Monday, 30 June 2014

Evidence stacks up in favour of dairy

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Eating full-fat dairy products does not appear to increase a person’s risk of dying. Eating full-fat dairy products does not appear to increase a person’s risk of dying. Image: Southern CrossFit

EATING higher compared to lower amounts of cheese, milk, yoghurt or butter does not make a person more likely to die from cardiovascular disease, cancer or any other cause, according to a systematic review of the link between food sources of saturated fat and mortality.

The WA-led study compiled research from around the world and found that some but not all foods high in saturated fat were associated with an increased risk of dying.

High compared to low intakes of meat and processed meat were associated with a moderate increase in mortality.

But eating full-fat dairy products does not appear to increase a person’s risk of dying.

The review’s lead author Edith Cowan University dietician Therese O’Sullivan says there are good fats in dairy, such as omega-3s, as well as the saturated fat.

“Dairy fat has been shown to increase the good cholesterol in the blood,” she says.

“There can also be beneficial bacteria in the fermented dairies—like yoghurts—and those bacteria can maybe help with our gut biome and that can potentially influence things like your immune system.”

The researchers conducted a meta-analysis of 26 studies that investigated what participants were eating with follow-up over time.

But they noted few studies used a good assessment of diet or adjusted for a full range of factors such as smoking, body weight and physical activity.

The review represented data from more than 1.8 million participants and was published last year in the American Journal of Public Health.

Dr O’Sullivan says the review findings for meat intake were reversed in a sub-analysis of Asian studies, where eating higher compared to lower amounts of meat was associated with a lower risk of mortality.

“One potential reason is that they tend to have lower overall meat intakes there,” she says.

“Moderation with those foods might be the key rather than complete avoidance because obviously meat provides a lot of valuable nutrients as well.”

Dr O’Sullivan says more research is needed before the findings can be incorporated into nutritional guidelines.

“Currently our guidelines say that if you’re over the age of two you should be having predominantly low-fat dairy products,” she says.

“We’re just putting it out there that maybe, with a bit more good quality research, we might have to relook at that one because there doesn’t seem to be a strong evidence base suggesting that low-fat is the best way to go.”

Dr O’Sullivan says the guidelines were originally developed with limiting obesity in mind but some low-fat products, particularly yoghurts, often have added sugar and do not necessarily contain fewer calories.

Notes: 

Therese O’Sullivan participated in the WA final of FameLab, a competition that gives early-career researchers the chance to talk about their science in plain English, at the Maritime Museum in April 2014.

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