Monday, December 05, 2011

Federal effort to commandeer the nation’s salt shakers is based on bad science

"Put down the salt shaker and back away from the table. And don't even think about going for the chips." Those are lines you may hear on a TV police drama of the future, when the federal drive to curb salt consumption reaches cruising speed.

Last year, the government's Institute of Medicine urged the Food and Drug Administration to "gradually step down the maximum amount of salt that can be added to foods, beverages, and meals." The FDA is listening. In September, it published a notice concerning issues "associated with the development of targets for sodium reduction in foods to promote reduction of excess sodium intake."

It is currently focusing on voluntary steps to "promote gradual, achievable and sustainable reduction of sodium intake over time." But if it doesn't get its way, it may go beyond gentle encouragement. "Nothing is off the table," a spokesperson declared last year.

Salt has always been prized as a culinary marvel —perking up flavors, masking bitter elements and preventing spoilage. Soup without salt is excellent for nourishing your garden, but unfit to eat. Any number of dishes taste better with a dash or two.

But many experts and public health organizations see salt as a killer, which in excess amounts causes high blood pressure and heart disease. They think we would all be better off eating less, and they want the government to make sure we do. Dr. Walter Willett, chairman of the nutrition department at the Harvard School of Public Health, says that "we must treat sodium reduction as a critical public health priority."

But this clear certitude keeps getting clouded by confounding evidence. "For every study that suggests that salt is unhealthy, another does not," an article this year in Scientific American noted.

The Journal of the American Medical Association has reported that people who consume less salt are actually more likely to die of heart disease. Recently, a study in the American Journal of Hypertension found that reducing dietary sodium can cause a harmful response from the body. "I can't really see, if you look at the total evidence, that there is any reason to believe there is a net benefit of decreasing sodium intake in the general population," the chief researcher told Reuters.

Nor is it clear that third parties can get people to reduce their ingestion of sodium. We have been hearing for decades about the alleged hazards of a high-salt diet, and anyone looking for alternatives can easily find them. But today, Americans consume the same amount of salt as they did 50 years ago, when bacon, eggs and hash browns were regarded as a wholesome breakfast.

One survey of 33 countries found that despite vast differences in cuisine, people generally take in about 3,700 milligrams of sodium a day, well above what the FDA recommends, decade after decade.

How come? The theory is that we are all biologically predisposed to seek out that much and no more. The Salt Institute, which represents salt companies, makes the argument —self-serving but not implausible— that if it is reduced in food, people will up their calorie intake to satisfy their craving.

But even if we assume too much salt is a bad thing, federal regulators have no grounds to dictate how much our food may contain. Any consumers who want less sodium, after all, are free to spurn restaurant meals and grocery items laden with heavy doses.

Food companies don't use salt because they like it but because their customers do. If consumer preferences change—say, in response to incessant warnings from medical groups—food products will change as well.

Classifying excess sodium consumption as a "public health" danger mutilates a useful concept. Air pollution, West Nile virus, and E. coli are matters of public health because they inflict harm on broad groups of people against their will and often without their knowledge. No one, however, ingests salt without raising fork to mouth.

If I burn toxic waste in my yard, I may force you to inhale compounds that cause illness or death. If I make a meal of pretzels and Virginia ham, by contrast, I pose no hazard to anyone but myself. You can avoid this "public health" threat without the FDA barging into your kitchen. Eating foods with salt is not a public decision but a private one. That's private, as in: Keep out.


New IVF technique helpful in certain cases

Microarray comparative genomic hybridisation, or CGH, involves a full chromosome count of embryos and allows doctors to ensure only the healthiest embryos are implanted. Fertility clinic Genea will today release data showing almost nine out of 10 patients aged under 38 whose embryos underwent CGH achieved a pregnancy with a foetal heartbeat seen at seven weeks gestation.

The data, to be presented at the World Congress on Human Reproduction in Melbourne this week, shows a success rate of 65 per cent for women older than 38.

Fertility specialist Dr Devora Lieberman said random chromosome abnormalities were one of the main causes of failed IVF cycles and of repeated miscarriages in women who conceive naturally. By using CGH, only embryos containing the correct number and sequence of chromosomes were considered.

Dr Liberman said CGH, which adds about $3000 cost to a cycle of IVF treatment, was not recommended for all IVF patients. "It most appropriate for women who have had multiple, unexplained miscarriages," she said. "Those women often have a "quality control" problem which allows embryos with chromosome abnormalities implant, but they generally go on to miscarry."


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