This excerpt is taken from Rhonda’s recent podcast with Tim Ferriss. Rhonda talking about the nootropic properties of sulforaphane:
Getting past all of the usual suspects on our list of nootropics here, the other nootropic that I actually take frequently is SULFORAPHANE! It’s not even usually considered a nootropic by most people but I think it has potential to be considered at least a mild nootropic for a variety of reasons. One of the the best reasons to make this argument is the fact that sulforaphane crosses the blood-brain barrier, at least in mice. This is the first criteria that a substance must meet in order for there to be a compelling argument that it somehow exerts effects on the brain — but, in addition to that, it also affects the activities of the immune system which is now known to affect the brain through a series of lymphatic vessels. this new understanding of the immune system’s ability to interact with the brain also helps to explain why manipulating levels of systemic inflammation has, in clinical trials, been shown to affect feelings of depression either inducing depression in the presence of an artificial increase in activity in the immune system by injecting things like interferons into human trial participants or reducing depression caused by this artificial increase in inflammation through the co-administration of a natural anti-inflammatory, such as eicosapentaenoic acid, better known as the omega-3 fatty acid EPA.
In addition to sulforaphane crossing the blood-brain barrier in mice, the compound has been shown in a couple of randomized, double-blinded, placebo-controlled studies in humans to have one sort of effect or another on brain and behavior. For example, treatment with sulforaphane extracted from broccoli sprouts at doses ranging from about 9 mg to about 25 mg, which is an amount that might be found in around 65 grams of fresh broccoli sprouts on the high end, was able to improve autistic behavior checklist scores by 34% and significantly improved social interaction, abnormal behavior, and verbal communication in young men with autism spectrum disorder. Similarly, some measurable effects have been shown in a small trial of people with schizophrenia.
The fact that sulforaphane is exhibiting clear effects on the brain and behavior of people, such as those with autism spectrum disorder, hints that it might continue to show promise in other areas of cognition too. This is because animal studies have really shown a diversity of very interesting effects that are really just waiting to be replicated in humans.
For example: Sulforaphane has been shown to improve spatial working memory and short term memory in mice in the context of conditions that can affect memory in a deleterious way, such as Alzheimer’s Disease. It has been shown to increase neurite outgrowth, which is how damaged neurons and synapses repair themselves after damage from traumatic brain injury. The effect of sulforaphane on a rodent model of Alzheimer’s Disease in some respects is particularly interesting, because, if we go back to our conversation a little bit earlier about the potential choline may have for mitigating some of the negative effects of this disorder, sulforaphane has also been shown to significantly reduce memory impairment that has been experimentally induced by a drug that works specifically by interfering with the effects of acetylcholine in the nervous system, a drug known as scopolamine.
Sulforaphane was, in this animal trial to which I am referring, able to improve the cholinergic system by increasing acetylcholine levels, decreasing acetylcholine esterase activity, and increasing choline acetyltransferase, which is the enzyme responsible for synthesizing acetylcholine in the hippocampus and frontal cortex. This ties in nicely with some of our discussion earlier about the potential importance of the choline system in cognition. Finally, sulforaphane has been shown to have a positive effect on mood and alleviated depressive symptoms and anxiety as effectively as the antidepressant Prozac in a mouse model of depression and I understand that there is at least one trial currently in the beginning stages looking to confirm this effect in humans as well.
If you consider the variety of brain and behavioral effects demonstrated already in humans, I’m optimistically hoping that some of the groups out there working on these questions will have something good to show for it in the future.
See the full Tim Ferriss podcast for more info.