Originally published via Armageddon Prose:

“Eat your lime peels,” my Irish-Catholic Midwestern grandmammy used to admonish me from behind a veil of cigarette smoke at the lunch table after Mass. This was a simpler time, when adults were still allowed to expose children to secondhand smoke without CPS getting called.

Related: The Essential Nootropics Stack

And eat my lime peels, I did, Oh My Brothers, for I knew well that, if I protested, out would come the rod with the Passion of the Christ, and it would be my own personal Angela’s Ashes right there in a dingy Topeka, Kansas basement.

Bless her heart, it appears that she knew of what she spoke.

Nature hides the good stuff in the damnedest places.

“Citrus fruit [peels], which are generally discarded as waste in the environment, can act as potential nutraceutical resources,” per the Journal of the Saudi Society of Agricultural Sciences.

So why toss them out?

Via an extensive literature review published in Nutrients:

“Citrus [polymethoxylated flavones], such as nobiletin and tangeretin, exerted beneficial effects on cognitive function in numerous experimental models—e.g., AD, Parkinson’s disease, and cardiovascular dementia by modulating pathological features such as Aβ/tau pathology, oxidative stress, and neuroinflammation and improving synaptic plasticity in several experimental models. Besides, flavanones such as hesperidin, naringin, and narirutin exerted neuroprotection in several neurodegenerative disorder models… 

A recent study documented the synergistic effects of citrus peel powder and perilla seed oil (PO) on cognition. PO is rich in α-linolenic acid (ALA) and improves cognitive function and mental health in healthy and older adults…

Preclinical studies indicated that flavanones, such as hesperidin and narirutin, improve cognitive impairments induced by oxidative stress, inflammation, and ischemia. These flavanones have also been reported to improve cognitive function through various mechanisms, including increasing BDNF levels and improving neurological function… 

A prospective cohort study including 82,643 women without a diagnosis of depression from the NHS (53–80 years old) and the NHSII (36–55 years old) showed an inverse correlation between the development of depression and citrus consumption. Moreover, maximum flavanone consumption (>64.2 mg/day) markedly reduced the risk of depression (by 10%). Thus, high flavonoid intake may reduce the risk of depression…

This review explored the effects of citrus components on brain health and related functions. Numerous clinical and epidemiological studies have demonstrated the benefits of acute and chronic consumption of citrus components on cognitive functions for healthy or preclinical individuals and patients. Another great advantage of citrus flavonoids is their safety. Indeed, high-dose and chronic intake of citrus peels and extracts have no serious adverse effects* on humans or animals.”

*How many “side effects may include stroke and spontaneous limb growth from head” pharmaceutical drugs can be honestly said to “have no serious adverse effects”?

Why the peels; why not just drink the juice? Because “the citrus fruit peel flavedo (outer layer) and the albedo contain more flavonoids than the juice sacs,” notes Antioxidants.

The aptly named limonene, a terpene found in limes, is also great for heart health — which may, in part, explain its brain benefits, as proper blood flow is necessary for optimal brain function.

Via The European Journal of Pharmacology:

“In the preventive treatment, d-limonene decreased the size of white and brown adipocytes, lowered serum triglyceride (TG) and fasting blood glucose levels, and prevented liver lipid accumulations in high-fat diet-fed C57BL/6 mice. In the therapeutic treatment, d-limonene reduced serum TG, low-density lipoprotein cholesterol (LDL-c) and fasting blood glucose levels and glucose tolerance, and increased serum high-density lipoprotein cholesterol (HDL-c) in obese mice.”

So my unsolicited advice is to get your fat ass peeling.

As far as practical application of the above knowledge, for a long while until recently I just chewed the peels until my molars ground them into swallowable bits — an exercise in masochism and a true test of my gag reflex.

More recently, I’ve begun using a cheese grater, which works wonders with some elbow grease.

Ben Bartee, author of Broken English Teacher: Notes From Exile, is an independent Bangkok-based American journalist with opposable thumbs.

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