The Chemistry of Beetroot 2015
Click to enlarge

The latest of the food science graphics looks at the chemistry of beetroot. An unusual effect of beetroot is that it can cause ‘beeturia’, or a red colouration to the urine, after ingestion. This is a condition that only affects an estimated 10-14% of the population, so what are the chemical compounds behind it, and why isn’t it a universal effect?

Perhaps unsurprisingly, it’s the compounds that give beetroot its red colour that can also lead to red-coloured urine. Beetroot’s deep red appearance is due to the presence of a class of compounds called betacyanins. This class comprises a number of compounds with similar chemical structures; betanin is a major player as far as colouration goes, and is actually extracted from beetroots and used as a food colouring (named ‘Beetroot Red’ and designated with the E number E162). Another family of compounds present are the betaxanthins. These have a yellow colour independently, and are present in lower concentrations than the betacyanins.

Betacyanins can cause beeturia because they don’t always break down in the digestive system of some people. The reasons for this are still a little uncertain; it has been suggested that, at low stomach acid pH, the compounds are broken down, and that when the stomach acid is not as strong, this does not occur. Therefore, the compounds are able to pass through the remainder of the digestive system, absorbed through the intestinal walls in the colon into the bloodstream, then filtered out by the kidneys and into the urine. Of course, some of the unmetabolised compound may well remain in the colon and wind up giving the delightful effect of purple poo.

It’s possible that the breakdown of these compounds could also be influenced by genetic factors which have yet to be precisely determined. For example, if a person genetically has a stronger acidity in their stomach, they may well break the compound down effectively and never experience beeturia. However, some studies have downplayed genetic factors, and instead suggest that we all excrete betanin in our urine to some extent after eating beetroot, and it is only environmental factors that influence whether or not this concentration is high enough to give a red colouration. In another interesting suggestion, beeturia has been potentially linked to being an early indicator of haemochromatosis (over-accumulation of iron in the body).

After more food & drink chemistry? Check out the Compound Interest book, coming in October 2015.

Enjoyed this post & graphic? Consider supporting Compound Interest on Patreon, and get previews of upcoming posts & more!



The graphic in this article is licensed under a  Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. See the site’s content usage guidelines.

References & Further Reading

23 CommentsClose Comments


  • Trackback: Food and Drink | Pearltrees
  • Trackback: Red Peas and Beets | Jeff Pearlman
  • MotherGinger
    Posted March 6, 2015 at 2:32 pm 0Likes

    My personal experience: beeturia regularly, then I started taking HCl (stomach acid) daily for an unrelated health problem, and after two years of taking it, started having signs that I now had enough HCl. I ate beets recently and guess what? No beeturia! I did have pink poop, though …

    Posted September 22, 2015 at 4:00 am 0Likes

    I have experienced beeturia every time I eat Beetroot.
    I also suffer with IBS.
    Wonder if they are linked??
    Beetroot used to really make me flare up with IBS, but I have slowly upped my intake and now can eat them in uncertain quantities cooked or pickled.

    • Linda Lovelush
      Posted September 24, 2015 at 8:07 pm 0Likes

      Odd… I too have IBS and just today I had fresh (cooked) beets for lunch and now it looks as though I’ve started my period, haha. Anytime I eat beets (or even drink red Koolaid) it turns my urine red or pink and also #2 gets so red it scared me a couple of times, until I remembered I’d eaten beets or drank red liquid, because I thought it was blood.

      • Shreedhar Reddy
        Posted September 25, 2015 at 6:49 pm 0Likes

        Hey linda,Same problem here…today i drunk a liter lo vegetable juice with 1 very large beetroot..and now my color is in lite brown? is that a serious thing?? have u gone through any medical test??

        • Linda Lovelush
          Posted September 25, 2015 at 7:58 pm 0Likes

          No, I haven’t gone through any medical tests, but I don’t have any issues (other than IBS) that I know of. I don’t think it’s really anything to worry about, but if you’re concerned, ask your doctor about it and see what he/she says. I’m still seeing a little bit of pink from eating those beets yesterday. And it’s quick to go through me, meaning the pink/red will start showing up in my ‘eliminations’ within the hour of eating beets or drinking any red-colored liquid (like I mentioned, Koolaid will do it).

          What’s weird, though, is this is a new thing for me. I’ve eaten lots of beets in my life and have drank plenty of Koolaid, especially as a kid, and it never discolored my urine (and #2 as well) like this before. So I *am* going to bring it up to my doctor October 2nd when I go in for a check-up and see if it’s anything she’s concerned about.

          • Lt. Nimitz
            Posted December 10, 2016 at 5:21 pm 0Likes

            It is all related on how alkalizing is the drink you are having. I used squized lemons today together my beets juice for the first time and I had redish urine for the first time.

          • Linda Lovelush
            Posted December 14, 2016 at 12:25 pm 0Likes

            I’ve read that it affects some people that way. I love fresh boiled beets and every time I eat them, my urine is pink for a while until it clears out of my system.

  • Trackback: Getty Stewart How to Plant Beets in the Garden
  • AIDS
    Posted December 8, 2015 at 1:23 pm 0Likes

    I only get beeturia when I juice beets but not when I eat them. The urine looks like mike Tyson punched me in my kidneys. Rns

  • Trackback: ¿Por qué la orina es roja cuando comemos remolacha? | Asociación Con/Ciencia
  • Trackback: How to Plant Beets in the Garden
  • Trackback: Beets Are Beautiful – Modern Day Ma
  • Trackback: Whole Food Republic
  • PharmaceuticsPharmacy Practice
    Posted June 30, 2016 at 7:59 am 0Likes

    We can make lipsticks from the natural dye obtained from Beetroots.

  • Lt. Nimitz
    Posted December 10, 2016 at 5:11 pm 0Likes

    Just experienced this. My urine were pinkish/redish after drinking beetroots juice. I came and look for answers and handed up here. After reading this I am pretty sure is because I squeezed 1 full lemon inside the beet juice making the acid in the stomac less effective. From now on I will use lemonated water only away from any food but I wonder if the red pigment arriving intact to the intestinal walls have some kind of benefit to it. Thank you.

    • Compound Interest
      Posted December 18, 2016 at 7:35 pm 0Likes

      Whether there are any health benefits of these compounds is somewhat unclear, though this review does claim some effects:

      Lemons in beetroot juice would be unlikely to affect your stomach acid in any way – lemons contain citric acid, which wouldn’t undergo any reaction with hydrochloric acid. The use of lemon juice with the beetroot and the appearance of red urine could be linked, but could also be coincidental. I’m not aware of any research that can clear that one up, sadly!

  • Trackback: Science Corner: Beet Edition – Mattblastblog
  • Trackback: Beet Salad with Orange and Pistachios — Modern Vegan Wellness
  • Trackback: Beet Hummus - Sandwich Spread • BurntPorkChops
  • Trackback: Beets Pink Urine Stomach Acid – Stomach Acid Treatments

Comments are closed.