SNIPPETS

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Volume 16. Number 5. 2011
013-075NPO



TECHNIQUE ALLOWS RESEARCHERS TO IDENTIFY KEY MAIZE GENES FOR INCREASED YIELD

http://www.news.cornell.edu/stories/Jan11/BucklerLeaf.html
A study published online in Nature Genetics on Jan. 9 has identified the genes related to leaf angle in corn (maize) a key trait for planting crops closer together, which has led to an eight-fold increase in yield since the early 1900s. The study, led by researchers from Cornell and the U.S. Department of Agriculture -- Agricultural Research Service (USDA-ARS) at Cornell and North Carolina State University, is the first to relate genetic variation across the entire maize genome to traits in a genomewide association study. The researchers have so far located 1.6 million sites on the maize genome where one individual may vary from another, and they used those sites to identify the genes related to changes in leaf angle that have allowed greater crop density.
Yield increases have mostly resulted from adaptations made by breeders to maize so crops can be planted closer together. Along with changes in roots and nutrient uptake that also play roles in increased crop densities; the leaves of maize crop plants have become more upright to maintain access to sunlight in crowded plots. BIOLINES AUG 2011

GOING ORGANIC CUTS POULTRY FARMS’ “SUPERBUG” BACTERIA IN SINGLE GENERATION

The government has come under fire this week for revelations that it knew about antibiotic resistant Salmonella in poultry products that has killed at least one person and sickened more than 100 across the country. Although this is one of the largest turkey recalls—affecting some 16 329 tonnes of ground turkey—the prevalence of bacteria that is immune to common drugs is on the rise on animal farms, which is where the bulk of U.S. antibiotics get used.
But by going organic, poultry farms can cut the amount of antibiotic resistant bacteria in a single generation by nearly five times, according to a new study published online this week in Environmental Health Perspectives.
“We were surprised to see that the differences were so significant across several different classes of antibiotics. Even in the very first flock that was produced after the transition to organic standards,” Amy Sapkota, of the University of Maryland School of Public Health, and co-author of the new study, said in a prepared statement.
The team studied Enterococci bacteria, which are common in poultry and are also frequently found in hospitals and can become immune to antibiotic treatments, making them “a good model for studying the impact of changes in antibiotic use on farms,” Sapkota said. In humans, the bug can cause urinary tract infections, blood infection, inflammation of the heart and even meningitis. And when these bacteria become resistant to antibiotics, infections are harder—and sometimes impossible—to treat with available drugs.
Farmers can’t expect to get rid of the bacteria altogether, but by cutting down on the birds’ exposure to antibiotics, the amount of bacteria that builds up resistance is not only possible, but also quick. The first generation of poultry that was raised organically at previously conventional farms had way less of the superbug breed of bacteria. Tests of the feed, water and poultry litter showed that on 10 newly organic farms, about 17 percent of the Enterococci bacteria was resistant to multiple classes of antibiotics, whereas on 10 farms that continued to raise their birds via conventional methods with prophylactic antibiotic use, some 84 percent of the bacteria had developed multi-drug resistance.
Scientific American Blogs. 12 August 2011 (Is there something to be said for Organic after all? Ed.)
http://blogs.scientificamerican.com/observations/2011/08/12/going-organic-cuts-poultry-farms-superbug-bacteria-in-single-generation/?WT_mc_id=SA_CAT_HLTH_20110816

BEAT GLUTTONY WITH GULLIBILITY

Eating-behaviour expert Brian Wansink offers tips on fooling yourself into eating less.
Our eyes are bigger than our stomachs. And visual perception plays a big fat role in eating—often without our realising it. So says Brian Wansink, a professor of consumer behavior and nutritional science at Cornell. His research has shown that people eat more when their food is served on larger dishes. Because lots of folks use an empty plate—rather than a full stomach—as a cue to put down their fork. Wansink reviewed his findings recently at the American Psychological Association meeting in Washington.
In one experiment, he had unsuspecting subjects eat soup from bowls that continually refilled from the bottom. And volunteers who unknowingly ate from these bowls consumed on average 73 percent more soup than those who had had a finite supply. But both groups thought they had eaten about the same amount. Scientific American Podcast. 9 august 2011
http://www.scientificamerican.com/podcast/episode.cfm?id=beat-gluttony-with-gullibility-11-08-09&WT.mc_id=SA_CAT_HLTH_20110816

LOW FAT CHOCOLATE

The problem of obesity is supposed to be connected to the high-caloric snack foods consumed between meals or as a treat rather than as a part of a meal. Jenifer Norton at the University of Birmingham believes the idea of low-fat chocolate shows promises.
Its main ingredients are cocoa butter, cocoa solids, sugar and in milk chocolate, milk or milk powder. The main fat in chocolate, and therefore the main source of calories, is the cocoa butter. The ultimate in low-calorie ingredient is water. As in the low-fat margarine, which is water-in-oil emulsion, the researcher started by making an emulsion of water and cocoa butter. At earlier attempts the emulsion of cocoa butter and water was not stable. The researcher overcame this problem by adding sugar to make the emulsion stable. Now she has created a stable cocoa butter with up to 60% water. Low fat chocolate is now undergoing tests for its storage properties. The researcher expects to have a commercial product by the end of three years. SciTech in Brief. Vol. 6, Issue 1.

THE ‘DIRTY DOZEN’ FRUITS, VEGGIES NOT SO DIRTY?

Since 1995, the Environmental Working Group (EWG), a U.S.-based environmental advocacy organization, has developed an annual list of fruits and vegetables, frequently referred to as the “Dirty Dozen,” suspected of having the greatest potential for contamination with residues of pesticides. For these specified produce items, the EWG recommends consumers choose organic forms. The June 2010 list published by the EWG contains the following fruits and veggies: celery, peaches, strawberries, apples, blueberries, nectarines, bell peppers, spinach, cherries, kale, potatoes, and grapes. According to the EWG release, “consumers can lower their pesticide consumption by nearly four-fifths by avoiding conventionally grown varieties of the 12 most contaminated fruits and vegetables.”
However, in a recent study published in the Journal of Toxicology, Carl Winter and Josh Katz from the University of California question EWG’s statement, since the methodology doesn’t include quantifying consumer exposure to pesticide residues in the 12 foods. To more accurately assess the potential health impacts from consumer exposure to pesticide residues from the “Dirty Dozen,” Winter and Katz utilized a probabilistic modeling approach to estimate exposures. In addition, they compared the exposure estimates with toxicological endpoints to determine the health significance of such exposures.
The researchers analyzed USDA Pesticide Data Program (PDP) results to identify the 10 most frequently detected pesticides on each of the 12 foods. Then, the probabilistic modeling method was used to determine the mean exposure of each pesticide for each food. The researchers compared this mean exposure estimate to the U.S. Environmental Protection Agency’s (EPA) chronic reference dose, which is the estimated amount of a chemical that a person could be exposed to on a daily basis throughout the person’s lifetime without causing harm.
Winter and Katz found that the EPA’s reference doses for each of the pesticides exceeded the mean exposure estimates in all cases. In addition, the reference doses were more than 1,000 times higher than the exposure estimates in more than 90% of the comparisons.
“Such findings suggest that the potential consumer risks from exposure to the most frequently detected pesticides on the ‘Dirty Dozen’ list of foods are negligible and cast doubts as to how consumers avoiding conventional forms of such produce items are improving their health status,” wrote the authors.
Specifically, the researchers found that blueberries, cherries, and kale had reference doses that were 30,000 times higher than the exposure estimates for all of the 10 most frequently detected pesticides. Therefore, they concluded that these three commodities shouldn’t appear on the “Dirty Dozen” list. In addition, the researchers stressed that organic produce is not pesticide-free produce. In fact, while conventional produce was between 2.9–4.8 times more likely to contain detectable pesticide residues than organic produce, 23% of organic food samples still tested positive for pesticide residues. IFT Weekly Newsletter 10 Aug. 2011

ILLINOIS SCIENTISTS LEARN STARTLING NEW TRUTH ABOUT SUGAR

Flying in the face of years of scientific belief, University of Illinois researchers have demonstrated that sugar doesn't melt, it decomposes.
"This discovery is important to food scientists and candy lovers because it will give them yummier caramel flavours and more tantalising textures. It even gives the pharmaceutical industry a way to improve excipients, the proverbial spoonful of sugar that helps your medicine go down," said Shelly J. Schmidt, a University of Illinois professor of food chemistry.
In a presentation to the Institute of Food Technologists about the importance of the new discovery, Schmidt told the food scientists they could use the new findings to manipulate sugars and improve their products' flavour and consistency.
Candy makers will be able to use a predictable time-temperature relationship, as the dairy industry does in milk pasteurisation, to achieve better results, she said. Schmidt and graduate student Joo Won Lee didn't intend to turn an established rule of food science on its head. But they began to suspect that something was amiss when they couldn't get a constant melting point for sucrose in the work that they were doing.
The scientists determined that the melting point of sugar was heating-rate dependent.
"As soon as we detected melting, decomposition components of sucrose started showing up," she said.
To distinguish "melting" caused by decomposition from thermodynamic melting, the researchers have coined a new name--"apparent melting." Schmidt and her colleagues have shown that glucose and fructose are also apparent melting materials.
Source Press release: Shelly Schmidt, 217-333-6369, sjs@illinois.edu Jul. 25, 2011

SODIUM AND POTASSIUM INTAKE AND MORTALITY AMONG US ADULTS.

Prospective Data from the Third National Health and Nutrition Examination Survey
Background: Several epidemiologic studies suggested that higher sodium and lower potassium intakes were associated with increased risk of cardiovascular diseases (CVD). Few studies have examined joint effects of dietary sodium and potassium intake on risk of mortality.
Results: During a mean follow-up period of 14.8 years, we documented a total of 2270 deaths, including 825 CVD deaths and 443 IHD deaths. After multivariable adjustment, higher sodium intake was associated with increased all-cause mortality (hazard ratio [HR], 1.20; 95% confidence interval [CI], 1.03-1.41 per 1000 mg/d), whereas higher potassium intake was associated with lower mortality risk (HR, 0.80; 95% CI, 0.67-0.94 per 1000 mg/d). These findings did not differ significantly by sex, race/ethnicity, body mass index, hypertension status, education levels, or physical activity.
Conclusion: Our findings suggest that a higher sodium-potassium ratio is associated with significantly increased risk of CVD and all-cause mortality, and higher sodium intake is associated with increased total mortality in the general US population. Arch Intern Med. 2011;171(13):1183-1191. doi:10.1001/archinternmed.2011.257
(For your information http://www.dietandfitnesstoday.com/recommended-dietary-allowance.php? gives the RDA for adults as Na 1500 mg and P 4700 mg and one must note that the best sources of potassium are fresh fruit and vegetables. Ed.)

CHALLENGING THE ROLE OF ANTIOXIDANTS

A review paper in Journal of Agricultural and Food Chemistry challenges the food industry to reassess how it uses the term 'antioxidant' and challenges too the idea that antioxidants necessarily prevent cell damage and ageing by scavenging free radicals and oxygen containing chemicals. Citing almost 120 references, the six authors argue that the message that oxidative stress is the basis for chronic diseases and ageing (due to research from the 1950s) is not supported by more recent work. They state that accumulating evidence suggests that reactive oxygen species (ROS) exert essential metabolic functions and that removal of too many ROS can upset cell signalling pathways and actually increase the risk of chronic disease. The authors firmly conclude that the available scientific evidence does not necessarily support the assumption that all ROS present health risks and should be reduced to as low level as possible. They go on to say that this has implications for the fortification of foods with antioxidants, as well as for the consumption of many dietary supplements, arguing that some antioxidants may block beneficial actions of other physiological processes, and at high doses some antioxidants may be toxic. The authors present a clear case for exercising caution both in the use of antioxidants, and also in the promotion and description of ingredients that are deemed to have anti-oxidant properties.
http://pubs.acs.org/doi/abs/10.1021/jf2013875. Food e-News Edition 516 – 15 June 2011.

WHAT CONSUMERS NEED TO KNOW ABOUT OMEGA-3 FATTY ACIDS

A short communication entitled “omega-3 fatty acids. What consumers need to know” published in the journal Appetite has aimed to summarise the current understandings of fatty acid physiological metabolism and interaction. McManus et al. state that the general public is increasingly aware of the health benefits associated with consumption of omega-3 fatty acids. Omega-3 long chain polyunsaturated fatty acids (n-3 LC-PUFAs) are currently enjoying considerable commercial popularity as a result of consistent findings of health benefits associated with their consumption. Globally, the market for n-3 LC-PUFAs supplements is estimated at over US$700 million with growth rates of 8% per annum. However, consumers are typically unaware of differences in the efficacy of different omega-3 fatty acids and this lack of knowledge can result in consumers being misled within the marketplace. While there are three n-3 LC-PUFAs commonly found in food, evidence of health benefits is predominantly associated with the marine sourced n-3 LC-PUFAs: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The strongest associations between n-3 LC-PUFAs and health have been demonstrated with DHA intake and more recently with a dietary pattern that includes seafood. This indicates that marine based n-3 LC-PUFAs have a greater positive impact on health than non-marine sourced n-3 LC-PUFAs. It is thought that consumers are largely unaware of differences in efficacy of n-3 LC-PUFAs. Demonstrable evidence of health benefits associated with consumption of marine sourced n-3 LC-PUFAs, DHA and EPA, is strong and continues to mount. There is a need for a straightforward consumer communication strategy to inform consumers that consumption of diet that includes moderate levels of seafood is the simplest and best way to obtain the health benefits associated with n-3 LC-PUFA consumption. Health professionals can reduce the propensity for consumer misinformation by communicating the superior efficacy of marine sourced n-3 LC-PUFAs and the beneficial role of seafood within a balanced diet. Food e-News Edition 516 – 15 June 2011.

Snippets - contributions are welcome. Edited and produced by Dr. B Cole. – drcole@cybersmart.co.za / Fx 011 660 6444 with the help of the Northern Branch Committee.