In last week’s newsletter we noted that the original dietary fat trials did not support the introduction of the dietary fat guidelines. These dietary fat trials did report large reductions in cholesterol levels – in both the diet and the control groups – and we explored possible reasons for this. One was simply because most of the subjects in these trials had just had a heart attack (that’s why they were in the trials) and so cholesterol would have been high at the time that they had the heart attack (and joined the trial) and then would have fallen over time.
We then looked at some work that Ancel Keys had done in 1957 – measuring the impact of different fats on blood cholesterol levels – and noted that the fats containing plant sterols were strongly associated with reduced cholesterol levels. The consumption of plant sterols also provided an explanation for the falls in cholesterol levels that were reported in the original dietary fat trials.
This then begs the question – is taking plant sterols to lower cholesterol a good idea? If we know that plant sterols can lower cholesterol, does this end up having a positive impact on health? If the answer were yes, we could then take plant sterol supplements (you can buy them in any pharmacy or health food shop) and gain a health benefit.
While I was doing my PhD, my supervisor received an invitation to write an editorial in The Journal of Biological Sciences. He wondered if I had anything that we could submit and it was at the time I was looking at the plant sterol/cholesterol/heart disease issue. Hence it was timely to review the evidence and to see what it said. What follows is what we found... (Ref 1).
