[Northern Xinjiang science experts say: Not that safe] Vitamin C: Guardian of health or invisible killer?

In the world of nutrition, vitamin C is known as a "double-edged sword". It can slay demons in the world of health, but it can also "get you into trouble" when you are not careful. People have gone to great lengths to wield this sword: some people put colorful fruits and vegetables on the table, trying to use the magic of nature to enhance their immunity; others look for the mysterious vitamin C supplement in a pile of medicine bottles, hoping it can become their own health amulet.

However, the "swordsman" of vitamin C is not so easy to control. If you are not careful, excessive sword energy may cause diarrhea, stomach pain, and even leave "oxalate stones" in the urinary system.

What health problems may arise from excessive or improper supplementation of vitamin C?

Gastrointestinal problems : The acidic nature of vitamin C may cause gastrointestinal discomfort, especially for people with excessive stomach acid or digestive system diseases such as gastric ulcers. Excessive intake may aggravate symptoms. Long-term and large intake of vitamin C may cause diarrhea, abdominal pain and nausea, and in severe cases may even cause dehydration.

Kidney stone risk : Vitamin C can increase the excretion of oxalic acid in urine, which is one of the main components of kidney stones. For people with a history of kidney stones or a susceptible constitution, excessive intake of vitamin C may increase the risk of stone formation.

Drug interactions : Vitamin C may affect the effects of certain medications, especially those that require precise dosing. For example, it may interfere with the effectiveness of anticoagulant drugs such as warfarin, leading to an increased risk of bleeding. Therefore, people who are taking these medications should consult their doctor before increasing their vitamin C intake.

Iron overload : For patients with iron metabolism disorders such as hereditary hemochromatosis, excessive vitamin C intake may promote iron absorption, leading to excessive iron levels in the body, thus aggravating the condition. Iron overload may cause damage to organs such as the heart, liver, and pancreas.

Tooth damage : Long-term and excessive intake of vitamin C, especially on an empty stomach, may erode teeth due to its acidity, causing softening of tooth enamel and increasing the risk of tooth decay.

Vitamin C Dependence : After long-term, high-dose intake of vitamin C, the body may adapt to this high level of intake. Once supplementation is stopped, the body may not be able to adjust quickly, leading to the appearance of vitamin C deficiency symptoms, such as scurvy.

To ensure the safety of vitamin C intake, it is recommended to follow the following principles:

Eat a balanced diet : The most natural and safe way to get vitamin C is through a varied diet, such as fresh fruits and vegetables.

Supplement appropriately : If it is difficult to meet the vitamin C requirement in your diet, you can consider supplementing appropriately. The recommended daily intake (RNI) for adults is 100 mg, and the daily intake for preventing non-communicable chronic diseases is 200 mg. However, it should not exceed the daily upper limit (UL) of 2000 mg.

Consult a Professional : Before starting any supplementation program, especially for those with specific health issues or taking medications, a doctor or nutritionist should be consulted.

Monitor your body's reactions : When taking vitamin C supplements, pay attention to your body's reactions. If you feel any discomfort, stop taking it immediately and seek medical advice.

In this adventure of vitamin C, everyone has to be careful to enjoy its health benefits while avoiding being hurt by its sword. Vitamin C supplementation is not a panacea, and excessive intake may not only be unhelpful, but may also bring health risks.

Therefore, it is important to plan your diet and supplementation plan appropriately to ensure that your vitamin C intake meets your body's needs without exceeding a safe range.

References:

[1] Zeng Xiangyun. Physiological functions and dietary protection of vitamin C[J]. Chinese Food and Nutrition, 2005, (04): 52-54.

[2] Cao Qingming, Wang Weijie, Zhang Lin, et al. Practice of balanced diet pattern among Chinese residents: Interpretation of Dietary Guidelines for Chinese Residents (2022)[J]. Food and Machinery, 2022, 38(06): 22-29.

[3] Yang Yuexin, Ge Keyou, et al. Encyclopedia of Chinese Nutrition Science[M]. 2020.7.

Author: Liu Yang

Registered dietitian, Clinical Nutrition Department, Affiliated Hospital of Inner Mongolia Medical University