Feed Your Head: Brain Food On and Off the Bike
By Monique Ryan
Consuming the right mix of foods and nutrients for training clearly supports your recovery and performance, but did you ever consider that the food you consume can directly affect your brain’s performance? It not, give it a thought, it might help improve your performance in life, work, and in triathlon.
Your brain is made of approximately 100 billion nerve cells called neurons, which have the ability to gather and transmit electrochemical signals. For these brain cells to communicate effectively with each other, they require chemicals called neurotransmitters. The connections between our neurons are constantly and rapidly changing and rewiring. Although we all naturally lose brain cells throughout our lives, this does not necessarily accelerate with age. Loss of mental agility might actually be from the neuron’s failure to communicate effectively.
Chemicals in your brain called neurotransmitters, carry messages from neuron to neuron, and influence mood, thinking, and sleep patterns. Neurotransmitters are made from amino acids found in protein foods and specific vitamins and minerals are used in this process. Three key neurotransmitters include acetylcholine, dopamine and serotonin. Your brain cells are covered by a sheath consisting mainly of fat, which provides insulation and allows the neurons to operate at high speed.
Carbohydrates are brain food – on and off the bike. Your brain actually has very high nutrient and energy needs, with glucose being it’s only fuel supply under normal and healthy conditions. Unlike your muscle cells, brain cells cannot store glucose and thus depend on a steady supply of this precious fuel, consuming about 120g daily. During periods of glucose deficit you may experience confusion or dizziness as a brain fuel shortage can occur.
You likely have experienced the effects of brain glucose shortage, either during the day when skipping or skimping on breakfast, or during workouts when you have bonked. From your morning meal onward, eating every 3-5 hours seems to offset the up and down pattern of blood glucose levels. Meals and snacks fill up liver glycogen stores which then maintain blood glucose levels. Of course you need to plan your meals, snacks and on-bike fueling around your training and work schedule so that you can maintain blood glucose levels not only during the day, but when training as well.
Recent data has looked at the brain benefits of consuming sports drinks during training. Besides providing a carbohydrate boost for muscle fuel, one of the most important functions of a sports drink may be delaying brain fatigue during training. Referred to as “central fatigue” we know that when blood glucose runs low that there are increased levels of serotonin and adenosine in the brain, which causes fatigue, while there are decreased levels of dopamine, a neurotransmitter that increases focus and concentration. Another important adenosine antagonist is caffeine, which blocks adenosine. Carbohydrate intake during training also lowers blood levels of the hormone cortisol and increases insulin, which in turn decreases levels of ammonia in the brain and blood. Ammonia is toxic to the brains and also likely impairs muscle metabolism.
You may have experienced the performance benefits of consuming caffeine during training, and many experts now believe that it is caffeine’s effect on the central nervous system that is most effective. Caffeine is an antagonist to adenosine and helps to prevent brain fatigue.
In a study published in the Journal of Physiology, researchers at the University of Birmingham in the UK had trained cyclists rinse their mouths with a glucose solution or sweetened placebo during a time trial. An MRI demonstrated that this mouth exposure to glucose activated reward-related brain regions. A second study with a maltodextrin rinse found that the time to complete a time trial was significantly reduced when compared to a placebo. Researchers felt that these results suggest that improvements in exercise performance observed when carbohydrate is in the mouth may be due to activation of specific brain regions.
However, in a counter study, published in the International Journal of Sport Nutrition and Exercise Metabolism, research performed a similar study and had subjects exercise two hours after consuming a standardized breakfast. There was no difference in performance times however, in this fed state. They concluded that the proposed presence of carbohydrate receptors in the mouth and their potential role in affecting mood and performance during exercise when carbohydrate stores run low warranted more research.
Additional research from four studies has found some performance improvements with mouth rinse carbohydrate during exercise lasting 60 minutes or less indicating that activation of brain receptors is a possibility during exercise that is not limited by carbohydrate stores- such as longer endurance workouts.
Other nutrients besides carbohydrate are also essential for brain function. The majority of your blood is water, and blood delivers nutrients to the brain. When your brain is fully hydrated, its circuitry works well and functions at optimum levels, so water and optimal hydration is essential for concentration and alertness.
Much of your brain sheath is composed of fats. The healthy omega-3 fats seem to improve brain cell communication as well as regulate our immune systems and decrease inflammation. Inadequate amounts of omega-3s can be associated with depression and other brain disorders. The best sources of omega-3s are fatty fish such as salmon, sardines, and trout. In contrast, too high an intake of saturated and trans fat from fatty meats, whole milk products and hydrogenated oils can lead to blockage of the arteries in the brain, just as they would in the heart muscle.
Your brain uses a lot of oxygen, using about half of the body’s total oxygen consumption during mental activity. Free radicals, which are highly reactive substances and byproducts of oxygen use may play a role in the deterioration of the brain. Antioxidant nutrients can deactivate these free radicals.
Researchers are now studying how certain dietary plant compounds can affect brain function. Beside vitamin antioxidant such as vitamin C, fruits, vegetables, nuts, seeds, and grains contain thousands of other types of compounds called phytochemicals that contribute significantly to our dietary intake of antioxidants. Some potent sources include blueberries, blackberries, cranberries, raspberries, broccoli, oranges, red grapes, red bell peppers, and kiwis.
B vitamins are also vital to normal brain and nerve function. Adequate amounts of vitamin B12 prevent brain tissues, spinal cord, and nerve degeneration. Good sources are animal foods such as milk, cheese, yogurt and poultry. Vegans should consumed B12 fortified foods or supplement with this nutrient. Vitamin B6 or pyridoxine help convert tryptophan into serotonin, and is found in chicken, fish, pork, as well as whole-grain cereals, nuts, and legumes. Folic acid is essential for the metabolism of fatty acids in the brain, and is found in orange juice, leafy green vegetables, and dried peas and beans.
Clearly a well balanced diet and variety of nutrients play a role in giving your brain a boost.
Monique Ryan, MS, RD, CSSD, LDN is the leading endurance sports nutritionist. Her nearly 30 years of professional experience working with Olympic (consultant to USAT and USA Cycling), elite and age group endurance athletes and professional sports teams make her one of the most experienced and qualified sports nutritionists in the U.S. Ryan is founder of Chicago-based Personal Nutrition Designs and the best-selling author of Sports Nutrition for Endurance Athletes (3rd edition, VeloPress) and three other sports nutrition books. PND provides detailed nutrition plans for triathletes across North America competing in all race distances, with programs at www.moniqueryan.com. Ryan is a Certified Specialist in Sports Dietetics.