The facts about why margarine is worse for us than butter

Take a straw poll in the street on whether margarine or butter is better for your health, and I bet the vast majority of people would opt for margarine every time. One of margarine’s supposed virtues is that it can help reduce cholesterol levels in the bloodstream, and thereby afford some protection from ‘cardiovascular’ conditions such as heart disease and stroke.

Research published in October’s edition of the journal Food and Chemical Toxicology has been used to further support the use of margarine in cholesterol reduction and health. In this study, individuals eating margarine enriched with plant substances known as stanols or sterols (these have the capacity to reduce blood cholesterol levels by blocking its absorption in the gut) were found to have lower levels of cholesterol compared to those not eating such margarines. The lead author of this study described the effect of stanol and sterol enriched margarine as modest, but added that: it can still reduce the risk of coronary heart disease and thereby result in health benefits in the general population.

However, before we all rush to the supermarket to stock-up on a stanol or sterol-enriched margarine (such as Benecol or Flora Pro-Activ), I suggest we take a closer look at this particular piece of ‘science’, and also put it in the context of other available evidence which has examined the link between cholesterol levels, margarine-eating and health.

First of all, while the Food and Chemical Toxicology study found those eating margarine had lower cholesterol levels, we do not know whether this was due to the eating of margarine per se. Individuals who eat margarines specially designed for cholesterol reduction may well be doing other things to reduce cholesterol levels (for instance, they may increase their consumption of other cholesterol-reducing foods such as yoghurt, oats and nuts). Because these factors were not taken into consideration in the study, we really have no way of telling whether or not the apparent lower levels of cholesterol were due to the eating of enriched margarine.

Also, can we assume that the cholesterol reduction associated with the eating of specialised margarine necessarily translates into significant benefits for health? What evidence is there, for instance, that taking dietary steps to reduce cholesterol saves lives? Many studies have looked at this, and 17 of these were assessed in a study published in 2005 in the Annals of Internal Medicine. Overall, the studies led to an average 10 per cent decrease in cholesterol levels, but there was NO DECREASE IN OVERALL RISK OF DEATH. This sort of evidence casts serious doubt over the supposed ‘benefits’ of cholesterol reduction. Interestingly, the recent study in Food and Chemical Toxicology found that only just over a quarter of those eating an enriched margarine enjoyed a 10 per cent of more reduction in cholesterol.

Even if cholesterol reduction through dietary means had been proven to be beneficial to health (which it hasn’t), does that mean that something that reduces cholesterol is automatically healthy? I mean, if arsenic and cyanide were shown to have cholesterol-reducing properties, would it make sense for us to be consuming these substances every day?

The point here is that while food manufacturers (or drug companies) can bang on about the effect of their products on cholesterol, the really important thing is the effect on HEALTH. With this in mind, what studies exists which have pitted margarine against, say, butter, in terms of their effect on health? To know for sure whether margarine really is healthier than butter, we would need to have the results from what are known as double-blind placebo controlled trials (trials in which individuals are given butter or margarine to eat, though neither they nor the researchers are allowed to know which. After some time, the researchers would then assess which group, if any, had the better health outcome). Unfortunately, no such studies have been published. There is, however, one study in the scientific literature published in the journal Epidemiology exists which examined the risk of heart disease and margarine eating in men. In the long term, for each teaspoon of margarine consumed each day, risk of heart disease was up (yes, UP) by 10 per cent.

A major tenet of my advice regarding nutrition is that a healthy diet is one which is, as far as possible, made natural, unprocessed foods (preferably those that we have been eating a very long time in terms of our evolution). Margarine is made from chemically processed vegetables oils which have generally been bleached, coloured, deodorised and flavoured to make them ‘edible’. Does that sound like a food you want to be putting in your mouth every day? The recent Food and Chemical Toxicology study seems to be nothing more than the usual pro-margarine propaganda. My advice: DON’T SWALLOW IT.

References:

1. Marion W, et al. Effectiveness of customary use of phytosterol/stanol enriched margarines on blood cholesterol lowering Food and Chemical Toxicology 2006 44:10; 1682-1688

2. Studer M, et al. Effects of different antilipidemic agents and diets on mortality – a systematic review. Archives of Internal Medicine 2005 165: 725-730

3. Gillman MW, et al. Margarine intake and subsequent coronary heart disease in men. Epidemiology. 1997 8(2):144-149