News Briefs – March 2013Michael Downey March 1, 2013
Study Confirms Link Between Dietary Glycemic Load and Diabetes Risk
Scientists have now determined that there is a strong association between a diet that reduces the glycemic load (GL) and a reduced risk of developing Type 2 diabetes. (The glycemic load of food is a number that estimates how much the food will raise the blood sugar level after eating it. Although much is known about the association between dietary glycemic load and Type 2 diabetes, studies have not, until now, consistently shown a positive dose-response relation.)
Researchers conducted a systematic review of 24 past studies and meta-analyses. Multiple analyses indicated that the relationship between a low-glycemic diet and diabetes tended to have been underestimated. Findings indicated a strong and significantly lower risk of Type 2 diabetes among persons who consume lower-glycemic diets.
This study will be published in the March 2013 issue of the American Journal of Clinical Nutrition. Access to the full study is currently available at https://tinyurl.com/dymw3t7 with a journal subscription or payment of an access fee.
Number Of Drinks Per Occasion Riskier Than More Frequent Drinking
Researchers have found that the usual quantity of alcohol that a person consumes per occasion is a more important determinant of diabetes risk than weekly drinking frequency. Those who consume less than one alcoholic drink per drinking occasion, even if drinking six days a week, have a significantly lower risk of developing Type 2 diabetes than those who consume more than one drink per occasion, even if they drink much less frequently. (Findings of past studies on the effect of drinking patterns on diabetes risk have been inconsistent and researchers aimed to determine the true role of quantity consumed as well as frequency of drinking in the development of Type 2 diabetes.)
This research showed that while abstainers and moderate drinkers have a relatively low risk of diabetes, those who have the lowest risk are those who consume an amount less than one drinking unit on six or more days of the week. However, at highest risk of diabetes are those who consume three or more drinks per occasion – no matter how infrequently they drink. This study was released January 23, 2013 by the American Journal of Clinical Nutrition and will be published in a future issue. It is available online at https://tinyurl.com/awrcp2v with subscription or access fee.
Did You Know…?
Older adults with mild vitamin B12 deficiency may be at increase risk of accelerated cognitive decline, reported the Journal of the American Geriatrics Society.
Brightly-Coloured Produce May Prevent ALS
New research suggests that increased consumption of foods containing colourful carotenoids, particularly beta-carotene and lutein, may prevent or delay the onset of amyotrophic lateral sclerosis (ALS). However, the study also found that diets high in lycopene, beta-cryptoxanthin, and vitamin C did not reduce ALS risk.
(ALS is also known as Lou Gehrig’s disease and attacks nerve cells in the brain and spinal cord. Prior studies report that oxidative stress plays a role in the development of ALS. Further studies have shown that individuals with high intake of antioxidants, such as vitamin E, have a reduced ALS risk. Because vitamin C or carotenoids are also antioxidants, researchers examined their relation to ALS in the largest study to date to examine the role of dietary antioxidants in preventing ALS.)
Subjects with diets high in beta-carotene and lutein, found in dark green vegetables, had a lower risk. Carotenoids give fruits and vegetables their bright orange, red, or yellow colours, and are a source of dietary vitamin A. Long-term vitamin C supplement intake was not associated with lower ALS risk. The study was released online January 29, 2013 by the Annals of Neurology. It can now be accessed at https://tinyurl.com/abu84yb with fee.
Testosterone Found Not To Increase Muscles After All
Two new studies have found that, despite longstanding belief, there is no increase in muscle growth or protein synthesis as a result of testosterone or human growth hormone levels. (Bodybuilders have long believed these hormones drive muscle synthesis. But as a Canadian scientist involved in both studies stressed, “That is simply not the case.”)
First, researchers examined physiological responses of men and women to intense exercise. The bodies of all participants synthesized muscle protein at the same rate despite 45-fold higher testosterone levels among men. Second, scientists analyzed hormonal levels of males following each training episode for five days a week for 12 weeks. Muscle gains ranged from virtually nothing to over 12 pounds, but there was no relationship between individual muscle gain and corresponding growth hormone level. Large gains were found as often with lowest growth hormone levels as with highest. The first study was published in the Journal of Applied Physiology and has now become accessible at https://tinyurl.com/8a6gyfm with subscription or fee. The second study was published in the European Journal of Applied Physiology and has now become available for download at https://tinyurl.com/7x67h36 without cost.
Obese Women Risk Having Babies With Low Vitamin D Levels
A study found that babies born to lean mothers had a one-third higher level of vitamin D compared to babies born to obese moms, despite the fact that vitamin D levels were similarly sufficient for both the lean and obese mothers. (Vitamin D is fat-soluble and previous studies have found that people who are obese tend to have lower levels of the vitamin in their blood. It is unknown what health risks babies born with vitamin D insufficiency may face, but recent studies have linked low vitamin D in adults to an increase in autoimmune diseases, inflammation, obesity.)
Because almost all of the 61 mothers regularly took prenatal vitamin supplements, the report warned that obese women may be passing on insufficient levels of vitamin D to their babies, despite its availability in their own bodies, due to their different amount of body-fat tissue. The scientists suggested that in obese women, vitamin D may get sequestered within the cells of excess fat and not transferred sufficiently from an obese pregnant woman to her baby. Surprisingly, babies born with higher vitamin D levels had more body fat; the opposite had been shown in children and adults – those with higher vitamin D levels have lower body fat.
This study was published in the January 2013 issue of the Journal of Clinical Endocrinology & Metabolism. It is available at https://tinyurl.com/b2kgxs6 with access fee.
Women More Likely Than Men To Die From Myocardial Infarction
Researchers have found that women have a worse prognosis than men when they suffer a myocardial infarction: they are more likely to die, have complications, or require longer hospital stays. (Myocardial infarction, commonly known as a heart attack, is an interruption of the blood supply to the heart, which causes irreversible necrosis, meaning the death of heart cells. About 22-64 percent of infarctions are silent, or clinically unrecognized. Women may experience fewer typical symptoms than men. The most common symptoms of heart attack are shortness of breath, weakness, a feeling of indigestion, and fatigue.)
Women are less likely to call promptly for assistance or receive aggressive treatment; however, the gender gap in outcomes was independent of patient characteristics or treatment modalities. This study of 5,000 patients, ongoing since 2006, assessed only males and females admitted to a cardiology unit within 24 hours of symptom onset. Despite the poorer prognosis, women were still far less likely to suffer a myocardial infarction, with female patients representing just 23.5 percent of all patients. This research was presented at the Acute Cardiac Care Congress. It has yet to be published or posted.
Did You Know…?
Women who have both clinical depression and deficient vitamin D levels (blood levels of 25-hydroxyvitamin D below 50 ng/mL) experienced a reduction in their depression symptoms after bringing up their vitamin D blood levels to above the deficiency level, reported one study.
Unwanted Smoke Of Others Often Affects Residents Of Apartments
A study has found that one third of those who live in apartments are regularly subjected to unwanted cigarette smoke from other building tenants. Tenants with children were 50 percent more likely to be subjected to smoke in the building. Researchers excluded from the study, anyone in whose apartment someone had smoked during the previous three months. Scientists reported that 26 percent were subjected to smoke within their building. When they included only apartment dwellers with children living at home, they found that a greater proportion, 41 percent, was subjected to smoke. Of those subjected to smoke within their building, half of these people were subjected to cigarette smoke within their own apartments, despite the absence of smokers in their home. About 12 percent of subjects encountered the cigarette smoke of others within their apartment building on a daily basis. The lead study author reported that this exposure is sufficient to place children, and those with some health conditions, at risk for respiratory diseases and illness. Presented in Boston at the annual meeting of the Pediatric Academic Societies.
Did You Know…?
- Breathing second-hand smoke substantially increases the risk of invasive meningococcal disease in children, reports a 2012 study.
- Think your taste buds are objective? Research shows beverages in blue cups seem more thirst-quenching; beverages in pink cups taste more sugary; hot chocolate in orange- or cream-coloured cups tastes better; and yellow cups boost lemon flavours in soft drinks.
- Commonly assumed to be inert storage depots, fat cells actually secrete hormones and chemicals that increase the risk of cancer, heart disease, and diabetes – and boost hunger.
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Michael Downey is a former columnist with Vitality Magazine.