LoyolaMedicine.org – Winter can be especially hazardous to human health with frostbite and frostnip being among the more common hazards people are likely to encounter.

Frostbite and frostnip occur when the human body is exposed to extremely low temperatures for a period of time without the proper clothing for the conditions. Extreme cold causes the blood vessels of the body to begin to narrow and constrict, reducing blood flow to the extremities, such as ears, the nose, hands and feet.

“The two conditions are natural survival responses the body makes in order to keep your vital organs from becoming damaged by the cold,” said emergency medicine physician Dr. Melanie Cerinich of Loyola University Medical Center in Maywood, IL. “The body shifts warm blood from its extremities to its center where the organs most vital to survival are. Since the extremities receive less warm blood, they become more vulnerable to cold.”

Frostnip is the precursor to frostbite and is far less serious. Frostnip commonly affects the fingers, face, ears, cheeks, toes and other areas of the body over-exposed to the cold. People with frostnip will notice that the skin of the affected area is stiff, numb and white in color but the tissue underneath will still be warm and soft.

“Treatment for frostnip is as easy as warming the affected area by rubbing, moving and covering it up with extra layers of clothing,” Cerinich said. “You can also dip the frost-nipped area in warm – never hot – water until normal sensation returns.

Frostbite is the more serious form of frostnip. Frostbite occurs when parts of the body actually freeze. Mild frostbite is characterized by numbness in the frostbitten area. The skin may appear white or gray. Also, there may be some blistering of the skin.

“Treatment for mild frostbite isn’t too dissimilar to treatment for frostnip.” Cerinich said. “First, get out of the cold and warm the affected area and then cover it with extra layers of clothing. Dipping the affected area in warm water until normal sensation returns also can be done.”

In severe cases of frostbite, the tissue underneath the skin can be frozen to the bone. Severe frostbite can not only affect fingers, the face, ears, cheeks and toes but even entire arms and legs. Frostbitten skin will be hard, numb, and appear pale, white or gray. The condition can lead to gangrene, amputation and even death.

“People with severe frostbite should never rub or apply snow to the affected area. That will only increase injury to the tissue,” Cerinich said. “The best thing to do is to get out of the cold as fast as possible and wrap the frostbitten area immediately in some warm clothing or warm it with your body. Then seek immediate medical attention.”

Of course, limiting your exposure to extreme cold as well as wearing dry, layered clothing, a hat and mittens, which are warmer than gloves, are without a doubt the best ways to avoid frostnip, frostbite and other winter-related illnesses, Cerinich added.

KI.se – Spinach – a vegetable with multiple health benefits – appears to have a newly discovered benefit for both athletes and those with cardiovascular problems. The muscles’ cellular power plants – the mitochondria – are boosted by nitrate, a substance found in abundance in vegetables such as lettuce, spinach and beetroot.

For half a century, inorganic nitrate has been associated with negative health effects, but more recently, evidence of the contrary has mounted. In the 1990s, a research group at Karolinska Institutet demonstrated how the body can convert nitrate to NO (nitric oxide), a molecule involved in many important bodily functions, such as blood pressure regulation, the immune defense and cell metabolism.

In this new study, the same team had healthy people take nitrate equivalent to 200 to 300 grams of spinach or lettuce for three days, after which they were given a cycling task to perform. The researchers then analyzed samples from their thigh muscles and compared them with similar samples from the same subjects when they had taken a placebo instead. After nitrate ingestion, a significant improvement was seen in the mitochondrial efficiency, which consumed less oxygen and produced more of the energy-rich substance ATP per consumed oxygen molecule.

“The mitochondria play a key role in cellular metabolism,” says Professor Eddie Weitzberg, who is heading the study with Professor Jon Lundberg. “Improved mitochondrial function probably has many positive effects on the body, and could explain some of the health benefits of vegetables.”

The results, which are published in Cell Metabolism, are of sports physiology interest, as they show that nitrate reduces oxygen consumption during physical exercise; however, they are also of potential significance to diseases involving mitochondrial dysfunction, such as diabetes and cardiovascular disease.

The group has also recently shown that nitrate reduces the blood pressure of healthy individuals and that in laboratory animals it counteracts components of the metabolic syndrome, a pre-stage of diabetes. Other scientists have demonstrated protective effects of nitrate and nitrite in animal models against heart attack and stroke.

The abstract of the article is available online free here:

Nitrate, spinach, mitochondria, muscle, exercise

Reference: Filip J Larsen, et al. Dietary inorganic nitrate improves mitochondrial efficiency in humans. Cell Metabolism, 2 February 2011.

A recent UCLA study on the actions of a cellular antioxidant regulator, Nrf2, found that it had some connection to the formation of atherosclerotic plaque, and that reducing Nrf2 decreased atherosclerosis. But should these study findings scare you away from eating Nrf2-promoting dietary antioxidants found in broccoli, blueberries, and dark chocolate, or from taking the so-called “anti-aging” supplement resveratrol?

It is known from several prior studies that one of the ways certain dietary antioxidants might promote health is through either boosting or normalizing the activity of the protein transcription factor, Nrf2, that helps to regulate the activity of other antioxidant and anti-inflammatory chemicals in the body. In fact, Nrf2 is thought of as a “master regulator” of the cell’s overall antioxidant response. Nrf2 activity is known to decline as we age, and is also thought to be stunted (in lung tissue) by toxins in cigarette smoke. The lungs of patients with COPD show markedly decreased levels of NRF2-dependent antioxidants, and a decrease in NRF2 protein.

Nrf2 activity, however, appears to be enhanced by certain dietary antioxidant compounds that are generally thought of as health-promoting. Epicatechin in dark chocolate appears to protect brain cells from stroke damage in part by turning on Nrf2 activity. Polyphenols in blueberries may be able to decrease liver fibrosis by increasing expression of Nrf2. Sulforaphane in cruciferous vegetables like broccoli and wasabi help normalize Nrf2 activity by reducing the action of KEAP1, a chemical known to inhibit Nrf2. Activation of sirtuin activity by resveratrol is also thought ultimately to enhance Nrf2 activity.

So with all of these prior findings of the likely benefits of optimizing Nrf2 levels and the activity of all its related proteins that protect and rejuvenate cells, what are we to make of this recent UCLA study?

The study was done by researchers hoping to find or at least to understand possible Nrf2 benefits for cardiovascular problems. Their findings, however, do not necessarily negate Nrf2 potential for optimizing health in humans. At this point they simply raise intriguing questions.

Considering the research design is important in trying to interpret this study. The researchers were studying mice, not humans or even human tissue. It was essentially a gene “knock-out” study – a useful but extreme and “unnatural” kind of study in which a gene that encodes for a particular RNA or protein is bred completely out of the entire organism. The lower level of atherosclerosis seen in the male (not female) study mice was found in the “unnatural” mice that completely lacked Nrf2. When some Nrf2 activity was added back in, the pattern of atherosclerosis returned to the “normal” pattern seen in regular mice.

Thus the study findings were actually that if all Nrf2 activity in male mice is totally eliminated, atherosclerosis in the aorta can be lowered by 53 percent compared to normal. The study does not say that modestly boosting Nrf2 activity above normal, or raising Nrf2 levels back to a normal range in old or sickly individuals, will accelerate atherosclerosis beyond its “normal” pace.

Also, no one is advocating blocking all Nrf2 activity as a way to reduce atherosclerotic plaque. And even if it did reduce plaque, the side-effects of such an extreme biological action would likely be devastating.

In conclusion, the study does not offer any evidence that aging baby-boomers concerned about their health should start limiting their dietary intake of berries, cruciferous vegetables, or dark chocolate or cocoa.

The Nrf2-knockout study, however, might be relevant for a certain group of high-risk patients with high cholesterol problems who continue to recklessly eat trans fats and fast foods, all the while taking high dose resveratrol thinking that the pill alone will save them. For such patients, it might be a good idea to have their doctor check both their lipid panel and their liver function tests (AST and ALT, for example) periodically, just to make sure their mega-dose supplement is not causing more harm than good, via as yet poorly understood Nrf2 pathways – John Zebrun, MD.

Berkeley.edu – Children who were exposed to common, organophosphate pesticides while still in their mother’s womb were more likely to develop attention-deficit disorders years later, according to a new study by researchers at the University of California, Berkeley. The study raises the public health issue of whether organic produce might be a better choice for pregnant women. In addition, such studies raise questions about the long-term effects of food control bills in Congress, such as HR 2749, that would likely decrease availability of organic produce if passed.

The new findings, to be published August 19, 2010 in the journal Environmental Health Perspectives (EHP), are the first to examine the influence of prenatal organophosphate exposure on the later development of attention problems. The researchers found that prenatal levels of organophosphate metabolites were significantly linked to attention problems at age 5, with the effects apparently stronger among boys.

Earlier this year, a different study by researchers at Harvard University associated greater exposure to organophosphate pesticides in school-aged children with higher rates of attention deficit hyperactivity disorder (ADHD) symptoms.

“These studies provide a growing body of evidence that organophosphate pesticide exposure can impact human neurodevelopment, particularly among children,” said the study’s principal investigator, Brenda Eskenazi, UC Berkeley professor of epidemiology and of maternal and child health. “We were especially interested in prenatal exposure because that is the period when a baby’s nervous system is developing the most.”

The study follows more than 300 children participating in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS), a longitudinal study led by Eskenazi that examines environmental exposures and reproductive health. Because the mothers and children in the study are Mexican-Americans living in an agricultural community, their exposure to pesticides is likely higher and more chronic, on average, than that of the general U.S. population.

Yet, the researchers pointed out that the pesticides they examined are widely used, and that the results from this study are a red flag that warrants precautionary measures.

“It’s known that food is a significant source of pesticide exposure among the general population,” said Eskenazi. “I would recommend thoroughly washing fruits and vegetables before eating them, especially if you’re pregnant.”

Organophosphate pesticides act by disrupting neurotransmitters, particularly acetylcholine, which plays an important role in sustaining attention and short-term memory.

“Given that these compounds are designed to attack the nervous system of organisms, there is reason to be cautious, especially in situations where exposure may coincide with critical periods of fetal and child development,” said study lead author Amy Marks, who was an analyst at UC Berkeley’s School of Public Health at the time of the study.

Many of these same UC Berkeley researchers are also finding that children with certain genetic traits may be at greater risk, a finding that is being published the same day in a separate EHP paper. That study found that 2-year-olds with lower levels of paraoxonase 1 (PON1), an enzyme that breaks down the toxic metabolites of organophosphate pesticides, had more neurodevelopmental delays than those with higher levels of the enzyme. The authors suggest that people with certain PON1 genotypes could be particularly vulnerable to pesticide exposure.

In the study on attention problems, researchers tested for six metabolites of organophosphate pesticides in mothers twice during pregnancy and in the children several times after birth. Together, the metabolites represent the breakdown products of about 80 percent of all the organophosphate pesticides used in the Salinas Valley.

The researchers then evaluated the children at age 3.5 and 5 years for symptoms of attention disorders and ADHD using maternal reports of child behavior, performance on standardized computer tests, and behavior ratings from examiners. They controlled for potentially confounding factors such as birthweight, lead exposure and breastfeeding.

Each tenfold increase in prenatal pesticide metabolites was linked to having five times the odds of scoring high on the computerized tests at age 5, suggesting a greater likelihood of a child having clinical ADHD. The effect appeared to be stronger for boys than for girls.

While a positive link between prenatal pesticide exposure and attention problems was seen for 3.5-year-olds, it was not statistically significant, a finding that did not surprise the researchers.

“Symptoms of attention disorders are harder to recognize in toddlers, since kids at that age are not expected to sit down for significant lengths of time,” said Marks. “Diagnoses of ADHD often occur after a child enters school.”

The UC Berkeley researchers are continuing to follow the children in the CHAMACOS study as they get older, and expect to present more results in the years to come.

The findings add to the list of chemical assaults that have been linked to ADHD in recent years. In addition to pesticides, studies have found associations with exposure to lead and to phthalates (from plastics, plasticizers), which are commonly used in toys and plastics.

“High levels of the symptoms of ADHD by age 5 are a major contributor to learning and achievement problems in school, accidental injuries at home and in the neighborhood, and a host of problems in peer relationships and other essential competencies,” said UC Berkeley psychology professor Stephen Hinshaw, one of the country’s leading experts on ADHD, who was not part of this study. “Finding preventable risk factors is therefore a major public health concern.”