• Heartburn, nausea

If the patient encounters one of the above manifestations, then it is advisable to immediately and go to the nearest medical facility for further monitoring, which should not be given through some mild manifestations that can lead to more unpredictable complications.

SEE MORE:

• Side effects of vitamin C
• Harm when excess or vitamin C deficiency
• Uses, dosage and side effects of Vitamin C