Health, Fitness & Nutrition Information

Below are research articles on fitness and nutrition for your information.

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HEALTHY BENEFITS OF REGULAR PHYSICAL ACTIVITY

• Lower resting blood pressure 
• Less abdominal adiposity
• Improved blood lipids
• Better glucose management
• Extended active life expectancy
  
• Preserved physical function in older people
  

Value of Calcium in Maintaining Bone Health

 A broad range of scientific research has demonstrated that an adequate intake of calcium plays an important role in building and maintaining optimum bone mass, and a recent meta-analysis published should not cause consumers to doubt the value of calcium supplements for maintaining bone health.

"Adequate calcium intake is vital to building and maintaining healthy bones, and to preventing osteoporosis—which is caused by a failure to build adequate bone mass or by bone loss that occurs as we age. Most people do not get enough calcium from diet alone, and this is where a calcium supplement can be important to consumers of all ages," said Andrew Shao from the Council for Responsible Nutrition.

The authors of the meta-analysis examined the effects of calcium supplements on the risk of cardiovascular events, concluding there is an increased risk, and calling for a reassessment of the role of calcium supplements for osteoporosis. According to CRN, these conclusions are dramatically overstated, considering the limitations of meta-analysis, in general, and this meta-analysis, specifically.

For example, the analysis could have potentially included over 300 scientific studies on calcium supplementation's effect on bone, but only 15 randomized clinical trials were deemed "eligible for analysis."

Further, seven of the 15 trials evaluated had no, or incomplete, data on cardiovascular outcomes, and only five of the 15 studies accounted for almost all of the cardiovascular outcomes. Further, because the researchers chose to exclude any trials administering calcium plus vitamin D , many large, important trials—including the Women's Health Initiative, which found calcium plus vitamin D had no effect on the risk of coronary heart disease or stroke—were not included.

"The authors characterize these findings as though all of the selected studies suggest increased risk. In fact, the opposite is true: most of the studies do not suggest increased risk," says Dr. Shao. "Bone health is one of the most common reasons why healthcare professionals recommend calcium supplements; there are other health benefits that may be associated with calcium supplementation, such as reduction of colon cancer risk. This is not even considered by the authors. It's unfortunate that these researchers are making sweeping judgments about the value of calcium supplements by only assessing a handful of handpicked studies."

Dr. Shao also pointed out that none of the original studies included in the meta-analysis were designed to evaluate cardiovascular outcomes. Additionally, the data on cardiovascular events was never previously published, so the meta-analysts had to track the information down separately, in some cases, 10 even 20 years after the original study was published.

"Meta-analysis can be a useful tool for scientific evaluation, but we have to recognize its limitations, and keep in mind that its findings are based on a collection of past studies that may have different designs, doses and study populations," says Dr. Shao. "This analysis should not dissuade consumers, particularly young women, from taking calcium supplements. They should talk with their doctors about their current and long-term needs and determine how much calcium they are getting from their diets, and supplement accordingly—likely in combination with vitamin D."

Building Muscle Can Be Achieved by Using Lighter Weights 

Current gym dogma holds that to build muscle size you need to lift heavy weights. However, a new study has shown that a similar degree of muscle building can be achieved by using lighter weights. The secret is to pump iron until you reach muscle fatigue.

"Rather than grunting and straining to lift heavy weights, you can grab something much lighter but you have to lift it until you can't lift it anymore," says Stuart Phillips, associate professor of kinesiology at McMaster University. "We're convinced that growing muscle means stimulating your muscle to make new muscle proteins, a process in the body that over time accumulates into bigger muscles."

Phillips praised lead author Nicholas Burd for masterminding the project that showed it's really not the weight that you lift but the fact that you get muscular fatigue that's the critical point in building muscle. The study used light weights that represented a percentage of what the subjects could lift. The heavier weights were set to 90% of a person's best lift and the light weights at a mere 30% of what people could lift. "It's a very light weight," says Phillips noting that the 90-80% range is usually something people can lift from 5-10 times before fatigue sets in. At 30%, Burd reported that subjects could lift that weight at least 24 times before they felt fatigue.

"We're excited to see where this new paradigm will lead," says Phillips, adding that these new data have practical significance for gym enthusiasts but more importantly for people with compromised skeletal muscle mass, such as the elderly, patients with cancer, or those who are recovering from trauma, surgery or even stroke.

Low Skeletal Muscle Mass Associated With Insulin Resistance

Dieting to be thin is on its own not enough to stave off diabetes. It is also important to be fit and, in particular, to have good muscle mass and strength.

Sarcopenia — low skeletal muscle mass and strength — is often found in obese people and older adults; it has been hypothesized that sarcopenia puts individuals at risk for developing type 2 diabetes.

To gauge the effect of sarcopenia on insulin resistance (the root cause of type 2 diabetes) and blood glucose levels in both obese and non-obese people, researchers performed a cross-sectional analysis of data on 14,528 people from the National Health and Nutrition Examination Survey III.

They found that sarcopenia was associated with insulin resistance in both obese and non-obese individuals. It was also associated with high blood-sugar levels in obese people but not in thin people. These associations were stronger in people under age 60, in whom sarcopenia was associated with high levels of blood sugar in both obese and thin people, and with diabetes in obese individuals.