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Health Condition

Phenylketonuria

  • Branched-Chain Amino Acids

    Regular use of branched-chain amino acids (BCAAs) may improve mental functioning.

    Dose:

    Take under medical supervision: 150 mg daily per 2.2 lbs (1 kg) of body weight each of valine and isoleucine, and 200 mg daily per 2.2 lbs (1 kg) of body weight of leucine
    Branched-Chain Amino Acids
    ×
    In a double-blind trial, regular use of branched-chain amino acids (BCAAs) (i.e., valine, isoleucine, and leucine) by adolescents and young adults with PKU improved performance on some tests of mental functioning.7Participants received either placebo, or 150 mg per 2.2 pounds of body weight each of valine and isoleucine, and 200 mg per 2.2 pounds of body of leucine, taken with meals and at bedtime. Participants received one mixture or the other for four three-month periods, for a total of six months’ supplementation of each regimen over the course of a year.

  • Fish Oil

    The PKU diet is low in fatty acids, some of which are essential for proper brain development. Supplementing with fish oil may improve the deficiency.

    Dose:

    125 mg of oil or 15 mg of docosahexaenoic acid per 2.2 lbs (1 kg) of body weight daily
    Fish Oil
    ×
    The PKU diet is low in fatty acids, some of which are essential for proper brain development.8 In one controlled study of children with PKU who were deficient in fatty acids, supplementation with fish oil (but not with black currant seed oil) for six months improved the deficiency. The children received 500 mg of oil per 8.8 pounds of body weight each day for 6 months. The amount varied from 5–8 capsules (each containing 500 mg) per day for each child.9 In another study, fish oil supplementation (providing 15 mg of docosahexaenoic acid per 2.2 pounds of body weight per day) improved body coordination and fine motor skills in children with PKU.10

  • L-Tyrosine

    Supplementing with L-Tyrosine may help prevent a deficiency caused by the PKU diet and improve behavoir.

    Dose:

    Consult a qualified healthcare practitioner
    L-Tyrosine
    ×
    PKU results from a deficiency or malfunction of the enzyme, phenylalanine hydroxylase, which converts phenylalanine to . People with PKU have elevated concentrations of phenylalanine and low levels of L-tyrosine, which may contribute to behavior problems. In addition, low L-tyrosine levels in women with PKU may contribute to fetal damage. In some, but not all, double-blind studies, keeping L-tyrosine levels in the normal range by adding supplemental L-tyrosine to the diet improved behavior. In a preliminary study, blood L-tyrosine levels fluctuated significantly in people with PKU, suggesting a need for careful laboratory monitoring of people supplementing with L-tyrosine.

  • Selenium

    Selenium deficiency may develop on the PKU diet, and supplementation may help correct this.

    Dose:

    Adolescents and adults: 55 mcg daily; for infants and children: 15 to 40 mcg daily, according to age
    Selenium
    ×

    People with PKU may be deficient in several nutrients, due to the restricted diet which is low in protein and animal fat. Deficiencies of long-chain polyunsaturated fatty acids (LC-PUFAs),11,12,13selenium,14,15,16,17vitamin B12,18 and vitamin K may develop on this diet.19

    Selenium is important for normal antioxidant function. Research suggests that selenium deficiency and decreased antioxidant activity may contribute to the brain and nerve disorders associated with PKU.16 In two preliminary studies involving selenium-deficient people with PKU, supplementation with selenium in the form of sodium selenite corrected the deficiency,15 whereas supplementation with selenium in the form of selenomethionine did not.22

  • Vitamin K

    People with PKU may be deficient in vitamin K, due to the restricted PKU diet. Supplementing with vitamin K may correct a deficiency.

    Dose:

    Refer to label instructions
    Vitamin K
    ×

    People with PKU may be deficient in several nutrients, due to the restricted diet which is low in protein and animal fat. Deficiencies of long-chain polyunsaturated fatty acids (LC-PUFAs),21,22,23selenium,24,25,26,27vitamin B12,28 and vitamin K may develop on this diet.29

    Because the PKU diet is low in animal products, fat intake is also significantly reduced. The results of a preliminary study of children with PKU suggested that the low-fat PKU diet intake may impair the absorption of vitamin K, a fat-soluble vitamin, from the diet, possibly resulting in a vitamin K deficiency. In that study, children with PKU on a strict diet had low levels of certain vitamin K-dependent proteins needed for normal blood clotting.29

What Are Star Ratings
×
Reliable and relatively consistent scientific data showing a substantial health benefit.
Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.

References

1. Diamond A. Evidence for the importance of dopamine for prefrontal cortex functions early in life. Philos Trans R Soc Lond B Biol Sci 1996;351:1483-93 [review].

2. Cabalska MB, Nowaczewska I, Sendecka E, Zorska K. Longitudinal study on early diagnosis and treatment of phenylketonuria in Poland. Eur J Pediatr 1996;155 Suppl 1:S53-5.

3. Eisensmith RC, Woo SL. Gene therapy for phenylketonuria. Eur J Pediatr 1996;155 Suppl 1:S16-9 [review].

4. Lin CM, Tan Y, Lee YM, et al. Expression of human phenylalanine hydroxylase activity in T lymphocytes of classical phenylketonuria children by retroviral-mediated gene transfer. J Inherit Metab Dis 1997;20:742-54.

5. Sarkissian CN, Shao Z, Blain F, et al. A different approach to treatment of phenylketonuria: phenylalanine degradation with recombinant phenylalanine ammonia lyase. Proc Natl Acad Sci 1999;96:2339-44.

6. Pietz J, Kreis R, Rupp A, et al. Large neutral amino acids block phenylalanine transport into brain tissue in patients with phenylketonuria. J Clin Invest 1999;103:1169-78.

7. Berry HK, Brunner RL, Hunt MM, et al. Valine, isoleucine, and leucine. A new treatment for phenylketonuria. Am J Dis Child 1990;144:539-43.

8. Giovannini M, Agostoni C, Biasucci G, et al. Fatty acid metabolism in phenylketonuria. Eur J Pediatr 1996;155 Suppl 1:S132-5.

9. Agostoni C, Riva E, Biasucci G, et al. The effects of n-3 and n-6 polyunsaturated fatty acids on plasma lipids and fatty acids of treated phenylketonuric children. Prostaglandins Leukot Essent Fatty Acids 1995;53:401-4.

10. Beblo S, Reinhardt H, Demmelmair H, et al. Effect of fish oil supplementation on fatty acid status, coordination, and fine motor skills in children with phenylketonuria. J Pediatr 2007;150:479-84.

11. Agostoni C, Marangoni F, Riva E, et al. Plasma arachidonic acid and serum thromboxane B2 concentrations in phenylketonuric children negatively correlate with dietary compliance. Prostaglandins Leukot Essent Fatty Acids 1997;56:219-22.

12. Giovannini M, Agostoni C, Biasucci G, et al. Fatty acid metabolism in phenylketonuria. Eur J Pediatr 1996;155 Suppl 1:S132-5.

13. Poge AP, Baumann K, Muller E, et al. Long-chain polyunsaturated fatty acids in plasma and erythrocyte membrane lipids of children with phenylketonuria after controlled linoleic acid intake. J Inherit Metab Dis 1998;21:373-81.

14. Jochum F, Terwolbeck K, Meinhold H, et al. Effects of a low selenium state in patients with phenylketonuria. Acta Paediatr 1997;86:775-7.

15. Kauf E, Seidel J, Winnefeld K, et al. Selenium in phenylketonuria patients. Effects of sodium selenite administration. Med Klin 1997;92 Suppl 3:31-4 [in German].

16. Sierra C, Vilaseca MA, Moyano D, et al. Antioxidant status in hyperphenylalaninemia. Clin Chim Acta 1998;276:1-9.

17. Gropper SS, Naglak MC, Nardella M, et al. Nutrient intakes of adolescents with phenylketonuria and infants and children with maple syrup urine disease on semisynthetic diets. J Am Coll Nutr 1993;12:108-14.

18. Hanley WB, Feigenbaum AS, Clarke JT, et al. Vitamin B12 deficiency in adolescents and young adults with phenylketonuria. Eur J Pediatr 1996;155 Suppl 1:S145-7.

19. Schulpis KH, Platokouki H, Papakonstantinou ED, et al. Haemostatic variables in phenylketonuric children under dietary treatment. J Inherit Metab Dis 1996;19:603-9.

20. Lombeck I, Jochum F, Terwolbeck K. Selenium status in infants and children with phenylketonuria and in maternal phenylketonuria. Eur J Pediatr 1996;155 Suppl 1:S140-4.

21. Agostoni C, Marangoni F, Riva E, et al. Plasma arachidonic acid and serum thromboxane B2 concentrations in phenylketonuric children negatively correlate with dietary compliance. Prostaglandins Leukot Essent Fatty Acids 1997;56:219-22.

22. Giovannini M, Agostoni C, Biasucci G, et al. Fatty acid metabolism in phenylketonuria. Eur J Pediatr 1996;155 Suppl 1:S132-5.

23. Poge AP, Baumann K, Muller E, et al. Long-chain polyunsaturated fatty acids in plasma and erythrocyte membrane lipids of children with phenylketonuria after controlled linoleic acid intake. J Inherit Metab Dis 1998;21:373-81.

24. Jochum F, Terwolbeck K, Meinhold H, et al. Effects of a low selenium state in patients with phenylketonuria. Acta Paediatr 1997;86:775-7.

25. Kauf E, Seidel J, Winnefeld K, et al. Selenium in phenylketonuria patients. Effects of sodium selenite administration. Med Klin 1997;92 Suppl 3:31-4 [in German].

26. Sierra C, Vilaseca MA, Moyano D, et al. Antioxidant status in hyperphenylalaninemia. Clin Chim Acta 1998;276:1-9.

27. Gropper SS, Naglak MC, Nardella M, et al. Nutrient intakes of adolescents with phenylketonuria and infants and children with maple syrup urine disease on semisynthetic diets. J Am Coll Nutr 1993;12:108-14.

28. Hanley WB, Feigenbaum AS, Clarke JT, et al. Vitamin B12 deficiency in adolescents and young adults with phenylketonuria. Eur J Pediatr 1996;155 Suppl 1:S145-7.

29. Schulpis KH, Platokouki H, Papakonstantinou ED, et al. Haemostatic variables in phenylketonuric children under dietary treatment. J Inherit Metab Dis 1996;19:603-9.

30. Mackey SA, Berlin CM Jr. Effect of dietary aspartame on plasma concentrations of phenylalanine and tyrosine in normal and homozygous phenylketonuric patients. Clin Pediatr 1992;31:394-9.

31. Diamond A. Evidence for the importance of dopamine for prefrontal cortex functions early in life. Philos Trans R Soc Lond B Biol Sci 1996;351:1483-93 [review].

32. Cockburn F, Clark BJ. Recommendations for protein and amino acid intake in phenylketonuric patients. Eur J Pediatr 1996;155 Suppl 1:S125-9.

33. Koch R, Moseley K, Ning J, et al. Long-term beneficial effects of the phenylalanine-restricted diet in late-diagnosed individuals with phenylketonuria. Mol Genet Metab 1999;67:148-55.

34. Yannicelli S, Ryan A. Improvements in behavior and physical manifestations in previously untreated adults with phenylketonuria using a phenylalanine-restricted diet: a national survey. J Inherit Metab Dis 1995;18:131-4.

35. Williams K. Benefits of normalizing plasma phenylalanine: impact on behavior and health. A case report. J Inherit Metab Dis 1998;21:785-90.

36. Arnold G, Kramer BM, Kirby RS, et al. Factors affecting cognitive, motor, behavioral and executive functioning in children with phenylketonuria. Acta Paediatr 1998;87:565-70.

37. Baumeister AA, Baumeister AA. Dietary treatment of destructive behavior associated with hyperphenylalaninemia. Clin Neuropharmacol 1998;21:18-27 [review].

38. Griffiths P, Ward N, Harvie A, Cockburn F. Neuropsychological outcome of experimental manipulation of phenylalanine intake in treated phenylketonuria. J Inherit Metab Dis 1998;21:29-38.

39. Griffiths P, Smith C, Harvie A. Transitory hyperphenylalaninaemia in children with continuously treated phenylketonuria. Am J Ment Retard 1997;102:27-36.

40. Cerone R, Schiaffino MC, Di Stefano S, Veneselli E. Phenylketonuria: diet for life or not? Acta Paediatrica 1999;88:664-6.

41. Diamond A, Prevor MB, Callender G, Druin DP. Prefrontal cortex cognitive deficits in children treated early and continuously for PKU. Monogr Soc Res Child Dev 1997;62:1-208.

42. Ullrich K. Rationale for the German recommendations for phenylalanine level control in phenylketonuria 1997. Eur J Pediatr 1999;158:46-54.

43. Fisch RO, Matalon R, Weisberg S, Michals K. Phenylketonuria: current dietary treatment practices in the United States and Canada. J Am Coll Nutr 1997;16:147-51.

44. Start K. Treating phenylketonuria by a phenylalanine-free diet. Prof Care Mother Child 1998;8:109-10 [review].

45. Schulpis KH, Nyalala JO, Papakonstantinou ED, et al. Biotin recycling impairment in phenylketonuric children with seborrheic dermatitis. Int J Dermatol 1998;37:918-21.

46. Waisbren SE, Rokni H, Bailey I, et al. Social factors and the meaning of food in adherence to medical diets: results of a maternal phenylketonuria summer camp. J Inherit Metab Dis 1997;20:21-7.

47. Scheibenreiter S, Tiefenthaler M, Hinteregger V, et al. Austrian report on longitudinal outcome in phenylketonuria. Eur J Pediatr 1996;155 Suppl 1:S45-9.

48. Weglage J, Funders B, Ullrich K, et al. Psychosocial aspects in phenylketonuria. Eur J Pediatr 1996;155 Suppl 1:S101-4.

49. Brenton DP, Lilburn M. Maternal phenylketonuria. A study from the United Kingdom. Eur J Pediatr 1996;155 Suppl 1:S177-80.

50. Levy HL, Ghavami M. Maternal phenylketonuria: a metabolic teratogen. Teratology 1996;53:176-84 [review].

51. Cechak P, Hejcmanova L, Rupp A. Long-term follow-up of patients treated for phenylketonuria (PKU). Results from the Prague PKU Center. Eur J Pediatr 1996;155 Suppl 1:S59-63.

52. Cipcic-Schmidt S, Trefz FK, Funders B, et al. German Maternal Phenylketonuria Study. Eur J Pediatr 1996;155 Suppl 1:S173-6.

53. Rouse B, Azen C, Koch R, et al. Maternal Phenylketonuria Collaborative Study (MPKUCS) offspring: facial anomalies, malformations, and early neurological sequelae. Am J Med Genet 1997;69:89-95.

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The information presented by TraceGains is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires December 2025.