Genetic and environmental factors are likely involved in the development of mood disorders. In this regard expression or inhibition of certain enzymes and changes to diet are two factors that are linked to changes in mood. One common factor that appears to link the genetic and environmental components is the balance of oxidative stress. It has been known for a long time for example, that oxidative stress is associated with many psychiatric disorders, and this likely relates to the fact that the brain is highly susceptible to lipid peroxidation from excessive free radical generation. Not only does the brain contain high amounts of polyunsaturated fats that can be oxidised easily, it also contains metals such as copper and iron that can increase the generation of free radicals. The metabolism of catecholamine neurotransmitters such as noradrenaline and dopamine is also one of the major sources of free radicals and so increases in turnover of these compounds can induce oxidative stress.
Many studies have shown associations between oxidative stress and disease. For example, studies have shown that malondialdehyde levels increase in patients with mood disorders and psychiatric patients. Malondialdehyde levels are considered a measure of oxidative stress. Because it is difficult and damaging to determine malondialdehyde levels in the brain, human studies have tended to measure malondialdehyde levels in blood. However, animal studies have measured malondialdehyde levels in brain tissues of animals and shown that they increase in response to stress and anxious and depressive symptoms in the animals. Diets specifically designed to increase oxidative stress in animals have been shown to detrimentally alter the behaviour of the animals in a way that is suggestive of changes in depression of mood. Highly palatable diets high in sucrose for example is particularly effective in this regard. In contrast high quality plant diets reduce oxidative stress and are associated with beneficial effects.
During times of stress, overstimulation of particular pathways in the brain, such as the glutamate pathway, can cause the generation of free radicals. This can be a significant cause of oxidative stress. Calming these pathways through the use of inhibitory neurotransmitters such as GABA may explain the beneficial effects of high GABA foods such as fortified tea and yogurt in treating mood disorders such as anxiety and depression. Many anti-anxiety drugs work through activation of the GABA system and many plant phytochemicals can also activate this system. Foods such as tea, red wine, chocolate and fruits and vegetables contain high amounts of antioxidants and may be used as part of a healthy diet for good mental health.
Studying the scientific literature on moods disorder shows that plants are a very common treatment for anxiety and depression and this may relate to the way that they are able to modulate oxidative stress. Herbs, spice and whole foods have been shown repeatedly to be beneficial to mental health. Plants contain antioxidants, which they used a signal molecules and in the protection of their tissues from environmental stressors. When humans and animals eat the plants, they consume the antioxidants that are absorbed to their own tissues, and this can have protective effects against free radicals and oxidative stress. Further some plants are also able to decrease inflammation and inhibit the damaging effect of stress, two other factors that can contribute to mood disorders. Diets high in a variety of plants foods are therefore protective of the development of mood disorders, and while individual plants have been tested, the evidence to date suggests that combinations of plants should be superior with regard this protection.
Eat Well, Stay Healthy, Protect Yourself
RdB
