February 3, 2012

SUPPLEMENTS: Do I Need a Daily Aspirin and Multivitamin?

Note: Here's a slogan I've come to believe: "there are no coincidences." I've been looking forward to doing this series of posts on our increasing use of dietary supplements. I wrote the post below as the second in the series on Thursday morning. That afternoon, my arthritic back was bothering me. I rarely use pain pills, but I decided to take a couple of them. When I got up from my afternoon nap, I quickly realized I'd taken two 5-HTP pills -- a supplement that works splendidly FOR ME, but has adverse side effects if I take more that 25 milligrams. (Since the lowest dosage available is 50mg, I cut the pill in half.). I'll report more on this and the important lessons learned as an appropriate coda to this series of posts on supplements.

Many of us have developed the habit of starting the morning by taking a baby aspirin to prevent a heart attack, and a multivitamin to help fight off everything else -- standard medical advice for years. But now new studies question whether those pills do much good. Some research even suggests they may cause harm.

Daily Aspirin
Aspirin, sometimes referred to as a blood thinner, helps keep blood from forming clots that can block flow to the heart or brain. But aspirin can also lead to excessive internal bleeding. As a compromise, medical authorities have recommended a dosage under 100mg -- the so-called "baby aspirin."

New studies now question that advice, and suggest that the daily aspirin regimen remains appropriate only for people who have suffered a heart attack, or have narrowed arteries. Those new reports indicate that the risks outweigh the benefits for healthy adults with no sign of cardiovascular disease.

The latest study analyzed data involving over 100,000 adults who were randomly assigned to take a low-dose aspirin or a placebo. None of the participants had cardiovascular disease when the six-year study began. Results showed that aspirin-takers were ten percent less likely to experience cardiovascular problems (primarily heart attack or stroke). No difference was found between men and women. But older people seemed to benefit more than younger ones. On the other hand, aspirin-takers were 70 percent more likely to experience bleeding problems, and 30 percent more likely to have serious bleeding, especially among young people. The study also concluded that the daily aspirin-takers did not reduce their risk of cancer. (Reported in the 1/9/2012 issue of Archives of Internal Medicine)

An international panel of experts on aspirin and cancer concluded it was too early to recommend low-dose aspirin to prevent cancer, since the side effects outweighed some evidence of its cancer-fighting potential. But that recommendation was made in 2009. Last year, British scientists published findings in a five-year study of 23,535 people that showed an impressive 34% lower risk of dying from cancer among those taking a daily low-dose aspirin. Aspirin was most effective against gastro-intestinal cancers, reducing the risk of death by 54% among the digestive tract cancers, like pancreatic, colorectal, and esophageal. While there was some indication of a trend toward fewer deaths from prostate and lung cancer, these reductions did not meet the UK scientists' tough standards for statistical evidence. (See Harvard Men's Health Watch, Oct, 2011)

So in 2009, a consensus was emerging that the risks outweighed the benefits of routine daily use of aspirin by generally healthy adults. Then the British study comes along last year and muddies the waters.

Daily Multivitamin?
Research on multivitamins over the years has produced mixed results. But most well-designed studies have not found a benefit -- except for those whose diets are consistently deficient  in one or more of the nutrients contained in the supplement.

Here's a basic issue with multivitamin studies: those who take them are already typically health-conscious, more likely to eat wisely, and least likely to need them.
Still . . . why not take a multivitamin anyway, just in case you're missing a particular nutrient or two? What's the risk?

Here's the risk: A new study -- the Iowa Women's Study -- analyzed data on 38,772 women (average age 61.8). As the women aged during the study (1986-2004), they were increasingly inclined to use supplements, rising from 62.7 percent in 1986 to 85.1 precent in 2004.

But of all the supplements studied, only extra calcium was associated with a lower risk of dying during an average 19-year follow-up. Multivitamins and supplements of vitamins B6, folic acid, magnesium, zinc, copper, and especially iron were associated with greater risk of dying. The researchers concluded:
Based on existing evidence, we see little justification for the general and widespread use of dietary supplements. We recommend that they be used with strong medically based cause, such as symptomatic nutrition deficiency disease.
See NIH summary of study.

Other scientists have noted that these findings contradict previous research, which had shown either lowered risk of death, or no effect. (And remember that finding an "association" between two things, like taking multivitamins and either a lowered or increased risk of death, does not prove cause-and-effect.)

Is there any general concensus? Yes. Virtually all experts -- for or against the routine use of multivitamins -- agree that the food we eat is the best place to get the nutrients we need.

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