Neuroprotective Herbs and Spices for Alzheimer’s and Dementia

by Eva Coles MS, RDNNutrition

As you may already know, herbs and spices have therapeutic potential for a wide variety of ailments. Currently, a growing body of research suggests that several botanicals and extracts may have a beneficial effect for preventing and treating Alzheimer’s and mild cognitive decline. So, what does the current research say?

Your Garden is a Pharmacy

We often think of medicine as a pill in a bottle that we picked up from the pharmacy. But, do you ever think of plants or herbs as medicine? You would be surprised to discover that your garden may be inhabited by plants with potent therapeutic uses. As a matter of fact, almost half of all medications have been derived from plants. Aspirin was famously formulated from a compound in the bark and leaves of the willow tree [12]. However, over time, we drifted farther away from the natural by formulating highly refined medications that have seemingly extreme efficacy, but also with extreme side effects. Plant extracts have not only shown promise to treat numerous illnesses and optimize health, but also have far fewer side effects than conventional medications. So what do we know about botanicals and their potential to treat Alzheimer’s and cognitive decline?

What Current Research Says

This section will provide you with a brief overview of some herbs and spices with potential neuroprotective properties as well the research regarding their potential therapeutic effect on Alzheimer's disease and mild cognitive decline. These botanicals are rich in polyphenols and phytochemicals that have numerous direct effects on our health. We have covered a few of these plants in a previous blog post discussing the 4 best herbs and spices for brain health.

HERBS

Ashwagandha (Withania Somnifera). Also called Indian ginseng, this herb is commonly used in Ayurveda to treat stress, adrenal fatigue, and has shown promise for improving cognitive function and memory [3].

Active Compounds: Alkaloids, steroidal lactones, saponins, and withanolides

In several in vitro and animal studies, ashwagandha extracts have been shown to reduce oxidative stress, block the formation of amyloid plaque, and enhance its clearance in the brain. [2].
One human study found that 8 weeks of supplementation with 300mg ashwagandha root extract twice daily led to significantly improved memory and executive function in 50 subjects with mild cognitive decline [3].

Brahmi (Bacopa monnieri). Also called herb of grace, this medicinal plant grows naturally in parts of Europe, Australia, Africa, Asia, North America, and South America. Traditionally, Brahmi has been used to treat stress, memory deficits, epilepsy, and insomnia [2].

Active Compounds: saponins, bacopasides, bacosides, bacosaponins, alkaloids, sterols, betulic acid, polyphenols, and sulfhydryl compounds.

In vitro and animal studies suggest that the phytochemicals in this plant can fight oxidative damage in the brain [2].
In a double-blind, randomized, placebo-controlled trial with 35 healthy subjects (>55 yrs), 125mg Brahmi extract per day for 12 weeks significantly improved learning and memory [2].
Another trial found that 320mg Brahmi extract per day significantly improved attention in ten subjects with mild cognitive decline [2].
In a larger study, 104 subjects diagnosed with mild cognitive decline given a combination of Brahmi extract, astaxanthin, phosphatidylserine, and vitamin E each day for 60 days saw significant improvements in their Alzheimer’s Disease Assessment Scale-Cognitive Subscale (ADAS-cog) and Clock-Drawing Test (CDT), both of which are used to assess the progression of mild cognitive decline to Alzheimer’s [2].

Cat’s Claw (Uncaria tomentosa). This woody vine named for its cat-like thorns is native to the Jungles of Central and South America. It has been used by natives for centuries as a remedy for viral infections, and cognitive impairment [2].

Active Compounds: alkaloids, flavonoids, proanthocyanidins, tannins, glycosides, and sterols.

In vitro research suggests that cat’s claw may have potent anti-inflammatory properties [2].
In mice with Alzheimer’s, supplementation with cat’s claw extract each day for 14 days significantly reduced amyloid plaque in the hippocampus and cortex [2].
Preclinical studies indicate that cat’s claw extract may prevent the formation of or dissolve amyloid plaque and tau tangles and reduce overactivation of microglia.
No human studies have been conducted

Gotu Kola (Centella asiatica). A perennial plant related to parsley and native to Asia, Africa, and Australia, gotu kola is commonly used in eastern medicine for various ailments, including cognitive deficits, skin problems, and to enhance liver and kidney function [2].

Active Compounds: asiaticosides, asiatic acid, madecassoside, and madasiatic acid.

In vitro studies demonstrate that extracts of gotu kola can protect from oxidative damage, and reduce toxicity of amyloid plaque
Gotu kola extracts have accelerated neuronal growth and improved learning memory in rats and reduced the formation of amyloid plaque in mice.
Asiatic acid, one of the many phytochemicals found in gotu kola, significantly improved memory in memory-impaired mice.
A randomized, placebo-controlled, double-blind trial showed that 750mg of gotu kola extract improved working memory and mood in 28 healthy subjects.

Shankhpushpi (Convolvulus pluricaulis). Native to India and Burma, this plant is believed to improve stress, anxiety, and enhance memory [2].

Active Compounds: triterpenoids, flavanol glycosides, anthocyanins, steroids.

Shankhpushpi extract has demonstrated potent antioxidant activity and improved memory in several studies with rats
There have not yet been any human trials

Triphala. Triphala is an Ayurvedic herbal remedy meaning “three fruits” because it is an equal combination of three fruits: Amalaki (Phyllanthus emblica), Bibhitaki (Terminalia bellirica), and Haritaki (Terminalia chebula). It is commonly used as treatment for various metabolic diseases and cancer [2].

Active Compounds: flavonoids, polyphenols, saponins, vitamin C, tannins, ellagic acid, gallic acid, lignans, terpenes, anthocyanins.

Triphala has been shown to stimulate autophagy and increase longevity in animal studies.
Triphala can stimulate the production of bifidobacteria and lactobacillus (beneficial) in the gut while inhibiting the growth of bad bacteria [5].
- Both of these bacteria have been shown to be beneficial for cognitive function and are generally the best for gut health.
In a randomized trial with 62 obese subjects, 5g of triphala twice daily for 12 weeks significantly reduced fasting glucose and insulin and body weight.
- This could indicate potential for targeting glycotoxic Alzheimer’s.
In numerous other randomized trials in humans with periodontal disease, mouthwashes formulated with Triphala reduced plaque accumulation and inflammation of gums.
- There is evidence that certain bacteria that cause gingivitis can travel to the brain and cause neuronal death, resulting in an increased risk of Alzheimer's disease [6].

SPICES

Saffron (Crocus sativus). This crimson-colored spice is the most expensive spice in the world, mainly because of the slow meticulous process through which it is extracted from its flower. Uses range from treating mood disorders to cardiovascular disease [7].

Active compounds: safranal

In vitro and in vivo research suggest that saffron may have antioxidant, anti-inflammatory, and amyloid-plaque-inhibiting properties.
In a study with 46 patients with mild AD, 30mg saffron extract per day led to improved cognitive scores. The same team later demonstrated that saffron extract was as effective as donepezil for improving cognition in Alzheimer’s patients with fewer side effects.
In another study, 30mg per day of saffron extract had comparable cognitive improvements to memantine in 68 patients with moderate to severe Alzheimer’s.

Turmeric (Curcuma longa). Turmeric, a relative to ginger, is a flowering plant native to Southeast Asia and India. Its root has been used for millenia for its potent anti-inflammatory, antibacterial, and antioxidant properties [2].

Active compounds: curcuminoids

In vitro studies have demonstrated that curcumin can prevent lipid peroxidation and reduce oxidative stress, two factors associated with Alzheimer's disease.
Curcumin can bind metals such as iron, zinc and copper, and prevent ensuing toxicity and inflammation.
In numerous mouse models of Alzheimer’s, oral supplementation with curcumin has significantly reduced amyloid plaque load, oxidative damage, and inflammation and improved cognitive function.
Even more, curcumin has been shown to reverse cognitive decline in mice with Alzheimer’s.

Cinnamon (Cinnamomum). This slightly sweet, warm flavoured spice is native to Sri Lanka and India. It can be obtained from the inner bark of several related tree species. Cinnamon has been recognized globally for its antioxidant, anti-inflammatory and anti-cholesterol activities [9].

Active Compounds: cinnamaldehyde, procyanidins

In vitro and animal studies have shown that cinnamon extract inhibits tau protein aggregation and amyloid plaque accumulation and toxicity [10].
Cinnamon extract may also improve vascular function, making it a potential therapeutic target for vascular Alzheimer’s disease [10].
Mice studies have demonstrated that cinnamon extract can also improve insulin sensitivity [10]. You can read more about the implications of this in our post about glycotoxic Alzheimer’s disease.

TREES

Ginkgo Biloba. Also known as maidenhair tree, ginkgo is native to China extracts from its leaves are believed treat age-related memory impairment and prevent Alzheimer’s and vascular dementia [4].

Active Compounds: flavonoids, terpenoids

Studies in gerbils demonstrated that ginkgo extract improved cognitive impairment from vascular dementia.
A number of studies in mice show that ginkgo extracts reverse amyloid plaque accumulation, improve short-term memory and memory retention.
Ginkgo may even be as effective as cholinesterase inhibitors for the treatment of Alzheimer’s.
In various randomized trials with Alzheimer’s patients, ginkgo supplementation improved cognitive impairment and activities of daily living [2].

EDIBLE MUSHROOMS

Lion’s Mane (Hericium erinaceus). This edible mushroom grows naturally in Asia, Europe and North America. It has been used for millenia in Traditional Chinese medicine to treat cancer, gastric ulcers, and improve brain function [8]. We covered Lion’s Mane in great detail and its potential to treat Alzheimer’s and mild cognitive decline in an earlier post.

Active Compounds: hericinones

In vitro and animal studies have shown that Lion’s mane extract can promote nerve growth factor (NGF) and Brain Derived Neurotrophic Factor (BDNF), and act as an antioxidant [11].
In mice models of Alzheimer’s, Lion’s mane supplementation reduced tau tangles and improved amyloid plaque burden [11].
In a study on men and women with mild cognitive impairment, 16 weeks of daily supplementation with dried Lion’s mane powder improved cognitive performance [11].
Another study found that 12 weeks of daily supplementation with fruiting body improved short-term memory [11].
In patients diagnosed with mild Alzheimer’s Disease, 49 weeks of daily supplementation with Lion’s Mane mycelium extract improved Cognition and Activities of Daily Living scores [11].

Should You Supplement?

All of this information may lead you to open a new browser page and find out where you can order extracts of the botanicals we have discusses in this blog post. I urge you to refrain from doing so before speaking to a knowledgeable healthcare professional and nutritionist. Most of these compounds have not been tested in humans, so we cannot confirm that the benefits will transfer if you supplement. Moreover, some of these extracts contain compounds that may interact with medications.

Before considering supplementation, try to incorporate these in your diet naturally by cooking with them or making teas with them:

You can grow herbs and spices in your garden
Purchase dried herbs or spices at the market if you are short on time or limited with garden space
Use essential oils with a diffuser
Always opt for organic to minimize toxic pesticide residues or other harmful chemicals

If you are interested in supplementing with any of these extracts, contact the Amos Institute to speak to a qualified dietitian nutritionist trained in functional medicine who can help you determine if any are right for you.

Takeaways

Herbs, spices, and plant extracts show immense promise for not only preventing cognitive decline and Alzheimer’s disease, but also for improving quality of life. That being said, each of these contain innumerable bioactive compounds of which we still know little about and have not been directly studied in humans. So, more research is needed to confirm the observed benefits and formulate standadrized therapies. Contact the Amos Institute today if you have any quesitons or concerns regarding supplementation for cognitive health.

References:

Guo et al., 2022: https://doi.org/10.3390/molecules27030901
Gregory et al., 2021: https://doi.org/10.3390%2Fbiom11040543
Choudhary et al., 2017: https://doi.org/10.1080/19390211.2017.1284970
Mohanta et al., 2014: http://dx.doi.org/10.1080/14786419.2013.879303
Peterson et al., 2017: https://doi.org/10.1089%2Facm.2017.0083
Harvard Medical School, 2019: https://www.health.harvard.edu/mind-and-mood/good-oral-health-may-help-protect-against-alzheimers
Bagur et al., 2018: https://doi.org/10.3390%2Fmolecules23010030
Friedman, 2015: https://pubs.acs.org/doi/10.1021/acs.jafc.5b02914
Hamidpour et al., 2015: https://doi.org/10.1016%2Fj.jtcme.2014.11.008
Momtaz et al., 2017: https://doi.org/10.1016/j.phrs.2017.12.011
Coles, 2022: https://amosinstitute.com/blog/could-lion%E2%80%99s-mane-mushroom-become-a-treatment-for-alzheimer%E2%80%99s-and-mild-cognitive-impairment/
Wong 2001: https://www.scientificamerican.com/article/mother-natures-medicine-c/#:~:text=Indeed%2C%20nearly%20half%20of%20all,by%20Bayer%20starting%20in%201899.