One of the most remarkable examples of recent human progress has been in the battle against cardiovascular disease. Since the middle of last century, the UK rate of death from heart attacks and strokes has fallen more than fivefold.
The reasons for this are many, including declining rates of smoking, better medical care and the use of statins, but dietary changes have certainly played a part.
Ever since rates of heart attacks spiralled upwards in the 1960s, public health advice has been to limit consumption of saturated fats from animal sources. Although these are hard words for a butter-loving chef to write, this advice is entirely sensible.
Seed oils may be the new nutritional demons (wrongly – don’t get me started), but there is decades worth of good-quality evidence to show that high consumption of saturated fat is associated with heart disease.
The trouble with vegetable oils
The problem is, animal fats and vegetable oils have very different structures and functions, so it is not possible to simply swap out one for the other. The saturated fats found in animals have straighter carbon chains that line up and crystalise at lower temperatures, while vegetable oils have more squiggly chains that don’t line up as easily, so remain liquid at room temperature (apologies for the complex scientific terminology).
The inherent hardness of animal fats provides important functionality in baking and spreads but also contributes deliciousness, richness and mouthfeel. Sixty years ago, the world badly needed vegetable fats that could do something similar.
The result was an increased use of partially hydrogenated oils which had been chemically modified to have less squiggly carbon chains. Although well-intentioned, this was a public health catastrophe. It wasn’t until the early 1990s that scientists realised the high levels of trans fats caused by partial hydrogenation were even more harmful than the animal products they were replacing.
This was food science’s darkest hour, resulting in thousands, perhaps millions, of needless deaths.
Since then, with partially hydrogenated fats largely removed from the UK food supply, there has been an increase in the consumption of tropical oils such as palm and coconut, as the only non-animal fats with naturally high levels of saturation. But of course, these come with huge environmental concerns, as increasing demand leads to tropical deforestation.
We desperately need alternatives. Some startups are trying to develop fats from precision fermentation, but these are likely to be prohibitively expensive, especially when competing against cheap commodities such as palm and tallow.
The promise of hydrogenated blends
More interestingly, there are new blends of fully hydrogenated fats mixed with unsaturated oils that have good functionality, but do not contain any trans fats, as these are only produced in partial hydrogenation.
These hydrogenated blends tick a lot of boxes. They are cost-effective, can be made entirely from locally grown sunflower or canola, and there is no evidence that they have any more health harms than other saturated fats. But after years of righteous public health campaigning, the term hydrogenation is poison, and the nuanced difference between full and partial will be a difficult one to explain.
Yet we cannot continue to consume tropical oils at the rate we do, and a wholesale return to animal fats would be unwise on health grounds. And we also cannot simply expect consumers to stop demanding the sorts of products that require hard fats.
Unless an alternative technological solution emerges soon, our historic dislike of the word ‘hydrogenation’ is going to have significant environmental costs.
Anthony Warner is a development chef at New Food Innovation
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