Da: http://www.velonews.com/train/articles/13178.0.html
(purtroppo in inglese)
Feed your head
by Monique Ryan
Cyclists rightfully focus their dietary attention on consuming the proper foods in adequate amounts so that they can sustain energy during long training rides, and replenish muscle fuel stores and recover nutritionally during the season. But you should also consider how your daily food intake and on-bike nutrition can affect and feed your brain. Just like your heart, your brain is an organ that benefits from optimal nutritional care. Nutrition can affect brain chemicals, brain cell structure and function and the ability of the brain to transmit electrical messages. Though nutritional neuroscience is relatively young, specific foods can feed your head, prevent brain drain, and even provide a central nervous system boost during training.
Your Brain
Despite being one of the most complex organisms in the body, your brain is the organ that we know the least about. Your brain consists of about a hundred billion neurons surrounded by glial cells whose main role is to provide the neurons with energy. Neurons communicate with each other by electrochemical signals. The connections between our neurons are rapidly and constantly changing and re-wiring and we does lose brain cells everyday as we age. What else is in your brain? The membranes of neurons are composed of a double layer consisting mainly of fatty acid molecules. Myelin is the protective sheath that surrounds neurons, and about 70-percent of it is composed of fat. Fat provides a good form of insulation and allows your neurons to operate at high speed.
Fuel
Another important question is "What does your brain run on?" The answer is almost entirely on glucose (except in cases of starvation). Your brain is very active metabolically and normal blood glucose levels ensure an adequate supply of fuel to the brain. When blood glucose levels run relatively low, a shortage can occur. Have you ever postponed eating, or missed breakfast and then felt your whole brain come alive when you finally sat down for a meal or snack? Perhaps a headache eases up and your concentration and focus return. Under normal conditions at rest, your brain and nervous system require a minimum of 150 grams of glucose daily.
Your brain power benefits when you consume meals and snacks on time or at regular intervals. A carbohydrate boost raises blood glucose levels and also stocks some back-up fuel in the liver as glycogen. One of the biggest brain drain mistakes you can make is skipping breakfast, or not consuming enough for breakfast. When you wake up in the morning liver glycogen stores are low and breakfast not only boosts blood glucose levels, but also restocks our liver glycogen supply. From your morning meal onward, eating every three to five hours seems to offset the waxing and waning of blood glucose levels. Of course, you need to plan meal and snack timing around your own training and work schedule. It is also important that you consume moderate portions of nutrient dense whole grains, fruits and vegetables. A large portion of your brain is also fluid, so your daily hydration efforts are also a good brain strategy.
Iron
While the brain is big on glucose utilization, many other nutrients contribute to the brain's correct functioning. Your brain is also a big user of oxygen. Adequate oxygen means that your brain cells can metabolize fuel for energy and iron deficiency or anemia is linked to a shortened attention span and mental sluggishness. Iron is also needed for the manufacture of brain proteins. Several blood tests can verify iron status. May female athletes require more iron than they consume in their diet, and are much more likely to be iron deficient than iron overloaded. In contrast , male athletes may consume more iron than they actually need, and their risk for iron overload is greater than that for developing anemia. Iron overload, or hemochromatosis results in excess iron absorption and can cause organ damage, and 1-in-200 white males carry the gene for this condition. If your physician does determine that you are iron deficient and need more iron in your diet, iron rich foods include lean red meat, pork, poultry, legumes, raisins, dried apricots, and iron fortified cereals. Iron supplementation should be done under a physician's guidance.
B Vitamins
Many B vitamins are linked to optimal brain and nerve function. Vitamin B12 is essential for a healthy nervous system, and a deficiency of this nutrient can result in brain tissue degeneration, as well as that of the spinal cord and peripheral nerves. Animal foods such as milk, cheese, yogurt, beef, and poultry supply plenty of B12. Vegans may need to ensure an adequate intake of foods fortified with B12 or take a B12 supplement.
Another important vitamin is B6 or pyridoxine which is required for normal nervous system development from conception to adulthood. Good food sources of B6 include wheat germ, whole grain cereals, pork, legumes, potatoes, bananas, and oatmeal. Niacin plays a role in the manufacture of many nerve chemicals, and good sources are chicken, salmon, peanut butter, and wheat germ. Pantothenic acid forms a coenzyme involved in the transmission of nerve impulses and is found in meat, poultry, fish, whole grain cereals, legumes, milk, vegetables, and fruit. Another B vitamin thiamine, is also essential for healthy brain cells and is found in whole grains and enriched bread, rice, pasta, cereal, and in pork. Finally, the B vitamin folic acid is important, as it helps to maintain blood choline levels. Choline is part of acetylcholine, an important neurotransmitter in the brain. Folic acid is found in orange juice,, dried beans such as kidney beans, and dark leafy green vegetables like spinach, asparagus, and broccoli. Food sources of choline include peanuts, eggs, cauliflower, soybeans, and oatmeal.
Antioxidants
Free radicals, which are highly reactive substances that need to be kept in check, are generated in our brain. Antioxdiant nutrients can deactivate free radicals and reduce the stress they place on our bodies. It has been theorized that free radical formation plays a role in the deterioration of the brain. Vitamin C and beta-carotene are two potent free radicals and are found widely in fruits and vegetables. Aim for over six servings daily. Some potent sources of a variety of antioxidants such as flavonoids include blueberries, blackberries, cranberries, raspberries, broccoli, oranges, red grapes, red bell peppers, and kiwis. Vitamin E another potent antioxidant can be found in liquid vegetable oils, wheat germ, avocado, almonds, and sunflower seeds.
Good Fats
Once again, including an ample supply of omega-3 fatty acids in your diet, with fish oil being the best source, offers another health benefits. While the mechanisms are not clear, Omega-3's appear to enhance brain cell communication.
Brain drain during training
As a cyclist, you should also consider that brain fatigue can occur during long training rides and races. At the very least, maintaining concentration and focus is important during harder efforts on the bike. Fortunately, all the skills that you have developed for fueling on the bike can help offset brain fatigue. That carbohydrate laden sports drink not only provides fuel for your muscles when glycogen stores run low, but is good brain fodder as well.
When you consume carbohydrate during training, you can help lessen an increase in free fatty acids in your bloodstream, as carbohydrate becomes the preferred fuel source. When the concentration of fat in the blood decreases, the concentration of free tryptophan also declines. Trytophan is an amino acid that the brain converts to serotonin. When more serotonin is produced it is believed there is an increase in "central" or brain fatigue. So by consuming the carbohydrate, you squash the steps that lead to an increase of serotonin in the brain.
Carbohydrate intake during exercise also lowers blood levels of the hormones glucagon and cortisol, and increase insulin. These changes in hormone levels would be expected to decrease levels of ammonia in the blood and brain. Ammonia is toxic to the brain and likely also impairs muscle metabolism.
Maintaining a good supply of glucose to the brain during exercise can also result in lower ratings of perceived exertion- a given intensity of exercise does not seem as hard. Adequate carbohydrate intake during exercise can also go a long way to improve motivation and mood.
During exercise there is also an increase in adenosine, a normal cell component regulated mainly by ATP metabolism, and which contributes to central fatigue by inhibiting the release of neurotransmitters that stimulate the brain, especially dopamine. Caffeine is a strong antagonist to adenosine and it is believed that one of the most important ways in which caffeine enhances performance during exercise is through stimulation of the central nervous system by blocking adenosine receptors in the brain.
While more research is needed on nutrition and the brain, a balanced diet that provides a variety of B vitamins, plenty of antioxidant rich sources of fruits and vegetables, and adding more fish to your diet are all good brain food strategies. During training staying on top of carbohydrate replacement by consuming a sports drink not only offsets glycogen depletion, but delays brain fatigue. Aim for 4 to 8 ounces of a sports drink every 15 to 20 minutes. In addition caffeine intake prior to exercise, at a moderate dose of 3 to 5 mg/kg of body can also offset brain fatigue. Research on caffeine consumption during exercise indicates that 1.5 mg/kg of body weight improves performance.
(purtroppo in inglese)
Feed your head
by Monique Ryan
Cyclists rightfully focus their dietary attention on consuming the proper foods in adequate amounts so that they can sustain energy during long training rides, and replenish muscle fuel stores and recover nutritionally during the season. But you should also consider how your daily food intake and on-bike nutrition can affect and feed your brain. Just like your heart, your brain is an organ that benefits from optimal nutritional care. Nutrition can affect brain chemicals, brain cell structure and function and the ability of the brain to transmit electrical messages. Though nutritional neuroscience is relatively young, specific foods can feed your head, prevent brain drain, and even provide a central nervous system boost during training.
Your Brain
Despite being one of the most complex organisms in the body, your brain is the organ that we know the least about. Your brain consists of about a hundred billion neurons surrounded by glial cells whose main role is to provide the neurons with energy. Neurons communicate with each other by electrochemical signals. The connections between our neurons are rapidly and constantly changing and re-wiring and we does lose brain cells everyday as we age. What else is in your brain? The membranes of neurons are composed of a double layer consisting mainly of fatty acid molecules. Myelin is the protective sheath that surrounds neurons, and about 70-percent of it is composed of fat. Fat provides a good form of insulation and allows your neurons to operate at high speed.
Fuel
Another important question is "What does your brain run on?" The answer is almost entirely on glucose (except in cases of starvation). Your brain is very active metabolically and normal blood glucose levels ensure an adequate supply of fuel to the brain. When blood glucose levels run relatively low, a shortage can occur. Have you ever postponed eating, or missed breakfast and then felt your whole brain come alive when you finally sat down for a meal or snack? Perhaps a headache eases up and your concentration and focus return. Under normal conditions at rest, your brain and nervous system require a minimum of 150 grams of glucose daily.
Your brain power benefits when you consume meals and snacks on time or at regular intervals. A carbohydrate boost raises blood glucose levels and also stocks some back-up fuel in the liver as glycogen. One of the biggest brain drain mistakes you can make is skipping breakfast, or not consuming enough for breakfast. When you wake up in the morning liver glycogen stores are low and breakfast not only boosts blood glucose levels, but also restocks our liver glycogen supply. From your morning meal onward, eating every three to five hours seems to offset the waxing and waning of blood glucose levels. Of course, you need to plan meal and snack timing around your own training and work schedule. It is also important that you consume moderate portions of nutrient dense whole grains, fruits and vegetables. A large portion of your brain is also fluid, so your daily hydration efforts are also a good brain strategy.
Iron
While the brain is big on glucose utilization, many other nutrients contribute to the brain's correct functioning. Your brain is also a big user of oxygen. Adequate oxygen means that your brain cells can metabolize fuel for energy and iron deficiency or anemia is linked to a shortened attention span and mental sluggishness. Iron is also needed for the manufacture of brain proteins. Several blood tests can verify iron status. May female athletes require more iron than they consume in their diet, and are much more likely to be iron deficient than iron overloaded. In contrast , male athletes may consume more iron than they actually need, and their risk for iron overload is greater than that for developing anemia. Iron overload, or hemochromatosis results in excess iron absorption and can cause organ damage, and 1-in-200 white males carry the gene for this condition. If your physician does determine that you are iron deficient and need more iron in your diet, iron rich foods include lean red meat, pork, poultry, legumes, raisins, dried apricots, and iron fortified cereals. Iron supplementation should be done under a physician's guidance.
B Vitamins
Many B vitamins are linked to optimal brain and nerve function. Vitamin B12 is essential for a healthy nervous system, and a deficiency of this nutrient can result in brain tissue degeneration, as well as that of the spinal cord and peripheral nerves. Animal foods such as milk, cheese, yogurt, beef, and poultry supply plenty of B12. Vegans may need to ensure an adequate intake of foods fortified with B12 or take a B12 supplement.
Another important vitamin is B6 or pyridoxine which is required for normal nervous system development from conception to adulthood. Good food sources of B6 include wheat germ, whole grain cereals, pork, legumes, potatoes, bananas, and oatmeal. Niacin plays a role in the manufacture of many nerve chemicals, and good sources are chicken, salmon, peanut butter, and wheat germ. Pantothenic acid forms a coenzyme involved in the transmission of nerve impulses and is found in meat, poultry, fish, whole grain cereals, legumes, milk, vegetables, and fruit. Another B vitamin thiamine, is also essential for healthy brain cells and is found in whole grains and enriched bread, rice, pasta, cereal, and in pork. Finally, the B vitamin folic acid is important, as it helps to maintain blood choline levels. Choline is part of acetylcholine, an important neurotransmitter in the brain. Folic acid is found in orange juice,, dried beans such as kidney beans, and dark leafy green vegetables like spinach, asparagus, and broccoli. Food sources of choline include peanuts, eggs, cauliflower, soybeans, and oatmeal.
Antioxidants
Free radicals, which are highly reactive substances that need to be kept in check, are generated in our brain. Antioxdiant nutrients can deactivate free radicals and reduce the stress they place on our bodies. It has been theorized that free radical formation plays a role in the deterioration of the brain. Vitamin C and beta-carotene are two potent free radicals and are found widely in fruits and vegetables. Aim for over six servings daily. Some potent sources of a variety of antioxidants such as flavonoids include blueberries, blackberries, cranberries, raspberries, broccoli, oranges, red grapes, red bell peppers, and kiwis. Vitamin E another potent antioxidant can be found in liquid vegetable oils, wheat germ, avocado, almonds, and sunflower seeds.
Good Fats
Once again, including an ample supply of omega-3 fatty acids in your diet, with fish oil being the best source, offers another health benefits. While the mechanisms are not clear, Omega-3's appear to enhance brain cell communication.
Brain drain during training
As a cyclist, you should also consider that brain fatigue can occur during long training rides and races. At the very least, maintaining concentration and focus is important during harder efforts on the bike. Fortunately, all the skills that you have developed for fueling on the bike can help offset brain fatigue. That carbohydrate laden sports drink not only provides fuel for your muscles when glycogen stores run low, but is good brain fodder as well.
When you consume carbohydrate during training, you can help lessen an increase in free fatty acids in your bloodstream, as carbohydrate becomes the preferred fuel source. When the concentration of fat in the blood decreases, the concentration of free tryptophan also declines. Trytophan is an amino acid that the brain converts to serotonin. When more serotonin is produced it is believed there is an increase in "central" or brain fatigue. So by consuming the carbohydrate, you squash the steps that lead to an increase of serotonin in the brain.
Carbohydrate intake during exercise also lowers blood levels of the hormones glucagon and cortisol, and increase insulin. These changes in hormone levels would be expected to decrease levels of ammonia in the blood and brain. Ammonia is toxic to the brain and likely also impairs muscle metabolism.
Maintaining a good supply of glucose to the brain during exercise can also result in lower ratings of perceived exertion- a given intensity of exercise does not seem as hard. Adequate carbohydrate intake during exercise can also go a long way to improve motivation and mood.
During exercise there is also an increase in adenosine, a normal cell component regulated mainly by ATP metabolism, and which contributes to central fatigue by inhibiting the release of neurotransmitters that stimulate the brain, especially dopamine. Caffeine is a strong antagonist to adenosine and it is believed that one of the most important ways in which caffeine enhances performance during exercise is through stimulation of the central nervous system by blocking adenosine receptors in the brain.
While more research is needed on nutrition and the brain, a balanced diet that provides a variety of B vitamins, plenty of antioxidant rich sources of fruits and vegetables, and adding more fish to your diet are all good brain food strategies. During training staying on top of carbohydrate replacement by consuming a sports drink not only offsets glycogen depletion, but delays brain fatigue. Aim for 4 to 8 ounces of a sports drink every 15 to 20 minutes. In addition caffeine intake prior to exercise, at a moderate dose of 3 to 5 mg/kg of body can also offset brain fatigue. Research on caffeine consumption during exercise indicates that 1.5 mg/kg of body weight improves performance.
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