Does L-ascorbic acid or Vitamin C Eliminate Probiotic Bacteria?

Does L-ascorbic acid or Vitamin C Eliminate Probiotic Bacteria?

I have read pseudoscience, incorrect advice from social media posts, and speculation lately that synthetic L-ascorbic acid, not natural sourced vitamin C harms your probiotic microbiome.

Where did all this speculation orginate?

My research has concluded that it originated from this article on Natural News.

The article is filled with anecdotal evidence, opinion, and no scientific studies or information to back up the claims.

The author of the article brings up that ascorbic acid is used as a preservative to keep bacteria in apple juice from overgrowing and spoiling the product.1 Yes, this is one of the only statements in the article based on fact. Acids can be used as a preservative to lower the pH of food products to keep bacteria growth to a minimum. Many bacteria have a difficult time surviving in a low pH environment, which is why vinegar, lime and lemon juice, and ascorbic acid which all have a low pH are used as preservatives. You lower pH in canning to prevent the serious medical condition botulism. Botulism is caused by ingesting toxins produced from the bacteria Clostridium botulinum which thrives in an anaerobic (without oxygen), dark, elevated pH environment.2 Does this mean that L-ascorbic acid ingested would reduce colonies of probiotic bacteria in the intestines?

The correct answer is that this is impossible. Ingestion of L-ascorbic acid (pH of 2.4 unless it is buffered) may slightly raise or lower pH levels in the stomach briefly (depending on the pH of your stomach) which if it lowers pH it can be helpful in keeping opportunistic bacteria like H. pylori at bay.3 The very low pH stomach chyme is neutralized by sodium bicarbonate and bile in the duodenum of the small intestine.4 In addition, the acid in your stomach (hydrochloric acid) has a lot lower pH than most ingested acids including L-ascorbic acid. So, if the proposed L-ascorbic acid harms intestinal flora theory is true, anytime you eat and stomach acid is produced all of the microogranisms in your stomach, small intestine, or colon would be eliminated because according to them it would not be neutralized. Buffered vitamin C supplements are not acidic and would negate the issue with the acidity of ascorbic acid affecting the microbiome. Finally, L-ascorbic acid is absorbed completely by the end of your small intestine (unless you are vitamin C megadosing which acts as an osmotive laxative) therefore it would not affect your colonic microbiome.5 6

Now I do recommend that if you are taking a probiotic supplement that it would be best that you take it away from any synthetic L-ascorbic acid supplement because of the possible slight decrease of pH in the stomach might kill some of the probiotic bacteria (which is why I recommend you take probiotics away from meals as well). I also recommend that you do not take a probiotic supplement at the same time as ingesting any acidic food, or during/after a meal. The best time to take a probiotic is three to four hours after eating, when stomach acid is at its lowest point, with a glass of nonchlorinated (diluted chlorine may reduce probiotic colonies it is antimicrobial) water. Bedtime is a good example of an optimal intake time for most people.

Synthetic L-ascorbic acid is not sourced from corn syrup. It is sourced from corn dextrose fermentation which is a very different product.7 Now one thing the author of the article got correct is that most synthetic L-ascorbic acid is sourced from genetically modified corn. However, more than likely there is no genetically modified protein or Bacillus thuringiensis toxin (BT toxin) in the final L-ascorbic acid product, therefore very few probiotic bacteria, if any, would be harmed by the genetically modified produced L-ascorbic acid. Finally, I do not recommend genetically modified sourced L-ascorbic acid products anyway. I recommend Nutribiotic sodium ascorbate, C-Salts, LipoNaturals vitamin C, and Doctor’s Best Quali-C which are all non genetically modified corn sourced.

Finally, the work of Dr. Linus Pauling and a multitude of scientific studies have proved that synthetic L-ascorbic acid is effective.8 If you want to ingest natural whole food sources of vitamin C, I recommend it. I believe for most people this it is the preferred method of ingesting vitamin C. However, I wish people would stop slandering that synthetic L-ascorbic acid (for example intravenous cancer treatments and pulsed dosing for acute viral infections) is harmful.

  1. I do not read or entertain Natural News, however, my personal experience with vitamin c in ascorbic acid form has been incredibly detrimental to my gut health. I have been doubled over in pain for 1 month after taking vitamin c as a flu prevenative for 4 months. It caused serious acid relux with bloating and stomach pain as well as lower intestinal pain….Dr said to get off the vitamin C and guess what? Within a 3 or 4 days of stopping the ascorbic acid I am back to normal! I cannot help believe there may be something to the Natural News Article? I now take whole food vitamin C and am doing fine….on a side note a probiotic that i started taking has ascorbic acid in it (without me knowing) and sure enough the symptoms came back.
    Thanks in advance for any thoughts
    you may share.

  2. John, I’m not buying the myth either, but what about time-released ascorbic acid capsules? As I understand, ascorbic acid has antibacterial properties, which is why I think taking it with a probiotic is not a good idea (you’re giving the same advice here, although you mention a different reason). But what about time-released capsules? What if they dissolve slow enough to enter the large intestine (semi) intact? That could have a detrimental effect on (beneficial) gut bacteria, would it not? This is why I stay off the time-released stuff, but I’d like to hear someone else’s opinion on this.

    • Ascorbic acid is antibacterial because of the low pH. Time release capsules may cause a small hit on the microbiome if they release in the more alkaline jejunum or ileum, but the colon is acidic, especially the caecum. Why time release ascorbic acid? To protect the stomach lining? Buffered ascorbates are better for that.

    • I see that this was written a while ago but I’ll send a reply in case you get email notifications. Some people don’t tolerate ascorbic acid and do much better on a less acidic vitamin C. Although changing acidity plays a role, it is far from the only reason vitamin C has antibacterial properties. If you were interested in giving vitamin C another try (or for others who come across this comment), try calcium ascorbate or sodium ascorbate, etc. They are usually labeled “stomach friendly”. :)

  3. I take kefir once a say therefore my doc recommendsd the intake of probiotics in caps with acidophilus, rhamnosus, paracasei and lactis. Is that really necessary?

  4. So if I take 3000 mg a day of powder ascorbic acid will it change my pH to more acidic? I know having an acidic body while make you prone to cancer and diseases as all pathogens thrive in an acidic enviroment

    • It would change the acidity of your stomach, but not your body. Your pancreas would neutralize it with sodium bicarb.

  5. Hi!

    Thank you for the information.
    Do you think time-release vitamin C could be a problem in SIBO?
    I take 500 mg twice a day for other health reasons and I think it might be lowering my intestinal pH. They are supposed to be released over about 10 hours as far as I know.

    Thanks in advance!

    • It is possible that it would manipulate the intestinal pH unless the vitamin C is buffered. But is your stool more towards neutral or acidic. For most it is best to be slightly acidic.

  6. Hello,

    I have been pondering this question however I’m still unsure. I took high dose Vitamin C for quite some time and for some reason whenever I took it my skin dried out. Now I know that gut bacteria manufacture biotin and that was always my test for a good probiotic (or one that was alive) my skin used to go back soft again after taking it. But high dose vitamin C seems to make it dry again. I get what you’re saying about acid ph etc, but what about the compound’s effect not whether its acid or alkaline etc? Maybe L-Ascorbic acid as a compound kills bacteria..

  7. John,
    Thank you for thoroughly destroying this ridiculous myth. It’s incredible how much bad info is passed off as fact without being checked or tested.
    To Rob Dahl,
    I wish I’d seen your question earlier. when it comes down to the molecular level, the only thing that matters is whether the types of atoms are arranged with the proper number and in the right configuration. Whether from GMO, synthesized in a lab or otherwise, ascorbic acid is C6H8O6. If it is different in any way, then it is not ascorbic acid.

    It doesn’t matter where it comes from. GMO and non-GMO created vitamin C is totally pure and exactly the same in every way imaginable.

    It’s like this… Lets say you are totally against A-frame houses and need a 2×4 to build your Craftsman home. A wrecking crew just tore down an A-frame home down the block and they have perfectly good 2x4s for anyone who wants them.

    A 2×4 from the A-frame house is exactly the same as a 2×4 from a Craftsman house. the 2×4 doesn’t have “A-frame” characteristics. For the same reason, ascorbic acid from GMOs doesn’t have “GMO” characteristics.

    Does this make sense?

  8. Natural News guy is a fear monger who feasts on people’s fear and peddles his dubious products on them.

  9. This is what I really wanted to ask you about. Is ascorbic acid always from GMO corn? I saw it on this GMO mini-doc exposing stuff at Whole Foods. A very knowledgeable clerk showed the documentarian (hidden camera person asking employees questions) how there is ascorbic acid, which is always from corn, even in their vitamin C. Something to think about, no? Please let me know if I’m safe taking Pure Encapsulations magnesium (which has ascorbyl palmitate—not sure if that’s from corn) and Solaray (which definitely has the ascorbitate).

    Thanks again!

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