Hi J.---You've gotten many ideas on some short term interventions, but you really need to get to the bottom of the problem. One of my concerns would be the length of time the waste is in the intestines. When it sits in there, it has time to reabsorb the toxins the body is trying to excrete.
I just attended a health talk last night where the nurse, who is also a Naturopath and a has a doctorate in Nutritional Counseling, talked a lot about 'elimination'. Transit time for a normal functioning bowel is about 12-22 hours but, of course, doesn't happen that way for most people.
It could be that there is a mechanical problem with the intestines. That should be ruled out. But most likely, it is a matter of diet and lifestyle. Please understand that I am not suggesting that your diet and lifestyle are poor, but rather, it may not be good enough to help alleviate this problem. A proper functioning gut is vital to good health.
Reduce animal protein consumption and ELIMINATE cows milk. Cows milk is extremely constipating, more for some and not for others, and it also is a risk factor for type 1 diabetes, many types of allergies and prostate cancer. Please read these resources to learn more: www.pcrm.org, www.strongbones.org and www.notmilk.com. Also, a really, really good book on dietary habits and disease rates is The China Study by T Colin Campbell. Meat contains no fiber at all, very few nutrients and mostly saturated fat, calories and cholesterol. It slows digestion rates.
You should be eating mostly fruits, veggies, whole grains, legumes, nuts and seeds, about 90% of your daily calorie intake. Make as much of that raw as possible. Have you ever tried raw beets? They are delicious. Grate them and put them on a salad. Kale is also a hugely nutritious green. It is very 'chewy' but works well in soups or stews and also is fine when chopped fine and put in salads. Avoid lots of added sugar. Use ground flax seeds on cereal, in smoothies, pancakes and other baked goods. Flax is a superfood. Lots of fiber, protein, omega 3 fats, vitamins, minerals and cancer preventive lignans.
I would also reduce or eliminate use of packaged and prepared foods. These foods are not really food, but rather food products. They lack the fiber and nutrients necessary for good health. The also contain lots of chemical additives that could very well interfere with many healthy body processes.
I am taking a series of wellness classes taught by a Naturopath who has her PhD in Nutrition. So I have lots of resources I would be happy to share if you'd like to explore any of the topics I've touched on. Keep working with your daughter in a loving and caring way. But at 6, she should be able to understand that she needs to learn to take control of this problem. If she's a picky eater, than she needs to eat differently to help her to poop more easily. Maybe teach her how to 'hee-hee-who' while she's having a bowel movement. Anyone who's had a baby knows how to 'breathe' like that. Help her to learn how to fix her thoughts on something other than the discomfort she is experiencing. You will also likely need to retrain her bowels. I work with a nurse who talks about doing this. She teaches in terms of a food based supplement that helps to regain regularity, but I think it would work with regular food as well. Have a couple of serving of fruit with breakfast, 2-3 servings of veggies at lunch and dinner, then some more fruit before bedtime. Sound like a lot but it's not really. We are supposed to have 7-13 servings each day. Granted, kids would simply have smaller servings than adults. I have charts that tell what kids of different ages should have. Do try to have as many different kinds of fruit and veg as possible and strive to have different colors of the rainbow as well. Colors are nutrients and a wide variety is healthiest.
So, easy answers? Not likely. It will take patience and a desire on her part to make things different. I hope this helps in some small way. I am open to you contacting me with more questions, if you'd like. It would be my honor to help. I hate seeing people suffer with health issues when there are some simple solutions. Take care and good luck. D.