Health, mind, and food
Reports of research on drugs tend to exaggerate the drugs’ benefits, making them sound better than they really are, according to an article and editorial being published today in The Journal of the American Medical Association.
Different foods require radically different amounts of water. To grow a kilogram of wheat requires around 1,000 litres. But it takes as much as 15,000 litres of water to produce a kilo of beef. The meaty diet of Americans and Europeans requires around 5,000 litres of water a day to produce. The vegetarian diets of Africa and Asia use about 2,000 litres a day (for comparison, Westerners use just 100-250 litres a day in drinking and washing).
So the shift from vegetarian diets to meaty ones—which contributed to the food-price rise of 2007-08—has big implications for water, too. In 1985 Chinese people ate, on average, 20kg of meat; this year, they will eat around 50kg. This difference translates into 390km3 (1km3 is 1 trillion litres) of water—almost as much as total water use in Europe.
The shift of diet will be impossible to reverse since it is a product of rising wealth and urbanisation. In general, “water intensity” in food increases fastest as people begin to climb out of poverty, because that is when they start eating more meat. So if living standards in the poorest countries start to rise again, water use is likely to soar. Moreover, almost all the 2 billion people who will be added to the world’s population between now and 2030 are going to be third-world city dwellers—and city people use more water than rural folk.
The environmental impact of meat production varies because of the wide variety of agricultural practices employed around the world. All agriculture practices have been found to have a variety of effects on the environment. Some of the environmental effects that have been associated with meat production are pollution through fossil fuel usage, and water and land consumption. Meat is obtained through a variety of methods, including organic farming, free range farming, intensive livestock production, subsistence agriculture, hunting and fishing. As part of the conclusion to one of the largest international assessments of animal agriculture ever undertaken, the Food and Agriculture Organisation of the United Nations said:
The livestock sector is a major stressor on many ecosystems and on the planet as a whole. Globally it is one of the largest sources of greenhouse gasses and one of the leading causal factors in the loss of biodiversity, while in developed and emerging countries it is perhaps the leading source of water pollution.
Compare the proportion of obese people in America to those who are addicted to drugs and then try to argue that food isn’t as addictive as crack cocaine, says Dr. Nora Volkow, the director of the National Institute on Drug Abuse.
Can food really be as addictive as drugs? In an impassioned lecture at Rockefeller University on Wednesday, Dr. Nora Volkow, director of the National Institute on Drug Abuse, made the case that the answer is yes and that understanding the commonalities between food and drug addictions could offer insights into all types of compulsive behavior.
Many of the neural signals involved in addictive behaviour also appear to be active in food reward. Naturally occurring opioids in the brain (including endorphins, enkephalins, dynorphins, and endomorphins) play an important role in neural reward processes that can lead to addictive behaviour. Both homeostatic and reward-based feeding mechanisms involve opioid peptide systems and opioid receptors, and opioid receptor blockers (antagonists) inhibit consumption of both addictive drugs and palatable food. Clinical trials targeting opioid receptors have revealed weight loss potential for opioid antagonists in obese patients. These relationships suggest the existence of a form of opioid-related addiction focused on palatable foods, although there are still major gaps in our knowledge of the molecular mechanisms through which opioids influence the hedonic properties of food.
Obesity rates in Korea are among the lowest in the OECD, but have been increasing steadily. About 4% of the adult population is obese in Korea, and about 30% are overweight (including obese). OECD projections indicate that overweight rates will increase by a further 5% within ten years.
A two dimensional, reaction-diffusion model of compost piles
Thiansiri Luangwilai, Harvinder Sidhu, Mark Nelson
Abstract
We consider the self heating process in a two dimensional spatially dependent model of a compost pile which incorporates terms that account for self heating due to both biological and oxidation mechanisms. As moisture is a crucial factor in both the degradation process and spontaneous ignition within a compost pile, this model consists of four mass-balance equations, namely, energy, oxygen, vapour and liquid water concentrations. Analyses are undertaken for different initial water contents within the compost pile. We show that when the water content is too low, the reaction is almost negligible; whereas when it is too high, the reaction commences only when the water content evaporates and the water ratio drops to within an appropriate range. However, for an intermediate water content range, the biological reaction is at its optimum and there is a possibility of spontaneous ignition within the compost pile. Continue reading “model of compost piles”
When an estimated 60 million Americans fire up their barbecue grills this Fourth of July, they’ll be burning the equivalent of 2,300 acres of forest and consuming enough energy to meet the residential demand of a town the size of Flagstaff, Ariz., for an entire year.
Tristram West of the Department of Energy’s Oak Ridge National Laboratory also calculated that the grills would emit nearly 225,000 metric tons of carbon dioxide. A metric ton is equal to about 2,200 pounds. West’s estimate includes carbon dioxide emissions from production and combustion of the fuel. Carbon dioxide, considered a greenhouse gas, is increasing in the atmosphere each year and is thought to be a major factor in climate change.
July 4 is by far the most popular day of the year for cookouts, according to a Hearth, Patio & Barbecue Association (http://www.hpba.org/index.cfm) survey that found that 76 percent of the nation’s grill owners use at least one of their grills that day. The survey also found that 76 percent of American households own a grill and 42 percent own more than one. Sixty-one percent own a liquefied petroleum gas grill; 48 percent own a charcoal grill; 9 percent own a natural gas grill; and 7 percent own an electric grill.
West, a researcher in ORNL’s Environmental Sciences Division, assumed a 35,000 British thermal unit per hour output for the average grill and one hour of operation for each grill. In making his calculations, West took into account the carbon content and carbon dioxide emissions for each type of fuel.
“While more grills are fueled with liquefied petroleum gas, the majority of carbon dioxide emissions are from grills using charcoal briquettes, because the amount of carbon per Btu of gas is about one-third that of charcoal,” West said.
Although electric grills emit no on-site carbon dioxide, West said they have the highest emissions per hour of all the grills when accounting for fossil fuel emissions from producing and transmitting electricity. A liquefied petroleum gas grill operated for an hour would emit 5.6 pounds of carbon dioxide while a charcoal grill would emit about 11 pounds. An electric grill would account for about 15 pounds of carbon dioxide.
The smoky flavor and the char that one gets from a well-grilled steak is not particularly good . (http://www.bonappetit.com/test-kitchen/cooking-tips/article/is-grilling-good-for-you-or-bad-here-s-what-science-says ). When fat from the cooking meat drips down on the hot coals, the smoke that forms contains stuff called polycyclic aromatic hydrocarbons (PAH)( http://www.cancer.gov/cancertopics/factsheet/Risk/cooked-meats ). And the charred exterior of the meat (or inside, if you like things extremely well-done) is chock full of something called heterocyclic amines (HCA). Exposure to high levels of HCAs and PAHs can cause cancer in animals; however, whether such exposure causes cancer in humans is unclear.
Currently, no Federal guidelines address consumption levels of HCAs and PAHs formed in meat.
HCA and PAH formation can be reduced by avoiding direct exposure of meat to an open flame or a hot metal surface, reducing the cooking time, and using a microwave oven to partially cook meat before exposing it to high temperatures.
Ongoing studies are investigating the associations between meat intake, meat cooking methods, and cancer risk.
Both of these have been linked in studies, like one conducted by the National Cancer Institute in 1999, to higher rates of colorectal cancers, and both chemicals have been added to the DOH’s official list of carcinogens (PAH all the way back in 1981, HCA in 2005). In 2009, another study found that people who preferred their steaks “very well done” were 60 percent more likely to get pancreatic cancer than those who liked them bloody (or didn’t eat steak at all), and both compounds have been found to cause tumors in mice (and might cause even more tumors in humans, since mice process the chemicals differently).
10 July 2014
Cardiovascular disease (CVD) remains the leading cause of death
among Europeans and around the world. The Global Burden of
Disease study estimated that 29.6% of all deaths worldwide
(15 616.1 million deaths) were caused by CVD in 2010, more than
all communicable, maternal, neonatal and nutritional disorders combined,
and double the number of deaths caused by cancers.1 This
paper provides an update for 2014 on the burden of CVD, and in particular
coronary heart disease (CHD) and stroke, across the countries
of Europe. This overview updates the work published in this
journal in 20132 and provides an up-to-date synopsis of the key
data in relation to mortality and morbidity from CVD across Europe.
People can be obese but metabolically healthy and fit, with no greater risk of developing or dying from cardiovascular disease or cancer than normal weight people, according to the largest study ever to have investigated this, which is published online today (Wednesday) in the European Heart Journal [1].
The findings show there is a subset of obese people who are metabolically healthy – they don’t suffer from conditions such as insulin resistance, diabetes and high cholesterol or blood pressure – and who have a higher level of fitness, as measured by how well the heart and lungs perform, than other obese people. Being obese does not seem to have a detrimental effect on their health, and doctors should bear this in mind when considering what, if any, interventions are required, say the researchers.