The association of serum lipids, lipoproteins and apolipoproteins with selected trace elements and minerals in phenylketonuric patients on diet.

OBJECTIVE

Classical phenylketonuria (PKU) is an inborn error of metabolism characterized by high Phenylalanine (Phe) levels in blood and treated with a special low Phe diet which can be defined as "nonatherogenic". Since coronary heart disease (CHD) was reported to be a disease of zinc and copper imbalance, we aimed indirectly to evaluate the effect of the special diet on the size of LDL particles and to investigate whether some minerals and trace elements are involved in their lipoprotein metabolism.

METHODS

Eighty-six (N=86) PKU patients were divided into two groups. Group A (N=44) on a strict diet and group B (N=42) who did not adhere to their treatment. Healthy children (N=98) were the controls. Serum total cholesterol (t-Chol), triacylglycerol, High-density lipoprotein (HDL) and t-Chol in very-low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) were measured with enzymatic methods, whereas Apolipoprotein AI (Apo AI), Apolipoprotein AII (Apo AII) and Apolipoprotein B (Apo B) were determined by nephelometric techniques. LDL/Apo B positively correlated with LDL size. Magnesium (Mg), calcium (Ca), copper (Cu) and zinc (Zn) measurements were performed by atomic absorption spectrometry.

RESULTS

t-Chol, LDL, VLDL, Apo B, the ratio t-Chol/HDL, Apo AI/Apo B and LDL/Apo B as well as copper levels and the ratio Zn/Cu in group A statistically significantly differed as compared to those of group B and Controls. Positive correlations were found between Mg and HDL and Apo AI in all the groups whereas the mineral correlated with t-Chol, Apo B and the ratio LDL/Apo B only in the group A of patients. Copper negatively correlated with triacylglycerol, LDL, and Apo B and positively with t-Chol in group A. Zinc showed negative relationships in HDL and Apo A in all the studied groups. The ratio Zn/Cu negatively correlated with triacylglycerol and LDL in all the groups and positively with the ratios Apo AI/Apo B and LDL/Apo B in group A.

CONCLUSIONS

Some of the minerals and trace elements were correlated with the lipids and lipoproteins and were also involved in the size of LDL particles in PKU patients on strict diet. Larger and less atherogenic LDL particles were associated with a high Zn/Cu ratio.