* Low Testosterone Can Shorten Life
As men age, androgen levels decrease, a condition now termed andropause. Researchers at the University of Washington report that older men with low levels of testosterone who were admitted to a geriatric rehabilitation hospital died sooner and were less likely to survive an accident than men with high levels. (J Am Geriatr Soc, 52: 2077-2081, 2004)
There is no clear cause and effect demonstrated in this study, so the conclusions that can be drawn are conjecture at best. Still, we know that low testosterone levels in aging men are associated with muscle wasting, joint pain, osteoporosis, depression, heart disease, decline in mental function, and other conditions. It seems there is no good reason not to treat andropause with testosterone replacement.
*Prostate Cancer Drugs Increase Fracture Risk
About 30,000 men die each year from prostate cancer, making it the second leading cancer-related cause of death (lung cancer is still first). The first choice in treatment is often testosterone-suppressing drugs that work by decreasing levels of DHT, a derivative of testosterone metabolism linked to prostate cancer. University of Texas researchers found that men treated in this way had a 20 percent risk of suffering a fracture (verses 13 percent in those not taking the drugs). (N Engl J Med, 352: 154-164, 2005)
Prostate enlargement and cancer are not a given, even in men who are receiving hormone replacement therapy. Researchers from the Beth Israel Deaconess Medical Center in Boston report that testosterone replacement does not promote prostate cancer, even in men with a precancerous condition called prostatic intrepithelial neoplasia. The study covered a twelve-month period with no negative effects noted. (J Urology, 170: 2348-2351, 2004)
*DHEA Fights Depression
Congress is about to ban DHEA, relegating it to the same status as steroids. (Tom Harkin of Iowa is the moron behind this legislation.) Researchers from the National Institutes of Mental Health report that DHEA reduced major and minor depression and improved sexual performance in more than half of middle-aged men and women taking it during a six-week study. (Arch Gen Psychiatry, 62: 154-162, 2005)
Not every one responds to DHEA, although dosage is often a factor. This study supports scores of other studies reporting the same benefits, which also include increased muscle mass and strength, both of which are important for those who want to age with dignity.
Two New Creatine Studies
Creatine may be the most widely studied supplement in history. One new study shows that creatine, like glutamine, can reduce muscle wasting during immobilization. Brazilian scientists report that creatine prevented muscle wasting in the legs of immobilized rats and increased muscle creatine phosphate levels by 18 to 25 percent (this is a good thing). It appears that the creatine helps spur the production of satellite cells, which are crucial for protein synthesis. (Clin Nutr, 23: 1176-1183, 2004)
The other creatine study suggests that it can improve carbohydrate metabolism in muscle, a finding that could be helpful for treating metabolic syndrome and diabetes. Researchers from St. Louis University report that creatine increased levels of a glucose-transporting chemical called GLUT4, which increases the deposition of glucose in cells. (Am J Endocrinol Metab, 288: E347-E352, 2004)
Everyone should be using creatine at a dosage of 5 grams a day. Studies continue to reveal new benefits of this supplement, one of the safest known to science. What was once just a supplement for weight lifters and sprinters should now be a part of everyone's daily intake.
Thursday, August 25, 2005
Sunday, August 14, 2005
NY Times Defends Trans Fats
In what may be one of the dumbest articles on health I have ever read, a New York Times reporter defends trans fats, labeling a call by Dr. Thomas Frieden, the New York City health commissioner, to remove trans fats from restaurant foods the "panic du jour."
Author Gina Kolata suggests that the hype around the health risks of trans fats has been blown way out of proportion. She cites the valid fact that Americans consume much more saturated fat than trans fats as evidence that our concerns are misplaced. While it is true that saturated fats are the primary culprit in heart disease, it is also true that we need some saturated fat in our diets to maintain healthy hormone levels; around ten percent of fat calories consumed should be from saturated sources unless one is battling high cholesterol. Yet it is also true that we don't need ANY trans fats in our diets and that they serve no good purpose other than making processed foods more palatable. Trans fats could be completely removed from the American diet without any detriment to health and only a small financial loss for processed foods manufacturers.
What follows is an excerpt from an article I wrote on unhealthy fats for an issue of Equilibrium in the summer of 2003 that explains some of the science and dangers of trans fats.
First, the bad news: excess dietary fat has been linked to heart disease, obesity, autoimmune disorders, colon cancer, prostate cancer, breast cancer, and inflammatory diseases, such as arthritis. In terms of caloric intake, one gram of fat yields nine calories, while protein and carbohydrates each yield four calories. It has long been assumed that eating fat can make us fat -- in fact, eating the wrong fats can kill us.
Now, the good news: not all fats are equal. A handful of researchers, most notably the late Dr. Atkins, were able to prove that dietary fat is not the only factor that makes a person overweight. Their research and dietary strategies showed that carbohydrates -- and the associated rise in insulin levels -- are the most significant cause of body fat accumulation. These researchers also discovered that certain fats, such as the omega-3s, are good for us.
Saturated Fat
For years we have known that saturated fat increases serum cholesterol and is a leading cause of atherosclerosis (fat deposits in arteries). We know, therefore, that high-fat animal foods seriously increase the risk of heart disease and stroke. Unfortunately, this knowledge hasn't led to healthier dietary habits for the majority of Americans.
We also know that saturated fat is preferentially stored in adipose tissue (the body's fat cells), which explains why eating fat makes us fat. Because saturated fats have no double-bonded carbons in their structure, they can yield more energy per carbon than if they had double bonds (like the omega fatty acids), which is why the body stores them in adipose tissue.
The human body uses fats according to their structure. Polyunsaturated fats are used as the building materials for cell membranes due to their flexibility. Saturated fats are much more rigid, so the body will use them only as stored energy. Consuming saturated fats with a high carbohydrate meal (which significantly raises insulin) will result in the saturated fat quickly being shuttled into adipose tissue. A Big Mac, fries, and a chocolate shake is the perfect recipe for fat storage.
However, while the fat is still circulating in the blood, it has a tendency to clump due to its long-chain structure. These clumps of fat can be deposited within arteries, organs, and even muscle. When these clumps of fat are deposited in organs or around glands, they greatly increase the risk of cancer.
One possible explanation for the increase in cancer risk due to fat accumulation is the estrogenic properties of fat tissue. While estrogen is necessary for normal health, excess estrogen has been linked to breast and prostate cancers, and is suspected in several other forms of cancer, including colon and skin cancers. It turns out that adipose tissue not only has more estrogen receptors than normal cells, but it also can create estrogen. Therefore, the more adipose tissue a person carries, the higher the risk of developing certain types of cancer.
For many years, we thought saturated fat was the worst fat in the diet. But there has been a lot of research in recent years showing trans-fatty acids to be equally, if not more harmful.
Trans-Fatty Acids
Trans-fatty acids (TFAs) are created by the hydrogenation of mono- or polyunsaturated lipids. The process involves adding hydrogen to a vegetable oil in a complex chemical reaction involving high heat and pressure. The resultant oil is solid at room temperature and becomes rancid much more slowly. TFAs are used in most processed foods and are the foundation of margarine and vegetable shortenings.
Natural unsaturated oils are in a "cis" format, meaning that the hydrogen atoms are all on the same side. This allows the lipid to be more flexible, and most polyunsaturated fats are, in fact, curved, allowing them fit within cells without abnormally altering the cell's shape.
During the hydrogenation process, the hydrogen atoms move to the opposite side of the carbons, thus the designation "trans." This creates a fat molecule that is even more rigid than saturated fat -- a molecule produced naturally only in the stomachs of ruminate animals (and therefore found in small amounts in milk an animal fat). When TFA molecules, which resemble saturated fat more than unsaturated fat, are used in the formation of new cells and cellular membranes, they create more rigid -- and unhealthy -- cell structures.
Research has also shown that TFAs increase cholesterol at least as much as do saturated fats, possibly more. Although both types of fat seem to increase LDL cholesterol (the bad kind) equally, TFAs also reduce HDL cholesterol (the good kind). This factor alone makes them more harmful than saturated fats.
But trans fats are also implicated in increasing lipoprotein levels, which results in the formation of arterial plaque. The combined action of lowered HDL, increased LDL, increased cholesterol, and increased lipoproteins makes TFAs the single greatest dietary risk for coronary heart disease. In addition, TFAs contribute to the risk of type II diabetes and have been linked to the onset of several forms of cancer.
TFAs have absolutely no health benefits. All foods containing these products should carry a clear warning label, just like a pack of cigarettes. Personally, I believe that TFAs are as deadly as cigarettes. In fact, Holland has banned TFAs from food production, a step we unfortunately are not likely to see here.
Author Gina Kolata suggests that the hype around the health risks of trans fats has been blown way out of proportion. She cites the valid fact that Americans consume much more saturated fat than trans fats as evidence that our concerns are misplaced. While it is true that saturated fats are the primary culprit in heart disease, it is also true that we need some saturated fat in our diets to maintain healthy hormone levels; around ten percent of fat calories consumed should be from saturated sources unless one is battling high cholesterol. Yet it is also true that we don't need ANY trans fats in our diets and that they serve no good purpose other than making processed foods more palatable. Trans fats could be completely removed from the American diet without any detriment to health and only a small financial loss for processed foods manufacturers.
What follows is an excerpt from an article I wrote on unhealthy fats for an issue of Equilibrium in the summer of 2003 that explains some of the science and dangers of trans fats.
First, the bad news: excess dietary fat has been linked to heart disease, obesity, autoimmune disorders, colon cancer, prostate cancer, breast cancer, and inflammatory diseases, such as arthritis. In terms of caloric intake, one gram of fat yields nine calories, while protein and carbohydrates each yield four calories. It has long been assumed that eating fat can make us fat -- in fact, eating the wrong fats can kill us.
Now, the good news: not all fats are equal. A handful of researchers, most notably the late Dr. Atkins, were able to prove that dietary fat is not the only factor that makes a person overweight. Their research and dietary strategies showed that carbohydrates -- and the associated rise in insulin levels -- are the most significant cause of body fat accumulation. These researchers also discovered that certain fats, such as the omega-3s, are good for us.
Saturated Fat
For years we have known that saturated fat increases serum cholesterol and is a leading cause of atherosclerosis (fat deposits in arteries). We know, therefore, that high-fat animal foods seriously increase the risk of heart disease and stroke. Unfortunately, this knowledge hasn't led to healthier dietary habits for the majority of Americans.
We also know that saturated fat is preferentially stored in adipose tissue (the body's fat cells), which explains why eating fat makes us fat. Because saturated fats have no double-bonded carbons in their structure, they can yield more energy per carbon than if they had double bonds (like the omega fatty acids), which is why the body stores them in adipose tissue.
The human body uses fats according to their structure. Polyunsaturated fats are used as the building materials for cell membranes due to their flexibility. Saturated fats are much more rigid, so the body will use them only as stored energy. Consuming saturated fats with a high carbohydrate meal (which significantly raises insulin) will result in the saturated fat quickly being shuttled into adipose tissue. A Big Mac, fries, and a chocolate shake is the perfect recipe for fat storage.
However, while the fat is still circulating in the blood, it has a tendency to clump due to its long-chain structure. These clumps of fat can be deposited within arteries, organs, and even muscle. When these clumps of fat are deposited in organs or around glands, they greatly increase the risk of cancer.
One possible explanation for the increase in cancer risk due to fat accumulation is the estrogenic properties of fat tissue. While estrogen is necessary for normal health, excess estrogen has been linked to breast and prostate cancers, and is suspected in several other forms of cancer, including colon and skin cancers. It turns out that adipose tissue not only has more estrogen receptors than normal cells, but it also can create estrogen. Therefore, the more adipose tissue a person carries, the higher the risk of developing certain types of cancer.
For many years, we thought saturated fat was the worst fat in the diet. But there has been a lot of research in recent years showing trans-fatty acids to be equally, if not more harmful.
Trans-Fatty Acids
Trans-fatty acids (TFAs) are created by the hydrogenation of mono- or polyunsaturated lipids. The process involves adding hydrogen to a vegetable oil in a complex chemical reaction involving high heat and pressure. The resultant oil is solid at room temperature and becomes rancid much more slowly. TFAs are used in most processed foods and are the foundation of margarine and vegetable shortenings.
Natural unsaturated oils are in a "cis" format, meaning that the hydrogen atoms are all on the same side. This allows the lipid to be more flexible, and most polyunsaturated fats are, in fact, curved, allowing them fit within cells without abnormally altering the cell's shape.
During the hydrogenation process, the hydrogen atoms move to the opposite side of the carbons, thus the designation "trans." This creates a fat molecule that is even more rigid than saturated fat -- a molecule produced naturally only in the stomachs of ruminate animals (and therefore found in small amounts in milk an animal fat). When TFA molecules, which resemble saturated fat more than unsaturated fat, are used in the formation of new cells and cellular membranes, they create more rigid -- and unhealthy -- cell structures.
Research has also shown that TFAs increase cholesterol at least as much as do saturated fats, possibly more. Although both types of fat seem to increase LDL cholesterol (the bad kind) equally, TFAs also reduce HDL cholesterol (the good kind). This factor alone makes them more harmful than saturated fats.
But trans fats are also implicated in increasing lipoprotein levels, which results in the formation of arterial plaque. The combined action of lowered HDL, increased LDL, increased cholesterol, and increased lipoproteins makes TFAs the single greatest dietary risk for coronary heart disease. In addition, TFAs contribute to the risk of type II diabetes and have been linked to the onset of several forms of cancer.
TFAs have absolutely no health benefits. All foods containing these products should carry a clear warning label, just like a pack of cigarettes. Personally, I believe that TFAs are as deadly as cigarettes. In fact, Holland has banned TFAs from food production, a step we unfortunately are not likely to see here.
Monday, August 8, 2005
Praise the Bean!
I love coffee. Strong, black, rich-tasting coffee. But my enjoyment has been tempered in recent years by speculation that coffee (and its caffeine content) may reduce insulin sensitivity and lead to metabolic disorders such as diabetes.
However, a new meta-study looked at all the available information to assess the risk of type-II diabetes in habitual coffee drinkers.
The review consisted of a search in MEDLINE through January 2005 and examined the reference lists of studies that focused on habitual coffee consumption and risk of type 2 diabetes. Nine studies involving 192,473 participants met the criteria and were included in the review. Studies of Type 1 diabetes, animal studies, and studies of short-term exposure to coffee or caffeine were not included in the review.
The relative risk of type 2 diabetes was lowest in those who had the highest coffee consumption (6 to 7 cups per day) compared to those in the lowest consumption group (0 to 2 cups per day. The association did not differ substantially by gender, obesity, or region (United States and Europe). The results are consistent with cross-sectional studies conducted in northern Europe, southern Europe, and Japan. Higher coffee consumption was consistently associated with a lower prevalence of newly detected hyperglycemia, particularly post-prandial (following a meal) hyperglycemia.
The results of this review suggest that habitual coffee consumption is associated with a substantially lower risk of type 2 diabetes.
Van Dam, Rob. M & HU, Frank, B. Coffee Consumption and Risk of Type 2 Diabetes. JAMA. 2005; 294:97-104.
Information on this study is cited courtesy of FitBits, compiled by Jeannie Patton, MS, CSCS.
However, a new meta-study looked at all the available information to assess the risk of type-II diabetes in habitual coffee drinkers.
The review consisted of a search in MEDLINE through January 2005 and examined the reference lists of studies that focused on habitual coffee consumption and risk of type 2 diabetes. Nine studies involving 192,473 participants met the criteria and were included in the review. Studies of Type 1 diabetes, animal studies, and studies of short-term exposure to coffee or caffeine were not included in the review.
The relative risk of type 2 diabetes was lowest in those who had the highest coffee consumption (6 to 7 cups per day) compared to those in the lowest consumption group (0 to 2 cups per day. The association did not differ substantially by gender, obesity, or region (United States and Europe). The results are consistent with cross-sectional studies conducted in northern Europe, southern Europe, and Japan. Higher coffee consumption was consistently associated with a lower prevalence of newly detected hyperglycemia, particularly post-prandial (following a meal) hyperglycemia.
The results of this review suggest that habitual coffee consumption is associated with a substantially lower risk of type 2 diabetes.
Van Dam, Rob. M & HU, Frank, B. Coffee Consumption and Risk of Type 2 Diabetes. JAMA. 2005; 294:97-104.
Information on this study is cited courtesy of FitBits, compiled by Jeannie Patton, MS, CSCS.
Tuesday, August 2, 2005
Weight Training: Men Get Bigger, Women Get Stronger
From Exercise ETC's FitBits:
Men Get Bigger, Women Get Stronger In Response to Strength Training
Adults who begin resistance training often experience vastly different gains in strength and size than counterparts who are on similar programs. The purpose of this study was to document the range of responses in men and women to a progressive resistance program.
Five hundred eighty-five subjects (342 women, 243 men) ranging in age from 18-40 served as subjects. Subjects participated in 12 weeks of progressive resistance training of the non-dominant elbow flexors. Testing consisted of evaluating the isometric and dynamic strength of the elbow flexors, as well as measuring the cross sectional area of the biceps brachii, as determined by MRI.
The results showed that increases in the muscle cross sectional area ranged from 2% to 59%. Isometric strength increases ranged from 32% to 149% and dynamic strength increases ranged from 0% to 250%. Men experienced greater gains in the muscle's cross sectional area than women did, but women had greater gains in relative strength than men.
Results of this study show a wide range of strength and size gains in response to resistance training for men and women, with some participants showing no change and others showing dramatic changes. Men increased slightly more in size than women, but women showed considerably more increase in relative strength than men.
Hubal, Monica. et al. Variability in Muscle Size and Strength Gain after Unilateral Resistance Training. Medicine & Science in Sports & Exercise. 2005, 37(6), 964-972.
The most obvious difference here is in hormone levels. Higher levels of testosterone will result in greater protein synthesis, which results in larger muscles. However, it is interesting that the women showed greater increases in relative strength in the absence of higher T levels.
I'll post updated info whenever it becomes available. There has long been an assumption that women should train exactly as men train, but that may change as we find physiological training differences between the genders.
Men Get Bigger, Women Get Stronger In Response to Strength Training
Adults who begin resistance training often experience vastly different gains in strength and size than counterparts who are on similar programs. The purpose of this study was to document the range of responses in men and women to a progressive resistance program.
Five hundred eighty-five subjects (342 women, 243 men) ranging in age from 18-40 served as subjects. Subjects participated in 12 weeks of progressive resistance training of the non-dominant elbow flexors. Testing consisted of evaluating the isometric and dynamic strength of the elbow flexors, as well as measuring the cross sectional area of the biceps brachii, as determined by MRI.
The results showed that increases in the muscle cross sectional area ranged from 2% to 59%. Isometric strength increases ranged from 32% to 149% and dynamic strength increases ranged from 0% to 250%. Men experienced greater gains in the muscle's cross sectional area than women did, but women had greater gains in relative strength than men.
Results of this study show a wide range of strength and size gains in response to resistance training for men and women, with some participants showing no change and others showing dramatic changes. Men increased slightly more in size than women, but women showed considerably more increase in relative strength than men.
Hubal, Monica. et al. Variability in Muscle Size and Strength Gain after Unilateral Resistance Training. Medicine & Science in Sports & Exercise. 2005, 37(6), 964-972.
The most obvious difference here is in hormone levels. Higher levels of testosterone will result in greater protein synthesis, which results in larger muscles. However, it is interesting that the women showed greater increases in relative strength in the absence of higher T levels.
I'll post updated info whenever it becomes available. There has long been an assumption that women should train exactly as men train, but that may change as we find physiological training differences between the genders.
Monday, August 1, 2005
Fructose Increases Obesity
A new study found that consumption of fructose increased body weight despite a reduction in calories.
In the study, researchers at the University of Cincinnati allowed mice to freely consume either plain water or fructose-sweetened water and soft drinks. The mice that drank the fructose-sweetened water and soft drinks gained weight, even though they took in fewer calories from solid food. By the end of the study, the mice that consumed fructose-sweetened beverages had 90 percent more body fat than the mice that consumed water only.
I have been opposed to fructose for a while. In fact, I often advise against high-sugar fruits in an effort to avoid fructose. The liver isn't able to metabolize fructose for energy in the same that it does other sugars, so the fructose is converted to triglycerides and immediately stored as fat. Until now, it was assumed that the fructose would be burned for energy fairly quickly (after being converted to triglycerides), but this study suggests that even with a caloric deficit the body will store fructose as fat.
Bottom line: Avoid ALL sweetened soft drinks and fruit juices. Also make an effort to limit high-sugar fruits like oranges and bananas, and if you must eat them, do so earlier in the day when metabolism is running at its highest.
UPDATE:
An article on Science Daily has a little more info on this topic.
Results from an earlier study in humans led by Peter Havel, DVM, PhD, an endocrinology researcher at the University of California, Davis, and coauthored by Dr. Tschöp, found that several hormones involved in the regulation of body weight, including leptin, insulin and ghrelin, do not respond to fructose as they do to other types of carbohydrates, such as glucose.
Based on that study and their new data, the researchers now also believe that another factor contributing to the increased fat storage is that the liver metabolizes fructose differently than it does other carbohydrates.
“Similar to dietary fat, fructose doesn’t appear to fully trigger the hormonal systems involved in the long-term control of food intake and energy metabolism,” said coauthor Dr. Havel.
In the study, researchers at the University of Cincinnati allowed mice to freely consume either plain water or fructose-sweetened water and soft drinks. The mice that drank the fructose-sweetened water and soft drinks gained weight, even though they took in fewer calories from solid food. By the end of the study, the mice that consumed fructose-sweetened beverages had 90 percent more body fat than the mice that consumed water only.
I have been opposed to fructose for a while. In fact, I often advise against high-sugar fruits in an effort to avoid fructose. The liver isn't able to metabolize fructose for energy in the same that it does other sugars, so the fructose is converted to triglycerides and immediately stored as fat. Until now, it was assumed that the fructose would be burned for energy fairly quickly (after being converted to triglycerides), but this study suggests that even with a caloric deficit the body will store fructose as fat.
Bottom line: Avoid ALL sweetened soft drinks and fruit juices. Also make an effort to limit high-sugar fruits like oranges and bananas, and if you must eat them, do so earlier in the day when metabolism is running at its highest.
UPDATE:
An article on Science Daily has a little more info on this topic.
Results from an earlier study in humans led by Peter Havel, DVM, PhD, an endocrinology researcher at the University of California, Davis, and coauthored by Dr. Tschöp, found that several hormones involved in the regulation of body weight, including leptin, insulin and ghrelin, do not respond to fructose as they do to other types of carbohydrates, such as glucose.
Based on that study and their new data, the researchers now also believe that another factor contributing to the increased fat storage is that the liver metabolizes fructose differently than it does other carbohydrates.
“Similar to dietary fat, fructose doesn’t appear to fully trigger the hormonal systems involved in the long-term control of food intake and energy metabolism,” said coauthor Dr. Havel.
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