FOOD WE EAT MIGHT CONTROL OUR GENES
“You are what you eat.” The old adage has for decades weighed on the minds of consumers who fret over responsible food choices. Yet what if it was literally true? What if material from our food actually made its way into the innermost control centres of our cells, taking charge of fundamental gene expression?
That is in fact what happens, according to a recent study of plant-animal microRNA transfer led by Chen-Yu Zhang of Nanjing University in China. MicroRNAs are short sequences of nucleotides—the building blocks of genetic material. Although microRNAs do not code for proteins, they prevent specific genes from giving rise to the proteins they encode. Blood samples from 21 volunteers were tested for the presence of microRNAs from crop plants, such as rice, wheat, potatoes and cabbage.
The results, published in the journal Cell Research, showed that the subjects’ bloodstream contained approximately 30 different microRNAs from commonly eaten plants. It appears that they can also alter cell function: a specific rice microRNA was shown to bind to and inhibit the activity of receptors controlling the removal of LDL—“bad” cholesterol—from the bloodstream. Like vitamins and minerals, microRNA may represent a previously unrecognised type of functional molecule obtained from food. Scientific American. December 2011
CAN WE FEED THE WORLD AND SUSTAIN THE PLANET?
A five-step global plan could double food production by 2050 while greatly reducing environmental damage.
Right now about one billion people suffer from chronic hunger. The world’s farmers grow enough food to feed them, but it is not properly distributed and, even if it were, many cannot afford it, because prices are escalating.
But another challenge looms. By 2050 the world’s population will increase by two billion or three billion, which will likely double the demand for food, according to several studies. Demand will also rise because many more people will have higher incomes, which means they will eat more, especially meat. Increasing use of cropland for biofuels will put additional demands on our farms. So even if we solve today’s problems of poverty and access—a daunting task—we will also have to produce twice as much to guarantee adequate supply worldwide.
Hence, the world must solve three food problems simultaneously: end hunger, double food production by 2050, and do both while drastically reducing agriculture’s damage to the environment.
Five solutions, pursued together, can achieve these goals: stop agriculture from consuming more tropical land, boost the productivity of farms that have the lowest yields, raise the efficiency of water and fertiliser use world wide, reduce per capita meat consumption and reduce waste in food production and distribution.
A system for certifying foods based on how well each one delivers nutrition and food security and limits environmental and social costs would help the public choose products that push agriculture in a more sustainable direction. November 2011 Scientific American Magazine. Pg 42.
CLIMATE CHANGE: KNOWNS AND UNKNOWNS
We know the planet is warming, and human activity is largely responsible. But how much hotter is Earth on course to become? What will the global and local effects be? How will it affect our lives? Find out what we know – and don't know – about climate change in our special report. New Scientist Weekly Newsletter – 24 Oct. 2011
ALCOHOL CONSUMPTION RELATED TO BREAST CANCER RISK
A study published in the Journal of the American Medical Association (JAMA) shows that consuming 3–6 alcoholic drinks per week may increase the risk of breast cancer.
The researchers examined the association of breast cancer with alcohol consumption during adult life, including quantity, frequency, and age at consumption. The study included 105,986 women enrolled in the Nurses’ Health Study who were followed up from 1980 until 2008 with an early adult alcohol assessment and eight updated alcohol assessments. The primary outcome the researchers measured was the risk of developing invasive breast cancer.
During the follow-up period, there were 7,690 cases of invasive breast cancer diagnosed among the study participants. Analyses of data indicated that a low level of alcohol consumption (5.0–9.9 g/day, equivalent to 3–6 glasses of wine per week) was modestly but statistically significantly associated with a 15% increased risk of breast cancer. In addition, women who consumed at least 30 g of alcohol daily on average (at least 2 drinks per day) had a 51% increased risk of breast cancer compared with women who never consumed alcohol.
The researchers also found that when examined separately, alcohol consumption levels at ages 18–40 years and after age 40 years were both strongly associated with breast cancer risk. The association with drinking in early adult life still persisted even after controlling for alcohol intake after age 40 years. Binge drinking, but not frequency of drinking, was also associated with breast cancer risk after controlling for cumulative alcohol intake.
The authors add that although the exact mechanism for the association between alcohol consumption and breast cancer is not known, one probable explanation may involve alcohol’s effects on circulating estrogen levels. IFT Weekly Newsletter. 2 Nov 2011
Changing HDL and LDL levels does not always alter heart disease or stroke risk.
Most people who are even a little bit concerned about their cholesterol know that there is a “good” kind—known as HDL—and a “bad” kind—known as LDL. Research has shown that the higher the amount of HDL and the lower the amount of LDL in the blood, the less likely a person is to suffer a heart attack or stroke. As for the one in six Americans with unhealthy cholesterol levels, well, they can always hope to change their luck with a cholesterol-changing medication or two. Or can they?
Two major clinical trials in the past three years have greatly complicated the picture for these and perhaps other folks. The first study, from 2008, shows that lowering LDL levels does not always decrease the risk of having a heart attack. Similarly, results from the second study, released in the spring of this year, show that raising HDL levels does not always translate into fewer heart attacks or strokes.
These perplexing findings do not mean that people should stop taking their cholesterol drugs. The results have, however, underscored the danger of indulging in a common logical shortcut in medical thinking—assuming that artificially producing normal test results in a patient is the same as conferring good health on that patient. For one thing, drugs typically do not mimic normal conditions perfectly. For another, heart attacks and strokes occur after a complex series of processes that may take years to unfold. Simply altering one of these processes does not necessarily fix the whole problem. Scientific American. November 2011
Snippets - contributions are welcome. Edited and produced by Dr. B Cole. – firstname.lastname@example.org / Fx 011 660 6444 with the help of the Northern Branch Committee.