Apr 23, 2007

One burger could kill

Posted in Health at 1:00 pm by David Bradley -- 5 Comments; add your comment

Grandma always said, “Everything in moderation”, but then she always used to take her teeth out to eat soup, so what does she know? Apparently, even moderation can be dangerous, particularly when it comes to high fat food.

Tavis Campbell and colleagues at the University of Calgary have found that just one high-fat meal, a fast-food breakfast for instance, makes you prone to suffer the physical consequences of stress compared with someone eating a low-fat meal.

The team looked at the stress responses of two groups of students: fifteen students were fed a fatty breakfast meal (42 g fat) from a burger bar while the second group of fifteen got to dine on dry cereal with low-fat milk, cereal bars and non-fat yogurt (1 g fat). Both meals had the same number of calories and the low-fat breakfast included supplements to balance it for sodium and potassium, but the total fat content was very different.

Two hours later, the researchers carried out standard physical and mental stress tests and recorded the students’ cardiovascular responses. They performed a mathematical test designed to be stressful, completed a public speaking exercise about something emotionally provocative, held an arm in ice water, and had a blood pressure cuff inflated around an arm, which gradually causes a dull ache.

Regardless of the task, greater CV reactivity was seen in the high-fat group, including raised blood pressure, heart rate and blood vessel resistance. “What’s really shocking is that this is just one meal,” says Campbell.

“It’s been well documented that a high-fat diet leads to atherosclerosis and high blood pressure, and that exaggerated and prolonged cardiovascular responses to stress are associated with high blood pressure in the future,” he says, “So when we learn that even a single, high-fat meal can make you more reactive to stress, it’s cause for concern because it suggests a new and damaging way that a high-fat diet affects cardiovascular function.”

Thankfully, it is not all bad news. Campbell says more research is needed to fully understand how the mechanisms work. “Telling people to never eat something is probably not a good way to promote a better diet,” he says. “At the same time we do have an epidemic of obesity in North America and it’s important that people try to make informed choices.”

Science always hedges its bets in this way. If the argument were about whether to vote left or right, the politicians and lobbyists would make full-on assertions as to even the acute effects of a one-off high-fat vote. Yes, Campbell’s team has only carried out a small preliminary trial, and perhaps underfed and stressed students are not the best control group, but there findings do hint at yet another reason why we should side-step a high-fat diet.

The case is essentially closed on cigarettes in this sense, but individuals can make their own choice. Is it not about time, that the health message were made more forcefully. Maybe one burger is not going to kill you, but some people spend a fortune on finding ways to reduce stress and warding off the effects of aging, if even an occasional high-fat meal inverts all that effort, then perhaps it is time burgers carried a health warning too.

Details of the study are published today in the Journal of Nutrition, 2007, 137, 935-939

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