P E Pajukanta | PubMed Health

PubMed1996

The effects of the apolipoprotein B signal peptide (ins/del) and XbaI polymorphisms on plasma lipid responses to dietary change.

There is interindividual variation in plasma lipid response to dietary changes. The polymorphisms which are associated with plasma lipid levels could possibly explain part of this variation. Therefore, the apolipoprotein B (apo B) signal peptide insertion/deletion (ins/del) and XbaI restriction fragment length polymorphisms are possible regulators of plasma lipid responses. We examined their role in the regulation of plasma lipid responses in 87 North Karelians (43 men, 44 women). The dietary study consisted of a 2-week baseline period (34-35% of energy from fat), followed by an 8-week low-fat (24 En%), low-cholesterol (279 mg/d) diet period and an 8-week switchback period. In this study population the apo B ins/del and XbaI polymorphisms exhibited mainly similar and partly significant effects on the responses of plasma very low-density lipoprotein (VLDL) and high density lipoprotein2 (HDL2) cholesterol to dietary changes. After consumption of the low saturated fat, low-cholesterol diet, ins/ins X - /X - homozygotes showed the greatest increase in VLDL cholesterol (p < 0.05 for differences between ins/del genotypes) and the greatest fall in HDL2 cholesterol (p = 0.01 for ins/del and p = 0.05 for XbaI), while only minimal alterations were seen in the del/del and X + /X + groups. After returning to the original diet, the changes of these lipids were reversed, ins/ins and X -/X - homozygotes having the greatest reductions in VLDL cholesterol (p < 0.05 for XbaI) and the greatest increases in HLDL2 cholesterol (p < 0.001 for XbaI). The findings suggest that plasma VLDL and HDL2 cholesterol responsiveness to diet may be partly explained by variation at the apo B gene.

Aged↗

PubMed1995

Apolipoprotein E polymorphism and dietary plasma cholesterol response.

All studies have demonstrated a strong association between plasma cholesterol and apoE phenotypes in the following order: E4/E4 > E4/E3 > E3/E3 > E3/E2. It has been thought possible that the apoE gene might be involved in the modulation of dietary plasma cholesterol responses, perhaps explaining the differences in cholesterol concentrations. Some dietary intervention studies have suggested that apoE4 individuals react to dietary change with exaggerated cholesterol responses. In one study, apoE4/E4 individuals responded by increased cholesterol reductions during low fat intake, and by increased cholesterol elevations during switchback to high fat diet. Plausible mechanisms have been postulated which could explain such differences. However, other studies have reported no differences in plasma lipid responses among apoE phenotypes. The studies cannot be directly compared because of different designs and study populations with differing apoE allele frequencies. Thus the possible role of genetic variation in the apoE gene in the modulation of dietary plasma lipid responses remains to be confirmed in prospective dietary studies, involving diets both rich and poor in fat and cholesterol.

Apolipoproteins E↗