Relationship of coffee consumption with serum lipids and lipoproteins in Japanese men

To examine the relationship of instant coffee and brewed coffee with serum lipids and lipoproteins in Japanese men.

Study subjects were 4587 male self-defense officials aged 48-56 years who had a preretirement health examination at one of the three hospitals of the Self-Defense Forces from October 1986 to December 1992. A self-administered questionnaire ascertained lifestyle characteristics including consumption of a limited number of foods and beverages by all of the men. Serum concentrations of total cholesterol (TC), triglycerides (TG), and high density lipoprotein (HDL) cholesterol were measured, and low density lipoprotein (LDL) cholesterol levels were calculated from the values of TC, TG, and HDL cholesterol.

While the consumption of brewed coffee was unrelated to any parameter of serum lipids and lipoproteins, instant coffee consumption showed a highly significant positive association with serum LDL cholesterol levels and an inverse association with serum TG levels. After adjustment for body mass index, smoking, alcohol use, green tea consumption, rank, and hospital, for each cup of instant coffee per day, LDL cholesterol levels were 0.82 mg/dl (95% confidence interval (CI) 0.29-1.35) higher, and TG levels in a natural log-scale were 0.014 mg/dl (95% CI 0.006-0.022) lower. There was also a tendency for a positive association between instant coffee intake and serum TC levels (trend p = 0.09). HDL cholesterol levels were unrelated to instant coffee consumption. These associations did not change after additional adjustment for selected foods and beverages associated with serum lipids and lipoproteins.

The findings suggest that instant coffee, not brewed coffee, may be associated with raised levels of serum LDL cholesterol and decreased levels of serum TG.