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(Health) Vitamin B: Children 'Harmed' by Vegan Diets

 
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PostPosted: Tue Jan 03, 2006 4:27 pm    Post subject: (Health) Vitamin B: Children 'Harmed' by Vegan Diets Reply with quote






Children 'harmed' by vegan diets
By Michelle Roberts
BBC News health reporter, in Washington DC
21 February, 2005

Putting children on strict vegan diets is "unethical" and could harm their development, a US scientist has argued.
Lindsay Allen, of the US Agricultural Research Service, attacked parents who insisted their children lived by the maxim "meat is murder".

Animal source foods have some nutrients not found anywhere else, she told a Washington science conference.

The Vegan Society dismissed the claims, saying its research showed vegans were often healthier than meat eaters.

'Development affected'

Professor Allen said: "There have been sufficient studies clearly showing that when women avoid all animal foods, their babies are born small, they grow very slowly and they are developmentally retarded, possibly permanently."

"There's absolutely no question that it's unethical for parents to bring up their children as strict vegans", says
Professor Lindsay Allen, US Agricultural Research Service

"If you're talking about feeding young children, pregnant women and lactating women, I would go as far as to say it is unethical to withhold these foods [animal source foods] during that period of life."

She was especially critical of parents who imposed a vegan lifestyle on their children, denying them milk, cheese, butter and meat.

"There's absolutely no question that it's unethical for parents to bring up their children as strict vegans," she told the annual meeting of the American Association for the Advancement of Science (AAAS).


Missing nutrients

She said the damage to a child began while it was growing in the womb and continued once it had been born.

Research she carried out among African schoolchildren suggests as little as two spoonfuls of meat each day is enough to provide nutrients such as vitamin B12, zinc and iron.

The 544 children studied had been raised on diets chiefly consisting of starchy, low-nutrition corn and bean staples lacking these micronutrients.

This meant they were already malnourished.

Over two years, some of the children were given 2oz supplements of meat each day, equivalent to about two spoonfuls of mince.

Two other groups received either a cup of milk a day or an oil supplement containing the same amount of energy. The diet of a fourth group was left unaltered.

The changes seen in the children given the meat, and to a lesser extent the milk or oil, were dramatic.
These children grew more and performed better on problem-solving and intelligence tests than any of the other children at the end of the two years.

Adding either meat or milk to the diets also almost completely eliminated the very high rates of vitamin B12 deficiency previously seen in the children.

No quick fixes

Professor Allen stressed that although the study (which was partially supported by the National Cattleman's Beef Association) was conducted in a poor African community that was malnourished, its message was highly relevant to people in developed countries.

She accepted that adults could avoid animal foods if they took the right supplements, but she said adding animal source food into the diet was a better way to tackle malnutrition worldwide than quick fixes with supplements in the form of pills.

"Where feasible, it would be much better to do it through the diet than by giving pills," she said.

"With pills it's very hard to be certain that the quantity of nutrition is right for everybody and it's hard to sustain."

In Africa, good results had been obtained from giving people a dried meat on a stick snack which proved both nutritious and appealing.

Professor Montague Demment, from the University of California at Davis, said more emphasis should be placed on animal source food to combat global malnutrition.

Vegan defence

However, the claims have been dismissed by the Vegan Society in the UK.

In a statement, it said increasing numbers of people were opting for a plant-based diet.

Kostana Azmi, the chief executive officer, said: "The vegan diet can provide you with more energy, nutrition, and is bursting with goodness."

She said plant sources were sometimes a safer, and cheaper source of nutrients.

For instance, animal sources of omega-3 oils, needed for the development of the brain and nervous system, were often contaminated with pollutants, such as mercury in fish.

In addition, the vegan diet was often a healthier alternative. She said dairy and meat products were rich in saturated fat, while plant based diets were low in it.

The society does recommend that vegans supplement their diet with vitamin B-12 pills.

The US Agricultural Research Service is part of the US Department of Agriculture.

Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr.....282257.stm

*************************************************************

Questions to explore further this topic:

What is a vegetarian diet?

http://kidshealth.org/parent/n.....anism.html
http://www.annecollins.com/veg.....rition.htm
http://www.askdrsears.com/html/4/T045400.asp

What is Vitamin B?

http://en.wikipedia.org/wiki/Vitamin_B
http://www.psychologytoday.com.....-2692.html

Vitamin B1 (Thiamine)
http://www.umm.edu/altmed/Cons.....inecs.html

Vitamin B2 (Riboflavin)
http://www.umm.edu/altmed/Cons.....vincs.html

Vitamin B3(Niacin)
http://www.umm.edu/altmed/Cons.....cincs.html

Vitamin B5 (Pantothenic Acid)
http://www.umm.edu/altmed/Cons.....cidcs.html

Vitamin B6 (Pyridoxine)
http://www.umm.edu/altmed/Cons.....inecs.html

Vitamin B9 (Folic Acid)
http://www.umm.edu/altmed/Cons.....cidcs.html

Vitamin B12 (Cobalamin)
http://www.umm.edu/altmed/Cons.....mincs.html

How do these nutrients affect the nervous system?

http://faculty.washington.edu/chudler/nutr2.html

Why is Vitamin B12 important?

http://www.westonaprice.org/ba.....inb12.html

GAMES

http://www.applejuice.org/fungames.html
http://www.avocado.org/kids/games-children.php
http://kidnetic.com/Kore/Hunt.aspx
http://www.got-milk.com/fun/index.html
http://www.foodskool.ie/start.html
http://www.calstrawberry.com/s.....search.asp


Last edited by adedios on Sat Jan 27, 2007 4:50 pm; edited 2 times in total
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PostPosted: Wed Feb 22, 2006 7:30 am    Post subject: Science Class Experiment Reveals Vitamin B12 Secret Reply with quote

February 20, 2006
Science Class Experiment Reveals Vitamin B12 Secret
Howard Hughes Medical Institute
Research News

For decades, scientists have wondered how living organisms manufacture the essential vitamin B12. Now, using laundry whitener and dirt-dwelling bacteria—the everyday ingredients of an undergraduate science experiment—researchers may have found the major clue they need to solve the mystery.

Researchers led by Graham Walker, a Howard Hughes Medical Institute (HHMI) professor and American Cancer Society research professor at the Massachusetts Institute of Technology, have discovered the first known mutant bacteria with a specific defect in a gene involved in the least-understood part of B12 synthesis. They report their findings in the early online edition of the Proceedings of the National Academy of Sciences, published February 20, 2006. HHMI professors are leading research scientists who received $1 million grants from the Institute to find ways to bring the excitement of the research lab into undergraduate science classrooms.


“That is what is so great about basic research. It finds answers to things you cannot get at in a direct way.”
Graham C. Walker

In the ancient world, B12 was probably catalyzing reactions before cells even existed. Now, all animals need B12 to help make the building blocks of DNA, and children need enough of the vitamin to help their brain develop normally. Most people consume enough B12 through animal products or fortified foods in their diet. On the other hand, animals that do not eat other animal products acquire the nutrient from bacteria in their guts or from bacteria-infected dirt on their plant food. An estimated one-quarter of people older than 60 in this country have trouble absorbing B12. B12 deficiency can lead to nerve damage, anemia, and forgetfulness.

Walker's team's genetic discovery was made possible by a gimmick Walker designed to capture the attention of undergraduate biology students in the early 1980s. When he added a laundry whitener to a lab dish, the symbiotic bacteria he studied glowed in ultraviolet light, just as the additive makes clothes look brighter in the sun.

The teaching trick soon became a popular tool in Walker's lab for research that had nothing to do with vitamin B12. There, researchers have been focusing on how symbiotic bacteria form and invade the nodules in alfalfa roots that provide the plant with nitrogen and the bacteria with food. The scientists noticed that some of the bacteria on the glowing lab dishes did not light up. These stubborn dark spots revealed bacteria missing key genes needed to construct and enter the nodules in plant roots, they discovered. By analyzing various mutations, the researchers were able to track the molecular details of how the bacteria provide the plant with the nutrients it needs to grow.

Several years ago, Walker's graduate student Gordon Campbell decided to look for symbiosis defects in bacterial mutants that, instead of being dark spots on the glowing lab dish, were even brighter than their normal counterparts. His findings enabled Campbell and his co-authors to answer a question being asked by many researchers studying B12 synthesis.

“That is what is so great about basic research,” Walker said. “It finds answers to things you cannot get at in a direct way.”

Campbell isolated the brightest mutants and put them onto the roots of alfalfa seedlings. Healthy symbiotic partnerships show up on the plant roots as long pink nodules stuffed with bacteria. In contrast, seedlings sharing a dish with the most obviously defective bacteria were stunted and their roots had small white nubs with barely any bacteria inside. For one of these bright mutants, it turned out that the root of the problem was the mutant bacteria's inability to produce B12.

Adopting nomenclature traditional in their field, the researchers named the mutated gene bluB, after a similar gene found in another kind of bacteria.

“The important clue came when we noticed bluB was grouped with other genes important for making vitamin B12 in the other bacterium,” Walker said. “That's not something we are expert in.” So the researchers contacted co-author John Roth, a professor of molecular biology at University of California, Davis, who has studied in detail the intricate series of steps required to assemble B12, the largest known natural compound that is not made out of repeating units.

“Out of our conversations came the idea that bluB might be required for an unknown part of the pathway,” Walker said. “B12 is a big, complicated molecule. Researchers have been unable to crack the problem of how to make the lower ligand,” a segment of the molecule known as DMB.

It was a simple experiment, said Michiko Taga, a postdoctoral fellow and co-first author of the paper. Taga took over the research when Campbell graduated. “If the mutant was broken because it could not make DMB,” she said, “then if we added DMB back it should be okay. So we added DMB, and the bacteria went back to acting like ordinary [symbiotic] bacteria. That was the defining experiment.”

When the researchers provided DMB so that the bacteria did not have to manufacture it themselves, the bacteria's extraordinary brilliance subsided to a more uniform fluorescence on the lab dish with the laundry whitener. And in the lab dish with the seedlings, the restored bacteria produced a bigger, healthier plant. Chemist and co-author Kavita Mistry followed up with biochemical experiments to prove that the bluB mutant could not make B12 without added DMB.

“Our findings just mean bluB is necessary for the reaction,” Taga said. "We are currently doing experiments to show that it directly catalyzes the reaction.”

But Roth said the discovery gives him hope for finding all the steps in the pathway for synthesizing B12. “This is the part that has resisted genetics and chemistry,” he explained. “We've tried it. Others have tried it. This appears to be the first enzyme dedicated to synthesizing the part.”

Other bacteria, such as the Salmonella that Roth studies, appear to substitute other molecules in place of DMB, stymieing genetic approaches. But the form of B12 that people need contains DMB.

The discovery of the bluB mutant may overturn a theory that DMB spontaneously forms without enzymes to speed up the reaction, Roth said. Before the bluB mutant was identified, that theory made sense because the reactions that make B12 do not require energy, in contrast to most biosynthetic reactions.

Taga and Walker are following up to figure out how the bluB mutation affects the symbiotic relationship between the bacteria and the plant.
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PostPosted: Sat Apr 01, 2006 8:33 am    Post subject: New scientific review shows vegetarian diets weight loss Reply with quote

Physicians Committee for Responsible Medicine
1 April 2006

New scientific review shows vegetarian diets cause major weight loss
Controlled research trials prove diet's efficacy
WASHINGTON--A scientific review in April's Nutrition Reviews shows that a vegetarian diet is highly effective for weight loss. Vegetarian populations tend to be slimmer than meat-eaters, and they experience lower rates of heart disease, diabetes, high blood pressure, and other life-threatening conditions linked to overweight and obesity. The new review, compiling data from 87 previous studies, shows the weight-loss effect does not depend on exercise or calorie-counting, and it occurs at a rate of approximately 1 pound per week.
Rates of obesity in the general population are skyrocketing, while in vegetarians, obesity prevalence ranges from 0 percent to 6 percent, note study authors Susan E. Berkow, Ph.D., C.N.S., and Neal D. Barnard, M.D., of the Physicians Committee for Responsible Medicine (PCRM).

The authors found that the body weight of both male and female vegetarians is, on average, 3 percent to 20 percent lower than that of meat-eaters. Vegetarian and vegan diets have also been put to the test in clinical studies, as the review notes. The best of these clinical studies isolated the effects of diet by keeping exercise constant. The researchers found that a low-fat vegan diet leads to weight loss of about 1 pound per week, even without additional exercise or limits on portion sizes, calories, or carbohydrates.

"Our research reveals that people can enjoy unlimited portions of high-fiber foods such as fruits, vegetables, and whole grains to achieve or maintain a healthy body weight without feeling hungry," says Dr. Berkow, the lead author.

"There is evidence that a vegan diet causes an increased calorie burn after meals, meaning plant-based foods are being used more efficiently as fuel for the body, as opposed to being stored as fat," says Dr. Barnard. Insulin sensitivity is increased by a vegan diet, allowing nutrients to more rapidly enter the cells of the body to be converted to heat rather than to fat.

Earlier this month, a team of researchers led by Tim Key of Oxford University found that meat-eaters who switched to a plant-based diet gained less weight over a period of five years. Papers reviewed by Drs. Berkow and Barnard include several published by Dr. Key and his colleagues, as well as a recent study of more than 55,000 Swedish women showing that meat-eaters are more likely to be overweight than vegetarians and vegans.


###
For a copy of the new paper published in Nutrition Reviews or an interview with one of the authors, please contact Jeanne S. McVey at 202-686-2210, ext. 316, or jeannem@pcrm.org.

Founded in 1985, the Physicians Committee for Responsible Medicine is a nonprofit health organization that promotes preventive medicine, especially good nutrition. PCRM also conducts clinical research studies, opposes unethical human experimentation, and promotes alternatives to animal research.
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PostPosted: Mon Jun 12, 2006 11:56 am    Post subject: folic acid as a cancer prevention drug Reply with quote

John Wiley & Sons, Inc.
12 June 2006

Encouraging results for folic acid as a cancer prevention drug

Folic acid supplements may prevent cancer progression and promote regression of disease, according to a new study. Published in the July 15, 2006 issue of CANCER (http://www.interscience.wiley.com/cancer-newsroom), a peer-reviewed journal of the American Cancer Society, the small study found that 31 of 43 patients with the precancerous laryngeal lesion called leucoplakia demonstrated 50 percent or greater reduction in the lesion size after six months of taking folate supplements. In 12 of 31 responders, there was no evidence of the original lesion. Folate levels in the patients' blood also increased significantly from baseline while homocysteine levels decreased significantly. This study provides data to support the hypothesis that folate insufficiency is a risk factor for cancer progression.
Folate deficiency is the most common vitamin deficiency in the United States. Folate is a naturally occurring B vitamin (B-9) found abundantly in fresh vegetables and fruits. Folic acid is its more stable synthetic form found in dietary supplements and fortified foods. At the biochemical level, folate is incorporated into coenzymes that are essential in facilitating a variety of reactions in nucleic acid and amino acids metabolism. Some of which are critical to healthy life, such as DNA synthesis, DNA repair, and converting homocysteine to methionine. The latter is particularly important because excess homocysteine is linked to chronic health problems, such as cancer and cardiovascular disease.

Animal and human studies have increasingly demonstrated associations between folate deficiency, serum homocysteine elevations, and a variety of cancers. Some studies have suggested folate supplementation or at least a high folate dietary intake may protect against some cancers. This body of evidence suggests folate to be an effective chemopreventive drug. Other chemopreventive drugs are being tested, and while the retinoids demonstrate the most promise, they are highly toxic. Giovanni Almadori, M.D. of the Institute of Otolaryngology, Università Cattolica del Sacro Cuore, Policlinico A. Gemelli in Rome, Italy and colleagues investigated the efficacy of folic acid dietary supplementation to treat precancerous lesion and prevent cancer.

The investigators enrolled 43 patients with untreated laryngeal leucoplakia and treated them with folic acid (5mg three times a day) and evaluated the progression of leucoplakia every 30 days for six months.

Over six months of treatment, 12 patients (28 percent) had complete resolution of their leucoplakia lesions; 19 patients (44 percent) had reduction of 50 percent or more in the size of their lesions and 12 patients (28 percent) had no response. Mean folate levels increased and mean homocysteine levels decreased significantly. There were no moderate or severe adverse events reported.

Comparison to another promising chemopreventive drug regimen that includes a retinoid, "our complete response rate is lower than the one reported in a smaller population," the authors write. Nevertheless, folate "is characterized by a lower grade of toxicity," and there was no progression of disease.

These results suggest, according to the researchers, "folate supplementation, alone or in combination with other chemopreventive drugs, could effectively reduce the risk of progression in an already genetically altered mucosa, especially in patients with hypofolatemia."


###
Article: "Pilot Phase IIA Study for Evaluation of the Efficacy of Folic Acid in the Treatment of Laryngeal Leucoplakia," Giovanni Almadori, Francesco Bussu, Pierluigi Navarra, Jacopo Galli, Gaetano Paludetti, Bruno Giardina, Maurizio Maurizi, CANCER; Published Online: June 12, 2006 (DOI: 10.1002/cncr.22003); Print Issue Date: July 15, 2006.
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PostPosted: Thu Nov 30, 2006 2:07 pm    Post subject: Einstein researchers discover how a key dietary vitamin is a Reply with quote

Albert Einstein College of Medicine
30 November 2006

Einstein researchers discover how a key dietary vitamin is absorbed

Researchers at the Albert Einstein College of Medicine of Yeshiva University have found the mechanism by which the B vitamin folate—a crucially important nutrient—is absorbed by the intestinal tract. Their findings, published in the December 1 issue of the journal Cell, solve a longstanding mystery as to how folates in the diet are absorbed and pave the way for a genetic test that can save the lives of infants who lack the ability to absorb folate.

“We can’t live without folate,” says Dr. I. David Goldman, the study’s senior author and director of the Albert Einstein Cancer Center. “Adequate folate in our diet --and our small intestine’s ability to absorb it -- are crucial for synthesizing DNA and other important constituents of our bodies. Folate deficiency in the developing embryo can cause developmental nervous-system defects such as spina bifida. After birth, infants with folate deficiency can experience anemia, immune deficiency with severe infections, and neurological defects such as seizures and mental retardation. And in adults, folate deficiency has been associated with an increased risk of certain cancers.”

A water-soluble vitamin such as folate can’t readily penetrate the fatty membrane of cells. It needs a specialized uptake mechanism so it can be absorbed by intestinal cells and ultimately enter the bloodstream. The Einstein researchers identified the membrane protein, dubbed PCFT/HCP1, that transports folate molecules from the small intestine’s acidic milieu into intestinal cells. A study published last year aroused considerable scientific fanfare when it reported that this protein ferried heme linked to iron (which becomes hemoglobin when coupled with the protein globin) into intestinal cells. But the Einstein study shows that folate transport is the primary function of this protein.

The Einstein study also showed that a mutation in the PCFT/HCP1 gene is responsible for hereditary folate malabsorption, a rare but potentially fatal disorder. Infants born with this condition must be treated with high doses of folate to prevent severe anemia and neurological problems that can be fatal or cause irreversible damage. The researchers made the link between mutations in the folate transporter gene and hereditary folate malabsorption by studying a Puerto Rican family in which two children were affected by the condition.

“Families at risk for hereditary folate malabsorption now have a genetic test that can quickly detect this condition before birth or in their newborns,” says Dr. Goldman. “Rapid diagnosis of this disease will insure that these infants will be started on folate supplementation as soon as possible after birth.”

###
Other Einstein scientists involved in the research were Andong Qiu (the first author of the study), Michaela Jansen, Antoinette Sakaris, Sang Hee Min, Shrikanta Chattopadhyay, Eugenia Tsai and Rongbao Zhao. Dr. Claudio Sandoval of New York Medical College also contributed to the research.
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PostPosted: Fri Jan 26, 2007 1:54 pm    Post subject: Folic acid may prevent cleft lip and palate Reply with quote

NIH/National Institute of Environmental Health Sciences
26 January 2007

Folic acid may prevent cleft lip and palate

A new study finds that women who take folic acid supplements early in their pregnancy can substantially reduce their baby's chances of being born with a facial cleft.

Researchers at the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health, found that 0.4 milligrams (mg) a day of folic acid reduced by one third the baby's risk of isolated cleft lip (with or without cleft palate). Folic acid is a B vitamin found in leafy vegetables, citrus fruits, beans, and whole grains. It can also be taken as a vitamin supplement, and it is added to flour and other fortified foods. The recommended daily dietary allowance for folate for adults is 400 micrograms or 0.4 mg.

"These findings provide further evidence of the benefits of folic acid for women," said Allen J. Wilcox, M.D. Ph.D., lead NIEHS author on the new study published online in the British Medical Journal. "We already know that folic acid reduces the risk of neural tube defects, including spina bifida. Our research suggests that folic acid also helps prevent facial clefts, another common birth defect." In the United States, about one in every 750 babies is born with cleft lip and/or palate.

"Folic acid deficiency causes facial clefts in laboratory animals, so we had a good reason to focus on folic acid in our clefts study," said Wilcox. "It was one of our main hypotheses."

The researchers examined the association between facial clefts and mothers' intake of folic acid supplements, multivitamins, and folates in diet. The researchers found that folic acid supplementation of 400 micrograms or more per day reduced the risk of isolated cleft lip with or without cleft palate by one-third, but had no apparent effect on the risk of cleft palate alone.

"A mother's nutrition during pregnancy is clearly an environmental factor that can affect the health of her fetus," said NIEHS Director David A. Schwartz, M.D. The NIEHS researchers are continuing to analyze their data for evidence of other environmental exposures that increase the risk of facial clefts.

This population-based study was conducted in Norway, which has one of the highest rates of facial clefts in Europe and does not allow foods to be fortified with folic acid. The investigators contacted all families of newborn infants with clefts (either cleft lip with or without cleft palate (CLP) or cleft palate only (CPO)) born between 1996 and 2001 in Norway. The study included 377 babies with CLP and 196 with CLO; as well as 763 control babies randomly selected from all live births in Norway.

The researchers mailed two questionnaires to each of the mothers participating in the study. The first questionnaire mailed soon after delivery focused on general health information, including demographics, reproductive history and information about environmental exposures including smoking, alcohol and vitamins; whereas the second questionnaire focused on nutrition and diet during the pregnancy. Mothers who reported taking folic acid supplements and or multivitamins were asked to send in their empty bottles or labels to confirm dosage.

The nutrition questionnaire included questions on mothers' fruit and vegetable consumption during the first three months of pregnancy.

The researchers estimated that 22 percent of isolated CLP cases in Norway could be averted if all pregnant women took 0.4 mg of folic acid per day.


###
In addition to funding from NIEHS, this research was supported by the Johan Throne Holst Foundation for Nutrition Research, and the Thematic Perinatal Nutrition at the Medical Facility of University of Oslo, Norway. Researchers at the University of Bergen, the University of Oslo, and the Departments of Plastic Surgery in Oslo and Bergen, Norway, also contributed to this study.

The National Institute of Environmental Health Sciences (NIEHS), a component of the National Institutes of Health, supports research to understand the effects of the environment on human health. For more information on environmental health topics, please visit our website at http://www.niehs.nih.gov/.

The National Institutes of Health (NIH) — The Nation's Medical Research Agency — includes 27 Institutes and Centers and is a component of the U. S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical, and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov.

Reference: Wilcox AJ, Lie RT, Solvoll K, Taylor J, McConnaughey DR, Abyholm F, Vindenes H, Vollset SE, Drevon CA. "Folic Acid Supplements and the risk of facial clefts: A National population-based control study." British Medical Journal, 2007.
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PostPosted: Fri Mar 23, 2007 2:57 pm    Post subject: MIT biologists solve vitamin puzzle Reply with quote

MIT biologists solve vitamin puzzle
Anne Trafton, MIT News Office
March 21, 2007

Solving a mystery that has puzzled scientists for decades, MIT and Harvard researchers have discovered the final piece of the synthesis pathway of vitamin B12--the only vitamin synthesized exclusively by microorganisms.

B12, the most chemically complex of all vitamins, is essential for human health. Four Nobel Prizes have been awarded for research related to B12, but one fragment of the molecule remained an enigma--until now.

The researchers report that a single enzyme synthesizes the fragment, and they outline a novel reaction mechanism that requires cannibalization of another vitamin.

The work, which has roots in an MIT undergraduate teaching laboratory, "completes a piece of our understanding of a process very fundamental to life," said Graham Walker, MIT professor of biology and senior author of a paper on the work that will appear in the March 22 online edition of Nature.

Vitamin B12 is produced by soil microbes that live in symbiotic relationships with plant roots. During the 1980s, an undergraduate research course taught by Walker resulted in a novel method for identifying mutant strains of a soil microbe that could not form a symbiotic relationship with a plant.

Walker's team has now found that one such mutant has a defective form of an enzyme known as BluB that leaves it unable to synthesize B12.

BluB catalyzes the formation of the B12 fragment known as DMB, which joins with another fragment, produced by a separate pathway, to form the vitamin. One of several possible reasons why it took so long to identify BluB is that some bacteria lacking the enzyme can form DMB through an alternate pathway, Walker said.

One of the most unusual aspects of BluB-catalyzed synthesis is its cannibalization of a cofactor derived from another vitamin, B2. During the reaction, the B2 cofactor is split into more than two fragments, one of which becomes DMB.

Normally, the B2-derived cofactor would assist in a reaction by temporarily holding electrons and then giving them away. Such cofactors are not consumed in the reaction.

Cannibalization of a cofactor has very rarely been observed before in vitamin synthesis or any type of biosynthetic pathway, says Michiko Taga, an MIT postdoctoral fellow in Walker's lab and lead co-author of the Nature paper.

"There are almost no other examples where the cofactor is used as a substrate," she said.

One early clue to BluB's function was that a gene related to it is located near several other genes involved in B12 synthesis in a different bacterium. Still, the researchers were not convinced that one enzyme could perform all of the complicated chemistry needed to produce DMB.

"It looked like a number of things had to happen in order to make the DMB," said Walker. "We originally thought that BluB might be just one of several enzymes involved in DMB synthesis."

Therefore, it came as a surprise when Taga isolated the BluB protein and showed that it could make DMB all by itself.

Nicholas Larsen, lead co-author and a former college classmate of Taga's now at Harvard Medical School, did a crystallographic analysis of the protein after Taga told him about her research over coffee one day. The protein structure he developed clearly shows the "pocket" of BluB where the DMB synthesis reaction takes place.

Still to be explored is the question of why soil bacteria synthesize B12 at all, Walker said. Soil microorganisms don't require B12 to survive, and the plants they attach themselves to don't need it either, so he speculates that synthesizing B12 may enable the bacteria to withstand "challenges" made by the plants during the formation of the symbiotic relationship.

More than 30 genes are involved in vitamin B12 synthesis, and "that's a lot to carry around if you don't need to make it," Walker said.

The full implications of the new research will probably not be known for some years, which is often the case with basic research, Walker said. "I've been in many other situations in research where we did something very basic and did not immediately realize the importance of it, and subsequently the implications were found to be much more broad-reaching," he said.

Other authors on the paper are Annaleise Howard-Jones, a postdoctoral fellow at Harvard Medical School, and Christopher Walsh, professor of biological chemistry and molecular pharmacology at Harvard Medical School.

The research was funded by the National Institutes of Health and the Jane Coffin Childs Memorial Fund for Medical Research.
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PostPosted: Fri Jun 01, 2007 9:42 am    Post subject: Dietary vitamin B6, B12 and folate, may decrease pancreatic Reply with quote

American Association for Cancer Research
1 June 2007

Dietary vitamin B6, B12 and folate, may decrease pancreatic cancer risk among lean people
PHILADELPHIA − Researchers exploring the notion that certain nutrients might protect against pancreatic cancer found that lean individuals who got most of these nutrients from food were protected against developing cancer. The study also suggests this protective effect does not hold true if the nutrients come from vitamin supplements.

In a study published in the June 1 issue of Cancer Research, a journal of the American Association for Cancer Research, investigators combined data from four large studies and found that people who were at or below normal body weight decreased their risk for developing pancreatic cancer if they took in high levels of vitamin B6, vitamin B12, and folate from food. The study determined that their risk was 81 percent, 73 percent, and 59 percent lower, vitamin B6, vitamin B12, and folate respectively, compared with participants who did not eat as much of these nutrients or who weighed more. According to the researchers, that was the only statistically significant finding from the study, which is the largest yet to look at these nutrients and pancreatic cancer risk.

“All we can say is that a person who has reason to be concerned about their risk of developing this cancer, which is relatively rare but quite deadly, should maintain a normal weight and eat their fruit and vegetables,” said the study’s lead investigator, Eva Schernhammer, M.D., Dr.P.H., an assistant professor of medicine at Harvard Medical School.

The researchers also say that they uncovered another interesting trend − that some people who received these nutrients from multivitamin pills had an increased risk of developing the disease. According to the researchers, individuals who said they used multivitamins, and whose blood showed traces of these nutrients, had a 139 percent increased relative risk of developing pancreatic cancer.

“This is a preliminary, but intriguing, finding because it suggests that something in the vitamins may fuel pancreatic cancer growth,” Dr. Schernhammer said.

This isn’t the first study to suggest that folate, and vitamin B6 and B12 − so called one carbon nutrients − are protective against pancreatic cancer if they come from food, but not if they come from multivitamins, Dr. Schernhammer said.

One large Finnish study found one carbon food nutrients were associated with a decreased risk of developing pancreatic cancer, but that vitamin pills were not helpful. Two other large American studies also found the food nutrients to be protective, but that vitamin use was associated with a higher, yet non-significant risk of developing the cancer.

In this study, researchers combined four large prospective cohort studies, The Women’s Health Initiative, and three from the Harvard School of Public Health: the Nurses’ Health Study, the Health Professionals Follow-up Study, and the Physician’s Health Study. From this large database, they performed a prospective nested case-control study to examine plasma concentrations of the nutrients from participants who had donated blood and answered questionnaires about their food intake and vitamin use before any cancer developed. Their analysis included 208 pancreatic cancer cases and 623 cancer-free control cases.

No one knows why vitamin pills may not help ward off cancer, or why, in this study, it might have a deleterious effect, Dr. Schernhammer said, but some research in animals suggests that “if there is a dormant tumor, folate and other similar vitamins may stimulate growth.” That might be especially true if a person did not take in enough of these nutrients consistently through diet, and then suddenly started taking multivitamins in an effort to become healthy, she said.

“People think that dietary intake of these nutrients reflects a lifelong healthy eating habit, and in those cases, these nutrients may be protective, but they could have an opposite effect if they are used in a person with an occult cancer,” Dr. Schernhammer said. “It might all depend on whether a person is cancer-free at the time they start using these nutrients.”

The same kind of association has been found with use of soy, which is an estrogen-rich food, she said. “Women who have eaten soy all their lives, such as people in Asia, have a reduced risk of developing breast cancer, but some studies have found that increased soy intake in women who have not eaten it before appears to be harmful.”

The researchers say their study cannot definitively say that one carbon nutrients either pose a benefit or a hazard to most people, but they note that it is the best analysis that can be performed outside of a randomized clinical trial

###
The study was funded by the National Institutes of Health.

The mission of the American Association for Cancer Research is to prevent and cure cancer. Founded in 1907, AACR is the world's oldest and largest professional organization dedicated to advancing cancer research. The membership includes nearly 26,000 basic, translational, and clinical researchers; health care professionals; and cancer survivors and advocates in the United States and more than 70 other countries. AACR marshals the full spectrum of expertise from the cancer community to accelerate progress in the prevention, diagnosis and treatment of cancer through high-quality scientific and educational programs. It funds innovative, meritorious research grants. The AACR Annual Meeting attracts more than 17,000 participants who share the latest discoveries and developments in the field. Special Conferences throughout the year present novel data across a wide variety of topics in cancer research, treatment, and patient care. AACR publishes five major peer-reviewed journals: Cancer Research; Clinical Cancer Research; Molecular Cancer Therapeutics; Molecular Cancer Research; and Cancer Epidemiology, Biomarkers & Prevention. Its most recent publication, CR, is a magazine for cancer survivors, patient advocates, their families, physicians, and scientists. It provides a forum for sharing essential, evidence-based information and perspectives on progress in cancer research, survivorship, and advocacy.
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PostPosted: Tue Jun 26, 2007 10:51 am    Post subject: Adding folic acid to bread could help in the fight against d Reply with quote

26 June 2007


University of York

Adding folic acid to bread could help in the fight against depression

A unique study by researchers at the University of York and Hull York Medical School has confirmed a link between depression and low levels of folate, a vitamin which comes from vegetables.

In research published in the July edition of the Journal of Epidemiology and Community Health, the York team led by Dr Simon Gilbody, concluded that there was a link between depression and low folate levels, following a review of 11 previous studies involving 15,315 participants.

"Although the research does not prove that low folate causes depression, we can now be sure that the two are linked"
Dr Simon GilbodyLast month, the Food Standards Agency recommended to UK Health Ministers the introduction of mandatory fortification of either bread or flour with folic acid to prevent neural tube defects, which can result in miscarriage, neonatal death or lifelong disability. The York study suggests that the measure may also help in the fight against depression.

Dr Gilbody said: "Our study is unique in that for the first time all the relevant evidence in this controversial area has been brought together. Although the research does not prove that low folate causes depression, we can now be sure that the two are linked. Interestingly, there is also some trial evidence that suggests folic acid supplements can benefit people with depression. We recommend that large trials should be carried out to further test this suggestion."

Recent research from the same team published in the American Journal of Epidemiology has also proved that people with depression commonly have a gene that means that they process folate less efficiently. Folate is linked to the production of some of the 'feel good' chemicals in the brain, such as serotonin. The identification of this gene provides a plausible explanation as to why folic acid supplements may help people with depression.

For further information contact Ms Rachel Richardson, tel: 01904 321863, email: cr14@york.ac.uk or Dr Simon Gilbody, Tel: 01904 321370; email: sg519@york.ac.uk, mobile 07740 286588.

ENDS

Notes for Editors
Depression will soon become the second leading cause of disability worldwide. It affects between 5% and 10% of individuals and is the third most common reason for consultation in primary care.
Gilbody S, Lightfoot T and Sheldon T. ‘Is low folate a risk factor for depression? A meta-analysis and exploration of heterogeneity’. Journal of Epidemiology and Community Health 2007; 61: 631-637.The article is available at: jech.bmj.com/cgi/content/full/61/7/631.
Gilbody S, Lewis S and Lightfoot T. ‘MTHFR polymorphisms and psychiatric disorders: a HuGE review’. American Journal of Epidemiology 2007; 165: 1-13.
The University of York’s Department of Health Sciences is a large multi-disciplinary department, offering a broad range of taught and research programmes in the health care field, including nursing. It aims to develop the role of scientific evidence in health and health care through high quality research, teaching and other forms of dissemination.
The Hull York Medical School is a partnership between the Universities of York and Hull. Drawing on the expertise of both universities, it opened in 2003 and has already developed an enviable reputation for medical research and undergraduate teaching.
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PostPosted: Tue Jul 10, 2007 7:54 am    Post subject: Researchers probe risks, benefits of folic acid fortificatio Reply with quote

Tufts University, Health Sciences
10 July 2007

Researchers probe risks, benefits of folic acid fortification
Friedman Nutrition Notes

BOSTON — Since the institution of nationwide folic acid fortification of enriched grains in the mid 1990s, the number of infants born in the United States and Canada with neural tube defects has declined by 20 percent to 50 percent. Concurrent with the institution of fortification, however, the rate at which new cases of colorectal cancer were diagnosed in men and women increased, report researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging (USDA HNRCA) at Tufts University. Joel Mason, MD, director of the USDA HNRCA’s Vitamins and Carcinogenesis Laboratory, and colleagues analyze the temporal association between folic acid fortification and the rise in colorectal cancer rates, and present their resulting hypothesis in an article in the July issue of Cancer Epidemiology Biomarkers & Prevention.

“Nationwide fortification of enriched grains is generally considered one of the greatest advances in public health policy,” says Mason, who is also an associate professor at the Friedman School of Nutrition Science and Policy at Tufts. “But since the time that the food supply in North America was fortified with folic acid, we have been experiencing four to six additional cases of colorectal cancer for every 100,000 individuals each year compared to the trends that existed before fortification.

“Our analysis suggests that this increase is not explained by chance or by increased cancer screening. Therefore, it is important to analyze risks and benefits of fortification, and encourage scientific debate in countries that are considering instituting or enhancing folic acid fortification.”

Mason and colleagues analyzed data from national cancer registries, one in the United States and another in Canada. The US data were derived from the nationwide Surveillance Epidemiology and End Results (SEER) registry that publishes cancer occurrence rates and survival data, covering approximately 26 percent of the population. The Canadian data were obtained from Canadian Cancer Statistics, an annual publication by the Canadian Cancer Society and the National Cancer Institute of Canada.

In 1996 and 1998, there were abrupt reversals in the 15-year downward trends in colorectal cancer rates in the United States and Canada, respectively. Since peaking in 1998 in the United States and in 2000 in Canada, the rates have not returned to their earlier levels. Although folic acid fortification of enriched grains – including bread, cereal, flour, rice, and pasta – did not become mandatory until 1998, large food companies began voluntary fortification in 1996, first in the United States and later in Canada.

Folic acid is the synthetic form of folate, a B vitamin that is essential for cell growth. After intestinal absorption, folic acid is converted to methyltetrahydrofolate, found naturally in foods such as leafy green vegetables, legumes and citrus fruits. “The body's response to folic acid appears to be complex,” says Mason. “While fortification of the food supply is clearly beneficial for women of child-bearing age and their offspring, it is possible that it may, coincidentally, be linked to the increase in colorectal cancer rates. Our report is intended to create a foundation upon which to further explore that possibility.”

As Mason and colleagues note, there is a compelling body of scientific evidence suggesting that habitually high intakes of dietary folate are protective against colorectal cancer. Mason explains, however, that “There are several reasons why we may have inadvertently created the opposite effect with folic acid fortification. First, folate’s pivotal role in DNA synthesis also makes it a potential growth factor for cancerous or pre-cancerous cells, and when administered in large quantities to individuals who unknowingly harbor cancer cells, it could paradoxically enhance cancer development. The addition of substantial quantities of folic acid into the foodstream may have facilitated the transformation of benign growths into cancers, or small cancers into larger ones,” he says. “Second, the fact that a synthetic form of folate is used for fortification may be important,” suggests Mason. “As the total amount of folic acid ingested increases, the mechanism that converts folic acid to methyltetrahydrofolate can become saturated. The leftover folic acid in the circulation might have detrimental effects, as it is not a natural form of the vitamin.”

At a time when many countries are debating whether or not to institute or enhance folic acid fortification, Mason and colleagues urge caution and debate. “We must examine the effects of folic acid fortification on the population as a whole, which includes better defining the nature of the relationship between folic acid fortification and colorectal cancer,” says Mason. “Improved monitoring and further research in this field is important to our understanding of the long-term public health effects of fortification.”


###
Mason JB, Dickstein A, Jacques PF, Haggarty P, Selhub J, Dallal G, Rosenberg IH. Cancer Epidemiology Biomarkers & Prevention. 2007 (July); 16(7):1-5. “A Temporal Association between Folic Acid Fortification and a Rise in Colorectal Cancer Rates May be Illuminating Important Biological Principles: a Hypothesis.”

The Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University is the only independent school of nutrition in the United States. The school’s eight centers, which focus on questions relating to famine, hunger, poverty, and communications, are renowned for the application of scientific research to national and international policy. For two decades, the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University has studied the relationship between good nutrition and good health in aging populations. Tufts research scientists work with federal agencies to establish the USDA Dietary Guidelines, the Dietary Reference Intakes, and other significant public policies.

If you are a member of the media interested in learning more about this topic, or speaking with a faculty member at the Friedman School of Nutrition Science and Policy at Tufts University, or another Tufts health sciences researcher, please contact Siobhan Gallagher at 617-636-6586 or Christine Fennelly at 617-636-3707.
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PostPosted: Tue Aug 07, 2007 9:52 am    Post subject: Researchers find vitamin B1 deficiency key to vascular probl Reply with quote

Researchers find vitamin B1 deficiency key to vascular problems for diabetic patients
Warwick Medical School, University of Warwick
7 August 2007

Researchers at Warwick Medical School, University of Warwick, have discovered that deficiency of thiamine – Vitamin B1 - may be key to a range of vascular problems for people with diabetes. They have also solved the mystery as to why thiamine deficiency in diabetes had remained hidden until now.

Diabetes is increasing in incidence in the UK and elsewhere and one of the most significant health problems associated with the condition are vascular complications: microvascular complications, such as damage to the kidney, retina and nerves in arms and legs; and macrovascular complications, such as heart disease and stroke.

The University of Warwick researchers, led by Professor Paul Thornalley, have shown conclusively that diabetic patients are thiamine deficient in blood plasma. They were also able to solve the mystery of what was happening to thiamine in diabetic patients and connect it more closely to vascular complications in diabetic patients.

In a paper entitled "High prevalence of low plasma thiamine concentration in diabetes linked to a marker of vascular disease", published in Diabetologia on 4th August, the team found that thiamine concentration in blood plasma was decreased 76% in type 1 diabetic patients and 75% in type 2 diabetic patients. This significant decrease had been previously masked as the conventional way of assessing levels of thiamine status was to measure the activity of an enzyme called transketolase in red blood cells. Past studies had seen normal activity of this enzyme and assumed normal levels of thiamine when in fact the normal enzyme activity was due to increased amounts of two proteins THTR-1 and RFC-1 that help transport thiamine into red blood cells. The increased levels of these proteins were a direct response to there being a deficiency of thiamine in the body.

The researchers found that the decreased availability of thiamine in vascular cells in diabetes was linked to a marker of microvascular and macrovascular complications. It likely reflects problems in endothelial cells (endothelial cells line the body’s entire circulatory system) and increased risk of atherosclerosis (chronic inflammatuion in the artery walls).

The researchers found that the decreased plasma thiamine concentration in clinical diabetes was not due to a deficiency of dietary input of thiamine. Rather it was due to a profound increased rate of removal of thiamine from the blood into the urine.

The researchers feel that important areas for future study are: confirmation of low plasma thiamine concentrations in diabetic populations of other countries independent of local diet; the evaluation of thiamine and thiamine derivatives to correct low plasma thiamine concentration in diabetes, reverse vascular dysfunction and prevent vascular complications; and investigation of the mechanism of increased removal of thiamine from the blood into the urine in diabetes.

Note for Editors: This study was funded by a project grant from Diabetes UK

Paper online at: http://www.springerlink.com/co.....b&pi=1
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PostPosted: Mon Oct 08, 2007 3:00 pm    Post subject: Diet for small planet may be most efficient if it includes d Reply with quote

Oct. 4, 2007

Diet for small planet may be most efficient if it includes dairy and a little meat, Cornell researchers report

By Susan Lang

A low-fat vegetarian diet is very efficient in terms of how much land is needed to support it. But adding some dairy products and a limited amount of meat may actually increase this efficiency, Cornell researchers suggest.

For the full article:

http://www.news.cornell.edu/st.....nt.sl.html
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PostPosted: Sun Mar 23, 2008 1:29 pm    Post subject: The Costs of Meat and Fish Reply with quote

Week of March 22, 2008; Vol. 173, No. 12

The Costs of Meat and Fish
The animal protein in our diets can have a high environmental cost
Janet Raloff

"Can Meat and Fish Consumption Be Sustainable?" That's the provocative title of a press release just sent to us by the Worldwatch Institute, a small but venerable think tank that focuses on natural resource issues.

It's also the theme of a chapter in Worldwatch's 2008 State of the World report, its 25th annual book-length analysis of resource trends and economics. Here, its analysts take on the substantial—and often hidden—costs of producing animal protein to satisfy human hunger.

For the full article:

http://sciencenews.org/articles/20080322/food.asp
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PostPosted: Mon Sep 01, 2008 9:29 am    Post subject: New evidence on folic acid in the diet and colon cancer Reply with quote

New evidence on folic acid in the diet and colon cancer
1 September 2008
Journal of Proteome Research

Researchers in the United Kingdom and Texas are reporting a new, more detailed explanation for the link between low folate intake and an increased risk for colon cancer, the second leading cause of cancer death in the United States. Their study, which reinforces the importance of folate in a healthy diet, is scheduled for the current (August) issue of ACS' monthly Journal of Proteome Research.

Susan Duthie and colleagues note that researchers have known for years that a deficiency of folate, one of the B vitamins commonly called folic acid, increases the risk of birth defects. As a result, manufacturers enrich some foods with folate. Scientists also have found that low folate in the diet increases the risk of developing colon cancer in adults. However, scientists lack an adequate explanation of how folate depletion affects the genes, proteins, and cells involved in cancer.

In this new research, scientists grew human colon cells in folate-depleted and folate-enriched tissue culture. They found that folate depletion caused increased DNA damage and a cascade of other biological changes linked to an increased cancer risk.

ARTICLE #2 FOR IMMEDIATE RELEASE
"The Response of Human Colonocytes to Folate Deficiency in Vitro: Functional and Proteomic Analyses"

DOWNLOAD FULL TEXT ARTICLE
http://dx.doi.org/10.1021/pr700751y
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