Skip to 0 minutes and 14 secondsDavid: In this video, I'm going to talk about what flavonoids might actually do in the brain. That is, what do they do that gives rise to the potential changes in psychological states and cognitive function, that I talked about in the earlier video? There are at least four possible routes through which flavonoids can positively influence things in the brain. One of them is through their role as signaling molecules of a family of proteins called neurotrophins. The role of neurotrophins in the brain is to increase the longevity of the neurons, so the neurons are going to live longer.
Skip to 1 minute and 4 secondsDuring their longer life and other effects of the neurotrophins, is that it promotes the growth of connections between different neurons, and so overall would be more connections added to the already vast number in the human brain. A second possibility is related to the endothelial effects of flavonoids that I spoke about earlier, that result in dilation of blood vessels and increase blood flow by improving the plumbing in the brain that has an indirect effect on improving the electrical function of the neurons. A third possibility relates to recent findings in neuroscience, that there are a couple of regions of the brain where it's possible for adults to grow new neurons.
Skip to 1 minute and 58 secondsUntil recently, it was thought that everybody was born with all the neurons they'd ever have. Several regions have now been shown as regions where it is actually possible for new neurons to grow in adults. One of those is the hippocampus, which is particularly involved in the formation of memories. Work with animals has shown that flavonoids could influence this process of neurogenesis in the hippocampus. The final possibility is that flavonoids may reduce the inflammation that is caused by oxidative stress. By reducing that inflammation, they're going to reduce processes that result in cell death. That is the death of neurons. It's a different route to the same endpoint as the first neurotrophin-based mechanism, basically increasing the lifespans of neurons.
Skip to 3 minutes and 2 secondsNeuroscience does have a couple of ways of getting some information about how the human brain works. One of these is using EEG, which measures the electrical activity on the scalp. The second technique is using functional magnetic resonance imaging. That is using an MRI scanner to measure the blood flow in the brain, and how it varies from region to region in the brain. Given the tight coupling between the plumbing, the blood supply in the brain, and what the neurons are doing, and the fact that blood has to be supplied to where the neurons are most busy, measuring the blood flow with the scanner gives us a good idea of what's going on at the neuron level.
Skip to 3 minutes and 56 secondsSome studies have been run using both of these techniques. They have also been combined with the type of cognitive and behavioral testing that I spoke about in the last video. Interestingly, some of the studies have been able to identify physiological effects in the brain using MRI, but the cognitive tests didn't show anything. It's interesting that we can find what appear to be quite meaningful physiological effects that aren't being picked up with the slightly cruder behavioral measures. Overall, the consensus from the functional magnetic resonance imaging studies is that the effect of a single high flavonoid meal on your brain would be due to the endothelial explanation.
Skip to 4 minutes and 51 secondsHowever, it seems likely that any long-term changes due to adopting a higher flavonoid diet for weeks or months would be mediated by changes in the connections between neurons. Although, the evidence-base does get a bit thin for these longer-term interventions with the neuroscience MRI EEG based measurements. I think it is fair to say we've got good evidence that you can get a change in the blood flow from a single high flavonoid meal based on the functional Magnetic resonance imaging data.
Flavonoids effect on the brain
Do flavonoids have an effect on the brain?
We have seen in the previous video that the evidence in support of the idea that flavonoid can have an effect on cognitive functions is mixed. However, scientists are also looking for evidence that flavonoids can have a direct effect on the brain. While not all flavonoids can reach the brain and affect it, some do, and there are a number of possible biological mechanisms that could explain their effect.
In this video we will briefly review the studies that investigate this interesting field, while in the rest of the week we will discuss other superfoods that could affect the brain and cognitive functions. We will also invite you to discuss whether you are interested in superfood for their possible effects on brain and cognition, besides the ones on our physical health.