Archive for Brain
Sweet cravings, calories, and weight loss
Posted by: | CommentsDid you know that the brain can respond to the calorie content of food, even in the absence of taste?
Scientists have known that when people taste sweet foods, dopamine levels increase in the ventral striatum, a brain region related to reward and reinforcement. Our neural pathways have been established for palatability (the power of a food to make one eat it spontaneously and with gusto) as food is being eaten.
Research about the brain’s dopamine-reward system can explain why people who drink diet sodas still gain weight. A mismatch between artificially sweet taste and zero calorie content can lead to rebound eating because our brain is wired to respond to both calorie content and sweetness.
The researchers from Duke University also found significant differences in dopamine levels during eating, regardless of the ability to taste food. Normal mice showed a rise in dopamine when they gobbled the artificial sweetener solution, indicating palatability even without calories present. Mice without sweet taste released dopamine only during sucrose intake, even though they could not distinguish between the taste of water and sucrose. This confirmed that dopamine can be released by either sweet taste or caloric content.
It may mean that the role of dopamine transmission (the pleasure principle) in overeating and obesity might not be restricted to taste alone – dopamine signaling also can influence behavior by indicating a food’s caloric value.
How do you apply this to your weight loss goal? Wean yourself from sodas, and try to eliminate processed sugar from your diet as much as possible. The second idea is to practice “stimulus control” — which means keep junk food out of the house. Out of sight out of mind. Remember your brain is a calorie seeking missile.
Brain health and aging
Posted by: | CommentsThe secret to keeping our mind intact as we age? Research sponsored by the MacArthur Foundation Network on Successful Aging shows that there are four variables that affect mental fitness: physical activity, lung function, levels of education, and feelings of self-efficacy. The scientists believe that that regular exercise stimulates flow to the brain and promote nerve growth. This results in denser neuronal networks that are more resistant to disease. Moderate aerobic workouts can accomplish this.
Animal studies also support the hypothesis that mental and physical activity enhance brain health. The Beckman Institute for Advanced Science and Technology in Urbana, Illinois found that rats developed 25 percent more connections between their neurons compared to rats that did not get any mentally stimulating tasks. Rats that exercised on a treadmill developed more capillaries in their brains (which increased the flow to their brains) versus their couch potato peers.
Immune system: the mind body connection
Posted by: | CommentsThe “inflammatory reflex” theory, put forth by Kevin Tracey M.D. suggests that there is a direct link between the mind and the body, specifically the immune system. According to Tracey, “the literature shows that for centuries, doctors, monks, priests, acupuncturists and even laymen believed that individuals’ state of mind influenced their health. But nobody could explain how, until now”.
Scientists now know that messages from the brain, sent through the vagus nerve, can stop certain immune activities such as the release of TNF, also known as the “tumor necrosis factor.” Though TNF fulfills a critical function in suppressing infection (i.e., making the body respond better to an pathogen’s attack), too much can actually cause harm.
Meditation has shown that it can change the structure of the brain and the amount of activity in certain regions of the brain. The inflammatory reflex shows the direct link between thought and immune response. Mental process (and corresponding changes in brain chemistry) can affect the way our bodies respond to disease, i.e., our resilience to biological, chemical and psychological stress.
Exercise and brain function
Posted by: | CommentsExercise causes a protein called IGF-1 to travel across the -brain barrier. Once in the brain, it gives orders to produce an important substance called brain-derived neurotrophic factor (BDNF), which serves as the “fuel” for thinking. Regular exercise naturally builds up the levels of BDNF in the brain, allowing new neural pathways (i.e., learning) to occur.
Scientists have also discovered that neurogenesis, i.e., the production of new neurons in the brain, can be instigated by cardiovascular exercise. BDNF production affects the hippocampus (specifically, the dentate gyrus) which controls memory and learning.
Increased levels of this substance appear to reverse the age-induced deterioration of this part of the brain. In addition, exercise also increases the size of the frontal lobes, the areas responsible for higher level mental tasks such as planning and decision making.
The neuro-chemical relationship between exercise and mental functioning is increasingly being clarified by the research. The results indicate that exercise facilitates learning and slows down the deterioration brought about by the aging process.
We all know what needs to be done…
