Are saturated fats from meat and dairy equally bad for the heart?
Cardiovascular disease is the leading cause of death worldwide. From a dietary perspective, it is understood that consuming foods high in saturated fat is associated with low-density lipoprotein – otherwise known as ‘bad cholesterol’ – which increases risk of cardiovascular disease.
Meat and dairy are two significant contributors of saturated fat in the western diet. Indeed, according to data from the US government’s National Health and Nutrition Examination Survey (NHANES, the top sources of saturated fat in the American diet are cheese, beef, other fats and oils, milk, and finally, processed meats – notably frankfurters, sausages, and luncheon meats.
How saturated fat from different dietary sources – notably meat and dairy – impact risk of risk of cardiovascular disease has so far been ‘unclear’, according to Dr Rebecca Kelly from the Nuffield Department of Population Health at the University of Oxford, UK.
Together with a team of researchers from Oxford and Harvard, Dr Kelly has sought to make this relationship more transparent, by investigating how saturated fat from various foods relates to ischaemic heart disease, stroke, and total cardiovascular disease.
An 8.5-year study
The study, presented at the European Society of Cardiology (ESC) Congress 2021, analysed data from 114,285 UK Biobank participants who were free of cardiovascular disease at the start of the study.
They were asked to complete dietary assessments on what they had eaten over the previous 24 hours, to estimate their usual intake of total saturated fat, as well as saturated fat from specific food sources.
A detailed lifestyle questionnaire was also completed by each participant, as well as blood samples and body measurements taken to calculate their body mass index (BMI).
Over a period of around eight-and-a-half years, researchers analysed cases of cardiovascular disease, heart disease, and stroke. It was found that total cardiovascular disease was the most common of the three, with 4,365 counts, followed by heart disease (3,394), and stroke (1,041).
'The relationship may vary depending on the food source'
Having analysed the data – accounting for lifestyle, socioeconomic and medical factors – the researchers did not identify any significant associations between total saturated fat intake and cardiovascular disease outcomes.
However, associations could be made between saturated fat from meat intake and some outcomes. Specifically, the researchers found that consuming 5% higher total energy from saturated fat was associated with 19% and 21% elevated risk of total cardiovascular disease and heart disease respectively.
“Our findings are important because they provide a possible explanation – that the relationship may vary depending on the food source,” noted Dr Kelly.
The role of BMI, however, cannot be discounted. “We found that saturated fat from meat may be associated with a higher risk than other food sources – in part because those consuming large amounts of meat also had a higher BMI than low consumers.”
Concerning the impact of saturated fat from dairy on heart disease, the study revealed a lower risk in participants. However, BMI seemed to account of a large proportion of these associations.
“Our results suggest that differences in BMI may be responsible, in part, for the association between cardiovascular disease and saturated fat from meat. It is not possible to determine whether this is because of a specific impact of saturated fat from meat on BMI or because those with a higher BMI consume more meat,” concluded Dr Kelly.
“In addition, it is difficult to fully disentangle whether part of the effect of saturated fat on cardiovascular disease may be through higher LDL cholesterol in this cohort because cholesterol-lowering medication use is high in UK adults.”
Dr. Kelly continued: “We recommend following the dietary guidelines advice to consume less than 10% of daily energy from saturated fat. Our findings emphasise the importance of studying the different food sources of saturated fat when examining risk of cardiovascular disease. Further research is needed to ensure that these observations were not influenced by dietary or non-dietary factors that were not measured in this study.”
Source: ESC Congress 2021
'Associations between saturated fatty acids from different dietary sources and cardiovascular disease risk in 114,285 UK Biobank study participants'
Researchers: RK. Kelly, TYN. Tong, M. Guasch-Ferre, K. Papier, C. Piernas, GK. Fensom, JL. Carter, TJ. Key, A. Perez-Cornago.
