One of the things that keto folks sometimes notice is an increase in blood lipids on the keto diet. This may be in some part due to increased coffee consumption. I never used to drink coffee but I started drinking coffee on keto for extra energy.
Turns out there’s an associational study on the subject (Stensvold I1, Tverdal A, Foss OP. The effect of coffee on blood lipids and blood pressure. Results from a Norwegian cross-sectional study, men and women, 40-42 years. J Clin Epidemiol. 1989;42(9):877-84.).
The association between boiled and filter coffee consumption and levels of cholesterol, triglycerides and blood pressure was studied, including 14168 men and 14859 women. A total of 94% drank coffee, 55% of the men and 48% of the women drank more than 4 cups per day. The type of coffee consumed varied between the counties, from 11 to 49% boiled and 49 to 87% filter coffee. Serum cholesterol increased linearly with increasing coffee consumption, and most strongly for boiled coffee. Controlling for other variables gave, for boiled coffee, an 8% increase for men and 10% for women. For filter coffee drinkers the coffee dose-cholesterol association remained significant only for women. Triglycerides showed a negative association with coffee, significant after adjustment for other variables. This effect was stronger for filter than for boiled coffee in both sexes. For men and women drinking 1 cup of coffee or more, a significant negative association between both systolic and diastolic blood pressure and number of cups of filter coffee was found.
Not going to change my life but perhaps a talking point with my doctor if my numbers are high.
Here’s a good metanalysis of the same subject (Jee SH1, He J, Appel LJ, Whelton PK, Suh I, Klag MJ. Coffee consumption and serum lipids: a meta-analysis of randomized controlled clinical trials. Am J Epidemiol. 2001 Feb 15;153(4):353-62.).