I am skeptical of food restrictions. Especially when they involve removing many vegetables known to nutritious.
We have tried the low oxalate diet, Feingold diet, low histamine diet, and low salicylate diet all to no avail. I completely agree on perhaps decreasing protein to a minimum, but some is needed I believe. Of course get rid of aspartame (which is not part of a Wahls/PerfectHealth Diet anyway).
My feeling is that in many of our cases, the lack of BH4 is limiting the breakdown of phenylalanine. Low BH4 can be problematic in people with certain MTHFR mutations.
www.ncbi.nlm.nih.gov/pubmed/15556637Tetrahydrobiopterin protects phenylalanine hydroxylase activity in vivo: implications for tetrahydrobiopterin-responsive hyperphenylalaninemia.
Abstract
The natural cofactor of phenylalanine hydroxylase (PAH), tetrahydrobiopterin (BH4), regulates the enzyme activity as well as being essential in catalysis. BH4-responsive PAH deficiency is a variant of hyperphenylalaninemia or phenylketonuria (PKU) caused by mutations in the human PAH gene that respond to oral BH4 loading by stimulating enzyme activity and therefore lowering serum phenylalanine. Here, we showed in a coupled transcript
ion-translation in vitro assay that upon expression in the presence of BH4, wild-type PAH enzyme activity was enhanced. We then investigated the effect of BH4 on PAH activity in transgenic mice that had a complete or partial deficiency in the endogenous cofactor biosynthesis. The rate of hepatic PAH enzyme activity increased significantly with BH4 content without affecting gene expression or Pah-mRNA stability. These results indicate that BH4 has a chaperon-like effect on PAH synthesis and/or is a protecting cofactor against enzyme auto-inactivation and degradation also in vivo. Our findings thus contribute to the understanding of the regulation of PAH by its cofactor BH4 on an additional level and provide a molecular explanation for cofactor-responsive PKU.
I would first opt for trying to increase BH4 without nutritional elimination:
www.townsendletter.com/FebMarch2010/cureNO0210.htmlHow Can We Cure NO/ONOO− Cycle Diseases?
Table 2: Agents/Classes of Agents Predicted to Substantially Lower the Central Couplet
1) IV buffered ascorbate
7–50 g, repeated
1. Acts as peroxynitrite scavenger; 2. reduces B back to BH4, helping restore BH4 levels; 3. the very high levels obtained by IV treatment can lead to increased levels of hydrogen peroxide, leading to induction of GTP cyclohydrolase I, thus leading to increased de novo synthesis of BH4.
2)oral ascorbate
circa 2–3 g, repeated daily
Blood levels obtained are substantially lower than for IV treatment, above. However such levels may be adequate to trigger the first two mechanisms outlined immediately above.
3) sauna therapy
repeated
Induces GTP cyclohydrolase I, leading to increased de novo synthesis of BH4.
4) reduced glutathione, liposomal, time release, nasal spray, IV or inhalant
150–500 mg per day
Reduces BH2 back to BH4, thus helping restore normal BH4 levels and lowering the partial uncoupling of the nitric oxide synthases; some, particularly those with asthma-type symptoms, may have some difficulty tolerating this treatment, depending on dosage regimen.
5) Inosine, RNA, or D-ribose
varies
Each of these has the capability of producing two responses: restoration of adenine nucleotide pools and increased uric acid levels in blood. The latter will lead to lowered levels of peroxynitrite breakdown products, NO2 radical and carbonate radical. Each of these agents have drawbacks (see text).
6)5-methyl tetrahydro- folate (5-MTHF) or precursors folic or folinic acid
300 µg/day for 5-MTHF, higher doses for precursors
Acts as a potent peroxynitrite scavenger and will therefore help also restore BH4 pools; high dose folic or folinic acid will act to help raise 5-MTHF pools. 5-MTHF pools are depleted in CFS/ME, presumably due to peroxynitrite mediated oxidation.
7)tetrahydro- biopterin (BH4) or precursors of BH4 biopterin or sepiapterin
circa 5 mg or less, oral daily
Helps restore BH4 pools; also acts as peroxynitrite scavenger. This would be an off-label use of BH4.
8)vasoactive intestinal peptide (VIP)
IV or inhalant
Induces GTP cyclohydrolase I, leading to increased de novo synthesis of BH4; this would be an off-label use.
9) flavonoids, ellagic acid, other phenolic antioxidants
??, oral
Probably act to scavenge peroxynitrite and breakdown products and may also act more directly to help restore BH4; dosage and optimal sources are unclear.
10) hydroxocobalamin
IM injection, nasal spray or inhalant
Acts in the reduced form (cobalt II) as a potent nitric oxide scavenger; this will indirectly lower peroxynitrite because of the role of nitric oxide as a peroxynitrite scavenger.