Stool Color Changes: Food Effects and Health Concerns

Bowel issues

Hello Doctor, I previously inquired about orange-red or coffee-red water in my stool.
Subsequently, I underwent a fecal occult blood test at the end of October (two types, one for gastrointestinal bleeding which cost an additional $250, and one for colorectal bleeding).
Both results were normal.
I asked the doctor if it could be indirect bleeding, and the doctor explained that if there were bleeding, it would be continuous and not result in a false negative.
Additionally, the sensitivity of these two tests is extremely high, so it is likely that my symptoms are food-related.
Since I had a colonoscopy only three years ago, the doctor advised me that another one is unnecessary, and I returned home feeling reassured.
However, last Saturday night, I noticed orange-red water again when I used the restroom.
I don't recall eating anything with red coloring on Friday, except for red curry rice on Thursday afternoon, which was quite red.
I would like to ask the doctor if food coloring can affect stool appearance and take a day and a half to manifest? (I also have irritable bowel syndrome.) On Friday, the stool had a slight red tint on the outside, likely due to the coloring (it looked like the red curry color, and the toilet paper was normal).
On Saturday night, the stool appeared normal, but the toilet water was slightly red (possibly due to the stool), and the toilet paper was normal.
Since Sunday and today, the color has returned to normal.
Should I undergo another fecal occult blood test? I had my colonoscopy only three years ago (with no significant issues).
Additionally, how many days can food coloring potentially affect stool? Can it influence the stool appearance the day after consumption, or is it possible that the stool generated on Friday was just not expelled? Thank you, Doctor.

Niming, 20~29 year old female. Ask Date: 2021/11/15

Dr. Ke Fangxu reply Surgery

Food coloring may affect the results of a stool occult blood test for more than one day.
If there are no persistent color abnormalities, a colonoscopy may not be necessary.

Reply Date: 2021/11/15

More Info

Understanding stool color changes can be quite complex, as various factors can influence the appearance of stool, including diet, hydration, and underlying health conditions. In your case, the presence of orange-red or coffee-red water in the toilet after bowel movements raises some important considerations.

Firstly, it is essential to recognize that certain foods can indeed affect stool color. For example, foods that are rich in pigments, such as beets, tomatoes, and certain spices like curry, can lead to noticeable changes in stool color. In your situation, you mentioned consuming red curry rice, which could potentially contribute to the reddish hue observed in your stool. The pigments from these foods can take some time to pass through the digestive system, and it is not uncommon for the effects to be seen a day or more after consumption.
Regarding your question about whether food colorants can affect stool color a day and a half later, the answer is yes. The digestive process can vary significantly from person to person, and factors such as gastrointestinal transit time, the composition of the meal, and individual metabolism can all play a role. In general, it is possible for food to influence stool color for up to 48 hours after consumption, depending on how quickly your digestive system processes the food.
You also mentioned having irritable bowel syndrome (IBS), which can further complicate the situation. IBS can lead to changes in bowel habits and stool characteristics, including color. Stress and dietary changes often associated with IBS can also influence how your body reacts to certain foods, potentially leading to more pronounced color changes.

As for your concerns about the need for another fecal occult blood test (FOBT), since you have already undergone testing recently with normal results, and given that you have no other alarming symptoms (such as significant abdominal pain, weight loss, or changes in bowel habits), it may not be necessary to repeat the test immediately. However, if you continue to notice unusual stool colors or if any new symptoms arise, it would be prudent to consult your healthcare provider for further evaluation.

In summary, the reddish color in your stool could likely be attributed to the consumption of red curry rice, and it is possible for food pigments to affect stool color for a day or more. Given your recent normal test results and the absence of concerning symptoms, you may not need to repeat the fecal occult blood test at this time. However, remain vigilant about any changes in your health and communicate with your healthcare provider if you have ongoing concerns. Maintaining a balanced diet and staying hydrated can also support overall digestive health.

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