Nutrition Bytes
by Robbie Durand
Does Protein Quality Affect Muscle Growth?
The three key ingredients for increasing muscle size are weight training, positive energy balance and adequate protein intake. Jason Tang and Stuart Phillips from McMaster University in Canada, in a review of literature, concluded that resistance exercise and nutrition independently stimulate muscle growth. Consuming protein after weight training helps maximize training gains in bodybuilders. The protein quality has a small effect on muscle growth. While milk, whey, casein and Soy proteins can promote muscle protein synthesis, milk proteins and their isolated forms (i.e., casein and whey) promote muscle growth better than Soy. Protein mixtures containing large amounts of leucine work best for boosting muscle hypertrophy, particularly in older adults. Bodybuilders should train hard, eat plenty of calories and consume protein after they lift. (Current Opinion in Clinical Nutrition and Metabolic Care, 12: 6671, 2009)
High-Protein Meals Help Burn More Calories At Night
High-protein, low-carbohydrate diets promote weight loss better than high-carbohydrate diets. High-protein diets may depress appetite, stabilize blood sugar and increase the caloric cost of digestion. Australian researchers showed that they might also increase nighttime fat-burning. They found that overweight people metabolized fat better after consuming a high-protein meal. The study did not measure weight loss, so it???s unclear whether this is a short-term or long-term effect. Bodybuilders following a high-protein diet to cut fat should choose healthy foods such as fish, lean meats, low-fat dairy products, fruits and vegetables. They should avoid foods high in saturated fats, such as bacon and butter. (Nutrition & Dietetics, 3: 246-252, 2008)
Creatine Prevents Muscle Loss During Arm Casting
Immobilizing an arm or leg with a plaster cast causes rapid losses in muscle mass, strength and endurance. Creatine monohydrate boosts muscle size and strength in athletes, older adults and people suffering from degenerative diseases. Canadian researchers, led by Adam Johnson, found that Creatine supplements (5 grams, four times per day) prevented muscle deterioration in young men with their arms immobilized with plaster casts for two seven-day periods. Casting without Creatine caused a 3.7 percent decrease in muscle mass, a 21.5 percent decrease in strength and a 43 percent decrease in muscle endurance. During Creatine supplementation, muscle mass actually increases slightly, while strength and muscle endurance decrease by only 4.1 percent and 9.6 percent, respectively. Creatine monohydrate supplements prevent large losses in muscle mass, strength and endurance in cast-immobilized limbs in young men. (Journal Strength Conditioning Research, in press; published online in January 2009)
High Milk Intake Linked To Prostate Cancer
Large population studies found a link between high milk intake and an increased risk of prostate cancer. British researchers, in a review of literature, concluded that the benefits of drinking milk, such as a reduced risk of heart attack, stroke and colorectal cancer, compensate for the increased risk of prostate cancer. In Finland, the risk of prostate cancer increased by 63 percent in men with the highest intakes of dairy foods. High milk consumption reduced the risk of obesity and high blood pressure. Milk and other dairy products decrease angiotensin-converting enzyme (which increases blood pressure), inhibit blood clots that trigger heart attacks and promote brain endorphin activity (natural pain reliever). The benefits of drinking milk exceed the small increased risk of prostate cancer. Nonfat milk is an excellent post-workout drink because it supplies water and high-quality proteins and carbohydrates, which promote recovery and muscle growth. (British Nutrition Foundation Nutrition Bulletin, 33: 279-286, 2008)
Phytoestrogens In Animal Food Products
Phytoestrogens are chemicals found in plants that act like estrogens in the body. They may play a role in hormone-related cancers, cardiovascular disease, bone loss, obesity and type 2 diabetes. They can also create sexual side effects in men, including decreased sperm counts, reduced fertility, and breast tissue growth. A study from Cambridge University in the UK measured the phytoestrogen content of 115 foods of animal origin, including dairy products, eggs, meat, fish and seafood. Researchers found phytoestrogens in all the foods they measured but levels were dramatically higher in Soy products such as Soy milk, Soy infant formula, Soy ice cream and Soy-based meat substitutes. The long-term health effect of phytoestrogens in the diet is unknown. (Journal of Agricultural and Food Chemistry, 56: 10099-10104, 2008)
Caffeine + Carbohydrate Drink Increases Performance
Caffeine increases endurance capacity by preventing fatigue in the central nervous system and promoting muscle function. Carbohydrate ingestion during endurance exercise prevents fatigue by maintaining blood glucose (sugar) levels. British researchers from the University of Birmingham found that cyclists who drank a beverage containing caffeine and glucose during exercise improved endurance capacity by 4.6 percent compared to a glucose beverage alone, and by 9 percent compared to plain water. The caffeine had no effect on carbohydrate metabolism during exercise. Consuming caffeine-carbohydrate drinks during exercise prevents fatigue and promotes endurance capacity. (Medicine Science Sports Exercise, 40: 2096-2104, 2008)
Low-Fat Dairy Foods Speed Fat Loss
Low-fat dairy foods help control bodyweight and fat and promote metabolic health. These foods are high in protein and calcium, which helps cut appetite and maintain blood sugar. A University of Tennessee study led by Michael Zemel showed that consuming three portions per day of low-fat dairy foods helped dieters maintain lost weight. The study included a three-month weight-loss phase and a six-month weight-maintenance phase. During the weight-maintenance period, people consuming more dairy products could eat more food and burn more fat than those consuming less than one serving of dairy food per day. Dairy foods are rich in calcium and vitamin D; proteins and are important in a well-balanced diet. (Nutrition & Metabolism, 5:28 published online October 24, 2008)
Frequent High-Protein Meals Maintain Muscle Mass In Older Adults
People lose 20 percent of their active muscle mass between ages 40 and 60. By age 70, most older adults can???t lift 10 pounds overhead. Loss of muscle mass with age (sarcopenia) decreases quality of life and can lead to catastrophic falls that result in premature death. Douglas Paddon-Jones and Blake Rasmussen, from the University of Texas Medical Branch at Galveston, argued that aging does not reduce the anabolic effects of a high-protein meal. Consuming 25-30 grams of protein stimulates muscle growth in older and younger people. However, protein synthesis slows in aging muscle with inadequate protein intake (less than 20 grams per meal). They recommended that older adults consume 25-30 grams of high-quality protein during each meal. Also, increasing leucine intake helps maintain muscle mass. (Current Opinion in Clinical Nutrition and Metabolic Care, 12:86-90, 2008)
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by Robbie Durand
Does Protein Quality Affect Muscle Growth?
The three key ingredients for increasing muscle size are weight training, positive energy balance and adequate protein intake. Jason Tang and Stuart Phillips from McMaster University in Canada, in a review of literature, concluded that resistance exercise and nutrition independently stimulate muscle growth. Consuming protein after weight training helps maximize training gains in bodybuilders. The protein quality has a small effect on muscle growth. While milk, whey, casein and Soy proteins can promote muscle protein synthesis, milk proteins and their isolated forms (i.e., casein and whey) promote muscle growth better than Soy. Protein mixtures containing large amounts of leucine work best for boosting muscle hypertrophy, particularly in older adults. Bodybuilders should train hard, eat plenty of calories and consume protein after they lift. (Current Opinion in Clinical Nutrition and Metabolic Care, 12: 6671, 2009)
High-Protein Meals Help Burn More Calories At Night
High-protein, low-carbohydrate diets promote weight loss better than high-carbohydrate diets. High-protein diets may depress appetite, stabilize blood sugar and increase the caloric cost of digestion. Australian researchers showed that they might also increase nighttime fat-burning. They found that overweight people metabolized fat better after consuming a high-protein meal. The study did not measure weight loss, so it???s unclear whether this is a short-term or long-term effect. Bodybuilders following a high-protein diet to cut fat should choose healthy foods such as fish, lean meats, low-fat dairy products, fruits and vegetables. They should avoid foods high in saturated fats, such as bacon and butter. (Nutrition & Dietetics, 3: 246-252, 2008)
Creatine Prevents Muscle Loss During Arm Casting
Immobilizing an arm or leg with a plaster cast causes rapid losses in muscle mass, strength and endurance. Creatine monohydrate boosts muscle size and strength in athletes, older adults and people suffering from degenerative diseases. Canadian researchers, led by Adam Johnson, found that Creatine supplements (5 grams, four times per day) prevented muscle deterioration in young men with their arms immobilized with plaster casts for two seven-day periods. Casting without Creatine caused a 3.7 percent decrease in muscle mass, a 21.5 percent decrease in strength and a 43 percent decrease in muscle endurance. During Creatine supplementation, muscle mass actually increases slightly, while strength and muscle endurance decrease by only 4.1 percent and 9.6 percent, respectively. Creatine monohydrate supplements prevent large losses in muscle mass, strength and endurance in cast-immobilized limbs in young men. (Journal Strength Conditioning Research, in press; published online in January 2009)
High Milk Intake Linked To Prostate Cancer
Large population studies found a link between high milk intake and an increased risk of prostate cancer. British researchers, in a review of literature, concluded that the benefits of drinking milk, such as a reduced risk of heart attack, stroke and colorectal cancer, compensate for the increased risk of prostate cancer. In Finland, the risk of prostate cancer increased by 63 percent in men with the highest intakes of dairy foods. High milk consumption reduced the risk of obesity and high blood pressure. Milk and other dairy products decrease angiotensin-converting enzyme (which increases blood pressure), inhibit blood clots that trigger heart attacks and promote brain endorphin activity (natural pain reliever). The benefits of drinking milk exceed the small increased risk of prostate cancer. Nonfat milk is an excellent post-workout drink because it supplies water and high-quality proteins and carbohydrates, which promote recovery and muscle growth. (British Nutrition Foundation Nutrition Bulletin, 33: 279-286, 2008)
Phytoestrogens In Animal Food Products
Phytoestrogens are chemicals found in plants that act like estrogens in the body. They may play a role in hormone-related cancers, cardiovascular disease, bone loss, obesity and type 2 diabetes. They can also create sexual side effects in men, including decreased sperm counts, reduced fertility, and breast tissue growth. A study from Cambridge University in the UK measured the phytoestrogen content of 115 foods of animal origin, including dairy products, eggs, meat, fish and seafood. Researchers found phytoestrogens in all the foods they measured but levels were dramatically higher in Soy products such as Soy milk, Soy infant formula, Soy ice cream and Soy-based meat substitutes. The long-term health effect of phytoestrogens in the diet is unknown. (Journal of Agricultural and Food Chemistry, 56: 10099-10104, 2008)
Caffeine + Carbohydrate Drink Increases Performance
Caffeine increases endurance capacity by preventing fatigue in the central nervous system and promoting muscle function. Carbohydrate ingestion during endurance exercise prevents fatigue by maintaining blood glucose (sugar) levels. British researchers from the University of Birmingham found that cyclists who drank a beverage containing caffeine and glucose during exercise improved endurance capacity by 4.6 percent compared to a glucose beverage alone, and by 9 percent compared to plain water. The caffeine had no effect on carbohydrate metabolism during exercise. Consuming caffeine-carbohydrate drinks during exercise prevents fatigue and promotes endurance capacity. (Medicine Science Sports Exercise, 40: 2096-2104, 2008)
Low-Fat Dairy Foods Speed Fat Loss
Low-fat dairy foods help control bodyweight and fat and promote metabolic health. These foods are high in protein and calcium, which helps cut appetite and maintain blood sugar. A University of Tennessee study led by Michael Zemel showed that consuming three portions per day of low-fat dairy foods helped dieters maintain lost weight. The study included a three-month weight-loss phase and a six-month weight-maintenance phase. During the weight-maintenance period, people consuming more dairy products could eat more food and burn more fat than those consuming less than one serving of dairy food per day. Dairy foods are rich in calcium and vitamin D; proteins and are important in a well-balanced diet. (Nutrition & Metabolism, 5:28 published online October 24, 2008)
Frequent High-Protein Meals Maintain Muscle Mass In Older Adults
People lose 20 percent of their active muscle mass between ages 40 and 60. By age 70, most older adults can???t lift 10 pounds overhead. Loss of muscle mass with age (sarcopenia) decreases quality of life and can lead to catastrophic falls that result in premature death. Douglas Paddon-Jones and Blake Rasmussen, from the University of Texas Medical Branch at Galveston, argued that aging does not reduce the anabolic effects of a high-protein meal. Consuming 25-30 grams of protein stimulates muscle growth in older and younger people. However, protein synthesis slows in aging muscle with inadequate protein intake (less than 20 grams per meal). They recommended that older adults consume 25-30 grams of high-quality protein during each meal. Also, increasing leucine intake helps maintain muscle mass. (Current Opinion in Clinical Nutrition and Metabolic Care, 12:86-90, 2008)
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