Vitamin Therapy Can Still Reduce Stroke, Researchers Contend

ScienceDaily (Dec. 21, 2011) — A commentary by University of Western Ontario’s David Spence and Harvard School of Public Health’s Dr. Meir Stampfer in this week’s Journal of the American Medical Association argues vitamin therapy still has a role to play in reducing stroke.

Vitamin B therapy was once widely used to lower homocysteine levels and too much of this amino acid in the bloodstream was linked to increased risk of stroke and heart attack. But several randomized trials found lowering homocysteine levels with B vitamins did not result in a cardiovascular benefit.

A study by Spence, a scientist with the Robarts Research Institute at Western’s Schulich School of Medicine & Dentistry, found Vitamin B therapy actually increased cardiovascular risk in patients with diabetic nephropathy.

He says this commentary provides insights that overturn the widespread belief that homocysteine is dead. He says two key issues have been overlooked in the interpretation of several clinical trials: the key role of vitamin B12, and the newly recognized role of renal failure.

“It is now clear that the large trials showing no benefit of vitamin therapy obscured the benefit of vitamin therapy because they lumped together patients with renal failure and those with good renal function, says Spence, the author of How to Prevent Your Stroke. “The vitamins are harmful in renal failure, and beneficial in patients with good renal function, and they cancel each other out.”

The commentary also contends most of the trials did not use a high enough dose of vitamin B12.

Journal Reference:

J. D. Spence, M. J. Stampfer. Understanding the Complexity of Homocysteine Lowering With Vitamins: The Potential Role of Subgroup Analyses. JAMA: The Journal of the American Medical Association, 2011; 306 (23): 2610 DOI: 10.1001/jama.2011.1834

http://www.sciencedaily.com/releases/2011/12/111221140716.htm

Scientists Identify an Innate Function of Vitamin E

ScienceDaily (Dec. 20, 2011) — It’s rubbed on the skin to reduce signs of aging and consumed by athletes to improve endurance but scientists now have the first evidence of one of vitamin E’s normal body functions.
The powerful antioxidant found in most foods helps repair tears in the plasma membranes that protect cells from outside forces and screen what enters and exits, Georgia Health Sciences University researchers report in the journal Nature Communications.

Everyday activities such as eating and exercise can tear the plasma membrane and the new research shows that vitamin E is essential to repair. Without repair of muscle cells, for example, muscles eventually waste away and die in a process similar to what occurs in muscular dystrophy. Muscle weakness also is a common complaint in diabetes, another condition associated with inadequate plasma membrane repair.

“Without any special effort we consume vitamin E every day and we don’t even know what it does in our bodies,” said Dr. Paul McNeil, GHSU cell biologist and the study’s corresponding author. He now feels confident about at least one of its jobs.

Century-old animal studies linked vitamin E deficiency to muscle problems but how that happens remained a mystery until now, McNeil said. His understanding that a lack of membrane repair caused muscle wasting and death prompted McNeil to look at vitamin E.

Vitamin E appears to aid repair in several ways. As an antioxidant, it helps eliminate destructive byproducts from the body’s use of oxygen that impede repair. Because it’s lipid-soluble, vitamin E can actually insert itself into the membrane to prevent free radicals from attacking. It also can help keep phospholipids, a major membrane component, compliant so they can better repair after a tear.

For example, exercise causes the cell powerhouse, the mitochondria, to burn a lot more oxygen than normal. “As an unavoidable consequence you produce reactive oxygen species,” McNeil said. The physical force of exercise tears the membrane. Vitamin E enables adequate plasma membrane repair despite the oxidant challenge and keeps the situation in check.

When he mimicked what happens with exercise by using hydrogen peroxide to produce free radicals, he found that tears in skeletal muscle cells would not heal unless pretreated with vitamin E.

Next steps, which will be aided by two recent National Institutes of Health grants, include examining membrane repair in vitamin E-deficient animals.

McNeil also wants to further examine membrane repair failure in diabetes. Former GHSU graduate student Dr. Amber C. Howard showed in a recent paper in the journal Diabetes that cells taken from animal models of types 1 and 2 diabetes have faulty repair mechanisms. Howard found high glucose was a culprit by soaking cells in a high-glucose solution for eight to 12 weeks, during which time they developed a repair defect. It’s also well documented that reactive oxygen species levels are elevated in diabetes.

The Nature Communications paper showed that vitamin E treatment in an animal model of diabetes restored some membrane repair ability. Also, an analogue of the most biologically active form of vitamin E significantly reversed membrane repair deficits caused by high glucose and increased cell survival after tearing cells in culture.

Now McNeil wants to know if he can prevent the development of advanced glycation end products — a sugar that high glucose adds to proteins that his lab has shown can also impede membrane repair — in the animal models of diabetes. The researchers have a drug that at least in cultured animal cells, prevents repair defects from advanced glycation end products.

Howard, first author on the Nature Communications paper, is an instructor at Husson University in Bangor, Maine. McNeil is a faculty member in GHSU’s Medical College of Georgia and College of Graduate Studies.

Amber C. Howard, Anna K. McNeil, Paul L. McNeil. Promotion of plasma membrane repair by vitamin E. Nature Communications, 2011; 2: 597 DOI: 10.1038/ncomms1594

Breastfeeding Promotes Healthy Growth

Breastfeeding Promotes Healthy Growth

ScienceDaily (Dec. 20, 2011) — A PhD project from LIFE — the Faculty of Life Sciences at the University of Copenhagen has shown that breastfed children follow a different growth pattern than non-breastfed children. Breastfeeding lowers the levels of the growth hormones IGF-I and insulin in the blood, which means that growth is slightly slower. This is believed to reduce the risk of overweight and diabetes later in life.
The PhD project is part of SKOT, a large-scale Danish study of small children, diet and wellbeing, which has followed and examined 330 healthy children at 9, 18 and 36 months.

The SKOT project is to increase our knowledge of what Danish children eat in the critical phase when they move from breastmilk or formula to solids. The transition is critical because the food intake during this period has a significant bearing on the child’s growth and risk of developing lifestyle diseases later in life.

PhD Anja Lykke Madsen has gathered the first results of the SKOT study in her PhD project:

“We can see that breastfeeding has a significant, measurable effect on the important growth regulators in the blood, IGF-I and insulin. The more times the child was breastfed, the lower the hormone levels. This suggests that the child has a slightly lower risk of becoming overweight later in childhood. At the same time, there was a correlation between how long the children were breastfed and their weight at 18 months,” says LIFE PhD Anja Lykke Madsen.

Mother’s milk for healthy growth

According to Professor Kim Fleischer Michaelsen from LIFE, head of the SKOT project, the study provides valuable knowledge about the factors affecting the early onset of obesity.

“It is well-known that children who are breastfed grow slightly more slowly than children who are given formula, and it looks as if this growth pattern is optimal because it reduces the risk of developing lifestyle diseases later in life. However, the new results from SKOT show that breastfeeding also affects levels of IGF-I and insulin at 9 months, i.e. at a time when the children are well into eating solids,” says Professor Kim Fleischer Michaelsen from LIFE. He continues:

“Looking at the children’s growth up to 18 months identified a number of interesting correlations which may improve our understanding of the mechanisms behind early-onset obesity. The longer the children were breastfed, the lower their weight at 18 months. It’s as simple as that.”

The study also showed that the longer the children slept, the smaller their waist circumference. Moreover, the children of mothers who gained lot of weight during pregnancy had a slightly thicker layer of subcutaneous fat than the children of mothers who put on less weight.

Need to study long-term effects

Kim Fleischer Michaelsen stresses the need to follow up and to continue to examine the children to establish the long-term effects, while also looking at correlations in other studies.

University of Copenhagen (2011, December 20). Breastfeeding promotes healthy growth.

http://www.sciencedaily.com/releases/2011/12/111220133907.htm

The Effects of Chronic Betaine Supplementation on Exercise Performance, Skeletal Muscle Oxygen Saturation and Associated Biochemical Parameters in Resistance Trained Men

Trepanowski, John F; Farney, Tyler M; McCarthy, Cameron G; Schilling, Brian K; Craig, Stuart A; Bloomer, Richard J

Journal of Strength & Conditioning Research. 25(12):3461-3471, December 2011.

doi: 10.1519/JSC.0b013e318217d48d

Trepanowski, JF, Farney, TM, McCarthy, CG, Schilling, BK, Craig, SA, and Bloomer, RJ. The effects of chronic betaine supplementation on exercise performance, skeletal muscle oxygen saturation, and associated biochemical parameters in resistance trained men. J Strength Cond Res 25(12): 3461–3471, 2011—We examined the effects of chronic betaine supplementation on exercise performance and associated parameters in resistance trained men. Men were randomly assigned in a double-blind manner using a crossover design to consume betaine (2.5 g of betaine mixed in 500 ml of Gatorade®) or a placebo (500 ml of Gatorade®) for 14 days, with a 21-day washout period. Before and after each treatment period, tests of lower- and upper-body muscular power and isometric force were conducted, including a test of upper-body muscular endurance (10 sets of bench press exercise to failure). Muscle tissue oxygen saturation (StO2) during the bench press protocol was measured via near infrared spectroscopy. Blood samples were collected before and after the exercise test protocol for analysis of lactate, nitrate/nitrite (NOx), and malondialdehyde (MDA). When analyzed using a repeated measures analysis of variance, no significant differences were noted between conditions for exercise performance variables (p > 0.05). However, an increase in total repetitions (p = 0.01) and total volume load (p = 0.02) in the 10-set bench press protocol was noted with betaine supplementation (paired t-tests), with values increasing approximately 6.5% from preintervention to postintervention. Although not of statistical significance (p = 0.14), postexercise blood lactate increased to a lesser extent with betaine supplementation (210%) compared with placebo administration (270%). NOx was lower postintervention as compared with preintervention (p = 0.06), and MDA was relatively unchanged. The decrease in StO2 during the bench press protocol was greater with betaine vs. placebo (p = 0.01), possibly suggesting enhanced muscle oxygen consumption. These findings indicate that betaine supplementation results in a moderate increase in total repetitions and volume load in the bench press exercise, without favorably impacting other performance measures.

THE EFFECTS OF LOW FAT CHOCOLATE MILK ON POSTEXERCISE RECOVERY IN COLLEGIATE ATHLETES

Spaccarotella, Kim J; Andzel, Walter D

Journal of Strength & Conditioning Research. 25(12):3456-3460, December 2011.

doi: 10.1519/JSC.0b013e3182163071

Abstract:

Spaccarotella, KJ and Andzel, WD. The effects of low fat chocolate milk on postexercise recovery in collegiate athletes. J Strength Cond Res 25(12): 3456–3460, 2011—Drinking chocolate milk between exercise sessions may improve recovery. The purpose of this study was to examine the effects of low fat chocolate milk vs. a carbohydrate–electrolyte beverage (CE) on recovery between preseason practice sessions among 5 male and 8 female Division III soccer players. The study used a randomized crossover design: between morning and afternoon practices, athletes received either an amount of chocolate milk that provided 1 g carbohydrate per kilogram body weight or an equal volume of CE (mean volume of 615 ± 101 ml). After their afternoon practice, they completed a shuttle run to fatigue. Data were analyzed using the Wilcoxon paired rank-sign test (for shuttle run time) and the paired samples t-test (for dietary intake). No significant differences in run time were reported for the group. For the men only, there was a trend of increased time to fatigue with chocolate milk compared with the CE (exact p = 0.03). Low fat chocolate milk may therefore be as good as a CE at promoting recovery between training sessions during preseason.

CREATINE SUPPLEMENTATION DECREASES OXIDATIVE DNA DAMAGE AND LIPID PEROXIDATION INDUCED BY A SINGLE BOUT OF RESISTANCE EXERCISE

RAHMAN RAHIMI
Department of Physical Education and Sport Science, University of Kurdistan, Sanandaj, Iran; and Department of Exercise
Physiology, Faculty of Physical Education and Sport Science, University of Guilan, Rasht, Iran

ABSTRACT
Rahimi, R.

Creatine supplementation decreases oxidative DNA
damage and lipid peroxidation induced by a single bout of
resistance exercise. J Strength Cond Res 25(12): 3448–3455,
2011—Creatine (Cr), or methyl guanidine–acetic acid, can be
either ingested from exogenous sources, such as fish or meat,
or produced endogenously by the body, primarily in the liver. It is
used as an ergogenic aid to improve muscle mass, strength,
and endurance. Heretofore, Cr’s positive therapeutic benefits
in various oxidative stress-associated diseases have been
reported in the literature and, recently, Cr has also been shown
to exert direct antioxidant effects. Therefore, the purpose of
this study was to investigate the effects of an acute bout of
resistance exercise (RE) on oxidative stress response and
oxidative DNA damage in male athletes and whether supplementation
with Cr could negate any observed differences.
Twenty-seven resistance-trained men were randomly divided
into a Cr supplementation group (the Cr group [21.6 6 3.6
years], taking 4 3 5 g Cr monohydrate per day) or a placebo
(PL) supplementation group (the PL group [21.2 6 3.2 years],
taking 4 3 5 g maltodextrin per day). A double-blind research
design was employed for a 7-day supplementation period.
Before and after the seventh day of supplementation, the
subjects performed an RE protocol (7 sets of 4 exercises using
60–90 1 repetition maximum) in the flat pyramid loading
pattern. Blood and urine samples taken before, immediately,
and 24-hour postexercise were analyzed for plasma malondialdehyde
(MDA) and urinary 8-hydroxy-2-deoxyguanosine (8-
OHdG) excretion. Before the supplementation period, a significant
increase in the urinary 8-OHdG excretion and plasma
MDA levels was observed after RE. The Cr supplementation induces a significant increase in athletics performance, and it
attenuated the changes observed in the urinary 8-OHdG
excretion and plasma MDA. These results indicate that Cr
supplementation reduced oxidative DNA damage and lipid
peroxidation induced by a single bout of RE.

Address correspondence to R. Rahimi, rahman.rahimi@yahoo.com.
25(12)/3448–3455
Journal of Strength and Conditioning Research
2011 National Strength and Conditioning Association

Some Plant-Based Food Supplements Contain High Levels of Cancer Causing Agents, Study Suggests

ScienceDaily (Dec. 12, 2011) — While many consumers equal ‘natural’ with ‘safe’, botanicals and botanical preparations such as plant-based food supplements may contain compounds, like the so called alkenylbenzenes, that are of concern for human health. At high doses these chemical compounds can cause liver cancer in experimental animals. A new study, published in the last issue of the journal Food and Nutrition Sciences, reveals that in many plant-based food supplements levels of these compounds are so low that they are of no concern. Although there are also plant-based food supplements on the market that contain alkenylbenzenes at levels comparable to those causing tumours in laboratory animals. This indicates a need for better regulation and quality control of plant-based food supplements containing alkenylbenzenes.
Botanicals and botanical preparations such as plant-based food supplements are extensively used by consumers within the European Union and the market volume for these products is expanding. In order to assess the safety of plant-based food supplements used in the European Union, an extensive selection and analysis of botanical compounds of concern and present in plant-based food supplements was performed by researchers of Wageningen University, part of Wageningen UR, the University of Milan (Università degli Studi di Milano) and Proform SA collaborating under the EU project PlantLIBRA.

The researchers selected thirty botanical compounds that are of possible concern for human health because they are able to damage the genetic material and/or are carcinogenic. The majority of these compounds were found to belong to the group of the alkenylbenzenes or the group of pyrrolizidine alkaloids. For these botanical ingredients regulatory authorities are aware of the possible risk for human health and consequently the use of pyrrolizidine alkaloid-containing botanicals in food and plant-based food supplements is prohibited in most EU Member States for precautionary health protection reasons. The use of the alkenylbenzenes estragole, methyleugenol, safrole or β-asarone as flavouring agents in food is also banned within the EU. However, restrictions have not (yet) been made with regard to the presence of alkenylbenzenes in plant-based food supplements.

The analysis of several plant-based food supplements containing as main ingredient basil, fennel, nutmeg, sassafras, cinnamon or calamus or their essential oils revealed that some of these products contain relatively high levels of alkenylbenzenes. The researchers concluded that the use of such plant-based food supplements raises a concern for human health and might be of high priority for risk management actions to be taken.

The research team passes the remark that there are also plant-based food supplements in which the levels of the alkenylbenzenes were so low that they are of no concern. Furthermore, they underline that the results obtained in studies in which liver cancer was observed in experimental animals, are based on experiments in which high concentrations of the pure alkenylbenzenes were given to animals instead of administering the plant-based food supplements as such in combination with normal feed. The results obtained in those studies may present an overestimation of the effects compared to those of the alkenylbenzenes in the presence of other ingredients that can be found in the plant-based food supplements or in the normal food. Due to the presence of such a botanical or food pattern, the toxicity of the alkenylbenzenes might be reduced, diminishing the possible risk for human health. Future studies will place special focus on this subject. However, for the time being it is concluded that some — although not all — plant-based food supplements containing the alkenylbenzenes estragole, methyleugenol, safrole or β-asarone might raise a concern for human health and that this indicates a need for better regulation and quality control of plant-based food supplements containing these alkenylbenzenes.

The above story is reprinted from materials provided by Wageningen University and Research Centre.

Journal Reference:

Suzanne J.P.L. van den Berg, Patrizia Restani, Marelle G. Boersma, Luc Delmulle, Ivonne M.C.M. Rietjens. Levels of Genotoxic and Carcinogenic Compounds in Plant Food Supplements and Associated Risk Assessment. Food and Nutrition Sciences, Vol. 2, No. 9, 2011, pp. 989-1010

Caffeine Study Shows Sport Performance Increase

ScienceDaily (Dec. 14, 2011) — Caffeine combined with carbohydrate could be used to help athletes perform better on the field, according to new research by a sport nutrition expert.
Mayur Ranchordas, a senior lecturer and performance nutritionist at Sheffield Hallam University, carried out studies on footballers using caffeine and carbohydrates combined in a drink. Along with improvements in endurance caused by ingesting carbohydrate, the athletes’ skill level improved after taking caffeine and carbohydrate together.

Mayur said: “There is already plenty of research that shows that caffeine and carbohydrate improve endurance, but this study shows that there is also a positive effect on skill and performance.

“We carried out three different soccer-specific match simulations of 90 minutes each — two 45 minute sessions — that tested agility, dribbling, heading and kicking accuracy. The test was designed to mimic a football game where the participants had to carry out multiple repeated sprints, dribble the ball around cones and shoot accurately.

“We found that the combination of carbohydrate and caffeine allowed players to sustain higher work intensity for the sprints, as well as improving shooting accuracy and dribbling during simulated soccer activity.

“These findings suggest that, for athletes competing in team sports where endurance and skill are important factors, ingesting a carbohydrate and caffeine drink, as opposed to just a carbohydrate drink, may significantly enhance performance. Our findings suggest that soccer players should choose a carbohydrate caffeine drink over a carbohydrate drink to consume before kick off and at half-time.”

The above story is reprinted from materials provided by Sheffield Hallam University.

How Muscle Fatigue Originates in the Head

ScienceDaily (Dec. 5, 2011) — Researchers from the University of Zurich have now studied in detail what sportsmen and women know from experience: The head plays a key role in tiring endurance performances. They have discovered a mechanism in the brain that triggers a reduction in muscle performance during tiring activities and ensures that one’s own physiological limits are not exceeded. For the first time, the study demonstrates empirically that muscle fatigue and changes in the interaction between neuronal structures are linked.
The extent to which we are able to activate our muscles voluntarily depends on motivation and will power or the physical condition and level of fatigue of the muscles, for instance. The latter particularly leads to noticeable and measurable performance impairments. For a long time, the research on muscle fatigue was largely confined to changes in the muscle itself. Now, a joint research project between the University of Zurich and ETH Zurich has shifted the focus to brain research. Headed by neuro-psychologist Kai Lutz from the University of Zurich in collaboration with Urs Boutellier from the Institute of Human Movement Sciences and Sport at ETH Zurich, the researchers discovered neuronal processes for the first time that are responsible for reducing muscle activity during muscle-fatiguing exercise. The third and final part of this series of experiments, which was conducted by Lea Hilty as part of her doctoral thesis, has now been published in the “European Journal of Neuroscience.”

Muscle’s nerve impulses inhibit motoric area in the brain

In the initial study, the researchers showed that nerve impulses from the muscle — much like pain information — inhibit the primary motoric area during a tiring, energy-demanding exercise. They were able to prove this using measurements in which study participants repeated thigh contractions until they could no longer attain the force required. If the same exercise was conducted under narcotization of the spinal chord (spinal anesthesia), thus interrupting the response from the muscle to the primary motoric area, the corresponding fatigue-related inhibition processes became significantly weaker than when the muscle information was intact.

In a second step, using functional magnetic resonance imaging, the researchers were able to localize the brain regions that exhibit an increase in activity shortly before the interruption of a tiring, energy-demanding activity and are thus involved in signalizing the interruption: the thalamus and the insular cortex — both areas which analyze information that indicates a threat to the organism, such as pain or hunger.

Neuronal system has regulating effect on muscle performance

The third study has now shown that the inhibitory influences on motoric activity are actually mediated via the insular cortex: In tests using a bicycle ergometer, the researchers determined that the communication between the insular cortex and the primary motoric area became more intensive as the fatigue progressed. “This can be regarded as evidence that the neuronal system found not only informs the brain, but also actually has a regulating effect on motoric activity,” says Lea Hilty, summing up the current result. And Kai Lutz points to the new research field that now opens up with these results: “The findings are an important step in discovering the role the brain plays in muscle fatigue. Based on these studies, it won’t just be possible to develop strategies to optimize muscular performance, but also specifically investigate reasons for reduced muscular performance in various diseases.” Prolonged reduced physical performance is a symptom that is frequently observed in daily clinical practice. It can also appear as a side effect of certain medication. However, so-called chronic fatigue syndrome is often diagnosed without any apparent cause.

Journal References:

Lea Hilty, Lutz Jäncke, Roger Luechinger, Urs Boutellier, Kai Lutz. Limitation of physical performance in a muscle fatiguing handgrip exercise is mediated by thalamo-insular activity. Human Brain Mapping, 2011; 32 (12): 2151 DOI: 10.1002/hbm.21177

Lea Hilty, Kai Lutz, Konrad Maurer, Tobias Rodenkirch, Christina M. Spengler, Urs Boutellier, Lutz Jäncke, Markus Amann. Spinal opioid receptor-sensitive muscle afferents contribute to the fatigue-induced increase in intracortical inhibition in healthy humans. Experimental Physiology, 2011; DOI: 10.1113/expphysiol.2010.056226

Lea Hilty, Nicolas Langer, Roberto Pascual-Marqui, Urs Boutellier, Kai Lutz. Fatigue-induced increase in intracortical communication between mid/anterior insular and motor cortex during cycling exercise. European Journal of Neuroscience, 2011; DOI: 10.1111/j.1460-9568.2011.07909.x

Physical Fitness Trumps Body Weight in Reducing Death Risks, Study Finds

ScienceDaily (Dec. 5, 2011) — If you maintain or improve your fitness level — even if your body weight has not changed or increased — you can reduce your risk of death, according to research reported in Circulation: Journal of the American Heart Association.
In a study of 14,345 adult men, mostly white and middle or upper class, researchers found that:

Maintaining or improving fitness was associated with a lower death risk even after controlling for Body Mass Index (BMI) change.
Every unit of increased fitness (measured as MET, metabolic equivalent of task) over six years was associated with a 19 percent lower risk of heart disease and stroke-related deaths and a 15 percent lower risk of death from any cause.
Becoming less fit was linked to higher death risk, regardless of BMI changes.
BMI change was not associated with death risks.

BMI is a measurement based on weight and height (kg/m2). MET measures the intensity of aerobic exercise — specifically, the ratio of metabolic rate during a specific physical activity to a reference rate of metabolic rate at rest.

“This is good news for people who are physically active but can’t seem to lose weight,” said Duck-chul Lee, Ph.D., the study’s lead researcher and physical activity epidemiologist in the Department of Exercise Science at the University of South Carolina’s Arnold School of Public Health in Columbia. “You can worry less about your weight as long as you continue to maintain or increase your fitness levels.”

Results of the study underscore the importance of physical inactivity as a risk factor for death from heart disease and stroke, said researchers. Researchers also found no association between changes in body fat percentage or body weight and death risk.

Participants, who were an average 44 years old, were part of the long-term, large-scale Aerobics Center Longitudinal Study. They underwent at least two comprehensive medical exams.

Researchers used maximal treadmill tests to estimate physical fitness (maximal METs), and height and weight measurements to calculate BMI. They recorded changes in BMI and physical fitness over six years.

After more than 11 years of follow-up, researchers determined the relative risks of dying among men who lost, maintained or gained fitness over six years. They accounted for other factors that can affect outcomes, including BMI change, age, family history of heart disease, beginning fitness level, changes in lifestyle factors such as smoking and physical activity, and medical conditions such as high blood pressure or diabetes.

One possible explanation for these results: about 90 percent of the men were either normal weight or overweight at the beginning of the study. Among obese people, changes in BMI might have a significant effect on death risks. So it’s unclear whether these results would apply to severely obese people, Lee said.

A BMI score under 25 is considered healthy, 25 to less than 30 is overweight, and 30 or greater is obese.

Because the study was mostly done in white middle and upper class men, it’s difficult to know whether the results apply to other racial and socioeconomic groups. Women would likely have similar results as the men in the study, Lee said.

Co-authors are: Xuemei Sui, M.D., M.P.H.; Enrique G. Artero, Ph.D.; I-Min Lee, M.B.B.S., M.P.H., Sc.D.; Timothy S. Church, M.D., Ph.D.; Paul A. McAuley, Ph.D.; Fatima C. Stanford, M.D., M.P.H.; Harold W. Kohl, III, Ph.D., M.S.P.H.; and Steven N. Blair, P.E.D.

This study was supported by the National Institutes of Health and by an unrestricted research grant from The Coca-Cola Company.

Journal Reference:

Duck-Chul Lee, Xuemei Sui, Enrique G. Artero, I-Min Lee, Timothy S. Church, Paul A. Mcauley, Fatima C. Stanford, Harold W. Kohl III, Steven N. Blair. Long-Term Effects of Changes in Cardiorespiratory Fitness and Body Mass Index on All-Cause and Cardiovascular Disease Mortality in Men: The Aerobics Center Longitudinal Study. Circulation., 2011; 124: 2483-2490 DOI: 10.1161/CIRCULATIONAHA.111.038422