People who consume saturated fatty acids (SFA) from meat could be at increased cardiovascular disease (CVD) risk, while those who rely on dairy sources or switch to grains and fruit and vegetables could be protected, indicates a UK study.
Examining the records of more than 114,000 people enrolled in the UK Biobank who completed dietary assessments, the researchers looked at the development of CVD over more than 8 years of follow-up.
Although there was no association between overall SFA intake and cardiovascular risk, the risk of total CVD increased by 19% for every 5% increase in energy consumption from meat SFA, while that for ischaemic heart disease rose by 21%.
In contrast, the risk of ischaemic heart disease appeared to be reduced by the consumption of SFA from dairy sources, falling by 11% for every 5% increase in intake.
Stroke Risk
The research, presented at the European Society of Cardiology Congress 2021 on August 27, also showed that replacing energy intake from meat SFA with either grains or fruits and vegetables reduced the risk of stroke by 14%.
First author Dr Rebecca Kelly, of the Nuffield Department of Population Health, University of Oxford, said that, overall, the results showed the “associations of saturated fat with CVD varied by source”.
This, she said, “may explain” the overall lack of association between total SFA consumption in this and previous observational studies.
However, body mass index (BMI) was found to account for “a large proportion” of the associations between intake of SFA from meat and cardiovascular outcomes, “suggesting confounding or mediation by adiposity”.
Professor Christi Deaton, chair of clinical nursing research, University of Cambridge, said that it is “plausible” that the increased CVD risk with SFA intake from meat is driven by an increase in ischaemic heart disease risk.
This is because previous studies show that “we would expect increased SFA consumption from meat to be associated with atherosclerosis and coronary artery disease”, she told Medscape News UK.
Professor Deaton continued that the study reinforces the recommendation that SFA intake be limited to 10% of total energy, but also “emphasises the importance of the sources of the SFA”.
Saturated Fats
Dr Kelly began by noting that previous studies “have suggested that different foods rich in saturated fatty acids, particularly meat and dairy, have diverging directions of association with risks” of total CVD and CVD subtypes.
“Therefore our study assessed the associations between saturated fats between different dietary sources and CVD risk, examining the role of potential mediators.”
The team looked at data on 114,285 participants in the UK Biobank who had completed at least two 24-hour dietary assessments and were free of CVD at the time of the most recent assessment.
Over a median follow-up of 8.5 years, there were 4365 cases of total CVD, including 3394 cases of ischaemic heart disease and 1041 of stroke.
Multivariate Cox regression analysis taking into account lifestyle and cardiovascular risk factors indicated that there was no significant association between total SFA intake and CVD outcomes.
However, intake of SFA from meat was associated with an increased risk of total CVD, at a hazard ratio for each 5% increase in energy intake of 1.19 (p=0.006), as well as for ischaemic heart disease, at a hazard ratio of 1.21 (p=0.010).
Adjustment for BMI attenuated these associations, at a nonsignificant hazard ratio for each 5% increase in energy intake of 1.11 for total CVD and of 1.12 for ischaemic heart disease.
Dairy Foods
The team also found that SFA from dairy foods was inversely associated with the risk of ischaemic heart disease, at a hazard ratio for each 5% increase in energy intake of 0.89 (p=0.003), although this again was attenuated by adjusting for BMI, at a hazard ratio of 0.91.
There was no association between consumption of SFA from processed food and total CVD, ischaemic heart disease or stroke.
Interestingly, replacing energy intake from meat with that from other sources appeared to reduce the risk of cardiovascular outcomes.
Each 5% substitution of SFA from meat with energy from whole grains was associated with a significant reduction in stroke incidence, at a hazard ratio of 0.86 (p=0.002), while substitution with carbohydrates from fruit and vegetables was also associated with a hazard ratio of 0.86 (p=0.003).
The researchers note that the effect survived taking into account both BMI and low-density lipoprotein cholesterol levels, at a hazard ratio for whole grains of 0.87 (p=0.006) and 0.86 for fruit and vegetables (p=0.003).
One limitation of the study is that information on statin therapy during follow-up is not complete and “therefore we cannot conclude that low density lipoprotein cholesterol has no effect on this situation”.
The study was funded by the Clarendon Fund and Jesus College Clarendon Old Members' Award Jesus College Graduate Scholarship.
No relevant financial relationships declared.
ESC Congress 2021: Abstract 84799. Presented 27 August.
