After a long time on the psychopharmacological route, there's a lot to be said about 'psychofarmacology'. Today, covering some flavonoid interventions, particularly citrus and also carotenoids.
Food for thought: the smart way to better brain health Sometimes I want a more evidence-based approach than an intuitive herbalism approach for heavier pathology. I like to try to stay as close to food as possible at it gives a wider margin of safety.
Flavonoids
Alongside eating well, I've always been interested in dietary flavonoid interventions, from berries to citrus to cacao [review], incorporating them in my diet, for their therapeutic benefits: such may exert powerful actions on cognition and may reverse age-related declines in memory and learning [1].
Single-dose flavonoid interventions have produced improvements in attention, inhibition, visuospatial memory, and executive function between 2–6 h post-consumption, whilst supplementation of flavonoids for 1.5–8 weeks has been associated with improved visuospatial memory and improved long-term memory.
Longer term, in a cognitively impaired population, Improvements in verbal fluency, short-term memory and long-term memory are observed. A meta-analysis suggests polyphenol-rich intervention are an inexpensive approach for enhancing circulation of pro-cognitive neurotrophic factors and to improve cognitive functioning in healthy individuals.
Source: USDA Database for Flavonoid Content of Selected Foods
I'm a fan of tea, cacao, berries but never really got into citrus flavonoids much. That said, I feel you often can't put all your eggs in one basket "___ will effectively help ___" etc. It's easy to get hyped up about one particular option, float on the wings of expectation, then crash and burn. When you're really mixing it up, I feel the magic starts to come alive. Dietary diversity is important
I find a commercial citrus flavonoid-rich (with ascorbic acid) preparation providing high levels of hesperidin allows some subjective benefits even quite acutely on my mood and cognition.
Preclinical studies and clinical trials demonstrated therapeutic effects of citrus flavonoids such as hesperidin, including in neurological and psychiatric disorders [2]
A limited number of clinical trials showed that hesperidin-enriched dietary intakes can significantly improve cerebral blood flow [3], cognition, and memory performance. Significant acute improvements were noted for for subjective alertness and improvements seen in executive function and psychomotor speed in healthy middle aged men [4] and chronic consumption is beneficial for cognitive function in healthy older adults [5].
It posseses significant antidepressant-like properties mediated by kappa-opioid [6] and 5-HT1A receptors [7], the NO/cGMP pathway, modulates pro-inflammatory cytokines, helps to maintain brain plasticity and acetylcholinesterase activity regulation [8] and significantly increases stress resilience by suppressing the augmentation of kynurenine levels by social stress [9] in animal models
Studies showed that it enhanced learning and memory through various mechanisms such as elevating brain-derived neurotrophic factor (BDNF). Hesperetin resulted in a significant improvement on memory retrieval and recognition memory consolidation, along with anti-inflammatory effects and restoration of antioxidant systems. Studies suggest that dietary intake or supplementation of natural flavonoids like hesperidin can be used for therapy of patients with brain injury and depression [10].
It augments antidepressants in animal models [11] and it may be "an effective medicine for PTSD" [12]
It is also noted for its neuroprotective, antinociceptive, anti-inflammatory, antioxidant, anti-cancer, lipid-lowering, and insulin-sensitising properties. Carotenoids
Another class of phytochemicals I like to dose up on are the carotenoids
Research has found significant relationships between serum and brain concentrations of dietary carotenoids and various measures of cognitive function.
Carotenoids significantly corresponded to global cognitive abilities including verbal learning, verbal fluency, memory recall, processing speed, and perceptual speed. Serum lutein, zeaxanthin, and β-carotene concentrations were most consistently related to better cognition. Serum zeaxanthin had significant relationships with most measures of cognitive function, with higher concentrations being significantly related to global cognitive performance,and better concept formation/abstraction. Serum concentrations of β-carotene were also significantly correlated to most measures of cognitive function. Serum lutein concentrations were significantly related to measures of global cognition, lower dementia severity, and executive function. Carotenoid levels have also been shown to protect cognitive function in older adults with mild cognitive impairment. Supplements have shown strong cognitive enhancement benefits over longer term studies and supplementation of carotenoids improves stress, serum cortisol, and general physical and emotional health
Carotenoids have strong anti-oxidant and anti-inflammatory action in the brain, lowering inflammatory markers, and preventing cognitive decline. Mechanisms by which certain carotenoids may function include modulation of functional properties of synaptic membranes along with changes in their physicochemical and structural features and increasing perfusion. They have direct effects, some directly modulating NMDARs, others signal transduction molecules including in dopaminergic systems. Crocins from saffron, one plant I have used lots of, have established monoaminergic effects, too.
Cortical carotenoids may be protective in nature and may also influence interneuronal communication and function via multiple mechanisms.
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