You wake up with a stuffy nose and your first reaction might be to down a glass of orange juice. Don’t bother: everything we know about research shows that mega-doses of vitamin C are absolutely, positively useless at fighting colds. All that extra orange juice will do nothing to shorten your sniffles.
Vitamin C is a kind of water-soluble vitamin. It can act as an antioxidant and protect the human body from free radicals and toxins.
In addition, vitamin C is even more important for the body’s metabolism. It is an indispensable nutrient for the activation of vitamin B complex, cholesterol metabolism, and the production of neurotransmitters.
Because of these diverse characteristics, how to properly ingest is often the subject of discussion. Traditionally, excessive intake is considered to have many harms. The following will introduce them one by one.
What are the natural sources of vitamin C?
Most vegetables and fruits are rich in vitamin C, including oranges, lemons, grapefruit, watermelon, papaya, strawberries, cantaloupe, mango, pineapple, raspberries and cherries; vegetables include tomatoes, broccoli, green peppers and kale.
As the vitamin C molecule is relatively unstable, air, light, and temperature will affect its activity, and incorrect heating and cooking methods will accelerate the loss
For most people, as long as you master the following skills: eat fresh, use steamed instead of decoction, avoid cooking for a long time to retain the most food nutrition.
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Will taking vitamin C cause kidney stones?
The formation of kidney stones is mainly related to dehydration or genetic tendency. It is caused by the supersaturation of insoluble substances in the urine (including calcium, oxalic acid, and phosphoric acid). According to US surveys, the prevalence rate is about 10%.
Vitamin C intake is first metabolized into dehydroascorbic acid in the human body, then converted into oxalic acid and discharged in the urine. Therefore, excessive intake is often thought to increase the incidence of kidney stones.
A recent large-scale follow-up study pointed out (the follow-up period was 11 years, with about 200,000 participants) that the risk of kidney stones caused by the intake of vitamin C (self-health products) was only observed in men, and the daily intake was greater than 1,000 mg It may increase the risk value by 19% (there is no correlation for women). Note 1
However, taking vitamin C from a natural diet has no effect on the risk of kidney stones
The author speculates that the difference in risk value is related to the different mechanisms by which men and women metabolize vitamin C. Therefore, men with kidney stones or those who are prone to disease should avoid excessive intake of vitamin C.
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Will too much vitamin C cause diarrhea?
Vitamin C is currently known as one of the least toxic ingredients, but the only adverse effects of high doses are intestinal discomfort (gas, gas) and diarrhea. These symptoms are usually not serious and will be relieved as long as they are reduced or stopped.
The dose that causes diarrhea usually varies from person to person (mostly between 2-6 g per day), but it also depends on the individual’s intestinal tolerance and physical health. Note 5
When the health condition is good, the tolerance may be 2 g a day, but the intestinal tolerance may be increased dozens of times when you have the flu, and you may not have any discomfort after taking dozens of grams
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Should Vitamin C be natural or synthetic? (Which kind of high absorption rate)
According to current research, there is no significant difference between the bioavailability of natural sources of vitamin C and synthetics
However, considering that natural sources (vegetables and fruits) contain additional trace and macronutrients, dietary fiber, and phytochemicals, these nutrients can multiply each other, increase synergy, and provide additional health benefits to the body, so supplement from natural diet Will be a more effective choice. Note 2
A systematic analysis pointed out that the vitamin C in the natural diet does have better disease resistance effects than health supplements. Note 3
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How to decide the intake of vitamin C?
Early studies pointed out that the absorption rate of vitamin C in a single dose of 200 mg or less is nearly 100%. When the dose is increased to 500 mg, the absorption rate drops to 75%, and when the dose is increased by 1,250 mg, only 40% is absorbed. Into the blood, the rest is excreted in urine. Note 4
Therefore, if you want to increase the absorption rate, you can use a small dose and use it in divided doses.
It is mentioned in the book “High-dose Vitamin C as Special Drugs” (the author is pharmacist Luo Zhengwu), the current recommended daily dose is 60 mg, but most studies believe that long-term use slightly higher than the recommended dose can help prevent chronic diseases
The optimal replenishment amount is 500 to 1000 mg, and the therapeutic dose is 1000 to 10,000 mg (but for high-dose users, it is recommended to inform the doctor before any medical examination to reduce symptom confusion and possible misjudgment) (see page 60 of this book) )