Dietary intake data of 15 treated patients with
phenylketonuria (PKU) (7-17 years) and six control siblings
(6-14 years) were used to evaluate the effectiveness of
medical foods to balance energy, protein, vitamin B-6, and
individual amino acids from natural foods and to evaluate
vitamin B-6 status. Four-day diet records were computer-analyzed
and the contribution of medical foods and natural
foods to the total diets of the patients was determined. A
fasting blood sample and two 24-hour urine collections were
obtained from each subject.
In eight patients consuming a strict diet, natural
foods provided 0.9 g protein and 39 mg phenylalanine
(phe)/100 calories, a significant reduction from control
intakes of 3.3 g protein and 153 mg phe/100 calories.
However, plasma phe levels were above the acceptable
treatment range. Medical foods were consumed in less than the recommended quantities to meet approximately 120% of the
Recommended Dietary Allowances (RDAs) for protein. These
foods contributed 73% of the total protein RDAs but only met
22% of the energy RDAs of patients consuming the strict
diet. Taste qualities of certain L-amino acids (L-AAs; Lmethionine,
L-glutamic and L-aspartic acids), which
constitute the protein in elemental medical foods (EMFs) for
school-aged patients, make acceptance of these products
difficult. Intakes of each of these L-AAs were above
nutritional standards and suggested that their levels could
be safely lowered in EMFs.
Natural foods and medical foods provided 0.057 and
0.046 mg vitamin B-6/g protein, respectively, above the
0.020 RDA standard and the mean control intake of 0.018 mg
vitamin B-6/g protein. The mean plasma pyridoxal 5'-
phosphate (PLP) concentration for the patients with PKU was
over twice that of the mean control concentration and above
literature values. However, more than half of the patients
excreted less than 30% of their vitamin B-6 as 4-pyridoxic
acid; values below the criterion suggested for inadequate
status.
This work provides data for a better understanding of
vitamin B-6 metabolism and status in PKU and supports the
design and testing of a new EMF to balance energy, protein,
and amino acids from natural foods and which may improve
dietary adherence. / Graduation date: 1991
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27082 |
| Date | 28 November 1990 |
| Creators | Prince, Annie |
| Contributors | Leklem, James E. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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