August 4/ABC Transcripts (Australia) -- A new study from the Queensland Institute of Medical Research suggests that full-fat dairy products might actually protect against heart attack or stroke. If confirmed, that would contradict a lot of accepted medical and nutritional wisdom about the health risks of obesity.

The National Health and Medical Research Council's guidelines say that dairy is beneficial, but they recommend low-fat options where possible. However, a new study raises a few questions about that advice.

Dr. Jolieke Van Der Pols from the Queensland Medical Research Institute says people with the highest intake of full-fat dairy are actually less likely to die from a heart attack. "We find that the persons who consumed the highest amount of full-fat dairy had a 70% reduced risk of dying from cardiovascular disease, compared to people who do not eat full-fat dairy; so that's quite a large effect."

Could it be that the cohort of people who are eating low-fat cheeses and drinking low-fat milk may be doing so because they had a problem with their weight to begin with? Van Der Pols noted, "That's a very good question, and we've allowed for that in the analysis. We've controlled for confounding factors such as total energy intake and body mass index."

Van Der Pols says more research is needed, because the study only found an association and does not explain why full-fat dairy might offer protection. She says one possible explanation lies in conjugated linoleic acids, which may provide some defence against a heart attack. "They're actually contained in the fat of the milk. So if you remove the fats, you will remove some of those components, and that's one of the hypotheses that might explain this finding."

Associate professor Manny Noakes from the CSIRO says the jury is still out on those components of milk. "There is some suggestion that these kinds of fats may have some protective effects against cancer, potentially cardiovascular disease. However, it's really only speculative at the moment, and no human studies have demonstrated a cause and effect relationship."

She also says it is possible those who drink full-fat milk may be less prone to fatal heart attacks for reasons that have nothing to do with dairy. "What we may be observing is that people who consume a lot of dairy, which certainly has a high level of nutrition, may also be eating a better diet overall, which may be protective."

The executive director of the Victor Chang Cardiac Research Institute, professor Robert Graham, says the study is too small to draw any solid conclusions. "I mean if this was a study of 30,000 people rather than 1,500, I'd be much more excited about their conclusions. I mean they may be correct, but I think at best what this study suggests is that we should look at the issue more carefully in a much larger group of patients."

Even if there does turn out to be a strong link, dieticians would still caution against reaching for that wheel of double cream camembert too often.

"What is the total fat intake that people are actually doing? The recommendation is still for saturated fat to be less than 15g," explains Julie Gilbert, a spokesperson for the Dieticians Association of Australia, "and if you do have a full-fat dairy product in your diet, you're still going to be meeting under that 15g. So I think it goes to the total diet, rather than just isolating one particular group.

Government guidelines make it clear that fat is not the only consideration. The National Health and Medical Research Council also says it is important moderate intake of salts sugars and alcohol as well.

From the August 16, 2010, Prepared Foods E-dition