Comparing Different Protein Sources.
All Protein Foods Are Not Created Equal:
The Importance of "Complete" Quality Protein
Dietary proteins are divided into two kinds of proteins: complete proteins, which include all essential amino acids in the exact amounts required by the body for growth and incomplete proteins, which are deficient in one or more essential amino acids.
Essential amino acids play major roles in performance, recovery and reactions to stress. Complete proteins supply the correct ratio of amino acids needed to promote muscle synthesis. The ratios are important because in order for the body to build muscle, all the essential amino acids must be available at the same time.
A deficiency of even one essential amino may suppress critical metabolic functions, which are necessary for the repair and buildup of tissues including muscles. Moreover, it has been assumed that a deficiency of essential amino acids would limit protein synthesis (and growth) proportionally to the extent of deficiency.
High Quality Complete Proteins:
High Quality Complete Proteins Include:
Protein From Animal Sources:
Protein that comes from animal sources contains all of the essential amino acids that we need. The obvious problem with animal proteins is that they can also contain large amounts of saturated fats, which can not only make you fat but put you at risk for heart disease and stroke. Fortunately, fat from animal proteins can easily be avoided proper food education that will help you make the right choices. Protein animal products include:
Meat Proteins:
Although tuna, chicken breasts, turkey, and other white fish are very good low-fat and high-protein sources lean red meat will provide you with better gains. Besides being packed with protein, they're good sources of B vitamins, iron and zinc. There are several studies have shown that people consuming red meat gained more mass than those consuming chicken and tuna, the other "meats" of choice in the bodybuilding community.
Tips For Purchasing:
When purchasing ground meat check the labels, since most stores offer several types of ground meat, with varying percentages of fat by weight. Look for packages with the lowest fat percentage - 15 percent or less.
Look for moistness and bright color. Red or pink meat can be a sign of freshness, although vacuum-packed meats may look slightly purplish for lack of exposure to air. Avoid meat that looks brown, as it may be spoiled.
Avoid meat that is heavily marbled. Marbled meat is streaked with fat. Look for meat with the least amount of visible fat. Choose lean cuts.
Lean cuts of beef include round, chuck, sirloin or tenderloin. Lean pork includes tenderloin and loin chops. Look for USDA Choice or USDA Select grades of beef rather than USDA Prime, which usually has more fat content.
When at home do not consume meat that does not smell fresh. Consumption of rancid protein has shown to be a source of health issues later in life.
With all that being said, it is also important to note that because the biological Value (BV) of meat can be 80 or less, more meat will have to be eaten to get the needed protein (as opposed to proteins with a higher Biological Value) which is often not desired during a low calorie diet.
Poultry Proteins:
Poultry can be an excellent source of protein, and is often a primary staple of those trying to lose weight, as well as competitive athletes, including bodybuilders.
The key however is to select lean cuts, limit added oils and condiments, and choose a low fat preparation method (broil, bake or steam; not fry).
The leanest poultry choice is white meat from the breast of chicken or turkey, without the skin. Although skinless dark meat is leaner than some cuts of beef or pork, it has nearly twice the fat calories as does white meat, so avoid the dark meat.
Tips For Purchasing:
Many grocery stores have both ground chicken and ground turkey, most of which is not low fat because they include more fattening parts of the bird, including skin, and actual fat in the grinding process. In these cases the ground poultry can actually have more fat than many cuts of beef. To make the leanest choice, choose ground breast meat, or look for extra lean (99%) low-fat ground chicken or turkey.
Fish Proteins:
Fish is high in protein, but low in saturated fat and cholesterol, making it a good substitute for poultry and meat. However, when selecting fish especially if you plan to eat it uncooked (e.g., sushi/sashimi) it is of paramount importance to select a reliable seafood source.
Be aware that even large chain supermarket or a specialty fish market can offer seafood that has been mishandled, or is close or past it's best date for consumption.
Tips For Purchasing:
Look for fresh seafood. Fresh fish has a moist, bright surface with shiny, well-attached scales. Also look for bright pink or red gills and firm, springy flesh.
Avoid seafood that is dry, flaky, discolored and is overly fishy-smelling. Consumption of rancid fish can cause several health issues; food borne diseases, and make you very ill.
Dairy Protein:
Milk is a nutrient rich complete ideal food. Milk contains all the essential nutrients required for growth. Milk is also rich in many vitamins and minerals such as calcium, phosphorus, sodium, potassium vitamin A, thiamine, riboflavin and nicotinic acid and vitamin B12 which is absent in vegetarian food items.
The proteins of milk are of a high biological value cow's milk provides 3.2gm of protein and 67kcl of energy per 100 ml. Buffalo milk provides even more (4.25gm of protein and 117kcl of energy) per 100 ml. For a comparison of nutritional value of various milks refer to the table below.
The all important protein from milk comes from the milk solids (Milk is composed of approximately 87% water and 13% solids). The solids contain approximately 37% lactose, 30% fat (2/3 of which is saturated fat) and 27% protein. The protein is comprised of casein (about 80%) and whey protein about 20 %). See Table 3 below.
Protein From Plant Sources:
Legumes:
Legumes are a class of vegetables that includes beans, peas and lentils - are typically low in fat, contain no cholesterol and are high in protein, iron, folate, potassium, magnesium, and phytochemicals.
Phytochemicals are a group of compounds that may help prevent chronic diseases such as cardiovascular disease and cancer. They are also a good source of fiber which has also shown to reduce the risk of developing diabetes and help lower blood cholesterol levels, which can reduce your risk of heart disease.
However, most legumes with the exception of soy are not complete proteins (i.e., they do not contain all of the essential amino acids that we need) which are why they are not preferred by bodybuilders. Beans, for example, are very high in total protein with about 12 -15 grams per cup, however, beans do not contain the essential amino acid methionine.
Similarly, grains are lack the essential amino acid lysine. Because protein from most plants lacks certain amino acids, it has a lower biological value than protein from animal sources.
There are some ways to balance out the amino acid profile. It has been frequently pointed out that combining two incomplete sources of vegetable protein such as rice and beans provides you with the full complement of essential amino acids.
In the following table I have listed some complimentary proteins that can help increase the overall amino acid panel, although I must state that eating this way is not the most efficient or best way for a bodybuilder.
Soy:
The most common source of plant protein regarding consumption is soy protein. Soy has been consumed for more than 2,000 years by people throughout East Asia.
In Western countries, soybeans had attracted people's attention only since the 1960s as an economical and high-quality vegetable protein source for humans.
Soy is found most commonly in the United States as tofu, but other common sources include, soy flour, soy nuts, soy milk, soybeans, "meat analog" products, such as soy sausages, burgers, franks, and cold cuts, all of which are intended as substitutes for their animal-based counterparts.
The main reported benefit of soy is that it is reported to help lower cholesterol. Data show that substitution of soy protein for animal protein is associated with significant decreases in total cholesterol (LDL-C) and triglycerides, while maintaining high density lipoprotein cholesterol (HDL-C)-the good cholesterol-concentrations.
Keeping cholesterol levels under control will enhance overall health, and prolong ones training efforts. This article aims to demystify the many, often confusing, aspects of cholesterol metabolism, while showing how to improve your cholesterol profile.
Soy also contains isoflavones which can act as antioxidants, which help reduce the risk of cancers. Isoflavones are also reported to reduce the risk of arteriosclerosis (plaque buildup in the arteries). Isoflavones improve bone retention and lumbar vertebral bone mineral combating osteoporosis.
Note: isoflavones do act as weaker plant-based estrogens it is currently not recommended that women who have had or are at risk of developing hormone dependent tumors consume a large amount of soy.
So, while soy can be beneficial, especially as a means to decrease saturated fat in the diet, moderate consumption is best under these circumstances. Other reported health benefits of soy include:
In order to reap the purported health benefits of soy, it is recommended that 25 grams or more of soy protein be consumed per day.
Other Sources Of Plant Protein:
Other sources of plant protein include some starchy foods and vegetables as well, although their protein content is fairly low.
Methods of Assessing Protein Quality:
Biological Value (BV):
Proteins are ranked according to Biological Values (BV), arbitrary numbers given to protein to show comparisons in their availability within the body.
At the time the system was introduced eggs were given the highest Biological Value of 100 because they are the most bio-available natural protein. Afterwards whey was isolated from milk and shown to have a higher Biological Value, and depending on the process used can yield percentage from 104 to 154 on the scale.
The Biological Value is based on how much of the protein consumed is actually absorbed and utilized by the body. It is an attempt to measure how efficiently protein is used in the body. The higher the amount of protein (nitrogen) that is actually retained, the greater the Biological Value.
To determine a food's Biological Value, scientists provide a measured intake of protein, and then note the nitrogen uptake vs. nitrogen excretion. A biological value of 100 is maximal, since a Biological Value of 100, means that all of the protein absorbed has been utilized with none lost, therefore it is impossible to have a Biological Value over 100.
When a protein supplement is listed as having a Biological Value over 100, the company has intentionally manipulated the number for marketing purposes or perhaps unintentionally confused Biological Value with another method of rating protein quality, such as perhaps the Chemical a comparison of the amino acid pattern in an ideal reference protein to a test protein and therefore the number can exceed 100.
Why Protein Biological Value Is NOT The Best Measure Of Protein Quality For The Athlete.
The biological value is not a universally accepted measure of protein quality because of several factors. For example, Biological Value testing is always done in the fasting state, which affects nitrogen uptake differently from what takes place when subjects are in a fed state.
Simply put, fasting changes the way the body absorbs nitrogen in protein. When this is done the utilization actually increases. As we all know this is not how bodybuilders eat.
Additionally, bodybuilders and athletes are a unique subset of the general population in that their needs and metabolisms are uniquely different from sedimentary people and the general population.
For instance, athletes in general will often have increased metabolic requirements for amino acids such as tyrosine, methionine-SamE or lysine-carnitine, which serve as building blocks for stress hormones and energy compounds.
These amino acids are often required in extra amounts by athletes due to high-energy demand and the need to perform under extreme mental and physical stress. Therefore, athletes generally speaking often will need extra protein with extra essential as well as conditionally essential amino acids which is why the Biological Value system alone is not a practical method to measure protein quality/needs for athletes, especially bodybuilders.
Why Protein Biological Value May Be Misleading:
The Biological Value of proteins has been measured via nitrogen balance. A positive nitrogen balance generally indicates high Biological Value and vice-versa.
There are however some serious concerns regarding the accuracy of this evaluation system. Biological Value tests are based on studies that measured protein utilization in a tightly controlled feeding environment, that doesn't resemble real life situations.
Furthermore, these tests were conducted primarily on proteins in their raw state, overlooking the fact that most protein foods are habitually consumed in a processed or cooked form.
Processing and cooking significantly change the amino score and Biological Value of raw protein foods. To make the matter even more confusing, protein Biological Value studies were based on small servings (100 to 200mg per kilogram of body weight).
In such a small servings, even inferior proteins are almost fully utilized with a relatively high Biological Value score. Unfortunately, these high scores dramatically decline when protein is consumed in normal or large amounts, such as with athletes or bodybuilders, a fact that must be calculated when designing a nutritional program.
The most efficient conventional method to evaluate protein quality is the so-called PDCAAS (Protein Digestibility Corrected Amino Acid Score) developed by the Food and Agriculture Organization.
Factors That Promote Or Suppress Protein Biological Value:
The variables that influence protein Biological Value and utilization may appear as contradictory and somewhat confusing. Nonetheless, to put some order to this madness, here is a list of protein Biological Values most enhancing vs. most suppressing factors.
Note that real life protein Biological Value would likely indicate how much of it could be utilized for actual growth.
Real-Life Protein Biological Value Is Enhanced By:
Protein Biological Value Is Suppressed By:
Low calorie intake
Food processing
Protein denaturing (such as exposure to high heat)
Single source of protein
Large portions proteins
Excessive intake of dietary fiber
Vitamin and mineral deficiencies
Body Stress
Indigestion
*Biological Value measures the amount of protein (or more precisely - the nitrogen) retained in the human body per gram of protein absorbed. The measure started out as a percentage - with a whole egg being the best - 100% nitrogen absorbed.
However, as whey processing got better whey became a better source of protein than an egg. This would mean that whey would have to score higher than 100, which (because that number is a percentage) is not possible. So either the percentage must be dropped - because greater than 100% does not make much sense (and then whey can score the reported 159 Biological Value) or the reference point (the egg) would have to be dropped or lowered). This is one reason why Biological Value is no longer the measure of choice.
Upside Of High Biological Value Products:
Because high Biological Value products are easily absorbed by the body, consuming them immediately upon waking (when the body is hungry for protein) and immediately following training is ideal.
High Biological Value products can also be of great value when on a calorie restricted diet because of greater high Biological Value products has a higher utilization. In other words, when you are dieting higher quality (higher Biological Value) protein allows you to take in fewer calories for the amount of protein consumed.
Downsides Of High Biological Value Products:
The downside of the rapid is that the protein is rendered useless within the body quickly. This is why large amounts of high Biological Value products, like whey should not be consumed in large quantities.
High Biological Value products, like whey should be consumed more frequently (every 40-60 minutes) and in smaller quantities (15-20 grams), to avoid this problem. Consuming 50 grams of whey in one sitting will result in 25 to 50 percent of the product being wasted (assuming the protein has not denatured).
clicca qui per la PARTE 2
All Protein Foods Are Not Created Equal:
The Importance of "Complete" Quality Protein
Dietary proteins are divided into two kinds of proteins: complete proteins, which include all essential amino acids in the exact amounts required by the body for growth and incomplete proteins, which are deficient in one or more essential amino acids.
Essential amino acids play major roles in performance, recovery and reactions to stress. Complete proteins supply the correct ratio of amino acids needed to promote muscle synthesis. The ratios are important because in order for the body to build muscle, all the essential amino acids must be available at the same time.
A deficiency of even one essential amino may suppress critical metabolic functions, which are necessary for the repair and buildup of tissues including muscles. Moreover, it has been assumed that a deficiency of essential amino acids would limit protein synthesis (and growth) proportionally to the extent of deficiency.
High Quality Complete Proteins:
High Quality Complete Proteins Include:
- Chicken breast
- Turkey breast
- Egg whites
- Fish
- Lean red meats (top round, lean sirloin, and flank)
- Non-fat or low fat dairy products
Protein From Animal Sources:
Protein that comes from animal sources contains all of the essential amino acids that we need. The obvious problem with animal proteins is that they can also contain large amounts of saturated fats, which can not only make you fat but put you at risk for heart disease and stroke. Fortunately, fat from animal proteins can easily be avoided proper food education that will help you make the right choices. Protein animal products include:
Meat Proteins:
Although tuna, chicken breasts, turkey, and other white fish are very good low-fat and high-protein sources lean red meat will provide you with better gains. Besides being packed with protein, they're good sources of B vitamins, iron and zinc. There are several studies have shown that people consuming red meat gained more mass than those consuming chicken and tuna, the other "meats" of choice in the bodybuilding community.
Tips For Purchasing:
When purchasing ground meat check the labels, since most stores offer several types of ground meat, with varying percentages of fat by weight. Look for packages with the lowest fat percentage - 15 percent or less.
Look for moistness and bright color. Red or pink meat can be a sign of freshness, although vacuum-packed meats may look slightly purplish for lack of exposure to air. Avoid meat that looks brown, as it may be spoiled.
Avoid meat that is heavily marbled. Marbled meat is streaked with fat. Look for meat with the least amount of visible fat. Choose lean cuts.
Lean cuts of beef include round, chuck, sirloin or tenderloin. Lean pork includes tenderloin and loin chops. Look for USDA Choice or USDA Select grades of beef rather than USDA Prime, which usually has more fat content.
When at home do not consume meat that does not smell fresh. Consumption of rancid protein has shown to be a source of health issues later in life.
With all that being said, it is also important to note that because the biological Value (BV) of meat can be 80 or less, more meat will have to be eaten to get the needed protein (as opposed to proteins with a higher Biological Value) which is often not desired during a low calorie diet.
Poultry Proteins:
Poultry can be an excellent source of protein, and is often a primary staple of those trying to lose weight, as well as competitive athletes, including bodybuilders.
The key however is to select lean cuts, limit added oils and condiments, and choose a low fat preparation method (broil, bake or steam; not fry).
The leanest poultry choice is white meat from the breast of chicken or turkey, without the skin. Although skinless dark meat is leaner than some cuts of beef or pork, it has nearly twice the fat calories as does white meat, so avoid the dark meat.
Tips For Purchasing:
Many grocery stores have both ground chicken and ground turkey, most of which is not low fat because they include more fattening parts of the bird, including skin, and actual fat in the grinding process. In these cases the ground poultry can actually have more fat than many cuts of beef. To make the leanest choice, choose ground breast meat, or look for extra lean (99%) low-fat ground chicken or turkey.
Fish Proteins:
Fish is high in protein, but low in saturated fat and cholesterol, making it a good substitute for poultry and meat. However, when selecting fish especially if you plan to eat it uncooked (e.g., sushi/sashimi) it is of paramount importance to select a reliable seafood source.
Be aware that even large chain supermarket or a specialty fish market can offer seafood that has been mishandled, or is close or past it's best date for consumption.
Tips For Purchasing:
Look for fresh seafood. Fresh fish has a moist, bright surface with shiny, well-attached scales. Also look for bright pink or red gills and firm, springy flesh.
Avoid seafood that is dry, flaky, discolored and is overly fishy-smelling. Consumption of rancid fish can cause several health issues; food borne diseases, and make you very ill.
Dairy Protein:
Milk is a nutrient rich complete ideal food. Milk contains all the essential nutrients required for growth. Milk is also rich in many vitamins and minerals such as calcium, phosphorus, sodium, potassium vitamin A, thiamine, riboflavin and nicotinic acid and vitamin B12 which is absent in vegetarian food items.
The proteins of milk are of a high biological value cow's milk provides 3.2gm of protein and 67kcl of energy per 100 ml. Buffalo milk provides even more (4.25gm of protein and 117kcl of energy) per 100 ml. For a comparison of nutritional value of various milks refer to the table below.
The all important protein from milk comes from the milk solids (Milk is composed of approximately 87% water and 13% solids). The solids contain approximately 37% lactose, 30% fat (2/3 of which is saturated fat) and 27% protein. The protein is comprised of casein (about 80%) and whey protein about 20 %). See Table 3 below.
Protein From Plant Sources:
Legumes:
Legumes are a class of vegetables that includes beans, peas and lentils - are typically low in fat, contain no cholesterol and are high in protein, iron, folate, potassium, magnesium, and phytochemicals.
Phytochemicals are a group of compounds that may help prevent chronic diseases such as cardiovascular disease and cancer. They are also a good source of fiber which has also shown to reduce the risk of developing diabetes and help lower blood cholesterol levels, which can reduce your risk of heart disease.
However, most legumes with the exception of soy are not complete proteins (i.e., they do not contain all of the essential amino acids that we need) which are why they are not preferred by bodybuilders. Beans, for example, are very high in total protein with about 12 -15 grams per cup, however, beans do not contain the essential amino acid methionine.
Similarly, grains are lack the essential amino acid lysine. Because protein from most plants lacks certain amino acids, it has a lower biological value than protein from animal sources.
There are some ways to balance out the amino acid profile. It has been frequently pointed out that combining two incomplete sources of vegetable protein such as rice and beans provides you with the full complement of essential amino acids.
In the following table I have listed some complimentary proteins that can help increase the overall amino acid panel, although I must state that eating this way is not the most efficient or best way for a bodybuilder.
Soy:
The most common source of plant protein regarding consumption is soy protein. Soy has been consumed for more than 2,000 years by people throughout East Asia.
In Western countries, soybeans had attracted people's attention only since the 1960s as an economical and high-quality vegetable protein source for humans.
Soy is found most commonly in the United States as tofu, but other common sources include, soy flour, soy nuts, soy milk, soybeans, "meat analog" products, such as soy sausages, burgers, franks, and cold cuts, all of which are intended as substitutes for their animal-based counterparts.
The main reported benefit of soy is that it is reported to help lower cholesterol. Data show that substitution of soy protein for animal protein is associated with significant decreases in total cholesterol (LDL-C) and triglycerides, while maintaining high density lipoprotein cholesterol (HDL-C)-the good cholesterol-concentrations.
Keeping cholesterol levels under control will enhance overall health, and prolong ones training efforts. This article aims to demystify the many, often confusing, aspects of cholesterol metabolism, while showing how to improve your cholesterol profile.
Soy also contains isoflavones which can act as antioxidants, which help reduce the risk of cancers. Isoflavones are also reported to reduce the risk of arteriosclerosis (plaque buildup in the arteries). Isoflavones improve bone retention and lumbar vertebral bone mineral combating osteoporosis.
Note: isoflavones do act as weaker plant-based estrogens it is currently not recommended that women who have had or are at risk of developing hormone dependent tumors consume a large amount of soy.
So, while soy can be beneficial, especially as a means to decrease saturated fat in the diet, moderate consumption is best under these circumstances. Other reported health benefits of soy include:
- Low in saturated fat and high in other healthful compounds.
- Contains genistein which is reported to can block cancer development and prevent tumors from creating blood vessels, thus blocking nourishment to the tumorous cells.
- Contains phytates (plant chemicals) which also have antioxidant effects.
In order to reap the purported health benefits of soy, it is recommended that 25 grams or more of soy protein be consumed per day.
- 1 cup of tofu provides approximately 20 grams of soy protein.
- 2 cups of soy milk, provides approximately 20 grams of soy protein.
- An 8-ounce glass of plain soymilk contains 10 grams of protein.
- One soy protein bar delivers 14 grams of protein.
- A quarter cup of roasted soy nuts contains 19 grams of soy protein.
- Four soy "sausage" links provides approximately 24 grams of soy protein.
- Two soy "burgers" provides approximately 20-25 grams of soy protein.
- One-half cup of tempeh (a chewy made from whole, cooked soybeans used as a meat substitute) provides 19.5 grams of protein.
Other Sources Of Plant Protein:
Other sources of plant protein include some starchy foods and vegetables as well, although their protein content is fairly low.
Methods of Assessing Protein Quality:
Biological Value (BV):
Proteins are ranked according to Biological Values (BV), arbitrary numbers given to protein to show comparisons in their availability within the body.
At the time the system was introduced eggs were given the highest Biological Value of 100 because they are the most bio-available natural protein. Afterwards whey was isolated from milk and shown to have a higher Biological Value, and depending on the process used can yield percentage from 104 to 154 on the scale.
The Biological Value is based on how much of the protein consumed is actually absorbed and utilized by the body. It is an attempt to measure how efficiently protein is used in the body. The higher the amount of protein (nitrogen) that is actually retained, the greater the Biological Value.
To determine a food's Biological Value, scientists provide a measured intake of protein, and then note the nitrogen uptake vs. nitrogen excretion. A biological value of 100 is maximal, since a Biological Value of 100, means that all of the protein absorbed has been utilized with none lost, therefore it is impossible to have a Biological Value over 100.
When a protein supplement is listed as having a Biological Value over 100, the company has intentionally manipulated the number for marketing purposes or perhaps unintentionally confused Biological Value with another method of rating protein quality, such as perhaps the Chemical a comparison of the amino acid pattern in an ideal reference protein to a test protein and therefore the number can exceed 100.
Why Protein Biological Value Is NOT The Best Measure Of Protein Quality For The Athlete.
The biological value is not a universally accepted measure of protein quality because of several factors. For example, Biological Value testing is always done in the fasting state, which affects nitrogen uptake differently from what takes place when subjects are in a fed state.
Simply put, fasting changes the way the body absorbs nitrogen in protein. When this is done the utilization actually increases. As we all know this is not how bodybuilders eat.
Additionally, bodybuilders and athletes are a unique subset of the general population in that their needs and metabolisms are uniquely different from sedimentary people and the general population.
For instance, athletes in general will often have increased metabolic requirements for amino acids such as tyrosine, methionine-SamE or lysine-carnitine, which serve as building blocks for stress hormones and energy compounds.
These amino acids are often required in extra amounts by athletes due to high-energy demand and the need to perform under extreme mental and physical stress. Therefore, athletes generally speaking often will need extra protein with extra essential as well as conditionally essential amino acids which is why the Biological Value system alone is not a practical method to measure protein quality/needs for athletes, especially bodybuilders.
Why Protein Biological Value May Be Misleading:
The Biological Value of proteins has been measured via nitrogen balance. A positive nitrogen balance generally indicates high Biological Value and vice-versa.
There are however some serious concerns regarding the accuracy of this evaluation system. Biological Value tests are based on studies that measured protein utilization in a tightly controlled feeding environment, that doesn't resemble real life situations.
Furthermore, these tests were conducted primarily on proteins in their raw state, overlooking the fact that most protein foods are habitually consumed in a processed or cooked form.
Processing and cooking significantly change the amino score and Biological Value of raw protein foods. To make the matter even more confusing, protein Biological Value studies were based on small servings (100 to 200mg per kilogram of body weight).
In such a small servings, even inferior proteins are almost fully utilized with a relatively high Biological Value score. Unfortunately, these high scores dramatically decline when protein is consumed in normal or large amounts, such as with athletes or bodybuilders, a fact that must be calculated when designing a nutritional program.
The most efficient conventional method to evaluate protein quality is the so-called PDCAAS (Protein Digestibility Corrected Amino Acid Score) developed by the Food and Agriculture Organization.
Factors That Promote Or Suppress Protein Biological Value:
The variables that influence protein Biological Value and utilization may appear as contradictory and somewhat confusing. Nonetheless, to put some order to this madness, here is a list of protein Biological Values most enhancing vs. most suppressing factors.
Note that real life protein Biological Value would likely indicate how much of it could be utilized for actual growth.
Real-Life Protein Biological Value Is Enhanced By:
- Small servings of proteins
- High calorie intake
- Food combinations
- Fasting and under eating
- Raw (unprocessed) state of food
- Free-form amino acid supplementation
- Probiotics and enzymes
Protein Biological Value Is Suppressed By:
Low calorie intake
Food processing
Protein denaturing (such as exposure to high heat)
Single source of protein
Large portions proteins
Excessive intake of dietary fiber
Vitamin and mineral deficiencies
Body Stress
Indigestion
*Biological Value measures the amount of protein (or more precisely - the nitrogen) retained in the human body per gram of protein absorbed. The measure started out as a percentage - with a whole egg being the best - 100% nitrogen absorbed.
However, as whey processing got better whey became a better source of protein than an egg. This would mean that whey would have to score higher than 100, which (because that number is a percentage) is not possible. So either the percentage must be dropped - because greater than 100% does not make much sense (and then whey can score the reported 159 Biological Value) or the reference point (the egg) would have to be dropped or lowered). This is one reason why Biological Value is no longer the measure of choice.
Upside Of High Biological Value Products:
Because high Biological Value products are easily absorbed by the body, consuming them immediately upon waking (when the body is hungry for protein) and immediately following training is ideal.
High Biological Value products can also be of great value when on a calorie restricted diet because of greater high Biological Value products has a higher utilization. In other words, when you are dieting higher quality (higher Biological Value) protein allows you to take in fewer calories for the amount of protein consumed.
Downsides Of High Biological Value Products:
The downside of the rapid is that the protein is rendered useless within the body quickly. This is why large amounts of high Biological Value products, like whey should not be consumed in large quantities.
High Biological Value products, like whey should be consumed more frequently (every 40-60 minutes) and in smaller quantities (15-20 grams), to avoid this problem. Consuming 50 grams of whey in one sitting will result in 25 to 50 percent of the product being wasted (assuming the protein has not denatured).
clicca qui per la PARTE 2