#502: Sydney Diet-Heart Study – Is Linoleic Acid Causing Heart Disease?
Sigma Nutrition Radio
Danny Lennon
4.8 • 633 Ratings
🗓️ 21 November 2023
⏱️ 41 minutes
🧾️ Download transcript
Summary
Links:
- Go to episode page (with study links)
- Subscribe to Premium
- Past episodes referenced: Episodes 493, 481 & 317
- Further reading: How Diet Influences Heart Disease Risk
About This Episode:
The Sydney Diet-Heart Study was a clinical trial conducted in the 1960s and 1970s that aimed to examine the hypothesis that reducing saturated fat intake in the diet would lead to a reduced risk of heart disease.
However, it really only gained attention after a more recent re-analysis by Ramsden et al., which in recent years has been used as supporting evidence for the idea that increased polyunsaturated fat (PUFA), and specifically linoleic acid, in addition to reduced saturated fat intake, can increase heart disease risk.
This was based on the findings that substituting linoleic acid in place of saturated fat increased all-cause, CVD and CHD mortality.
This is of course counter to prevailing consensus and guidelines in this area, which routinely show reduced risk on replacing SFA with PUFA.
Could this trial undermine the common conclusions that replacing saturated fat with polyunsaturated fat decreases heart disease risk?
In this episode Alan and Danny discuss some of the crucial aspects to understand about this study and what it means for what conclusions can be made about the impact of PUFA broadly, and linoleic acid specifically, on our health.
Transcript
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| 0:00.0 | Hello and welcome to Sigma Nutrition Radio. |
| 0:16.2 | This is episode 502 of the podcast. |
| 0:19.5 | You are very welcome. |
| 0:22.9 | My name is Danny Lennon and of course, |
| 0:26.4 | alongside me is Dr. Alan Flanagan. Alan, how are you doing today? |
| 0:32.1 | I'm very well. Very well. I'm looking forward to this little run-on diet heart study as I think we're going to get into over the next few weeks. |
| 0:35.4 | Indeed. So for as a heads up for people, this episode will be the first of at least three |
| 0:40.4 | where we're going to be looking specifically at big diet heart studies that have made a |
| 0:46.7 | splash for various different reasons at different time points. |
| 0:50.2 | And certainly that goes for today's study that we're going to be talking about, which is often cited, |
| 0:55.7 | often referenced, often brought up in discussions and debates about heart disease, particularly |
| 1:02.4 | in relation to polyunsaturated fats or linoleic acid, depending on what conversation is being had. |
| 1:08.5 | And we'll get into the details of why that is the case. |
| 1:11.2 | Today we're going to be talking about the Sydney Diet Heart Study, which in fact was |
| 1:14.6 | quite an old study conducted starting back in the 60s, but really only gained more attention |
| 1:21.1 | after a more recent analysis by Ramston and colleagues. And so the Sydney Diet Heart |
| 1:26.5 | Study is a randomized control trial in men with coronary heart |
| 1:30.1 | disease. |
| 1:31.2 | And essentially, the big headline finding, and is the reason why it gets thrown about as a |
| 1:37.2 | study of significance in some people's eyes at least, is that there's this finding that |
| 1:42.0 | substituting the nettoleic acid in place of saturated fat |
| 1:45.7 | increased all-cause mortality, cardiovascular disease and coronary heart disease mortality as well. |
... |
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