Low Doses, Big Effects: Scientists Seek 'Fundamental Changes' in Testing, Regulation of Hormone-like Chemicals

Small doses can have big health effects.

That is a main finding of a report, three years in the making, published Wednesday by a team of 12 scientists who study hormone-altering chemicals.

Dozens of substances that can mimic or block estrogen, testosterone and other hormones are found in the environment, the food supply and consumer products, including plastics, pesticides and cosmetics. One of the biggest, longest-lasting controversies about these chemicals is whether the tiny doses that most people are exposed to are harmful.

In the new report, researchers led by Tufts University's Laura Vandenberg concluded after examining hundreds of studies that health effects "are remarkably common" when people or animals are exposed to low doses of endocrine-disrupting compounds. As examples, they provide evidence for several controversial chemicals, including bisphenol A, found in polycarbonate plastic, canned foods and paper receipts, and the pesticide atrazine, used in large volumes mainly on corn.

The scientists concluded that scientific evidence "clearly indicates that low doses cannot be ignored." They cited evidence of a wide range of health effects in people - from fetuses to aging adults - including links to infertility, cardiovascular disease, obesity, cancer and other disorders.

"Whether low doses of endocrine-disrupting compounds influence human disorders is no longer conjecture, as epidemiological studies show that environmental exposures are associated with human diseases and disabilities," they wrote. 

Scientists turn 'bad fat' good

Brown fat burns calories while white fat stores them 'Good' baby fat keeps adults slimMore obesity ops 'will save cash' Scientists say they have found a way to turn body fat into a better type of fat that burns off calories and weight.

The US Johns Hopkins team made the breakthrough in rats but believe the same could be done in humans, offering the hope of a new way to treat obesity.

Modifying the expression of a protein linked to appetite not only reduced the animals' calorie intake and weight, but also transformed their fat composition.

"Bad" white fat became "good" brown fat, Cell Metabolism journal reports.

Brown fat is abundant in babies, which they use as a power source to generate body heat, expending calories at the same time.

But as we age our brown fat largely disappears and gets replaced by "bad" white fat, which typically sits as a spare tyre around the waist.

Continue reading the main story“Start QuoteWe will need a lot more work to tease this out, but it could offer a feasible way to develop new treatments for obesity”

End QuoteUK obesity expert Dr Jeremy Tomlinson Experts have reasoned that stimulating the body to make more brown fat rather than white fat could be a helpful way to control weight and prevent obesity and its related health problems like type 2 diabetes.

Novel approach

Various teams have been searching for a way to do this, and Dr Sheng Bi and colleagues at the Johns Hopkins University School of Medicine believe they may have cracked it.

They designed an experiment to see if suppressing an appetite-stimulating protein called NPY would decrease body weight in rats.

When they silenced NPY in the brains of the rodents they found their appetite and food intake decreased.

Even when the rats were fed a very rich, high-fat diet they still managed to keep more weight off than rats who had fully functioning NPY.

The scientists then checked the fat composition of the rats and found an interesting change had occurred.

In the rats with silenced NPY expression, some of the bad white fat had been replaced with good brown fat.

The researchers are hopeful that it may be possible to achieve the same effect in people by injecting brown fat stem cells under the skin to burn white fat and stimulate weight loss.

Dr Bi said: "If we could get the human body to turn bad fat into good fat that burns calories instead of storing them, we could add a serious new tool to tackle the obesity epidemic.

"Only future research will tell us if that is possible."

Dr Jeremy Tomlinson, an expert at the University of Birmingham's Centre for Obesity Research, said: "This is exciting, novel and interesting.

"We will need a lot more work to tease this out, but it could offer a feasible way to develop new treatments for obesity."

Scientists say it's healthy to be nutty about walnuts

Eating raw walnuts gives the full benefits of antioxidants Walnuts are the healthiest of all the nuts and should be eaten more as part of a healthy diet, US scientists say.

Scientists from Pennsylvania told the American Chemical Society that walnuts contain the highest level of antioxidants compared to other nuts.

Antioxidants are known to help protect the body against disease.

The scientists said that all nuts have good nutritional qualities but walnuts are healthier than peanuts, almonds, pecans and pistachios.

Dr Joe Vinson, from the University of Scranton, analysed the antioxidant levels of nine different types of nuts and discovered that a handful of walnuts contained twice as many antioxidants as a handful of any other commonly eaten nut.

He found that these antioxidants were higher in quality and potency than in any other nut.

Antioxidants are good because they stop the chain reactions that damage cells in the body when oxidation occurs.

Roasted nuts

The antioxidants found in walnuts were also two to 15 times as powerful as vitamin E, which is known to protect the body against damaging natural chemicals involved in causing disease, the study says.

Nuts are known to be healthy and nutritious, containing high-quality protein, lots of vitamins and minerals as well as dietary fibre. They are also dairy and gluten-free.

Previous research has shown that regular consumption of small amounts of nuts can reduce the risk of heart disease, some types of cancer, type two diabetes and other health problems.

Dr Vinson said there was another advantage in choosing walnuts as a source of antioxidants: "The heat from roasting nuts generally reduces the quality of the antioxidants.

"People usually eat walnuts raw or unroasted, and get the full effectiveness of those antioxidants."

UN Scientists Say Emission Pledges Fall Well Short of Halting Climate Change

UN research shows that the pledges and promises made last year by 80 countries to reduce climate change emissions fall well short of what is needed to hold the global temperature rise to 2C and avoid the worst consequences of global warming.

The findings by 30 leading scientists suggest that if countries do everything they have promised, there will still be a 5bn tonne gap per year between their ambition and what the science says is needed. This gap, said the UN, is the equivalent of the emissions released by all the world's vehicles in a year. Many countries have committed themselves to holding temperature rises to no more than 2C (3.6F) by 2080 but to achieve this global emissions must be reduced from 56bn tonnes annually today to 44bn tonnes by 2020.

If only the weakest pledges made last year in the Copenhagen accord are implemented, emissions could be lowered to 53bn tonnes a year by 2020, leaving a gap of 9bn tonnes.

In the best case, says the report, emissions could drop to 49bn tonnes, reducing the gap to 5bn. But if nothing is done, then the emissions gap would rise to 12bn tonnes by 2020 - roughly what all the world's power stations emit.