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| Fonte: http://www.informacaonutricional.blog.br |
"Dr., me passe uma vitamina bem boa!"
"Dr., qual é a melhor vitamina pra eu tomar?"
"Dr., qual a vitamina mais completa?"
Quantas vezes não escutamos essa pergunta de pacientes hígidos e eutróficos, pela crença de que polivitamínicos melhoram a saúde e/ou ajudam a ficar "fortes"? Ou pela crença da necessidade após tratamento antiparasitário?
Bem, somos responsáveis pela medicina que nós e nossos colegas praticam, então é importante esclarecermos nossos pacientes da ausência de benefícios e, na verdade, até presença de malefícios do consumo indiscriminado de polivitamínicos.
Evitemos "passar por passar" polivitamínicos só para agradar o paciente ou para evitar "perder tempo" explicando...
Americanos gastam anualmente e, em sua maioria, inadequadamente, 28 bilhões de dólares com polivitamínicos... Qual será a nossa cota??
Claro que existem patologias que necessitam da reposição vitamínica e existem situações de risco para sua depleção, então, como para todo paciente, é imprescindível uma avaliação médica com boa boa anamnese...
Mas afinal, existe algum efeito comprovado do uso de polivitamínicos em pessoas saudáveis com o objetivo de prevenir doenças cardiovasculares, perda cognitiva, câncer ou morte? Infelizmente, as evidências científicas não animadoras...
Para ajudar nos argumentos, segue texto extraído do ACP Internist com artigos publicados no Annals of Internal Medicine que ajudam a embasar.
Fonte:
The last nail in the coffin for multivitamins
How much money would the U.S. auto industry be making if every car they sold never started? How much could video game console makers charge if their products didn't play any games? Well, in 2010 the U.S. dietary supplement industry sold $28 billion dollars in vitamins, minerals and other supplements that, as far as we can tell, benefited virtually no one.
Annals of Internal Medicine published 3 studies examining the effects of multivitamins. This is not the first investigation of a mysterious unexplored field. Lots of studies have already shown that in well-nourished people living in the Western Hemisphere, multivitamins are not helpful. Think of this more as sweeping away any traces of doubt.
One study explored the effects of a high-dose vitamin and mineral supplement on heart disease. About 1,700 patients who had a heart attack in the past were randomized to the supplement or a placebo. They were followed for four years to measure their rates of recurrent cardiovascular events. There was no difference in the occurrence of these events between the group receiving the supplement and the group receiving placebo.
Another study examined the effects of a multivitamin on cognitive decline. About 6,000 male physicians aged 65 and older were randomized to a multivitamin or placebo and given a battery of 5 tests of cognition and memory over 12 years of follow up. The 2 groups did the same.
The third study was a review of prior studies of vitamin and mineral supplements for the prevention of cancer or cardiovascular disease. The study conclusion was negative. There is no reason to take vitamins or minerals for cancer or cardiovascular disease prevention. And the review highlighted the harms of some vitamins. β-carotene and vitamin A increase lung cancer risk in smokers, and vitamin E increases the risk of prostate cancer.
An editorial in the same journal issue crystalized our current knowledge: In conclusion, β-carotene, vitamin E, and possibly high doses of vitamin A supplements are harmful. Other antioxidants, folic acid and B vitamins, and multivitamin and mineral supplements are ineffective for preventing mortality or morbidity due to major chronic diseases.
Their conclusion: The message is simple: Most supplements do not prevent chronic disease or death, their use is not justified, and they should be avoided.
There are specific patient populations who are especially vulnerable to vitamin malabsorption, such as those who have had intestinal surgery and patients on long-term acid suppressing medications. They may be recommended specific vitamin supplements. Women in their child-bearing years should take folic acid. And it's possible that vitamin D in the elderly prevents falls. But apart from those narrow groups, well-nourished people don't benefit from supplements. (I don't take any vitamins or minerals.)
Perhaps the latest studies and the barrage of resulting media coverage will make a difference. Then maybe we could save some of that $28 billion and spend it to buy some skepticism.
Learn more:
Multivitamins Found to Have Little Benefit (Wall Street Journal)
How do Americans waste $28 billion a year? On vitamins, doctors say (Los Angeles Times)
The Case Against Multivitamins Grows Stronger (Shots, NPR's health news)
Oral High-Dose Multivitamins and Minerals After Myocardial Infarction: A Randomized Trial (Annals of Internal Medicine article. Abstract available without subscription)
Long-Term Multivitamin Supplementation and Cognitive Function in Men: A Randomized Trial (Annals of Internal Medicine article. Abstract available without subscription)
Vitamin and Mineral Supplements in the Primary Prevention of Cardiovascular Disease and Cancer: An Updated Systematic Evidence Review for the U.S. Preventive Services Task Force (Annals of Internal Medicine. Available without subscription.)
Enough Is Enough: Stop Wasting Money on Vitamin and Mineral Supplements (Annals of Internal Medicine editorial. Subscription required.)
A Reminder to Dump Your Multivitamin (my post from 2011 reviewing the known effects of various vitamin supplements)
Albert Fuchs, MD, FACP, graduated from the University of California, Los Angeles School of Medicine, where he also did his internal medicine training. Certified by the American Board of Internal Medicine, Dr. Fuchs spent three years as a full-time faculty member at UCLA School of Medicine before opening his private practice in Beverly Hills in 2000. Holding privileges at Cedars-Sinai Medical Center, he is also an assistant clinical professor at UCLA's Department of Medicine. This post originally appeared at his blog.
Enviado via iPhone de Rainardo Puster
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