Factors Influencing Serum Cholesterol Response to Dairy Fat Consumption in Overweight Adults: Secondary Analysis From an RCT

Abstract Objectives Recent evidence has demonstrated beneficial effects of dairy fat consumption on serum cholesterol levels when consumed in the form of cheese1. However, inter-individual variance in response to food consumption is known to affect the risk of diet-related diseases2,3. The extent of this variability and the determinants of response to dairy fat are currently unknown. Therefore, the aim of this study was to identify factors associated with lipid metabolism response to a dairy fat intervention study and investigate the relationship between them. Methods A 6-wk randomised parallel intervention trial1 was carried out in overweight, but otherwise healthy adults (≥50 years). Participants (n = 104) consumed ∼40g dairy fat daily in addition to their usual diet, in 1 of 3 different forms; butter, cheese, or cheese + butter. Intervention diets were also balanced for protein and calcium1. For this analysis, intervention diet groups were considered together as one dairy fat intervention. Participants were categorised into tertiles based on their % change in serum total cholesterol (TC) post-intervention, ranked from the largest decrease to the largest increase. Multivariate analysis (bonferroni-corrected) was used to assess differences between tertiles of responders in baseline characteristics (age, gender, metabolic markers, and body composition) (p < 0.05). Results Participants showing the largest % decrease in TC had significantly higher levels of TC, low-density lipoprotein (LDL-c) and high-density lipoprotein (HDL-c), and lower levels of triglycerides (TAG) at baseline compared to those displaying the largest % increase. Those with the largest % decrease in LDL-c displayed similar differences across groups, reporting higher baseline levels of LDL-c and TAG. No differences were apparent when categorised by HDL. Multiple regression analysis revealed that the variation of % change in TC and LDL is associated with baseline TC, TAG, body weight and high-sensitivity C-reactive protein (hsCRP; p < 0.05). Conclusions Our preliminary results indicate that the variance in cholesterol response to 6 weeks’ consumption of dairy fat is associated with baseline TC, TAG, body weight and hsCRP in overweight adults. Further analysis to understand the mechanisms associated with response to dairy fat is warranted. Funding Sources Food for Health Ireland, Enterprise Ireland.