Nutritional neuroscience
Nutritional neuroscience is the scientific discipline that studies the effects various components of the diet such as minerals, vitamins, protein, carbohydrates, fats, dietary supplements, synthetic hormones, and food additives have on neurochemistry, neurobiology, behavior, and cognition.
Recent research on nutritional mechanisms and their effect on the brain show they are involved in almost every facet of neurological functioning including alterations in neurogenesis, neurotrophic factors, neural pathways and neuroplasticity, throughout the life cycle.
Changes in intestinal tract absorbability and permeability due, in part, to viral, protozoal, and bacteria pathogens may also encourage fecal losses of zinc.
A 1994 randomized, double-blind, placebo-controlled trial showed that zinc (14 mg per day) doubled the rate of body mass increase in the treatment of anorexia nervosa.
[34] In animal studies, rats who were deprived of zinc during early fetal development exhibited increased emotionality, poor memory, and abnormal response to stress which interfered with performance in learning situations.
This increase in unmediated reactive radicals is generally termed oxidative stress, and is an active area of research in a variety of diseases where copper may play an important but more subtle role than in acute toxicity.
[84] Enhanced excretion of manganese prompted by chelation therapy brings its blood levels down but the symptoms remain largely unchanged, raising questions about efficacy of this form of treatment.
[85][86] Increased ferroportin protein expression in human embryonic kidney (HEK293) cells is associated with decreased intracellular Mn concentration and attenuated cytotoxicity, characterized by the reversal of Mn-reduced glutamate uptake and diminished lactate dehydrogenase (LDH) leakage.
[99] This vitamin is important for the facilitation of glucose use, thus ensuring the production of energy for the brain,[100] and normal functioning of the nervous system, muscles, and heart.
[103] In industrialized nations, thiamine deficiency is a clinically significant problem in individuals with chronic alcoholism or other disorders that interfere with normal ingestion of food.
[107] Individuals with chronic alcoholism may fall short on minimum daily requirements of thiamine in part due to anorexia, erratic eating habits, lack of available food, or a combination of any of these factors.
[109] Wernicke encephalopathy is a neurological disorder resulting from a deficiency in thiamine, sharing the same predominant features of cerebral beriberi, as characterized by ocular abnormalities, ataxia of gait, a global state of confusion, and neuropathy.
[109] Characteristics of the neuropathology are varied, but generally consist of bilaterally symmetrical midline lesions of brainstem areas, including the mammillary bodies, thalamus, periaqueductal region, hypothalamus, and the cerebellar vermis.
[114] Neuropsychiatric manifestations of pellagra include headache, irritability, poor concentration, anxiety, hallucinations, stupor, apathy, psychomotor unrest, photophobia, tremor, ataxia, spastic paresis, fatigue, and depression.
Without, pellagra will gradually progress and lead to death within 4–5 years, often a result of malnutrition from prolonged diarrhea, or complications as caused by concurrent infections or neurological symptoms.
Foods that contain high concentrations of niacin in the free form include beans and organ meat, as well as enriched grain and cereal products.
Although the protective effects of folic acid are well documented, there remains legitimate concern that fortification could lead to toxic levels in a subset of the population.
[124] Folate and vitamin B12 play a vital role in the synthesis of S-adenosylmethionine, which is of key importance in the maintenance and repairment of all cells, including neurons.
[125] In addition, folate has been linked to the maintenance of adequate brain levels of cofactors necessary for chemicals reactions that lead to the synthesis of serotonin and catecholamine neurotransmitters.
[130] The process of neural tube transformation into structures that will eventually develop into the central nervous system is known as neurulation, the success of which is dependent on the presence of folate within the body.
[124] In addition, folate concentrations within blood plasma have been found to be lower in patients with both unipolar and bipolar depressive disorders when compared with control groups.
In addition, depressive groups with low folate concentrations responded less well to standard antidepressant therapy than did those with normal levels within plasma.
[135] Because neurulation may be completed before pregnancy is recognized, it is recommended that women capable of becoming pregnant take about 400μg of folic acid from fortified foods, supplements, or a combination of the two in order to reduce the risk of neural tube defects.
[136] Good sources of folate include liver, ready-to-eat breakfast cereals, beans, asparagus, spinach, broccoli, and orange juice.
[142] Another study found that a single ten-gram oral dose of choline, given to normal volunteers (again, without neurological disorders) significantly decreased the number of trials needed to master a serial-learning word test.
[154] In addition, vegans, and to a lesser extent vegetarians, are at risk for consuming a diet low in cobalamin as they voluntarily abstain from animal sources of B12.
[150] Mild to moderate cases of pernicious anemia may show symptoms of bleeding gums, headache, poor concentration, shortness of breath, and weakness.
[154] In order to get adequate amounts of the vitamin, orally administered pills or fortified foods such as cereals and soy milk, are recommended for vegans.
An omega-3 deficient diet increases omega-6 levels in the brain disrupting endocannabinoid signaling in the prefrontal cortex and nucleus accumbens contributing to anxiety and depression-like behaviors in mice.
To prevent brain damage, these individuals can restrict dietary phenylalanine intake by avoiding protein and supplementing their diet with essential amino acids.
