The great heart disease mystery: Meat is not the murderer
Over the last few years, we've been bombarded with challenges to our received wisdom on what foods are good for you. Alcohol was supposed to be bad until we noticed the beneficial effects of red wine in older drinkers. Tea has gone from a boring staple to a wonder food high in anti-oxidants. Even chocolate has been rehabilitated.
But one 'bad' food remains: meat, particularly red meat. Everybody knows that too much fat is bad for you — especially animal fat, right? Except, reports Jim Pollard, more and more evidence is emerging that it is not as simple as that.
Saturated fats — the fats found in meat and dairy products like cheese — have been closely linked with heart disease ever since the 1950s when American scientist Ancel Keys looked at the statistics from six different countries and saw a relationship between eating a lot of saturated fat and having high levels of heart disease.
Keys, who practiced what he preached and lived to 100, is seen as one of the pioneering food scientists. His work saw him receive the US establishment's ultimate accolade: the front cover of Time magazine in 1961. But while he was right to look at these overall trends, perhaps he didn't look widely enough.
Before long scientists were trying to explain the so-called French paradox: the fact that while the French eat a lot of saturated fats, they generally have low levels of heart disease. That's where the red wine theory first came in. But is that good enough?
You've probably noticed yourself that the simple high saturated fats equals high cholesterol equals heart disease story that we used to be told has changed a little.
Now we talk about good cholesterol (HDL) and bad cholesterol (LDL). Although saturated fats do increase LDL, they also increase HDL and it is low levels of HDL that can be risky. Having said that, the second link in the chain — that between cholesterol and heart disease — is also far from clear. Tony Edwards, whose excellent review of the research appeared recently in What Doctors Don't Tell You magazine, says 'more and more doctors are recognising that 60% of heart attacks are in people with normal cholesterol and that most people with high cholesterol never have a heart attack at all.'
Hot on the heels of the foie-gras loving, healthy hearted French, umpteen other 'paradoxes' have emerged which, taken together, suggest that the whole business is more complex than we think.
In 1962, it was shown that heart disease in northern India was just one-seventh of the rate in southern India yet northern Indians who had a mostly meat diet consumed 17 times as much animal fat as southern Indians who were mostly vegetarian. In 1972, the Masai people— now best-known for the trendy trainers that carry their name — offered an African paradox: they have virtually no heart disease yet eat mainly meat, blood and milk. A similar picture emerged from Australia in 1986 where aborigines had a diet that was two-thirds fat but had very little heart disease.
The killer paradox, however, was to be found in America itself where from around the first world war onwards, heart disease was increasing yet consumption of animal fat was declining.
So what was going on? The answer is to be found in the humble tub of margarine, sales of which were rocketing in the USA after the war. Margarine was — and is - not a natural product like the butter it frequently replaced, it was a manufactured one, an industrial one. It contained not animal fats but a product called trans fats which were created when vegetable oils were converted into something solid and 'spreadable' usually through a process called hydrogenation.
Consumers like trans fats because they give margarine and other products a realistic 'mouth-feel' and food manufacturers and supermarkets like them because they give the food a long shelf-life and are cheap.
The result is that today about 40% of the products you can buy in the supermarket contain trans fats. Not just most margarines but most baked products and cereals also fried foods, sweets, chocolate products, spreads, soups, salad dressings, snacks, ice cream and frozen breaded products.
But just because you can buy something easily doesn't mean it is safe — look at fags and booze. Indeed, Denmark has outlawed trans fats and in 2006 New York City banned them in all restaurants. Now even the British British Retail Consortium which includes Asda, Boots, Co-op, Iceland, Marks and Spencer, Sainsbury's, Tesco and Waitrose are promising to eliminate trans fats from their own-brand produce by the end of 2007.
The reason? A study by the Harvard School of Public Health in 2006 confirming a view that they and others had been developing since the 1990s that trans fats rather than saturated fats were the real villain. Survey director Professor Walter Willetts said that the association of trans fats with heart disease was 'considerably stronger' than for saturated fat.
Indeed, the best advice now is that while there is no safe level for trans fats, saturated fats (albeit in small quantities) are essential for a healthy immune system, hormones and cells, especially brain cells.
Too low-levels of saturated fat are linked with depression, tiredness and poor concentration.
This should leave vegetarians questioning their motivation. If you want to be vegetarian for moral reasons (and given how animals are treated by the food industry that's a pretty strong reason) then go ahead but the idea of being a vegetarian for health reasons no longer stands up.
So why were saturated fats seen as the bad guy for so long?
Nutritionist Mary Enig found the answer in her study 'Trans Fatty Acids in the Food Supply: A Comprehensive Report Covering 60 Years of Research'. Now while this report sounds like the literary equivalent of watching paint dry, it reveals the crucial statistical glitch that until the 1990s saturated fats were usually lumped together with trans fats in the various US databases used by diet researchers. As Enig puts it 'natural saturated fats were tarred with the black brush of unnatural hydrogenated vegetable oils'.
In other words, all those studies suggesting that saturated fats were bad for you were overstating the risk by counting the very much higher risk trans fats as if they were saturated fats.
The problem is that this has never been frankly admitted. Tony Edwards thinks he knows why. 'The high fat, high cholesterol heart disease industry is massive,' he says. 'It's not a conspiracy but there is enormous vested interest in nutritionists, doctors and food manufacturers all wanting us to believe that low-fat is the way.
'Once you see how statistics for saturated fats and trans fats were lumped together and begin to unpick them, it all falls into place. The trouble is that nobody is yet prepared to say that publicly or admit that they're not 100% on the right road. They're all cogs in a huge machine. Statins, remember, are one of the biggest selling, most profitable drugs in history.'
Indeed, the market for these cholesterol-lowering drugs is already worth over $22 billion worldwide. The NHS alone spends £600,000,000 on them. And analysts are speculating that all of us could be on them by the time we're 55. You do the maths. A bit of red meat from time to time might even help you count all those zeroes.
How do you know if a food contains trans fats?
In the UK, unlike the US, manufacturers don't have to explicitly label trans fats unless they want to make a claim like 'low in trans fats'. The key words to look for on a food label are trans, hydrogenated and shortening. Avoid them all.
Look particularly for the following on the ingredients list:
- - hydrogenated vegetable oil
- - partially hydrogenated vegetable oil
- - vegetable shortening
- - margarine
- - trans fats or trans fatty acids
In restaurants, it's more difficult. You could ask but if they can't tell you, avoid deep-friend food as it's odds on cooked in trans fats.
Page created on February 1st, 2007
Page updated on December 18th, 2009