You may have missed it because it didn’t get much play in the Indian mainstream media. And I doubt if your doctor drew your attention to it – assuming of course that he had noticed it himself. But there has been a tectonic shift in the orthodoxy when it comes to food and heart disease.
For years, anyone over 40 has been told to avoid certain foods because they contain cholesterol. And cholesterol, as any doctor will tell you, contributes to heart disease.
The origins of this recommendation lie within the US government, which regularly issues reports recommending the perfect diet for Americans. It is a US government report that created the myth of the miraculous Mediterranean diet, which led first, to the olive oil boom and then, indirectly, contributed to the epidemic of obesity in the US as Americans stuffed themselves with carbohydrates.
A 2010 US government report reiterated the old stand that nobody should eat more than 300mg of cholesterol a day to avoid heart disease. It is on this basis that our own doctors keep advising us to steer clear of eggs, butter, lobster, oysters, red meat and God alone knows what else. (This was always suspect: chicken has as much cholesterol as red meat).
But now, the US government has finally accepted that it got this wrong. The 572-page scientific report of the 2015 Dietary Guidelines Advisory Committee (DGAC) contains this clarification: “Previously the Dietary Guidelines for Americans recommended that cholesterol intake be limited to no more than 300mg per day. The 2015 DGAC will not bring forward this recommendation because available evidence shows no appreciable relationship between consumption of dietary cholesterol and serum (blood) cholesterol. Cholesterol is not a nutrient of concern for over consumption.”
So that’s that, then. Forget all those jokes about ‘heart attack on a plate’ and stop referring to foods as ‘cholesterol rich’ – that is not a bad thing any longer.
Yes, many doctors still believe that excess cholesterol can harm your arteries and put pressure on your heart. The question is: where does the cholesterol come from?
Between 85 per cent to 88 per cent of the cholesterol in our bodies is manufactured by the liver. We only get between 12 per cent and 15 per cent of our cholesterol from our diet.
So the claim that cutting down on cholesterol-rich foods would reduce our chances of heart disease, or even the levels of cholesterol in our blood stream, was always suspect. A very small percentage of our cholesterol comes from outside. Even if you reduced consumption of so-called ‘bad foods’ it could not have made much difference.
Doctors knew this, but continued to bad-mouth cholesterol-rich foods anyway.
But now, studies have shown that there is little evidence that cholesterol in food remains in the body and shows up as cholesterol in the blood stream. The cholesterol in a lobster may well pass out of our systems. It doesn’t hang around, looking for arteries to clog. The claim that, once a food rich in cholesterol is consumed, its cholesterol content will remain in our bodies, has been withdrawn.
This reversal demonstrates, once again, how little scientists really understand about the way in which our bodies function. And it reminds us to not believe every diet tip given to us by our doctors. They are wonderful guys but they don’t all necessarily keep up with their reading.
It also confirms what many of us have long suspected: there is no point in listening to medical advice about what is good for you and what is bad for you because this advice changes from year to year without warning.
Take the recent medical obsession with ‘inflammation’, the buzz word for this decade. If doctors are right, then the traditional clogged-artery view of heart disease may be an inadequate explanation for the phenomenon.
Last year, an article on inflammation in The New Yorker quoted Peter Libby, a professor at Harvard Medical School as saying, “Atherosclerosis was all about fats and grease. Most physicians saw atherosclerosis as a straight plumbing problem.” (Atherosclerosis is the medical term for the blockage of blood flow to the heart or brain).
Libby suggested that heart attacks were, in fact, caused by an inflammation of the arteries, not by cholesterol blockages. Yes, cholesterol did have a role to play. Particles of LDL (the so-called bad cholesterol) could trigger an inflammatory response in the lining of the arteries. These were the real reason arteries were blocked.
But it wasn’t just cholesterol. Patients without high levels of cholesterol also had blockages and heart attacks. Scientists tracked a molecule called C-reactive protein, which seemed to be connected to the inflammations. Statins, prescribed to lower cholesterol, did have some effect on levels of C-reactive protein. But the benefit was modest. Only one per cent of patients in a study were less likely to have a heart attack because statins had reduced their levels of C-reactive protein.
Researchers are now looking for anti-inflammatory drugs to reduce the risk of heart attacks. So not only is the old eat-cholesterol-and-it-shows-up-in-your-blood theory dead, but even the fatty-foods-clog-your-arteries orthodoxy is being revised.
And there’s more. In 2014, the medical journal Annals of Internal Medicine, published new research that found that people who ate high levels of saturated fat did not have more heart disease than those who ate less. Nor did the researchers find lower levels of heart disease in those who stuck to mono-unsaturated fats like olive oil.
The researchers did find a link between trans fats (found in some processed foods) and heart disease but saw no danger in saturated fats (butter, cheese, red meat etc).
This kind of research result is revolutionary and yet, it is not. It is revolutionary because it goes against the traditional approach. For instance, the American Heart Association recommends that saturated fat should be restricted to five per cent of total calories. This is a joke – for a normal person, five per cent is roughly two tablespoons of butter – and was never taken seriously, which allowed doctors to say, when their patients fell ill, “Well, we told you so”.
The new research also makes a mockery of the American Heart Association’s recommendation that we should all eat unsaturated fat; this study shows it makes no difference.
But it is also not revolutionary because the researchers agree that LDL (or bad cholesterol) can be dangerous. That’s not because it clogs the arteries but because small, dense particles of LDL can set off an inflammation.
On the other hand, these researchers think that the real danger comes, not from fat at all. The New York Times quotes Dr Rajeev Chowdhury of Cambridge University, the lead author of the study, as saying “it is the high-carbohydrates or sugary diet that should be the focus of dietary guidelines. If anything is driving your low-density lipoproteins in a more adverse way, its carbohydrates.”
Or, let’s put in layman’s language. If you go to a fast-food place and order a beef burger with a milkshake, the beef (or goat or lamb) is actually the healthiest (and least likely to cause heart disease) part of your order. The danger comes from the bun and milkshake.
Where does all this leave you and me? (More me, really: the middle-aged man who likes good food!) Well, look, the evidence for the claim that fat-causes-cholesterol-causes-heart-disease has always been dubious. We have all heard of the French paradox. The French break every American Heart Association rule. But while Americans are dying of heart-attacks, the French are chuckling into their foie-gras.
But there are other examples. In his book, 100 Million Years of Food, Stephen Le, a biological anthropologist, refers to the Spanish Paradox. Spanish people consumed 30 per cent more fat in 1980 than they had in 1966. When it came to saturated fat, the increase in consumption was more marked: 48 per cent. And yet, levels of heart disease came down during the same period.
Which is not to say that eating more fat is good for you. In fact, eating too much of anything is bad for you. But there are some things we know are very bad: lots of sugar, lots of salt and lots of processed carbohydrate (ie commercial white bread, hamburger buns etc.)
Cut down on those and eat everything else in moderation. That way you don’t have to feel guilty about what you eat.
Besides, doctors will probably change their minds about the link between food and heart disease in a couple of years anyway! And we will all be asked to follow completely new guidelines!
From HT Brunch, May 29, 2016 Follow us on twitter.com/HTBrunch Connect with us on facebook.com/hindustantimesbrunch