Blog Posts by David Katz, MD, PREVENTION

  • Should you skip C (calcium) and D?

    You are likely aware that a committee of the Institute of Medicine has just issued recommendations for calcium and vitamin D intake. The big news is that the committee is recommending not as much more of both nutrients as enthusiasts might have hoped, and sounds a precautionary note about excess dosing.

    Are the supplement enthusiasts right, and IOM wrong- or vice versa? Is the IOM report a reliable basis for your own decisions?

    Natural cures docs swear by

    Let's start with the strong points -- of both the IOM in general, and this particular report. The Dietary Reference Intakes --of which the new report is a small part, and home to the RDAs -- are evidence-based. As a scientist and physician, I consider that a good thing. But it comes with caveats nonetheless.

    An evidence review is only as good as the available evidence. While the IOM committee report on calcium and vitamin D refers to "1000 papers reviewed," it says nothing (at least not before accessing the fine print)

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  • Why we're cheering the proposed ban on caffeinated alcohol

    The writing would seem to be on the wall for Four Loko and other beverages that combine alcohol and caffeine, as the FDA considers an outright ban of the combination. Anyone who is for sanity and safety in marketing should read it and cheer, not weep.

    How bad are your health vices?

    Combining alcohol and caffeine is -- in a word -- crazy. Don't do it! It has an excellent chance of hurting you, and a fairly good chance of killing you. Recent news reports feature tragic victims of this deadly duo. As the companies and federal authorities decide what to do, you can make up your own mind to steer clear of this bad brew.

    As I suspect everyone knows, alcohol is a central nervous system depressant. It is certainly possible to drink enough alcohol for it to be lethal -- people have. But the depressant effect tends to limit the damage, because people fall asleep or pass out before they reach a truly lethal level of intake. Alcohol is more likely to kill by impairing judgment, and responses

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  • Getting to the bottom of the great mammogram debate

    Music, we're told, can soothe the savage breast. Data about breasts, in contrast, can ignite rather savage controversy, and propagate confusion.

    That seems to be the immediate result of a newly reported study that found a 26% mortality reduction with routine mammography for women in their 40s. This would just be good news, if prior studies had not failed to confirm just such a benefit- and if the US Preventive Services Task Force had not recently weighed in against routine screening for women under age 50.

    12 myths to ignore about breast cancer

    The new study, conducted in Sweden, involved roughly a million women. Combine a large study; high profile media coverage; a politically charged topic; and a large reservoir of passion, and you have a very combustible mix indeed! Let's put out the fire.

    First, the new study looked at the benefits of mammography only, not its harms. It took advantage of a natural experiment in Sweden: some counties offered mammograms routinely, others did not.

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  • 4 truths about the flu vaccine

    'Tis the season (at least here in New England) for apple picking, county fairs, pumpkins, and a seasonal brew of recommendations, fulminations, recriminations, allegations, and generalized befuddlement regarding the flu vaccine. What to do, this year, about flu?

    Two words: Get vaccinated. But if only it were that simple.

    Among the roadblocks, there are, for starters, the numerous conspiracy theorists-highly loquacious in cyberspace-who contend not only that flu vaccination is overtly dangerous, but that there is a systematic effort to delude the public about those dangers. Even readers who are not entirely convinced that the CDC is genocidal in its recommendation that everyone over 6 months of age be vaccinated are given pause by such allegations. I realize, despite the cold hard facts, that there is something about immunization that just makes people nervous. Consider this, though: among the bloggers and pundits who propagate this anxiety, there are very few who have ever

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  • Are you in denial about your weight?

    A poll of a nationally representative sample of Americans, reported recently by HealthDay News, shows us that many of us overlook and/or underestimate our excess body fat. 'Denial,' it seems, is not just a river in Egypt.

    Leaving aside the particulars of the survey and its findings, let's just address the fundamentals here: There are overweight people in many of our homes, and we don't see them! This is as understandable as it is ominous.

    Our obesity "blind spot" is understandable because:

    1. We have, to date, done a fine job of equating the fight against obesity with a fight against... the obese! This is wrong, woefully wrong, and overdue for a fundamental remedy. Yes, the proximal cause of excess weight gain is how we use our feet and our forks; but the root cause, to which we are all subject, is living in the modern world. Throughout most of human history, calories were relatively scarce and hard to get, and physical activity was unavoidable; we have devised a modern world in

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  • Can you be fat and fit?

    In a word, yes.

    Research from the Harvard School of Public Health in roughly 100,000 people shows pretty much what one would expect about the population: lots of people are both heavy and unfit; far fewer are thin and unfit; some are both lean and fit; and only a very small number indeed are heavy, but fit. Possible, yes, but exception rather than rule, and for the most obvious of reasons: generally people who become and stay fit are attentive to their health, and a focus on health may be the best bet there is for lasting weight control.

    One-minute weight loss secrets

    But the exceptions to the rule are worth noting- particularly if you- like my friend Dr. Steven Blair, Director of Research at the Cooper Institute in Dallas, TX, are one of them! Some people are, indeed, fit and healthy- while their body remains defiantly heavy. There are others who simply have excess body fat in places where it does no real harm- notably in the hips, buttocks, and thighs- as opposed to around the

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  • Will your diabetes drug give you a heart attack?

    That, in essence, is the question a special panel at the FDA has been wrestling with in an effort to reach a decision about the status of Avandia. The widely used oral medication for diabetes is associated with an increased risk of heart disease.

    For starters, that's almost paradoxical: Since the major cause of death in diabetes is cardiovascular disease, one would think a drug good for controlling diabetes is good for preventing heart disease as well. But in fact, we've long known this is not reliably true. An earlier class of oral drugs for diabetes, called sulfonylureas, is also associated with a slight increase in heart disease risk.

    28 Days, 28 Little Ways to a Healthier Heart

    The question is, increase heart disease risk relative to what? Relative to the risk in those who have their diabetes controlled by other means: not relative to those whose diabetes is entirely out of control! That's important: Even in the worst case scenario, Avandia is a better choice than out-of-control

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  • Are your kids drinking lead in their juice?

    At first glance, a recent report by the Environmental Law Foundation, a California non-profit, indicating there is lead in a variety of popular children's juices, canned fruits, and baby foods-even the organic varieties-almost seems like cause for despair and panic. I can quickly reassure you that it is not, although it is certainly cause for concern, some cautious actions, and consternation over our abuses of this magnificent planet.

    7 weird places where lead lurks

    The ELF sampled a variety of the foods mentioned above in its own lab and found levels of lead that exceeded allowances under California's Proposition 65, a law that requires notice to consumers by means of warning labels when foods are tainted. The complete list includes 125 products-apple juice, grape juice, packaged peaches, pears, and fruit cocktail-from brands such as Del Monte, Gerber, Welch's, Trader Joe's, and more (visit for the whole list).

    Print a list of the 49 healthiest supermarket foods


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  • Are pesticides in food making your kids sick?

    Concerns that contaminants in foods-such as trace pesticide residues-can be harmful to health have helped propagate the growth of the organic food movement perhaps as much as devotion to "going green" and protecting the planet. That has at times caused difficulties for a nutrition specialist like me, because organic and nutritious are not the same. Nutrititious means good for the health of the person; organic does not mean that, as evidenced by the fact that gummy bears may be organic, and broccoli may not be.

    25 Ridiculously Healthy Foods

    But now comes an important new chapter in this on-going story. A study led by researchers at the Department of Environmental and Occupational Health, University of Montreal, Quebec, Canada, examined a representative sample of over 1,100 children in the U.S. between the ages of 8 and 15, and found higher
    levels of pesticide metabolites in the urine of those with attention deficit disorder.
    In an observational study such as this, the association

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  • Can your multivitamin give you breast cancer?

    One recent study in the American Journal of Clinical Nutrition says yes. The study followed nearly 35,000 women for close to ten years; 25% of the women in the study routinely took a multivitamin and the other 75% did not. Authors found that multivitamin use was associated with a 19% increase in the likelihood of being diagnosed with breast cancer.

    But I'm not convinced that multis trigger breast cancer, and you have no cause to panic. First, let's talk about the study.

    1) The numbers sound scarier than they are. In women not taking multis, the risk of breast cancer in given person in any given year was about 0.26%. Among multivitamin users, the absolute risk of breast cancer in any given year was 0.32%. The relative difference between a risk of 0.32% and 0.26% is, indeed, about 19%. But the absolute difference is 0.06%. In other words, if multivitamins are truly the cause of the apparent risk difference, they would increase your breast cancer risk by considerably less than one tenth

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