Plasma Lycopene Concentrations in Humans Are Determined by Lycopene Intake, Plasma Cholesterol Concentrations and Selected Demographic Factors

Abstract

Higher plasma lycopene concentrations have been associated with a reduced risk of several chronic diseases. Determinants of lycopene concentrations in humans have received limited attention. We had blood lycopene concentrations and lycopene consumption data available from 111 participants in a two-center cancer prevention trial involving beta-carotene and examined determinants of plasma lycopene levels cross-sectionally. The median plasma lycopene level was 0.59 micromol/L (range 0.07-1.79). Low plasma concentrations of lycopene were associated with the following variables in univariate analyses: study site (Florida lower than Connecticut, P = 0.001), being nonmarried (P = 0.02), having lower income (P = 0.003), being nonwhite race/ethnicity (P = 0.03), having lower dietary lycopene intake (r = 0.29, P = 0.002), having lower plasma cholesterol (r = 0. 43, P = 0.0001) and triglyceride levels (r = 0.26, P = 0.005), and consuming less vitamin C (r = 0.20, P = 0.03). Women had slightly higher plasma lycopene levels than men (0.65 vs. 0.58 micromol/L; P = 0.31), despite lower dietary intake of lycopene (1,040 vs. 1,320 microg/d; P = 0.50). Plasma lycopene levels did not differ in smokers and nonsmokers. In stepwise regression analyses, the determinants of plasma lycopene were plasma cholesterol, dietary lycopene, and marital status; these three variables explained 26% of the variance in plasma lycopene. Relatively few lifestyle and demographic factors were important determinants of plasma lycopene levels, with plasma cholesterol, marital status, and lycopene intake being of greatest importance.

Tomato consumption and plasma lycopene concentration in people aged 65 y and over in a British national survey

“…Two recent studies (Mayne et al, 1999;Casso et al, 2000), which included younger as well as older adults living in the USA, reported significant direct correlations between serum or plasma lycopene concentration, and plasma total or LDL cholesterol concentrations, in agreement with the findings of the present study. One of these (Mayne et al, 1999) also found a direct correlation with plasma triglyceride concentration, which we did not observe.…”

“…The observed inverse relation between plasma lycopene concentration and age has been reported elsewhere by some (Gregory et al, 1990;Casso et al, 2000;Institute of Medicine, 2000) but not others (Mayne et al, 1999). The significant inverse relation between plasma lycopene concentration and BMI also observed in the present study, although occurring only in the institution sample, agrees with findings from the literature (Casso et al, 2000).…”

“…One of these (Mayne et al, 1999) also found a direct correlation with plasma triglyceride concentration, which we did not observe. However, their study included younger people and, since it is not disclosed, may also have included non-fasting blood samples.…”

“…This again suggests that the proportion of lycopene absorbed from foods may be more important in determining plasma lycopene concentrations than total lycopene intake. Seasonal variation in plasma lycopene concentration is inconsistent between published studies, with some reporting highest values during late summer/ autumn (May-October) (Scott et al, 1996;Casso et al, 2000;Dusinska et al, 2002), one reporting lowest values during winter (January-March) for a national sample of British men and women aged 16À64 y (Thurnham & Flora, 1988), and only one study failing to find significant seasonal differences (Mayne et al, 1999). TCP=tomato-containing products.…”

“…This finding is consistent with significantly lower plasma lycopene concentrations observed in smokers from a nationwide dietary and nutritional survey of younger British adults in 1986À1987 (Gregory et al, 1990). However, many researchers have not reported any significant difference in plasma lycopene concentration between smokers and non-smokers (Ross et al, 1995;Tsubono et al, 1996;Mayne et al, 1999;Chopra et al, 2000;Wei et al, 2001). …”