Vitamins that make up the vitamin B complex group (such as B12, riboflavin, niacin and thiamin) are all water soluble, so they cannot be stored in the body for extended periods of time like fat-soluble vitamins.
They are often expelled in the urine, meaning these vitamins can affect how your urine appears and can even result in bright yellow pee or urine with a greenish tinge. This may be concerning initially, but it's usually nothing more than an innocuous side effect of the vitamins you've taken.
Vitamin B Complex: Urine Discoloration
The Cleveland Clinic explains that B vitamins have been shown to give urine an unusual greenish tinge, but it is not necessarily a cause for concern. B vitamins cause urine to appear yellow more often than green.
Vitamin B complex supplements often combine all eight of the B vitamins within one convenient capsule. One of the eight is riboflavin, which helps metabolize fats, proteins and carbohydrates into glucose for energy. However, it also has a yellow-green fluorescent pigment, which is what causes the bright yellow pee.
Fortunately, this isn't a sign of illness, it just means your body is absorbing riboflavin as it should. The absorption of riboflavin also aids in converting tryptophan to niacin, which activates vitamin B6 — another beneficial vitamin of the B group. The Cleveland Clinic also says that vitamin B6 supplements may affect urine by giving it a strong odor, so naturally activated vitamin B6 — from food —may be a preferable option.
Role of Water-Soluble Vitamins
All water-soluble vitamins are part of the vitamin B group, except vitamin C. The Harvard Help Guide explains that eight vitamins make up the B group:
- Biotin (vitamin B7)
- Folic acid (folate, vitamin B9)
- Niacin (vitamin B3)
- Pantothenic acid (vitamin B5)
- Riboflavin (vitamin B2)
- Thiamin (vitamin B1)
- Vitamin B6
- Vitamin B12
Each has its own specific benefits and roles in the body, including maintaining the health of the nervous system and the metabolizing of fats and proteins into glucose so they can be used as energy.
For energy production, the key B vitamins are thiamin, riboflavin, niacin, pantothenic acid and biotin, so these are often the nutrients you may need to supplement if you are experiencing excessive tiredness or fatigue.
B vitamins are also integral for building proteins and cells, which aids with wound healing and the body's ability to regenerate. Specifically, Harvard says that vitamins B12, B6 and folic acid are key to protein and cell synthesis.
Urine and Vitamins: Myths
There are a lot of misconceptions surrounding vitamin supplements, specifically the supplements made up of water-soluble vitamins like those of the B complex. Unlike fat-soluble vitamins, water-soluble vitamins cannot be stored for extended periods of time so they are expelled from the body much more quickly than fat-soluble vitamins.
However, this does not mean that they are immediately removed from the body on a daily basis, and it definitely does not mean that all water-soluble vitamins consumed are then immediately urinated out of the system, providing no benefit at all.
To truly understand how inaccurate this assumption is, the purpose of urine should be examined: Urine accumulates in the kidneys once these organs have finished purifying the blood. Therefore, if there are any excess vitamins that can be disposed of, the body will do so through the urine, which is why it can occasionally become discolored.
What Happens to Excess Vitamins?
The key word here is excess — if the body is expelling excess amounts of a particular vitamin, it means you have a sufficient level present in your body. This is a good thing. Though a healthy lifestyle and balanced diet are definitely the best way to get the vitamins necessary for bodily functions to be carried out effectively, supplements can be a positive way to fortify this intake and reduce the likelihood of deficiency.
An April 2013 study published in the Journal of Nutritional Science found that when the body begins to run low on the B vitamins it requires, it reduces the amount actually passing through the urine and retains the amounts it needs. So any water-soluble vitamins present in urine following excretion are disposable and are not wasted supplement vitamins.
Urine Discoloration as a Symptom
Passing urine is so routine you may not even think about it — unless there is a significant change in color or odor such as bright yellow pee from riboflavin or a strong odor from vitamin B6.
However, while many of the side effects of vitamin B in urine are entirely innocuous, urine discoloration can also be a sign of something more serious.
- Dark yellow urine: This can signal dehydration — not overly worrisome in and of itself, but a problem that is easily solved by increasing the amount of fluid you drink. Continued dehydration can lead to much more serious health concerns, however.
- Red urine: This could be a sign of blood in the urine, which in turn is a potential sign of kidney stones, an infection or even a tumor in the urinary tract. If there is any blood present in your urine it is important to consult a health care professional as soon as possible for advice.
- Blue urine: Blue urine can occur from rare instances of a metabolic disorder in which intestinal breakdown of tryptophan cannot be completed. Contact your health care professional if your urine looks blue.
Medication and Urine Color
Harvard Health Publishing says that four urinary discolorations may be caused by particular medications:
- Red: Senna (Ex-Lax), chlorpromazine (Thorazine), thioridazine (Mellaril)
- Orange: Rifampin (Rifadin), warfarin (Coumadin), phenazopyridine (Pyridium)
- Blue/green: Amitriptyline (generic), indomethacin (Indocin), cimetidine (Tagamet), promethazine (Phenergan)
- Dark brown: Chloroquine (Aralen), primaquine (generic), metronidazole (Flagyl), nitrofurantoin (Furadantin)
If you are taking any of these medications and are experiencing any urinary discoloration, tell your health care professional about it to make sure the discoloration is not a symptom of anything more serious.
- Cleveland Clinic: "Changes in Urine"
- National Library of Medicine: "Riboflavin Deficiency"
- Harvard Help Guide: "Vitamins and Minerals"
- Orthomolecular: "The Expensive Urine Myth"
- National Library of Medicine: "Urinary Excretion of B-Group Vitamins Reflects the Nutritional Status of B-Group Vitamins in Rats"
- University of San Diego Health: "10 Colors That Suggest Urine Trouble"
- Harvard Medical School: "Urine Color and Odor Changes"
- Colorado State University: "Fat Soluble Vitamins"