News Briefs – May 2013Michael Downey May 1, 2013
Daily Vitamin C Required for Optimum Muscle Health
Research into the importance of vitamin C for optimal muscle function has found that many fruits do not deliver sufficient vitamin C for muscle needs, and the body musculature requires an amount of vitamin C every day that is equivalent to eating two kiwifruit. The study has shown that skeletal muscle is very sensitive to changes in vitamin C intake and that the vitamin C content in muscles will fall if overall daily intake decreases below certain levels; this is likely to affect muscle function. (Muscle is the largest store of vitamin C in our bodies.)
Researchers gave 54 males aged between 18 and 35 either half a kiwifruit or two kiwifruit a day over a six-week period. They then measured the vitamin C content in muscle and elsewhere in the body. The researchers found that general energy levels were increased with the two-per-day kiwifruit dose, and this is likely to reflect optimal muscle function. (Many people think that all fruits and vegetables are equally able to supply vitamin C, but this is not the case. The levels in food vary hugely across the spectrum. Unlike kiwifruit, many fruits contain only one tenth of a healthy daily vitamin C requirement. Two kiwifruit provide almost 200 mg of vitamin C.)
This study is published in the April 2013 issue of the American Journal of Clinical Nutrition. However, the entire study text can be downloaded online now at https://tinyurl.com/bxlkdlh free of charge.
Smoking During Pregnancy Causes Asthma in Future Grandchildren
A new study has found that a woman who smokes can trigger asthma in her future grandchildren, a surprising discovery suggesting that other environmental and health factors experienced today may transmit susceptibility to disease through several generations. (An earlier study found that pregnant rats given nicotine produced asthmatic pups that went on to produce their own asthmatic pups, despite the complete absence of nicotine exposure in the third generation. This finding suggests that nicotine can leave inherited epigenetic markers on the genome, meaning it can negatively reprogram how genes will be activated if and when certain circumstances are encountered.) Smoking by the first-generation women during pregnancy increased the risk of asthma in the third-generation children regardless of whether the second generation smoked or not.
Based on these findings, the researchers concluded that environmental factors experienced during pregnancy would affect not only the unborn child, but also future generations of the same family. (This could explain why 98% of inherited human diseases are difficult to account for simply by examining the family genetics.) Nicotine affects both lung and sex cells in ways that result in abnormal, asthmatic lungs. (Asthma rates are growing worldwide.) The risk likely extends to all smoke exposure, including secondhand smoke.
This research was published in the March 2013 edition of the Expert Review of Obstetrics & Gynecology.
Did You Know…?
Cholesterol levels seem to fluctuate significantly with the seasons, leaving people with borderline-high cholesterol at greater cardiovascular risk during the winter months, according to research presented March 2013 at the annual meeting of the American College of Cardiology.
Did You Know…?
Typically associated with digestive health, a diet high in fibre, especially soluble fibre, helps lower cholesterol and the risk of cardiovascular disease. More can be learned at https://tinyurl.com/c9sgyen.
Eating Greens Activates a Gene That Controls Intestinal Health
Scientists have discovered that certain proteins found in green, leafy, cruciferous vegetables send signals that switch on a gene called T-bet. This gene in turn produces critical immune cells in the lining of the digestive system that play a role in controlling food allergies, inflammatory diseases, and obesity, and may even prevent the development of bowel cancers. Turning on the gene known as T-bet is essential for producing a population of crucially important immune cells called innate lymphoid cells or ILCs, which line the digestive system and play a key role in protecting the body from harmful intestinal bacteria, inflammation, and obesity.
The study showed that T-bet can be turned on by signals in the green foods we eat, triggering precursor cells to become ILCs, which then monitor and beneficially influence the delicate balance among allergen tolerance, immune reactivity, and inflammation. (ILCs are known to produce a hormone called interleukin-22, which protects the body from invading bacteria and heals small intestinal wounds and abrasions that are common in gut tissues. They may also fix cancerous lesions. Scientists are just beginning to understand how ILCs regulate allergy, inflammation, and, potentially, other gastrointestinal disorders, such as Crohn’s disease.) This study was published in the March 3, 2013 issue of Nature Immunology. It can be read in full at https://tinyurl.com/arh6tex for a fee.
Red and Processed Meat Tied to Early Cancer and Cardiovascular Death
New research has found that people who regularly eat red or processed meat have higher mortality rates, especially due to cancer or cardiovascular disease, with regular consumers of processed meat showing a 44% greater risk of dying. Without eliminating processed meat consumption, about 3% of all current premature deaths would be prevented by a simple reduction in the amount of processed meat consumption overall.
This study carries substantial scientific weight in part because of its size: it included nearly 450,000 human subjects. The study does not absolutely prove a cause-and-effect link, but there are strong suggestions of a causal link. For instance, red meat is rich in cholesterol and saturated fat, which may be the link with coronary heart disease. Processed meat is also treated with nitrates to improve durability, colour, and taste; these nitrates also cause the formation of carcinogens strongly linked to the risk of colorectal and stomach cancer; and high iron intake from meat generally increases the risk for cancer. Also, eating comparatively more meat usually means eating fewer plant foods, which would otherwise protect against chronic disease. (Previous research supports the link between processed meat and health problems, and a wide array of studies have linked meat intake to higher rates of chronic disease.)
The researchers suggested that eating modest amounts of meat can still be healthy provided: red meat is limited; processed meats such as bologna, hot dogs, and sausages are avoided; and total processed meat consumption does not exceed 10 to 20 grams (or 1/3 to 2/3 of an ounce) a day. Those who consumed 160 grams of processed meat per day were found to have a 44% greater risk of death in the short term. This study was first released online on March 7, 2013. The full-text version can be accessed at the website of BMC Medical and downloaded at https://tinyurl.com/cfcckam
Lower Cognitive Function Linked to Total Germ Exposure
A study has found that those with a higher infectious burden, which is a composite measure of exposure to common pathogens such as cold sores and herpes, have a 25% greater risk of lower cognition. (Infectious burden is the overall exposure to infections. Previous research has shown that infectious burden is associated with vascular risk. This is the first study to examine the link between mental faculty and infections.)
Using a standard cognitive test known as the Mini-Mental State Examination (MMSE), the researchers compared test scores to infections and found that, even after adjusting for other potentially confounding risk factors, the infectious burden correlated well to lower MMSE scores. The infections assessed in subjects included five common low-grade infections: herpes simplex type 1 (oral); herpes simplex type 2 (genital); Cytomegalovirus; Chlamydia pneumoniae (a common respiratory infection); and Helicobacter pylori (a bacteria found in the stomach that is linked to ulcers). The link between lower scores and higher infectious burden was found at any age and advanced age had no bearing. (In other words, germ exposure did not show any separate or additional link with age-related cognitive decline.)
When the results were limited to viral infections, as opposed to bacterial and viral infections combined, the clear association still persisted. It is important to note that mere association does not necessarily indicate that either of these two factors caused the other. The research may suggest a potential double risk from infections, which have now been linked to cognitive ability as well as the risk of stroke, which can also affect cognitive ability. This study was released in the March 26, 2013 issue of the journal Neurology. It has now been posted online at https://tinyurl.com/cljveuo.
Higher Human Mercury Levels Linked to Diabetes
A new study has found that higher levels of mercury exposure in young adults increased their risks for Type 2 diabetes later in life by 65 percent. (The study is the first to establish the link between mercury and diabetes in humans. The main source of mercury in humans comes from the consumption of fish and shellfish, nearly all of which contain traces of mercury. Fish and shellfish also contain lean protein and other nutrients, such as magnesium and omega-3 polyunsaturated fatty acids, that make them important to a healthy diet.)
In the study, people with the highest levels of mercury also appeared to have healthier lifestyles, lower body-mass indices, smaller waist circumferences, and more exercise than other study participants. They also ate more fish, which is a possible marker of healthy diet or higher social economic status. Risk factors for Type 2 diabetes include being overweight. The study, which involved 3,875 men and women, established the link between mercury levels and Type 2 diabetes risk after controlling for lifestyle and other dietary factors such as magnesium and omega-3 polyunsaturated fatty acids, which could counter the effects of the mercury. (In other words, they found that the people who happened to have higher mercury levels also happened to have healthier lifestyles. This suggests that people who exercise more and watch their weight more are generally more concerned about their health. And people who are more concerned about their health may also be more inclined to include more fish in the diet. And more fish in their diet means more mercury. So those who are otherwise more health-conscious and healthier, subsequently eat more fish and get more mercury, and subsequently increase their risk of diabetes as a result.)
The findings point to the importance of selecting fish known to have low levels of mercury, and avoiding fish with higher levels such as swordfish and shark. (Other sources of mercury include dental amalgam fillings, coal fired plants, gold mines, and car exhaust fumes.) In the current study, the association between mercury exposure and diabetes incidence was strong. This study will be published in a future issue of Diabetes Care, but can be accessed online now at https://tinyurl.com/cvqludz with subscription or fee.
Eating While Distracted Increases Food Intake
New evidence indicates that watching television or sports while eating results in greater intake in the amount of food and overall calories; that attentive eating is likely to lower overall food intake; and that attentive-eating principles provide a novel approach to promote natural weight loss and maintenance without the need for conscious calorie counting. (Cognitive processes such as attention and memory may influence food intake, but the degree to which they do has been unclear until now.)
The objective of this study was to examine whether cognitive processes influence the amount of food eaten either immediately or in subsequent meals. Scientists systematically reviewed studies that examined experimentally the effect that manipulating memory, distraction, awareness, or attention showed on food intake. Twenty-four studies were reviewed, and evidence indicated that eating while distracted (such as while watching television or a computer screen) produced only a moderate 39% increase in immediate intake of food amount and calories. But intake during meals eaten sometime later than the meal that actually involved the distraction was found to be a substantial 76% higher in amount and calories. The effect of distraction on intake appeared to be independent of any deliberate attempt to eat less (dietary restraint).
Also, methods that enhanced the memory of food consumed at an earlier meal automatically reduced later food intake by 40 percent. Removing visual reminders about the amount of food eaten during a prior meal increased food intake by 48%. This study was published in the April 2013 issue of the American Journal of Clinical Nutrition. It is now available online at https://tinyurl.com/c9sag7l with fee.
All Levels of Secondhand Smoke Exposure Tied to Early Heart Disease
A major study has found shocking evidence that secondhand smoke exposure poses an equivalent or stronger risk for coronary artery calcification (CAC), an early sign of heart disease, than other long- and well-established risk factors such as high cholesterol, hypertension, and diabetes. (Many of those who suffer heart attacks do not exhibit any of the traditional risk factors, which has puzzled some researchers. Low-level passive smoke exposure at any time from childhood to adulthood may be the missing link for these victims. This study is considered strong, because it included a substantial number of healthy people of varying ages who had never smoked at all: 3,098.)
Passive exposure to smoke was determined to independently predict both the likelihood and extent of CAC and arterial plaque. In fact, after adjusting for other cardiovascular risk factors in the study population, those classified as having low, moderate, or high secondhand smoke exposure were found to be 50, 60, and 90%, respectively, more likely to have coronary artery calcification than those who reported minimal exposure. The effects of secondhand smoke on CAC remained regardless of whether the exposure was during childhood or adulthood. Passive inhalation of cigarette smoke was found to damage the coronary arteries of nonsmokers through many different ways, which can lead to plaque formation and then to heart attacks. Compared to those with lowest lifetime exposure, those with higher exposure were more likely to have diabetes, high cholesterol, and high blood pressure.
This study was presented March 10, 2013 in San Francisco at the annual scientific session of the American College of Cardiology. It will be published in a future issue of JACC: Cardiovascular Imaging.
Did You Know…?
New research has found that long after a smoker leaves the area, the lingering secondhand smoke becomes something much more deadly: it transforms into thirdhand smoke, which is absorbed into dust particles and inhaled, causing liver dysfunction that leads to dangerously delayed wound healing, and a highly increased risk of cardiovascular disease and diabetes.
High-Fruit Diet does not Boost Glucose Levels for Diabetics
New research reports that reducing fruit intake as part of standard medical nutrition therapy for overweight patients with newly diagnosed Type 2 diabetes does not reduce a key longer-term blood sugar marker (HbA1c), and does not reduce weight or waist circumference. As a result, the research team recommends that the intake of nutrient-rich fruits should not be restricted in patients with Type 2 diabetes. (Most guidelines recommend that non-diabetic individuals get a high intake of fibre-rich food, including fruits, based on the positive effects of fruits on human health. However, some health professionals have had concerns that fruits, with their high content of fructose, have a negative impact on glycemic control, and recommend restricting the fruit intake.)
Sixty-three newly diagnosed Type 2 diabetes patients were divided into two groups, one of which was advised to eat two or more servings of fruits daily, while the other was advised to eat between zero and two pieces of fruit a day. The high-fruit group ate two and a half times as much fruits, but there was no difference in blood sugar, weight, or waist size between the groups. The report concluded that the likely reduction in nutrition intake was not offset by any anti-diabetic benefit. This study was released March 5, 2013 by Nutrition Journal. The report is available at https://tinyurl.com/cxpvfaa
CDC Warns about Rise in Antibiotic-Resistant Bacterium
The U.S. Centers for Disease Control and Prevention (CDC) has issued a special call to action in the face of a rising tide of a family of especially deadly bacteria that has become increasingly resistant to last-resort antibiotics during the past decade, is lethally infecting an increasing number of patients, and in many cases, is simply impossible to cure. Data show these bacteria are resistant to all or nearly all antibiotics and kill half of all patients who contract the infection. (During a six-month period in 2012, almost 200 hospitals treated at least one patient infected with Carbapenem-Resistant Enterobacteriaceae, or CRE. One type of CRE has increased seven-fold in recent years.) A frightening aspect of this growing problem is that, in addition to spreading among patients, often on the hands of health care personnel, CRE bacteria can transfer resistance to other bacteria within their family. This type of spread can create additional life-threatening infections for patients in hospitals and potentially for otherwise healthy people. The CDC calls for urgent preventive action by the entire health community and issued general precautionary advice for medical staff, hospitals, and the public.
The warning was published March 5, 2013 in Vital Signs, the monthly report from the Centers for Disease Control and Prevention. It can be read online at https://tinyurl.com/bqf7r6b without charge.
Michael Downey is a former columnist with Vitality Magazine.