sexta-feira, 21 de janeiro de 2011

ORGÂNICOS NÃO SÃO MAIS SAUDÁVEIS QUE ALIMENTOS CONVENCIONAIS (ESTUDO BRITÂNICO)


As pessoas que apregoam os benefícios do consumo de produtos cultivados naturalmente não vão ficar muito satisfeitas com um novo estudo que afirma que eles não são muito mais saudáveis que os produzidos de forma convencional.






Não sei o que passava na cabeça de quem escreveu esse artigo, mas suspeito que tenha sido algo assim:
- Agora quero ver o que esses ecochatos da alimentação saudável vão dizer com os resultados dessa pesquisa...
E com o olhar completamente distorcido faz a tradução do título do artigo e o coloca como uma manchete. Tentarei explicar porque fico desconfiado assim.
Eu, particularmente, compro produtos orgânicos sempre que estão ao meu alcance, seja físico ou econômico.Deixo isso bem claro para que saibam qual a minha tendência na hora de escrever esse pequeno texto. Entretanto, jamais mentiria ou sairia escrevendo artigos por aí acreditando que ninguém seria capaz de verificar as fontes. E compro os orgânicos mesmo sabendo, ou melhor, suspeitando da insustentabilidade dessa opção, pois não sei se haveria produção suficiente de alimentos orgânicos para toda a população do nosso combalido planeta. Vou dar uma olhada melhor sobre essa questão. Ainda os compro com a nítida sensação de que isso só é possível segundo a lógica do privilégio. Ops, corrigindo, segundo a lógica escrota do privilégio.
Então vamos lá.
O título do artigo sobre o review que foi feito sobre produtos organicamente cultivados que aparece no site da London School of Hygiene and Tropical Medicine é “Organic food not nutritionally better than conventionally produced food”, que pode ser traduzido como “ Alimento orgânico não é nutricionalmente melhor que alimento convencionalmente produzido”. Espero que concordem quando eu questiono a tradução “ Orgânicos não são mais saudáveis que alimentos convencionais (estudo britânico)”, dada pelo jornalista. De onde saiu essa distorcida conclusão?
Talvez o texto do jornalista seja mais esclarecedor. Mas já no primeiro parágrafo ele insiste na meia informação quando diz que “Na pesquisa publicada esta semana em uma revista americana, os especialistas da London School of Hygiene and Tropical Medicine (LSHTM) afirmaram que não existem diferenças importantes entre os alimentos orgânicos e os produzidos de maneira convencional.”  Tudo bem que no segundo parágrafo, quando ele não usa suas próprias palavras, mas apenas tenta traduzir o artigo original a coisa fica um pouco mais clara, "Foi encontrado um pequeno número de diferenças no conteúdo de nutrientes entre cultivos e gados controlados organicamente e os de maneira convencional", declarou o dr. Alan Dangour, principal autor do estudo. "Mas é pouco provável que tenham alguma importância na saúde pública".
O subtítulo é ainda pior “As pessoas que apregoam os benefícios do consumo de produtos cultivados naturalmente não vão ficar muito satisfeitas com um novo estudo que afirma que eles não são muito mais saudáveis que os produzidos de forma convencional.”  Trata-se de conclusão absolutamente tendenciosa, pois em nenhuma parte do artigo há subsídios para tal constatação. Não se trata de defender o contrário dizendo que o alimento orgânico é muito mais saudável que o convencional, mas apenas de se ater aos dados. Como sustentar tal afirmação quando o artigo original deixa claro que “ The review focussed on nutritional content and did not include a review of the content of contaminants or chemical residues in foods from different agricultural production regimens”.
Quando você põe numa manchete que orgânicos não são melhores que os convencionais, sem mencionar que no estudo não foi levado em conta a presença de agrotóxicos, suspeito de duas coisas: má fé e/ou ignorância. O que se fala sobre agrotóxicos está no fim do artigo brasileiro e não estressa a ausência deles no review da American Journal of Clinical Nutrition[i].
Ora, creio que pouca gente[ii] crê que a diferença entre os dois tipos de alimentos em questão seja nutricional. Ou melhor, todos sabem que o sabor é diferente[iii], mas daí interpretar em ser mais nutritivo é um erro. O que se leva em conta é a presença ou não de agrotóxicos. Como químico familiarizado com muitas substâncias químicas e com análises de resíduos sei que o uso de agrotóxico pode ser melhorado, e muito, caso as indicações de uso escritas no rótulo fossem obedecidas. Mas gostaria que vocês imaginassem aquele trabalhador aplicando os pesticidas de havaiana e bermuda, sem nenhum equipamento de proteção fazendo as contas de diluição do produto[iv].
Assim sendo, se você puder escolher, seguindo a recomendação do The Guardian[v], citado pelo jornalista do último segundo, look beyond the headlines, e reduza a ingestão de substâncias perigosas em seu alimento. Agora, se você acha que agrotóxicos não dão nada, viva sua vida e pague seu plano de saúde. Que vamos morrer todos sabemos. Mas, pelo menos, podemos tentar, se de velhice, morrer bem.

Abraços, Antonio.

PS1  Abaixo, os textos citados pelo Último Segundo.
PS2  Será que o chamico usado pelos superlongevos lá do Equador[vi] é orgânico? O lá do meu jardim é…
  


Organic food not nutritionally better than conventionally produced food
Wednesday, 29 July 2009


Systematic review of literature over 50 years finds no evidence for superior nutritional content of organic produce
There is no evidence that organically produced foods are nutritionally superior to conventionally produced foodstuffs, according to a study published today in The American Journal of Clinical Nutrition (see abstract).
Consumers appear willing to pay higher prices for organic foods based on their perceived health and nutrition benefits, and the global organic food market was estimated in 2007 to be worth £29 billion (£2 billion in the UK alone). Some previous reviews have concluded that organically produced food has a superior nutrient composition to conventional food, but there has to date been no systematic review of the available published literature.
Researchers from the London School of Hygiene & Tropical Medicine have now completed the most extensive systematic review of the available published literature on nutrient content of organic food ever conducted. The review focussed on nutritional content and did not include a review of the content of contaminants or chemical residues in foods from different agricultural production regimens.
Over 50,000 papers were searched, and a total of 162 relevant articles were identified that were published over a fifty-year period up to 29 February 2008 and compared the nutrient content of organically and conventionally produced foodstuffs. To ensure methodological rigour the quality of each article was assessed. To be graded as satisfactory quality, the studies had to provide information on the organic certification scheme from which the foodstuffs were derived, the cultivar of crop or breed of livestock analysed, the nutrient or other nutritionally relevant substance assessed, the laboratory analytical methods used, and the methods used for statistical analysis. 55 of the identified papers were of satisfactory quality, and analysis was conducted comparing the content in organically and conventionally produced foods of the 13 most commonly reported nutrient categories.
The researchers found organically and conventionally produced foods to be comparable in their nutrient content. For 10 out of the 13 nutrient categories analysed, there were no significant differences between production methods in nutrient content. Differences that were detected were most likely to be due to differences in fertilizer use (nitrogen, phosphorus), and ripeness at harvest (acidity), and it is unlikely that consuming these nutrients at the levels reported in organic foods would provide any health benefit.
Alan Dangour, of the London School of Hygiene & Tropical Medicine’s Nutrition and Public Health Intervention Research Unit, and one of the report’s authors, comments: ‘A small number of differences in nutrient content were found to exist between organically and conventionally produced foodstuffs, but these are unlikely to be of any public health relevance. Our review indicates that there is currently no evidence to support the selection of organically over conventionally produced foods on the basis of nutritional superiority. Research in this area would benefit from greater scientific rigour and a better understanding of the various factors that determine the nutrient content of foodstuffs’.
For further information, or to interview any of the report’s authors, please contact Gemma Howe in the London School of Hygiene & Tropical Medicine Press Office: 
Gemma.howe@...
Tel: +44 (0)20 7927 2802/07828 617 901
Food Standards Agency Press Office:
Tel:+44 (0)20 7276 8888
Emer.timmins@...

Notes to Editors:
Nutritional quality of organic foods: a systematic review
Authors: Alan D Dangour, Sakhi K Dodhia, Arabella Hayter, Elizabeth Allen, Karen Lock, Ricardo Uauy
External review
An independent expert review panel was constituted to oversee and advise on the conduct of the review. The panel comprised a subject expert, Dr Julie Lovegrove (University of Reading, UK) and an expert in public health nutrition with systematic review experience, Professor Martin Wiseman (University of Southampton UK and World Cancer Research Fund International, UK).
Funding
The study was commissioned and funded by the UK Food Standards Agency. The funder had no role in study design, data collection, analysis, interpretation or writing of the report. The review team held six progress meetings with the funder. The corresponding author had full access to all the data and had final responsibility for the decision to submit for publication.


Good reasons for going organic


·                                 Article history

We would like to point out the misleading nature of both your headline (Organic food not healthier, says FSA, 30 July) and the Food Standards Agency's study. First, as you report, the study has noted that there is an increase in nutritional content, as have other studies; much more importantly, the study did not look at the health implications of the use of fertilisers and pesticides, the major health difference between conventional and organic foods. Furthermore, as your article stated, consumers are not primarily motivated to purchase organic food for personal health reasons but for much wider environmental and social reasons.
Serious questions need to be asked of the FSA as to why it commissioned a study with such a limited scope: it is like looking at the health impacts of smoking and only assessing the degree of tobacco staining on a user's fingers. Organic food is good for the local environment, creates jobs and will be increasingly recognised as essential in the fight against climate change and resource constraints.
Consumers would be advised to look beyond the headlines and continue to support organic producers whose wider societal impacts bring benefits to all.
Julie Brown, Antony Froggatt, Nick Plumeridge and Natasha Soares
Pear Necessities Organic Partnership
Organic farms have on average 30% more species and 50% more wildlife like birds, butterflies and bees. Compassion in World Farming, the recognised experts, says organic farming has the potential for the highest animal welfare standards. Other environmental benefits are self-evident – there's less dangerous waste on organic farms and almost no pesticide use. Artificial nitrogen fertiliser is banned in organic farming, so there's less runoff of nutrients that cause algae blooms in coastal waters.
There are more women and younger people involved in organic farming, and organic farmers are more optimistic about the future. That future will be dominated by climate change. Here organic farming is leading the way, insisting on using solar-powered fertility through crops like red clover that fix nitrogen into the soil for subsequent crops. For our own health and the health of the planet, organic food and farming will play a big part in our future.
Molly Conisbee
Aside from the fact that the FSA's study ignores the most up-to-date research on the nutritional benefits of organic food, a more useful study would have been one which acknowledges the growing body of evidence on the impacts of bioaccumulative and endocrine-disrupting chemicals used in intensive farming and the climate change impacts of carbon-intensive farming.
Organic farming is a holistic, integrated approach which conserves soils, encourages biodiversity, eliminates greenhouse gas-intensive nitrogen inputs, conserves genetic diversity, and brings more income to the grower. And is very probably healthier to boot.
In 2008 the Sustainable Development Commission's Green, Healthy and Fair report found that "conflicting policies from different areas of government are also making it impossible to achieve targets" including reducing carbon emissions and promoting the healthy development in children. The FSA's latest report is just such an own goal.
Andrew Lee
While there are many good reasons to eat organic, I think taste is an important influence. Here so-called blind tests are up against a problem as so many non-organic consumers' taste buds have been damaged by eating an excess of strong, spicy flavours, sweeteners, chemicals and so on. To a fully working palate there simply is no argument. Especially with such foods as chicken, tomatoes, strawberries, apples and so on. Add to that smell, and you can see why when food is whole and fresh and free from chemicals, grown in healthy, uncontaminated soil with access to natural sunlight, the phrase "evocative aroma" really means something!
And the truth is we don't need science to tell us this. Could it be that some natural, sensual, instinctive, intuitive awareness might be more accurate than a science limited to provable "facts"?
Mora McIntyre
Hove, East Sussex




[i] Am J Clin Nutr (July 29, 2009). doi:10.3945/ajcn.2009.28041
[ii] Quando eu digo gente, imagino aquele tipo que sabe o que é nutricional.
[iii] Melhor ou pior depende da sua posição com relação ao assunto. Mas, experimente cultivar morangos de maneira orgânica. O tamanho é decepcionante, mas o sabor... Algo a ver com a comunidade nipônica.
[iv] Eu conheço biólogo que não sabe... Geógrafo então...

quarta-feira, 19 de janeiro de 2011

EFEITOS DO ARSÊNIO NA SAÚDE - PROBLEMAS NA ÁSIA

Nas viagens que fazemos às cidades históricas em Minas Gerais devemos mencionar o problema da contaminação da água dos aquíferos.
Segue uma matéria sobre  a presença de arsênio em níveis não aceitáveis , ou quase, para o consumo humano que afeta, ou afetará nos próximos anos, 100 milhões de pessoas na Ásia.

Caso queira ler o artigo na página original, clique aqui.






Published online 17 January 2011 | Nature | doi:10.1038/news.2011.20

News

Arsenic sinks to new depths

Groundwater overuse can push poisonous element deeper — a serious risk for countries in Southern Asia.

man with skin lesions from drinking arsenic-laced waterDrinking arsenic-laced water can cause a range of health problems from lesions (shown) to cancer - and findings now show deeper wells may not be a solution.Reuters
More than a century of groundwater over-exploitation in Vietnam has drawn the water table down and, with it, arsenic. It may only be a matter of time before the toxic element also permeates deep aquifers in other Asian countries that follow the same practice, such as those around the Bengal Basin.
These conclusions, published today in theProceedings of the National Academy of Sciences1, point to high future costs in terms of both health and water-purification processes. Some 100 million people throughout Asia are currently at risk from unsafe levels of arsenic in their water supplies. The element can trigger conditions ranging from anaemia to skin cancer. With deeper aquifers so far thought to be arsenic-free, some municipal authorities in Bangladesh, and many in Vietnam, are drilling into lower sediments.
In Vietnam, a nation that began overusing its deep aquifers under French occupation more than 110 years ago, the effect is already pronounced. In the region surrounding the densely populated city of Hanoi — with nearly 2,000 people per square kilometre — it is difficult to escape arsenic-contaminated water, no matter how deeply you drill.
The researchers analysed 512 private tubewells reaching to depths ranging from 10 metres to more than 50 metres throughout the country's Red River Delta. Their findings revealed that 27% of the wells contained levels of arsenic in excess of the World Health Organization's standard of 10 micrograms per litre, says Michael Berg, a senior scientist at the Swiss Federal Institute of Aquatic Science and Technology in Dübendorf and a co-author on the study1. This puts some 3 million people at risk.
The survey, carried out in cooperation with the Hanoi University of Science and Technology, also found harmful levels of other elements — about 7 million people in the Red River Delta are exposed to unsafe levels of at least one element. After arsenic, the most important of these is manganese, which exceeded World Health Organization guidelines in 44% of the wells. Elevated levels of this element can affect neurological development in children.

Mapping the depths

From the survey data, Berg's team created the first three-dimensional groundwater map, using statistical modelling to show levels that are relatively arsenic-free. "It is now clear where water is safe and where it is unsafe. That is one of the most important findings for the public," says Berg.
The map makes it difficult for officials to ignore the arsenic problem, says Dieke Postma, a senior researcher at the Geological Survey of Denmark and Greenland, who has been working in the region since 2004 and is unconnected with the new study. "It's important for the Vietnamese authorities because they haven't had an overview of how big the problem is," he says.
3D map of arsenic distribution at depth in Red River sediments, Vietnam'Stacked' 3D map of arsenic pollution risk in Red River Delta sediments, Vietnam, shows that unsafe levels of the element (in red) have penetrated to deeper layers.Ref. 1; Michael Berg, www.eawag.ch
Postma says he hopes that an international scientific conference on the issue, to be held in Hanoi in November, will draw further official attention to arsenic contamination in the region.
The implications of the finding could be serious for countries around the Bengal Basin in South Asia. In Bangladesh, where some 70 million people2 are exposed, the use of deep aquifers is a more recent phenomenon. Decades ago, aid agencies introduced tube wells as a reliable and clean water source, only to find that the top-most sediment layers, formed in the 12,000 years since the start of the current Holocene epoch, contain naturally occurring arsenic that leaches into the groundwater.
To avoid contamination, wells in the Bengal Basin can be drilled into deep layers that were oxidized during the last ice age, in which the water is free of arsenic, Berg says. These aquifers were created during the Pleistocene epoch, between 12,000 and 2.5 million years ago, and lack the organic carbon that is needed for arsenic to leach into water.

Leaching lower

But if people in the Bengal Basin continue to exploit their water supplies at the current rates, arsenic-laden water from the upper layers may find its way into Pleistocene aquifers, the study suggests.
Berg's team is in contact with scientists in Dhaka to evaluate arsenic migration into deeper sediments.
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The group is the first to give real-life evidence that arsenic in deeper layers can get into groundwater. Other lab-based studies2,3 have suggested that sediments in deeper aquifers tend to keep arsenic out of the water, says William Burgess, a hydrogeologist at the Department of Earth Sciences at University College London. On the basis of the new study, he thinks that such sequestration may not always happen and probably depends on the composition of sediments and the complexity of water flow underground.
"Pumping from the Pleistocene aquifer has certainly had an adverse effect in terms of drawing down arsenic at significantly high concentrations over about 100 years," says Burgess. "These deep wells weren't being monitored 10, 20, 30 years ago, so we don't know how quickly arsenic got down there, but it got there sometime in the past 100 years." 
  • References

    1. Winkel, L. H. E. et al. Proc. Natl Acad. Sci. USAdoi:10.1073/pnas.1011915108 (2011).
    2. Burgess, W.G. et al. Nature Geosci. 3, 83-87 (2010). | Article | ISI
    3. Stollenwerk, K. G. et al. Sci. Tot. Environ. 379, 133-150 (2007). | Article | ISI