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Too Much Vitamin C

How Much Vitamin C is “Too Much”?

Vitamin C is probably one of the first things you reach for when you feel a cold or flu coming on. And for good reason – this vitamin is famous for its immune-boosting properties.

Vitamin C also boasts a whole host of other benefits for the body – which might tempt you to load up on this nutrient even when you’re not sniffling and sneezing.

But have you wondered if there’s such a thing as too much vitamin C? It’s a question worth considering. After all, your body is an intricate system that requires a healthy balance of nutrients to operate to the best of its potential. And when those nutrients get out of balance? Your body can pay the price.

So, if you’re wondering how much vitamin C is too much, read on.

Vitamin C: A Refresher

Vitamin C, also known as ascorbic acid, is a water-soluble vitamin. What does that mean? Well, fat-soluble vitamins like A, D, and E are stored in your body’s tissue.

Water-soluble vitamins, on the other hand, are consistently being excreted in your urine. In other words, your body doesn’t have backup stores of these water-soluble vitamins, so they need to be replaced daily through your diet.1

And it is important to make sure you’re getting enough vitamin C, as it’s responsible for performing a wide variety of functions in your body.

Vitamin C:

  • Helps develop and maintain connective tissue
  • Helps form strong bones
  • Assists in wound healing
  • Keeps gums healthy
  • Plays a role in numerous metabolic functions
  • Protects the immune system
  • Helps fight off infections
  • Acts as an antioxidant2

Too Much Vitamin C?

Given that so many of your body’s functions rely on ascorbic acid, you might think that more is better. This is not necessarily the case.

Now, because it’s a water-soluble vitamin, there isn’t much chance of experiencing a dangerous overdose of vitamin C. With the help of your kidneys, your body will simply excrete the excess levels of ascorbic acid.

But that doesn’t mean that high doses of ascorbic acid won’t have adverse effects on your health in the meantime. Some of the milder adverse effects you might experience are:

  • Diarrhea
  • Nausea
  • Vomiting
  • Heartburn
  • Abdominal cramps
  • Headache
  • Insomnia

Not so pleasant, right?

High doses of vitamin C can also pose more significant health problems, such as:

Kidney Stones

Several studies have found that daily supplementation of 1 to 2 grams of ascorbic acid increases the amount of a chemical called “oxalate” in the urine.4 Now when high levels of oxalate combine with calcium, they can lead to the formation of painful kidney stones.5 So, if you’re at risk for kidney stones, you may want to be especially careful with high doses of vitamin C.

Tooth Erosion

Now, this pertains specifically to chewable vitamin C supplements. A study demonstrated that daily intake of chewable vitamin C for three years can result in significant erosion of the surface of the teeth. The reason for this is most likely due to the low pH level of ascorbic acid, which can interfere with the surface of the teeth.6

Keep in mind, moderate intake of chewable vitamin C is generally not very risky, and is unlikely to produce any significant dental effects. As with so many things, moderation is key.

Interference with Clinical Lab Tests

There’s a chance that high doses of ascorbic acid may interfere with lab tests used to diagnose disorders or disease. So before undergoing any lab testing, be sure to inform your healthcare provider if you’re taking a vitamin C supplement.7

Interaction with Other Drugs

High doses of vitamin C supplements may interact with certain over-the-counter and prescription drugs, so tell your doctor about any supplements you’re taking to ensure it won’t result in any negative interactions.8

What’s the recommended intake of vitamin C?

So, is there an optimal intake of ascorbic acid that will provide your body with the benefits you need without the risk of negative side effects? Absolutely.

The National Institutes of Health recommends that:

Adult males get at least 90 mg of vitamin C daily, while women should aim for 75 mg.

For both men and women, 2,000 mg is the upper limit of what’s considered “safe” vitamin C intake.9

There’s a possible exception to this rule, and it may not come as a surprise.

A scientific trial studied a group of students suffering from cold and flu symptoms. The test group was given 1,000 mg of vitamin C every hour for six hours. After that, they were given 1,000 mg three times daily. This test group reported an 85% reduction in cold and flu symptoms in comparison to the group that received no vitamin C.10

So if you feel a cold or flu coming on, you may want to temporarily boost your daily dose of vitamin C. Talk to your doctor to figure out what’s right for you.

Vitamin C Foods

Many people can get adequate sources of vitamin C through their diets. Here are some great Gundry-approved foods to try:

  • Cooked broccoli: 54 mg per ½ cup
  • Cooked bok choy: 23 mg per ½ cup
  • Raw red cabbage: 42 mg per cup
  • Cooked brussels sprouts: 38-52 mg per 4 sprouts
  • Cooked kale: 28 mg per ½ cup
  • Cooked or raw cauliflower: 27-29 mg per ½ cup
  • Cooked asparagus: 22 mg per 6 spears
  • Sweet potatoes: 22 mg per potato
  • Avocado: 52 mg per avocado
  • Strawberries (in season): 52 mg per ½ cup11

In The End…

The key to healthy vitamin C intake is balance. While you can’t technically “overdose” on a water-soluble vitamin like ascorbic acid, you can certainly experience negative effects from high doses.

So, if you’re currently taking ascorbic acid and notice any mild side effects, you may want to consider lowering your dosage.

And if you’re at risk of developing kidney stones, talk with your doctor before starting any vitamin C supplementation. Likewise, talk to your doctor about any potential drug interactions that may occur with vitamin C supplementation.

In the meantime, why not enjoy this healthy, vitamin C-balanced sweet potato and kale recipe?

Speaking of antioxidants, if you’re battling dark hyperpigmentation spots, check out our groundbreaking polyphenol dark spot remover.



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