Skip to 0 minutes and 15 secondsIn the first week of the course we briefly discussed some metabolic aspects of the brain, such as its energy requirements. we saw that the brain needs a sustained and continuous flow of ‘fuel’ - and that under normal circumstances, this fuel consists of glucose. however, the brain doesn’t need only a steady supply of water, glucose and oxygen, to survive in a healthy state. Instead, there are micronutrients – vitamins and minerals – that are essential to healthy brain functioning. These requirements are not specific to the
Skip to 0 minutes and 56 secondsbrain: micronutrient deficiencies affect the whole body., However, sometimes they have a peculiar effect on our cognitive functions, and in extreme cases can lead to irreversible brain damage. Micronutrient deficiencies are common in case of chronic malnutrition. In some cases, such as insufficient dietary intake of vitamin b3, vitamin c or of iodine. These deficiencies and their associated Syndromes were widespread enough to have a social impact in the western world, such as in the case of scurvy, pellagra or congenital iodine-deficiency syndrome.
Skip to 1 minute and 41 secondsthe last two were, for instance, common in italy: pellagra was Widespread in the north-east, were farmers mainly ate maize porridge, or polenta, while iodine deficiency was reported in the kingdom of sardinia, in the north-west. In this lecture, we will focus on b group vitamins, and we will talk about neurological syndromes associated with a lack of one of these vitamins - vitamin B1, or thiamine This vitamin is required by fundamental cellular processes, such as the metabolism of sugars and amino acids. In the brain, it plays additional roles - for instance, it modulates the activity of neurons that use acetilcoline to transmit information. vitamin B1, like the other B vitamins, is soluble in water.
Skip to 2 minutes and 41 secondsAs you might recall from the first week, large water-soluble molecules cannot cross freely the blood-brain barrier and must be transported through it. Due to their importance, all B group vitamins have dedicated transport mechanisms. Once in the brain, these vitamins are used by the cells, and their concentration is tightly regulated by homeostatic mechanisms. The lack of vitamin B1 for prolonged periods causes a condition, known as beri beri, that can primarily affect the brain, the cardiovascular system or the digestive system, causing different symptoms. As for pellagra, beri beri historically affected
Skip to 3 minutes and 30 secondspeople from the lower social classes: it is the case, for instance, of japanese sailors in the late 19th century. During missions, low-ranking sailors subsisted on a diet of polished white rice, and casualties linked to beriberi were common. It was reported that during a single trip from japan to hawaii Almost half of a crew of 376 men fell ill, and 25 died. Beri beri was a serious problem in the Japanese Navy, and it was studied by doctors such as Takaki Kanehiro , but it wasn’t until the first decade of the 20th century that “anti-beriberi nutrients” were discovered in rice and barley bran.
Skip to 4 minutes and 24 secondsNowadays, in the western world thiamine deficiency syndromes are rare, but low-grade deficiencies are still common, even if many foods are fortified with thiamine and other micronutrients, to avoid public health crisis. In fact, the most severe case of thiamine deficiencies can be only observed in people suffering from specific medical conditions. This is the case, for instance, of long-term alcohol abuse. Long-term alcohol addicts can suffer from a condition know as Wernicke-Korsakoff syndrome. This syndrome is caused both by the lack of thiamine in their diet and by its reduced absorption due to gut and liver damage.
Skip to 5 minutes and 16 secondsIn the acute phase of this illness, known as Wernicke encephalopathy, people can suffer from confusion , disturbances of walking, disturbances of eye movements And amnesia for new events, depending on the severity of the illness. Most of these symptoms can be treated, and improve if the deficiency is treated early on, but if it is allowed to progress to the so-called alcoholic Korsakoff syndrome, the consequences are permanent cognitive damages, coma, and even death. Wernicke-Korsakoff syndrome is characterized by deficit in multiple cognitive tasks, but one of its defining features is confabulation, or the presence of invented memories taken by the patients as they were true, often to ‘fill-in’ gaps in memory.
Skip to 6 minutes and 12 secondsSevere deficiencies syndromes such as beriberi are the extreme consequence of the lack of micronutrients, and underline their importance for a healthy brain. However, as I said before, slight deficits, or marginal deficiencies, of micronutrients are still present even in western countries and can cause symptoms such as a lower mood or poorer memory performance. The evidence in that respect is less strong, but there are studies that investigate the effect of vitamines, prebiotic fibers and antioxidant in aging, as a preventative measure and to increase well being, and we will partly discuss these arguments in the last lecture of this week.
Micronutrient deficiencies and the brain
Nutritional deficiencies were once widespread even in the first world.
While luckily this is not the case anymore, nutritional deficiencies still affect parts of the population. It is, for instance, the case of thiamine deficiency, that can give rise to a neurological disease, called Wernicke-Korsakoff syndrome. This syndrome was described by the famous neurologist, Oliver Sacks, in his book “The Man Who Mistook His Wife for a Hat” (a must read for aspiring neuropsychologists and neurologists!).
This video is the beginning of the two ‘Food and our Bodies’ activities, in which we describe the effects of diets and some specific molecules on the brain, body and to a lesser extend cognition.