Tuesday 21 May 2019

Cheese is back on the menu

Recent research suggests that full-fat food is not the villian it has been painted for decades. Danielle Barron talks to obesity expert Professor Arne Astrup to find out why dairy is back in fashion

Cheesy does it: You can now enjoy your cheese, but in moderation
Cheesy does it: You can now enjoy your cheese, but in moderation

For the past few decades, we have been conditioned to think of anything full-fat as "bad" for us. Yet new research has shown that there may be significant health benefits from previously vilified food groups, including full-fat dairy.

According to Professor Arne Astrup, head of the department of nutrition, exercise and sports at the University of Copenhagen, decades-old dietary advice is slowly, but surely being turned on its head by relatively new research into a phenomenon known as the "food matrix".

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He recently presented at a major osteoporosis congress in Paris on how medics and scientists are beginning to realise that food is much more than just the sum of its parts. A major example is foods containing saturated fats such as milk and cheese - with generations having been told to avoid or limit them, it is now thought they may confer a myriad of health benefits. This complex effect is due to the dairy matrix, and even the experts don't fully understand its magic.

His presentation: "Beyond nutrients: health effects of the dairy matrix" was met with disbelief from some attendees and Astrup delved into the philosophical as he quoted Nietzsche: "People don't want to hear the truth because they don't want their illusions destroyed." Views on saturated fat are so entrenched within even the medical community, this latest research will take time to penetrate in order to change the status quo and dismiss the low-fat dogma, he said.

"Nutrition recommendations have historically focused on nutrients and are typically constructed to ensure the diet meets requirements for individual nutrients. Translation of nutritional requirements to dietary guidance has often resulted in advice such as, reduce intake of cholesterol and saturated fat."

However, people consume foods, not nutrients, and translation from individual nutrients to foods has proven problematic, Astrup explained.

"We have simplified the way we assess the health impact of foods by believing that we can simply look at the label of the food and the composition of the major nutrients in it and predict based on that," he explained after the congress.

"A good example is if you take a cheese - it is a food that is loaded with saturated fat, but there is also a lot of sodium in it. So, you would predict that the saturated fat is bad for your blood cholesterol and the sodium is bad for your blood pressure. But research has shown that if you feed people cheese you see something completely different because their blood pressure actually goes down and their blood cholesterol does not change in an adverse way - it actually is doing something good."

Studies have consistently shown that levels of HDL cholesterol and triglycerides - so-called "bad" cholesterol - do not increase as would be expected; meanwhile alterations to LDL "good" cholesterol particles may result in a beneficial effect, Astrup explained.

"This ties in with immunological studies from population surveys where reviews of all the available evidence have found that people who have a high intake of dairy, particularly the fermented substances such as cheese and yoghurts, have a much lower incidence of diabetes and coronary heart disease and stroke and mortality," he added.

Researchers aren't quite sure how or why this is the case; for cheese, it is thought that the calcium may modify how fat is absorbed and metabolised in the body.

Yet this research has the potential to upend traditional dietary recommendations, and indeed it transforms the whole basis of nutritional science, he admitted.

"The view that we can deduce health effects by simply looking at the label is far too simplistic - we now know there is a magic in the food that we don't always completely understand. A single nutrient does not make the food. We have to study whole foods instead of just thinking about the ingredients and deciding which is the most important one."

According to Astrup, there are many other foods where that thinking is now being applied.

"There are thousands of ingredients just in cabbage and while we can see that they have some very robust health effects such as lowering blood pressure, we don't know what it is in the food that is doing it."

Studies have also highlighted other consequences of the mysterious dairy matrix. Dairy is synonymous with bone health, for example, and is a much-needed source of calcium and vitamin D for the prevention of osteopenia and osteoporosis, but the precise nature of this effect is more enigmatic than originally thought.

Several clinical studies have shown that regular consumption of cheese leads to greater bone mass accrual than with calcium supplements. "Again, there seems to be some effect we don't really understand," admits Astrup. "To have healthy bones we thought you just needed some calcium and some vitamin D, today we know that it is far more complex, and you also need high quality protein. We have also discovered that there seems to be some minerals and other trace elements in food that seem to be needed for bone health."

The advice to avoid saturated fat goes back years, and it still remains a pillar of any dietary guidelines, the professor explains.

Yet for years cholesterol was seen as the bad guy, until researchers realised they'd gotten it all wrong.

"Until quite recently people were told they should avoid foods with cholesterol and that is why many people didn't eat eggs and also tried to avoid shellfish. Today we know that this is complete nonsense and even a couple of eggs a day has no negative impact on your cardiovascular disease risk, it is completely neutral and eggs have many other good nutrients such as protein and vitamin D - it is a really nutrient dense food. Most guidelines now include eggs as something that is healthy, but the myths around saturated fats persist. This is still something the World Health Organisation still talks about, the need to reduce saturated fat."

A diet including dairy, particularly yogurt and cheese, should be recommended for all to prevent and manage type 2 diabetes and cardiovascular disease, as well as osteopenia and osteoporosis, believes Astrup. But given how deeply the anti-saturated fat message is embedded in the popular psyche, will the latest findings be a hard sell to a public bamboozled by ever-changing dietary advice?

He is unequivocal in his response. "Absolutely. It's not just the general public who will find it difficult to swallow, but also healthcare professionals including doctors and dietitians. On principle, I think it is wrong to tell people to avoid something they really like or love and is part of our normal food culture. Plus now we have some really robust evidence that it does not have adverse effects… we have to admit that we got it wrong."

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