In its structure and function, the brain and nervous system is a masterpiece of complementary balance. The cells in the nervous system, known as neurons, come in a variety of forms, but share the same basic structure. The sections of the neuron include branched dendrites, which receive incoming impulses; the yang or compact cell body, where impulses gather and are processed, and the yin, extended axon where impulses are dispatched to neighboring cells.
On the whole, each cell in the nervous system functions as a spiral made up of incoming and outgoing impulses and energy.
When nerve impulses arrive at the end point, or terminal of the axon, they travel across the synapse, a narrow space that separates the axons of nerve cells from the dendrites of others. When impulses reach the terminal, they stimulate the release of neurotransmitters, substances that determine the way that the message will affect the neighboring cell. More yang, activating transmitters cause nerve cells to become excited and generate impulses at a higher rate. More yin, inhibiting transmitters slow or block the production of nervous impulses.
Foods such as whole grains, beans, and vegetables rich in complex carbohydrates increase the brain’s supply of serotonin, a more yin neurotransmitter that is believed to induce calm and relaxed mental states. Eggs and other animal food increase the levels of acetylcholine, another neurotransmitter. That may help explain why persons who consume grains and vegetables and little or no animal food often seem calm and even-tempered in comparison to persons who consume plenty of meat and other animal foods.
The low levels of serotonin that result from a diet high in animal foods may contribute to impulsive behavior. In studies of prison inmates conducted in Finland, those with the most impulsive behavior patterns were found to have the lowest levels of metabolized serotonin in the spinal fluid when compared to non-impulsive prisoners and controls. The impulsive inmates were also found to have low blood sugar levels. The researchers found that 81 percent of repeat offenders had abnormally low blood sugar levels. Low levels of serotonin, together with low levels of blood sugar, characterized 84 percent of the repeat offenders studied.
Diet affects the body’s secretion of hormones, and these influence behavior. In a study conducted at Yale, the intake of refined sugar was found to dramatically increase blood levels of adrenaline in children. In children who were tested after being given an amount of sugar equivalent to two cupcakes, levels of adrenaline increased ten times. Adrenaline, secreted by the adrenal glands during times of stress, initiates the “fight or flight” response. It produces such effects as rapid heartbeat, quick shallow breathing, and nervousness.
High adrenaline levels lead to anxiety and difficulty in thinking clearly. Parents often notice that children behave in an aggressive, hyperactive, and erratic manner after eating plenty of sugary foods, and this study offers a possible biochemical explanation for this reaction. Researchers are becoming aware that diet has a profound effect on the the brain and nervous system, and thus on our mental and emotional condition.
According to the National Institutes of Mental Health, about 5 percent of the American population suffers from major depressive illness. Milder forms of depression are much more common. Suicide is often the outcome of severe depression, and about 75,000 people commit suicide every year in the United States. Suicide is the second leading cause of death among men between the ages of twenty-five and forty-five, and the rate is increasing among young people.
Bouts of depression often occur in cycles. A bout of depression may last for one or two days or for several months or longer. Researchers have begun to observe a correlation between episodes of depression and natural rhythms such as the 24-hour daily cycle and the cycle of the seasons. Depression tends to be more severe in the afternoon and evening, and during the autumn and winter, times when the energy of the earth’s atmosphere becomes more yang or condensed.
In many cases, depression is the by-product of a condition known as hypoglycemia, or low blood sugar. Hypoglycemia is produced by an extreme or unbalanced diet, especially the regular intake of cheese, chicken, eggs, and other forms of animal food. These more yang or contractive items cause the pancreas to become hard and tight, and inhibit its secretion of glucagon, or anti-insulin, the more yin pancreatic hormone that raises the level of glucose in the blood. When the pancreas becomes hard and tight, it cannot secrete glucagon properly, although insulin, the more yang hormone that lowers blood sugar, keeps being secreted. The result is hypoglycemia. Hypoglycemia creates the desire to consume sugar, soft drinks, chocolate, alcohol, or drugs, all of which raise the level of sugar in the blood.
The brain is utterly dependent on glucose for its functioning, and when a deficit arises, the higher brain centers, including those governing imagination and creativity, shut down in order to conserve more fundamental brain activity essential for survival. The result is a sinking feeling or a feeling of being boxed in by circumstances. A person becomes unable to imagine a solution to whatever problems he may be experiencing, and, because of a lack of blood sugar, may not have enough energy to change his circumstances. The result is depression and a sense of hopelessness.
The principle of yin and yang can help clarify the biochemistry of depression and other mood disorders. When the blood sugar becomes elevated (yin), the pancreas secretes insulin (yang), in order to make balance. In the brain, production of more yang neurotransmitters–those involved in arousal and motor activity–is stepped up. Conversely, when blood sugar becomes low (yang), the pancreas reduces the output of insulin, while accelerating production of glucagon (yin). In the brain, production of activating neurotransmitters is reduced, in some cases, to the point of undersupply. The resulting shortage can lead to depression.
A naturally balanced, macrobiotic diet can help correct these imbalances in the internal chemistry of the body. A diet based on complex carbohydrates, such as those in whole grains, beans, and fresh local vegetables helps stabilize the metabolism of glucose, and can help relieve conditions such as depression, fear, and anxiety. Mind and body are one. The application of diet to the relief of mood disorders represents a new frontier in the field of psychology.
Blood sugar imbalances also play an important role in schizophrenia, a more severe form of mental illness. Chronic low blood sugar leads to cravings for refined sugar, alcohol, chocolate, drugs, and other extreme forms of yin. The repeated consumption of extreme yin items can cause the cells of the brain and nervous system to become chronically overexpanded, producing an eventual deterioration of mental functioning. The result can be schizophrenia.
Our mental processes depend on the brain’s ability to concentrate and simplify information. The concentration of information is more yang. In The Healing Brain, Robert Ornstein and David Sobel describe this process as follows:
Since the world is constantly changing, the brain is flooded with information. How would it know which of all these changes are important and which are irrelevant? A strategy emerged in which the brain and nervous system evolved to radically reduce and limit the information transmitted to the brain.
The nervous system organizes information so that a few actions, the appropriate actions, can take place. Much of the intricate network of receptors, ganglia, and analysis cells in the cortex serve to simplify. Senses select only a few meaningful elements from all the stimuli that reach us, organize them into the most likely occurrence, and remember only a small organized sample of what has occurred.
When brain cells become chronically yin or expanded, they easily become overly sensitive to yang stimuli, including activating neurotransmitters such as dopamine. According to a popular hypothesis, oversensitivity to dopamine produces chronic overstimulation in the brain. The patient becomes hypersensitive to stimulation from the immediate environment and loses touch with vibrations coming from greater distances. This leads to cognitive overload and a decline in more refined thinking abilities. A person in this condition has difficulty organizing the world by going beyond the immediate information he receives.
Coordinating the varied functions of the brain requires strong yang, or centripetal power. Ornstein and Sobel
describe these varied functions as follows:
The brain is divided into very many independent and well-defined areas, each of which possesses a rich concentration certain abilities. In this view, which is becoming more and more established, the brain is seen not as a single organ, but as a collage of different and independent systems, each of which contains component abilities.
In schizophrenia, the yang power of coordination and control breaks down. The various centers of the brain may start to act independently. The spiral of coordination begins to spin out of control. Loss of control is due to an overly yin condition in the brain and nerve cells. People with schizophrenia often show signs of excess sugar consumption. Refined sugar disrupts the balance of vitamins and minerals in the body. A common symptom of schizophrenia is numerous white spots on the fingernails, a sign of mineral deficiency resulting from the repeated consumption of simple sugar. Many schizophrenics have a sweet odor on their breath, also the result of consuming sugar. A variety of mineral deficiencies and imbalances are common among schizophrenics, especially deficiencies in zinc, manganese, magnesium, and sodium, and these result primarily from the repeated consumption of sugar.
The regular intake of simple sugars depletes B-complex vitamins that are necessary to smooth mental functioning. More than fifty years ago, it was discovered that vitamin B deficiencies were related to mental illness. About 10 percent of the people who were diagnosed with schizophrenia and committed to mental hospitals in the South were found to be suffering from pellegra, a vitamin B deficiency. When they were placed on corrective diets, their previously diagnosed “schizophrenia” cleared up.
A naturally balanced, macrobiotic diet, rich in B vitamins, minerals, complex carbohydrates, and other essential nutrients, could help many patients with schizophrenia. Restoring the brain and nervous system to a more normal balance of yin and yang is the first step toward the recovery from mental illness.
Source: This essay is from persnal notes and lectures, including research for the book, Crime and Diet: The Macrobiotic Approach, Japan Publications, Tokyo and New York, 1987, © all rights reserved.