June 6, 2011

Healthy Aging Advice Keeps Changing on Supplements, Diets: Niacin Now a No-No, "Pass the Salt" Debatable

I try to enhance whatever gold is left in my "golden years" by following the medical profession's advice on healthy living, but it isn't easy when that advice keeps changing. The past week's news has scientists and medical authorities questioning the validity of two of the most well-established ground rules: 1) Niacin is good for you, and 2) Lots of salt is bad.
Niacin Fails the Test

Authorities agree that the risk of heart attack and stroke can be reduced by cutting artery-clogging LDL ("bad" cholesterol). But, it was believed, boosting HDL ("good" cholesterol) would help clear the arteries. Research had shown that people with low HDL levels were more likely to suffer heart attacks or strokes.

Doubts about this HDL-boosting theory emerged when fenofibrate, an HDL-raising drug, failed in a 2005 study to cut heart attacks and strokes among diabetics. The next year, another HDL-raising drug, torcetrapib, actually increased the risk of heart attack and stroke.

Preliminary data based on several small studies suggested that the HDL-boosting drug niacin might do the trick. A federally funded study involving 3,414 people was launched three years ago with high hopes. But it was abruptly stopped last week when researchers concluded that those taking niacin were no less likely to suffer a heart attack or stroke than those taking the placebo. Moreover, the analysis found a small increase in "ischemic" strokes among those taking the niacin. (Ischemic strokes result from obstructions in blood flow to the brain.) Those taking niacin had 28 such strokes compared to 12 among those using the placebo. But it was unclear whether this result was a fluke or perhaps related to other factors.

The $52.7 million study was funded by the National Heart, Lung and Blood Institute. Its acting director, Susan Shurin, commented:  "This sends us back to the drawing boards."

Pass the Salt?

Now that I've got my pantry and freezer stocked with low-sodium foods comes this news in a 5/3/11 press release from the Journal of American Medicine Association (JAMA):

National policies that advise restricting sodium (salt) intake to reduce the risk of hypertension might not provide the anticipated cardiovascular benefits and may even be detrimental to health, report researchers in an article in today’s JAMA.
In the study, the researchers categorized the 3681 study participants according to sodium intake, using a procedure that measures sodium in the urine over a 24-hour period, considered the gold standard for such assessment. At a median of nearly 8 years later, participants in the group with the lowest sodium intake at the beginning of the trial were significantly more likely than the other 2 groups to die of cardiovascular disease.
The researchers also found that these 3 groups had the same risk of developing hypertension, regardless of initial sodium intake. They did find in a subgroup of 1499 study participants who had sodium intake measured at the beginning and at the end of the study that an increase in sodium intake was associated with an increase in systolic (but not diastolic) blood pressure. However, this relationship did not result in a higher risk of complications from hypertension or cardiovascular disease, such as heart attack or stroke.
So that settles it. Back to shaking it, right? Not so fast. Shortly after the JAMA article was published, Harvard School of Public Health weighed in with this critical response:
A new study would have you believe that low-salt diets raise your risk of dying from heart disease—a surprising finding, and one that’s sure to grab headlines worldwide. The only problem is that the study’s conclusions are most certainly wrong.
The chief weakness in the study, according to the Harvard School of Public Health, is its small size. With fewer than 4000 participants -- and only 84 cardiovascular-related death -- the study is much too small to support its authors' sweeping conclusions. the Harvard report argues.

Moreover, these conclusions fly in the face of many earlier studies that reported a clear relationship between sodium consumption and high blood pressure / heart disease. “Take this study with a huge grain of salt, and then dispose of it properly,” says Dr. Walter Willet, chair of the Department of Nutrition at the Harvard School of Public Health. “This study should not influence recommendations about sodium intake in any way.”

Bottom line on whether to pass the salt shaker or take a pass on salt? Tossing a coin might be one answer. But for me, I'll continue to limit my sodium intake like before, but perhaps without the same compulsion. Hey, I need to use up all those low-sodium foods I've bought!
 

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