"A new study found that lowsalt diets increase the risk of death from heart attacks and strokes and do not prevent high blood pressure httphealth.nytimes.comhealthguidesdiseasehypertensionoverview.htmlinlinenytclassifier but the researchs limitations mean the debate over the effects of salt in the diet httphealth.nytimes.comhealthguidesspecialtopicfoodguidepyramidoverview.htmlinlinenytclassifier is far from over. In fact officials at the Centers for Disease Control and Prevention felt so strongly that the study was flawed that they criticized it in an interview something they normally do not do. Dr. Peter Briss a medical director at the centers said that the study was small that its subjects were relatively young with an average age of  at the start and that with few cardiovascular events it was hard to draw conclusions. And the study Dr. Briss and others say flies in the face of a body of evidence indicating that higher sodium consumption can increase the risk of cardiovascular disease. At the moment this study might need to be taken with a grain of salt he said. The study is published in the May  issue of The Journal of the American Medical Association. It involved only those without high blood pressure at the start was observational considered at best suggestive and not conclusive. It included  middleaged Europeans who did not have high blood pressure or cardiovascular disease and followed them for an average of . years. The researchers assessed the participants sodium consumption at the studys start and at its conclusion by measuring the amount of sodium excreted in urine over a hour period.  All the sodium that is consumed is excreted in urine within a day so this method is the most precise way to determine sodium consumption. The investigators found that the less salt people ate the more likely they were to die of heart disease   people in the lowest third of salt consumption . grams of sodium per day died during the study as compared with  in the medium group . grams of sodium per day and  in the highest salt consumption group . grams of sodium per day.  And while those eating the most salt had on average a slight increase in systolic blood pressure httphealth.nytimes.comhealthguidestestbloodpressureoverview.htmlinlinenytclassifier  a .millimeter increase in pressure for each .gram increase in sodium per day  they were no more likely to develop hypertension. If the goal is to prevent hypertension with lower sodium consumption said the lead author Dr. Jan A. Staessen a professor of medicine at the University of Leuven in Belgium this study shows it does not work. But among the studys other problems Dr. Briss said its subjects who seemed to consume the smallest amount of sodium also provided less urine than those consuming more an indication that they might not have collected all of their urine in an hour period. Dr. Frank Sacks of the Harvard School of Public Health agreed and also said the study was flawed. Its a problematic study Dr. Sacks said. We shouldnt be guiding any kind of public health decisions on it. Dr. Michael Alderman a blood pressure httphealth.nytimes.comhealthguidestestbloodpressureoverview.htmlinlinenytclassifier researcher at Albert Einstein College of Medicine and editor of the American Journal of Hypertension said medical literature on salt and health effects was inconsistent. But Dr. Alderman said the new study is not the only one to find adverse effects of lowsodium diets. His own study with people who had high blood pressure found that those who ate the least salt were most likely to die. Dr. Alderman said that he once was an unpaid consultant for the Salt Institute but that he now did no consulting for it or for the food industry and did not receive any support or take any money from industry groups. Lowering salt consumption Dr. Alderman said has consequences beyond blood pressure. It also for example increases insulin resistance which can increase the risk of heart disease. Get the best of Well with the latest on health fitness and nutrition delivered to your inbox every week. Top of Form Bottom of Form Top of Form  Diet is a complicated business he said. There are going to be unintended consequences. One problem with the salt debates Dr. Alderman said is that all the studies are inadequate. Either they are shortterm intervention studies in which people are given huge amounts of salt and then deprived of salt to see effects on blood pressure or they are studies like this one that observe populations and ask if those who happen to consume less salt are healthier. Observational studies tell you what people will experience if they select a diet Dr. Alderman said. They do not tell you what will happen if you change peoples sodium intake. What is needed Dr. Alderman said is a large study in which people are randomly assigned to follow a lowsodium diet or not and followed for years to see if eating less salt improves health and reduces the death rate from cardiovascular disease. But that study others say will never happen. This is one of those really interesting situations said Dr. Lawrence Appel a professor of medicine epidemiology and international health at Johns Hopkins Medical Institutions. You can say O.K. lets dismiss the observational studies because they have all these problems.  But he said despite the virtues of a randomized controlled clinical trial such a study will never ever be done. It would be impossible to keep people on a lowsodium diet for years with so much sodium added to prepared foods. Dr. Briss adds that it would not be prudent to defer public health actions while researchers wait for results of a clinical trial that might not even be feasible.  Dr. Alderman disagrees. The lowsalt advocates suggest that all  million Americans be subjected to a lowsalt diet. But if they cant get people on a lowsalt diet for a clinical trial what are they talking about He added It will cost money but thats why we do science. It will also cost money to change the composition of food."