A low ammonia diet may be necessary when treating certain single nucleotide polymorphisms (SNPS). Ammonia is generated in the body when food is broken down in the intestines by bacteria which release ammonia in the body. The ones particularly affected by ammonia are the SUOX, NOS, A1298 and CBS. These snps affect certain metabolic pathways and can also lower levels of BH4. Raising levels of BH4 is also important as well as lowering levels of ammonia in the body.
Normally BH4 is used to recycle and detox ammonia, but when it is lowered and there are normal or elevated levels of ammonia these can cause a variety of health problems. These health problems can range from brain fog, fatigue, musclar fatigue/weakness among many others.
Ammonia toxicity symptoms (which might affect those with low BH4 levels), can range from brain fog, spacey, language issues, poor concentration, dark circles under eyes, poor learning and memory as well as food intolerances (particularly protein). In some rare cases it may be necessary for those dealing with liver or kidney problems as well.
It may cause other mental/physical symptoms as well such as anxiety and depression. When there are lower levels of BH4 it will prioritize detoxifaction of ammonia over other essential functions such as producing neurotransmitters. Neurotransmitters can affect many functions in the body, such as mood, appetite, memory and general mental function.
To compensate for the lowered amount of protein in the diet, it may be necessary to supplement with amino acids to compensate for the lack of amino acids from lower amounts of protein. There are certain foods which contain higher amounts of ammonia than others, a list of them are located here: http://wholefoodcatalog.info/nutrient/ammonia/foods/high/
As can be seen from the list it would be beneficial to go on a paleo template diet with a lowered amount of protein. To further compensate for lowered amounts of protein it would help to increase amount of carbohydrates and fat as well.
Proper supplementation can also help but should be done under a healthcare practitioner well trained or versed in methylation and complex health issues. Finding help for those with mthfr, detoxifaction can be difficult as many are either unaware or know very little about treating such issues.
Addressing adrenal, thyroid and gastrointestinal health is also important as well when treating such complex health issues. I found this note to be particularly helpful, especially explaining ammonia problems and treatment aims when dealing with certains SNPS: https://www.facebook.com/notes/insight-naturopathy/mthfr-a1298c-polymorphism/385764944792649