Guest article by Sam Hadadi,
Each and every day, it seems that we’re bombarded with well-meaning advice on how to eat healthily and how to feel our best.
From mountains of colourful fruit and vegetables to whole grains, pulses, proteins and healthy fats, there’s plenty we should be packing our food cupboards and fridges with to achieve a healthy lifestyle.
However, while you may think that we’ve finally got the nutritional world cracked, hold your horses – everything may not be quite as it seems. In fact, unbeknown to us, there’s always been one nutritional puzzle that’s baffled scientists. And now it seems that omega-3s aren’t quite the medical marvel that they always promised to be…
Living in one of the harshest climates on the planet, the Inuits enjoy one of most extreme diets imaginable. Based in the icy cold climes of the Arctic, it’s impossible for these people to enjoy fruits, vegetables or grains. In fact, the freezing conditions and ploughs of snow mean that it’s difficult enough to even find wild flowers to forage.
So, what do the Inuits actually consume? Well, generally, they eat whatever they can hunt at sea – think whales, seals and plenty of fish.
While this may seem logical given the environment, it’s long baffled Western scientists, who have struggled to understand how these people remain so healthy. You see, despite eating so much fatty meat and fish, the Inuit don’t have a lot of heart attacks – and that’s completely contrary to current nutritional advice.
Way back in the 1970s, Danish researchers studying Inuit metabolism suggested that it was the omega-3s (found in fish) that boosted their health so much. It was this research that paved the way for decades of advice telling us to eat more fish to prevent heart disease, sending health nuts across the globe scrambling for fish oil pills and smoked salmon to enjoy on top of their eggs.
Now, at least 10 per cent of Americans alone neck back fish oil supplements. Yet, all too often, these pills haven't been particularly effective at preventing heart attacks or stroke - in spite of dietary advice1.
And just when you thought that omega-3s were the holy grail of all things food, you can think again. A shocking new twist revealed that those omega-3s might not be so beneficial for the rest of us, after all…
A study published just a couple of weeks ago in the journal Science revealed that the ancestors of the Inuit had evolved to metabolise omega-3s and other fatty acids2. Thanks to these gene adaptations, the Inuit’s bodies were transformed – they became smaller in both height and in weight.
Author of the study, Rasmus Nielsen3, believes that this questions whether or not omega-3 fats really are beneficial for everyone - despite decades of health advice to the contrary. As he said: “The same diet may have different effects on different people.”
Following the study, Dr. Nielsen has suggested that the Inuit may have developed an evolutionary change when they transformed their diets to be mainly meat-based. In other words, what works for them, probably doesn’t work for you and I…
Over the last few years, Dr Nielsen – armed with a team of colleagues – worked alongside researchers at the University of Greenland to study Inuit DNA. Originally, they started their study by searching for mutations that could raise the risk of developing diseases, including diabetes.
However, they quickly switched their research angle, instead searching for mutations that would be beneficial to the Inuit.
To do this, the scientists selected 191 Greenlanders whose ancestry was 95 percent Inuit or greater. They then examined the DNA of these people for variations in genes important to metabolism.
Amazingly, the researchers found several genetic variants that were unusually common in the Inuit, yet not so much in us. Many of these variations were found among a cluster of genes that help to build enzymes called fatty acid desaturases (otherwise known as FADS).
This was particularly interesting since those clever science bods know that these enzymes help to regulate the different fats in our bodies - including omega-3s. Even more impressively, these gene mutations were found in almost every Inuit in the study.
As you’ve probably already guessed, these mutations are far less common in other populations - about a quarter of Chinese people have it, compared with just 2 per cent of Europeans.
So, why is this? Well, our old friend 'natural selection' is most likely the way in which this gene variant could have become so common in the Inuit. In fact, this adaptation could have happened as long ago as 20,000 years, when the ancestors of the Inuit were living in the Beringia region, which straddles Alaska and Siberia.
Over this time, it’s possible that the extra omega-3 in their diets could have led the Inuit to evolve in a way which brings the blood levels of fatty acids back into a healthy balance.
Incredibly, this change in gene also affected the body in different ways, too. For instance, Inuits who carried two copies of the variant gene were around an inch shorter and 10 pounds lighter than those without a copy.
Well, the belief we’ve carried for years and years – that omega-3s are essential to healthy, strong bodies – may not be as concrete as we originally thought.
In fact, it’s looking ever more likely that the Inuit simply adapted to eating fatty foods, shattering decades of health advice.
While we’re not suggesting you ditch the fish from your diet just yet, Dr. Nielsen and his colleagues are planning to investigate the long-term health effects of the gene variants they’ve found.
These further studies could begin to explain why some of us metabolise fats more effectively than others, and why omega-3s may not be all that they were cracked up to be.
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Sam Hadadi is an ex-BBC journalist and now a freelance writer specialising in fitness and food.