Sago palm

Other Names

Cycad SagoCycas aurea J.Verschaff.Cycas inermis Oudem.Cycas miquelii Warb.Cycas revolutaCycas revoluta var. brevifrons Miq.Cycas revoluta var. pendula DallièreCycas revoluta var. planifolia Miq.Cycas revoluta var. prolifera Siebold & Zucc.Cycas revoluta var. robusta MesseriCycas taitungensis C.F.Shen, K.D.Hill, C.H.Tsou & C.J.ChenEpicycas miquelii (Warb.) de Laub.Japanese Sago PalmKing SagoKing Sago PalmKungi PalmLumbiyaMetroxylon hermaphroditum Hassk.Metroxylon inerme (Roxb.) Mart.Metroxylon laeve (Giseke) Mart.Metroxylon longispinum (Giseke) Mart.Metroxylon micracanthum Mart.Metroxylon oxybracteatum Warb. ex K.Schum. & Lauterb.Metroxylon rumphii (Willd.) Mart.Metroxylon sago K.D.KoenigMetroxylon saguMetroxylon squarrosum Becc.Metroxylon sylvestre (Giseke) Mart.RumbiaSago CycadSago CycasSagopalmeSagoutierSaguSagus americana Poir.Sagus genuina GisekeSagus inermis Roxb.Sagus koenigii Griff.Sagus laevis JackSagus longispina (Giseke) BlumeSagus micracantha (Mart.) BlumeSagus rumphii Willd.Sagus sagu (Rottb.) H.Karst.Sagus spinosa Roxb.Sagus sylvestris (Giseke) BlumeSotetsuSu-tieTieshuTrue Sago Palm

Synopsis

Sago Palm: A Comprehensive Encyclopedic Reference

1. Identity: Botanical Classification, Nomenclature, and Common Forms

1.1 The Naming Problem: Two Distinct Plants, One Common Name

The term "sago palm" is applied commercially and colloquially to two entirely distinct and botanically unrelated plants. This ambiguity is scientifically and toxicologically significant and must be clearly delineated at the outset of any reference treatment.

Metroxylon sagu Rottboll — the true sago palm, a genuine monocot palm (family Palmae/Arecaceae), and the primary commercial source of sago starch. This is the subject of most food science, nutrition, and agricultural research.
Cycas revoluta Thunberg — the Japanese sago palm or king sago, a cycad (family Cycadaceae, order Cycadales), not a true palm and not closely related to angiosperms. This is primarily an ornamental plant and is well-characterized for its pronounced toxicity.

The word "sago" is originally Javanese, meaning starch-containing palm pith. The scientific name Metroxylon is derived from "metra," meaning pith or parenchyma, and "xylon," meaning xylem.

Metroxylon sagu is a true palm belonging to the order Arecales, family Palmae, and subfamily Calamoideae. Cycas revoluta, by contrast, is an extremely poisonous gymnosperm that belongs to the family Cycadaceae and the order Cycadales.

1.2 Metroxylon sagu: Botanical Description and Synonymy

Metroxylon sagu (true sago palm) is a species of palm in the genus Metroxylon, native to tropical southeastern Asia, namely Indonesia (western New Guinea and the Moluccas), Papua New Guinea, Malaysia (both Peninsular Malaysia and Sarawak) and possibly also the Philippines. It is also naturalized in Thailand, in the Indonesian islands of Java, Kalimantan, Sumatra, and in the Solomon Islands.

True sago palm is a suckering (multiple-stemmed) palm, each stem only flowering once (hapaxanthic) with a large upright terminal inflorescence. A stem grows 7–25 metres tall before it ends in an inflorescence. Its habitat is in lowland swamp forests. The tree is of commercial importance as the main source of sago, a starch obtained from the trunk by washing the starch kernels out of the pulverized pith with water.

Several botanical synonyms appear in older literature, including Sagus sagu (Rottb.) H.Karst., Sagus rumphii Willd., Sagus inermis Roxb., Sagus laevis Jack, Sagus koenigii Griff., and Metroxylon sylvestre (Giseke) Mart.

1.3 Cycas revoluta: Description and Distinction

Cycas is derived from the Greek name cyca, meaning "palm." Cycads are gymnosperms and, although palm-like, they are not related to true palms/angiosperms (flowering plants). The Latin revoluta refers to "rolled back," describing the leaflets of the sago palm that curl under. Cycas revoluta (sago palm), a cycad native to southern Japan, is widely cultivated and has a long history of ethnobotanical use, including as a famine food and in traditional medicine, but is also well known for its pronounced toxicity to humans and animals.

1.4 Common Forms and Preparations

Commercial sago from Metroxylon sagu is available in several distinct forms:

Sago flour/starch: Pure dried starch extracted from the pith.
Sago pearls: Sago can be purchased in two main forms — flour or pearls. While the flour is pure starch, the pearls are small balls of sago that are made by mixing the starch with water and partially heating them.
Sago porridge (papeda, linut): Traditional preparations described below.
Processed food products: In Sarawak, various types of food have been produced from sago and widely used in food industries including sago pearls, tabaloi (a traditional delicacy biscuit), keropok (shrimp crackers), puddings, jellies, and used as thickener in food products and made into noodles and vermicelli.
Modified resistant starches (RS3, RS4): Laboratory and food-industry processed forms used in functional food and research contexts.

2. Traditional and Historical Use

2.1 Metroxylon sagu: Indigenous Staple Food of Southeast Asia and Melanesia

Sago is a starch extracted from the soft, spongy core tissue of several tropical palm species, especially Metroxylon sagu. For centuries, it has been an important traditional staple food among many indigenous communities across the islands of Southeast Asia and the Melanesian region, including Malaysia, Indonesia, and Papua New Guinea.

New Guinea Island is the origin of sago palm. Sago became a food plant not only there but was also dispersed to Asian areas for use as a staple food. According to Ruddle (1979), in the thirteenth century when Marco Polo went to Sumatra and Maluku, he found that the local people on some islands — Mentawai, Lingga, and Maluku — ate sago starch.

Sago was noted by the Chinese historian Zhao Rukuo (1170–1231) during the Song dynasty. In his Zhu Fan Zhi (1225), a collection of descriptions of foreign countries, he writes that the kingdom of Boni "produces no wheat, but hemp and rice, and they use sha-hu (sago) for grain."

In Malaysia, sago is especially associated with the indigenous communities of Sarawak and Sabah, particularly the Melanau people. The Melanau community has a long historical connection with sago cultivation, processing, and consumption, making it one of the most culturally important foods in their society.

In Indonesia, some regions use sago as the main staple food source, such as in Maluku, Papua, and parts of Sulawesi such as East Kolaka. In places such as the Maluku Islands and Papua New Guinea, sago is commonly prepared as papeda, a thick sticky paste similar to linut, usually eaten with fish-based dishes and soups.

Sago palms grow in lower areas, up to about 1200 m, and is very important in the Sepik and Fly River areas, in the Trans-Fly, and in many coastal areas. In the Southern Highlands in the Kutubu area, sago is the staple food, while in other lowland areas it forms an important supplementary staple.

2.2 Traditional Extraction Methods

The original starch extraction method was to pulverize the sago pith with an ax and wash the pieces of pith by hand, which was practiced in New Guinea Island. This technology of starch extraction was then transferred to western Indonesia. Pith pulverization evolved from original chopping with an ax while sitting or standing, transferred to the west part of Indonesia and Malaysia, followed by further development in grater forms and adaptation to rasper machine use.

According to Avé (1977), the sago palm is a multifunctional plant: its starch can be used as a staple food, and the pith residue as waste can be used as a medicine, a pesticide, and also as a poison for fish.

2.3 Non-Food Traditional Uses of Metroxylon sagu

The leaves are used as thatching material, or woven into baskets and mats. The bark can be used as fuel or as flooring material. In Maluku, the sago tree was often used for construction material. The leaf midribs are dried for 14 days, and the thinner ends of the spine are cut and neatly assembled with pegs to create panels (gaba-gaba) used as partitions between interior and exterior spaces. These panels can also be used as ceilings. The trunk, when properly emptied, can also be used as a gutter between two roof parts.

2.4 Traditional Uses of Cycas revoluta

Cycas revoluta has a long history of ethnobotanical use, including as a famine food and in traditional medicine. The seeds are used in China as an anti-rheumatic, expectorant, and tonic. The shoots are utilized as an astringent and diuretic. The young leaves are edible and the juice of tender leaves is described in traditional practice as valuable for the treatment of flatulence and vomiting. It has also been used to relieve headaches, giddiness, and sore throat.

Historically, the inner bark of the sago palm (Cycas revoluta) was used as a food source in Japan during times of famine. However, it contains a powerful neurotoxin that can cause paralysis or even death if not prepared properly.

Medicinal use of cycad seed was linked in 1987 to single cases of young-onset ALS in Papua-Indonesia and the Kii Peninsula of Japan, where there was a long history of its use in Kampō medicine.

3. Key Constituents and Active Compounds

3.1 Principal Constituents of Metroxylon sagu Starch

Sago starch generally contains 81.73% carbohydrates, 0.12% protein, 0.80% fats, 0.63% fiber, 1.56% ash, and 15.80% moisture content. Sago starch does not add significantly to the protein calorie intake and may be associated with susceptibility to nutritional-associated illness when used as a sole or primary dietary source.

Amylose and Amylopectin: The amylose content of sago starch varies between 24% and 31%. The amylose contents of sago starches (26.11% and 24.07%, respectively) are significantly higher than those of corn starch (13.35%) and potato starch (11.67%). The amylose/amylopectin ratio of sago is reported to be higher (24–31%) as compared to short-medium grain rice (15–18%) and glutinous rice (4%), which are commonly consumed in Asia.

Resistant Starch (RS): RS content of sago native starch was reported to contain up to 68.99%. Chemical modifications such as phosphorylation, acetylation, and hydroxypropylation are known to increase the RS content of a starch. Acetylation has shown to increase the RS content of sago native starch to up to 74%, which is comparable to the commercially available wheat RS from Fibersym™.

Starch Granule Morphology: X-ray diffraction studies showed that sago starches exhibit a C-type diffraction pattern. Scanning electron microscopy showed they consist of oval granules with an average diameter around 30 μm.

Minor Constituents: Proximate composition studies showed that moisture content in sago samples varied between 10.6% and 20.0%, ash between 0.06% and 0.43%, crude fat between 0.10% and 0.13%, fiber between 0.26% and 0.32%, and crude protein between 0.19% and 0.25%.

3.2 Phytochemical Constituents of Cycas revoluta

The phytochemistry of Cycas revoluta includes diverse compounds, including biflavonoids, cycasin, β-N-methylamino-L-alanine (BMAA), and reported antimicrobial peptides, noting variability in compound verification and reproducibility. The extract of C. revoluta leaves is composed of alkaloids, steroids, tannins, and sugars. Seeds contain cycasin, which is highly toxic, along with beta-methylamino-L-alanine (BMAA), a neurotoxic amino acid.

Cycasin: Chemically, cycasin is methylazoxymethanol-β-d-glucoside. Cycasin is metabolized into methylazoxymethanol (MAM), which alkylates DNA, leading to liver damage, mutations, and cancer in experimental models.

BMAA (β-N-methylamino-L-alanine): BMAA has a number of toxic effects on motor neurons, including direct agonist action on NMDA and AMPA receptors, induction of oxidative stress, and depletion of glutathione. As a non-protein amino acid, there is also the strong possibility that BMAA could cause intraneuronal protein misfolding, the hallmark of neurodegeneration.

Additional toxins: All parts of the plant, and in particular the seeds, contain phytotoxins: the azoglycosides cycasin (hepatotoxic and carcinogenic), macrozamin and neocycasin, the neurotoxic amino acid β-N-methylamino-L-alanine (BMAA), and an unidentified high molecular weight compound.

4. Mechanisms of Action

4.1 Mechanisms of Sago Starch (Metroxylon sagu)

Resistant Starch and Glycemic Modulation: Resistant starch (RS) consumption with low glycemic index properties has been shown to be beneficial in managing postprandial hyperglycemia. The process whereby RS skips digestion in the small intestine and is fermented by microbiota in the colon prevents glucose spikes. In principle, the more the RS content, the slower the digestion rate and the lower the glycemic index, which determines the ability of food to raise blood glucose levels.

Prebiotic Fermentation: Sago RS3 was resistant to 180-minute hydrolysis by gastric acidity at pH 1 to 4 with less than 0.85% hydrolyzed. Both sago RS and HCl-sago RS were also resistant to hydrolysis by gastrointestinal tract enzymes, with 96.75% and 98.69% of RS3 recovered respectively after 3.5-hour digestion and overnight dialysis at 37°C. Fermentation of sago RS3 by Lactobacillus acidophilus, L. bulgaricus, L. casei, and Bifidobacterium bifidum was investigated by observing bacterial growth, carbohydrate consumption profiles, pH changes, and total short chain fatty acids (SCFA) produced in the fermentation media.

Enzyme Inhibition: Mechanisms involved in glucose lowering by sago RS were further explored by screening the in vitro inhibitory activities of α-glucosidase and dipeptidyl peptidase (DPP)-IV.

4.2 Mechanisms of Toxicity in Cycas revoluta

Hepatotoxicity of Cycasin: Cycasin, which is converted to its aglycone methylazoxymethanol (MAM), may cause centrilobular and midzonal coagulative hepatic necrosis and gastrointestinal irritation. In addition, cycasin is carcinogenic, mutagenic, and teratogenic. Beta-methylamino-L-alanine, a neurotoxic amino acid, causes ataxia in rats and is implicated in Guam disease in people.

Neurotoxicity of BMAA: The role of L-BMAA in selective degeneration of motor neurons in the cerebral cortex and spinal cord of primates is well established. Through numerous clinical, in vitro, in vivo, and mechanistic studies, L-BMAA has been implicated as the causal factor for the neurodegenerative diseases in humans, including Amyotrophic Lateral Sclerosis/Parkinsonism Dementia Complex (ALS/PDC).

Both in vitro and in vivo studies of the BMAA mode of action have focused on different molecular targets, demonstrating its toxicity to neuronal cells, especially motoneurons, and linking it to human neurodegenerative diseases. Historically, the hypothesis of BMAA-induced excitotoxicity following the stimulation of glutamate receptors has been established.

5. Scientific Evidence by Area of Use

5.1 Glycemic Index and Blood Glucose Regulation

Human clinical evidence (small studies): Sago starch was the staple carbohydrate source in Sarawak, Malaysia. Saguk and Linut are two well-known traditional sago foods whose glycemic indices had not been established until recently. A study aimed to determine the GI for Saguk and Linut: isoglucidic servings containing 50g available carbohydrate for both foods and a glucose drink as reference were consumed by 12 healthy subjects. Blood was drawn at predefined intervals for 2 hours. Linut and Saguk demonstrated "moderate to high GI" and "moderate to low GI" values of 69.8 ± 5.5 and 46.9 ± 5.1, respectively.

A study on alternative rice noodles from mixed sago palm flour (Metroxylon spp.) and Chiang rice flour enrolled 12 healthy subjects (6 males and 6 females, aged 21.2 ± 0.4, normal BMI 20.8 ± 1.3 kg/m²). The alternative rice noodles showed low GI (53.6 ± 8.3) and medium GI (63.1 ± 9.8) values. Serum insulin response was significantly lower for the alternative rice noodles compared to glucose solution at 45, 60, and 90 minutes (p<0.05).

Sago starch contains high amounts of RS type 2, and when consumed by individuals with type 2 diabetes (T2D), it led to reductions in daily caloric intake from daily meals. Among individuals with excess body weight, supplementation with RS leads to improved glucose tolerance, insulin sensitivity, and adiponectin, as well as reductions in body weight, fat mass, and waist circumference.

Evidence strength: These human studies are small (typically 12 subjects), unblinded or single-arm, and lack long-term follow-up. They demonstrate plausible glycemic benefit for sago-based foods but are insufficient to support therapeutic claims. The evidence is preliminary.

5.2 Prebiotic Potential and Gut Microbiome

In vitro and animal evidence only: The in vitro fermentability of sago (Metroxylon sagu) resistant starch type III (RS3) by selected probiotic bacteria was investigated. The results indicated that fermentation of sago RS3 significantly (P < 0.05) yielded the highest count of Lactobacillus sp.

The findings suggested that sago RS3 has prebiotic partial characteristics and it is suggested to further assess the suitability of sago RS3 as a prebiotic material.

An in vivo (rat) study demonstrated that Bifidobacterium spp. and Lactobacillus spp. showed significant increment (P<0.05) when supplemented with sago starch. Short chain fatty acids such as acetate, propionate, and butyrate showed increment trends, however not significant. The study demonstrated that sago starch has a similar effect to commercially available resistant starch, indicating potential as a prebiotic.

Evidence strength: Currently limited to in vitro fermentation and animal (rat) studies. No robust human clinical trials on sago starch as a prebiotic have been identified. Evidence is preclinical only.

5.3 Diabetes Management — Animal Evidence

A study aimed to identify the glucose-lowering effects of Sarawak sago RS, namely native (RS2) and chemically modified (RS4). An oral glucose tolerance test (OGTT) was performed before and after 1-month treatment with sago RS2 and RS4 in spontaneously type 2 diabetic (T2D), Goto-Kakizaki (GK) rats. The mechanisms were further explored by screening the in vitro inhibitory activities of α-glucosidase and dipeptidyl peptidase (DPP)-IV.

RS2 from Sarawak sago palm consumption improved glucose tolerance in diabetic rats, indicating preliminary proof of health benefit in diabetes management and potential for development as a functional ingredient or dietary supplement. The encouraging results justify further evaluation to be carried out in human T2D patients.

Evidence strength: Animal model data only (Goto-Kakizaki rat). Translational relevance to humans is unconfirmed. Evidence is preclinical, preliminary.

5.4 Exercise Performance and Recovery

Human clinical evidence (small trials): Sago proves suitable in a majority of published research as a high carbohydrate food or supplement source in the peri-exercise period for maintaining performance and improving recovery.

A published PMC review summarizes a series of trials: Eight well-trained male cyclists/triathletes (34 ± 9 years, VO2peak 70 ± 10 ml·kg⁻¹·min⁻¹, peak aerobic power 413 ± 75 W) completed two 15-minute time trials. Mean power output was not different between trials during Exercise 1 (286 ± 67 vs. 281 ± 59 W); however, it was reduced during Exercise 2 for the control group (274 ± 61 W) but not for the sago group (283 ± 60 W), leading to a significant performance decrement of 3.9% for control and an improvement of 3.7% for sago during Exercise 2 (P < 0.05). Sago ingestion was also associated with higher blood glucose concentrations during recovery compared to control. These results indicate that feeding sago during recovery from exercise in a warm-humid environment improves recovery of performance during a subsequent exercise bout when compared to a water-only control.

Southeast Asia is a region with over 600,000,000 inhabitants and a year-round tropical climate where sago palms are widely distributed. Previous research has identified sago as being rapidly digestible, quickly absorbed, and therefore suitable for consumption before, during, and in recovery from exercise. Most importantly, sago seems to possess physical and chemical properties suitable as a supplement during exercise in a warm, humid environment where it is commonly grown and consumed, although further research is needed to compare it to other known carbohydrate sources.

A subsequent trial found that consuming sago porridge during the recovery phase from exercise in warm-humid conditions enhanced performance in a later exercise session, compared to a control group that only consumed water.

Evidence strength: Small controlled trials (n=8) in trained athletes. Results are consistent with general carbohydrate supplementation literature but sample sizes are very small, and the comparator in key trials was water rather than an isocaloric carbohydrate comparator. Evidence is preliminary and limited.

5.5 Pharmacological Activities of Cycas revoluta (in vitro and preclinical)

Reported pharmacological activities of Cycas revoluta are derived mainly from in vitro and preclinical studies, with limited in vivo validation and no established clinical relevance, whereas toxicological evidence for neurotoxicity, genotoxicity, and hepatotoxicity is robust.

A review synthesized literature published between 1958–2025 on the ethnobotany, phytochemistry, pharmacology, and toxicology of C. revoluta. The study highlights diverse phytochemicals, including biflavonoids, cycasin, BMAA, and reported antimicrobial peptides, noting variability in compound verification and reproducibility.

Evidence strength: All reported beneficial pharmacological activities of Cycas revoluta extracts are in vitro only, with no clinical translation established. In contrast, its toxicological profile is extensively characterized.

6. Body Systems and Health Areas

6.1 Digestive and Metabolic Systems (Metroxylon sagu)

Carbohydrate metabolism: Sago starch functions primarily as a dietary energy source, with glycemic response varying by preparation method. Its high RS content provides potential for attenuated postprandial glucose excursions.
Gut microbiome: In vitro and animal studies suggest the RS fraction of sago starch can selectively support beneficial bacteria (Lactobacillus and Bifidobacterium species), a property consistent with classification as a prebiotic candidate.
Colon health: SCFA production (acetate, propionate, butyrate) was observed in animal studies following sago starch consumption, consistent with fermentation by colonic microbiota.

6.2 Musculoskeletal and Exercise Physiology (Metroxylon sagu)

As a carbohydrate source, sago starch has been studied for glycogen restoration and exercise recovery, particularly in hot-humid environments.
Sago, a carbohydrate-based dietary staple of Southeast Asia, is easily digestible and quickly absorbed, and thus has potential to be prescribed as an affordable pre- and post-exercise food.

6.3 Neurological System (Cycas revoluta)

The non-protein amino acid BMAA was first associated with the high incidence of Amyotrophic Lateral Sclerosis/Parkinsonism Dementia Complex (ALS/PDC) in Guam, and has been implicated as a potential environmental factor in ALS, Alzheimer's disease, and other neurodegenerative diseases.
The devastating paralytic syndrome is prevalent among the indigenous Chamorro people of Guam Island, acquired early in life and expressed clinically decades later. Amyotrophic lateral sclerosis and Parkinsonism-dementia complex (ALS/PDC) is an environmental neurodegenerative disease etiologically associated with exposure to chemicals in seeds of cycad plants of the genus Cycas.

6.4 Hepatic System (Cycas revoluta)

Cycasin may cause gastrointestinal exacerbation, which may lead to liver damage if consumed in higher doses.
The compounds believed to be responsible for toxicity are glycoside cycasin, an amino acid BMAA, and an unidentified high molecular weight compound. These toxins most commonly cause gastrointestinal effects, liver damage, and neurological signs, and the mortality rate in animals can be up to 33%.

7. Dosage Forms and Reported Dosages

7.1 Metroxylon sagu in Research

No standardized therapeutic dosage has been established for sago starch as a dietary supplement. Dosages used in the published research literature include:

Glycemic index studies: Isoglucidic servings containing 50g available carbohydrate for both foods and glucose drink as reference were consumed by 12 healthy subjects.
Resistant starch preparation: Sago RS3 with 12% RS content was prepared by enzymatic debranching of native sago starch with pullulanase enzyme, followed by autoclaving, cooling, and annealing.
Prebiotic characterization: Resistant starch type III (RS3) was produced from sago and evaluated for its characteristics as a prebiotic. Two RS3 samples contained 35.71% and 68.30% RS, respectively.
Exercise performance: Sago porridge was administered as a post-exercise recovery meal in warm-humid environment studies; specific gram quantities are reported in individual study protocols in the PMC literature.
Animal diabetes study: An oral glucose tolerance test (OGTT) was performed before and after 1-month treatment with sago RS2 and RS4 in the Goto-Kakizaki rat model.

Sago starch as a food ingredient is unregulated as a supplement and is consumed freely at cultural dietary levels in Southeast Asia and Melanesia.

7.2 Cycas revoluta

No safe therapeutic dose is established for any part of Cycas revoluta. All parts of the plant are toxic; no dose of raw or minimally processed plant material is considered safe. Traditional preparations historically involved extensive processing to reduce cycasin content, but the adequacy of such processing is variable and historically linked to toxic outcomes.

8. Safety Considerations and Interactions

8.1 Safety of Metroxylon sagu Starch

Sago starch from Metroxylon sagu is consumed as a staple food by millions of people across Southeast Asia and Melanesia and has a long, well-established record of food safety at normal dietary quantities. The starch itself is gluten-free and low in protein, fat, and micronutrients.

Nutritional deficiency risk: Sago starch does not add significantly to the protein calorie intake and may be associated with susceptibility to nutritional-associated illness when relied upon as a sole dietary staple without adequate complementary protein and micronutrient sources.

Gluten-free applicability: Naturally gluten-free, sago is a good substitute for wheat-based flour and grains in baking and cooking for those on restricted diets.

8.2 Toxicity of Cycas revoluta — Human Exposure

Cycas revoluta (sago cycad or palm) is a popular ornamental plant in the United States. All parts of the plant contain toxins such as cycasin and beta-methylamino-L-alanine, the ingestion of which can be harmful to humans and animals.

Of 192 total C. revoluta exposures reported to Texas poison centers, the most common exposure routes were ingestion (55.7%) and dermal (34.4%).

All parts of this plant are toxic; however, seeds contain the maximum cycasin component, a potent toxin. Ingestion can lead to severe symptoms, including vomiting, diarrhea, weakness, seizures, and liver failure.

8.3 Neurodegenerative Risk from Cycas revoluta BMAA

Early researchers suspected that something in cycad seeds, a dietary staple used by the Chamorro indigenous people to make flour, might be responsible for ALS/PDC. The discovery of BMAA in cycad flour suggested this might be the particular cause. BMAA in cycad seeds is derived from symbiotic cyanobacteria in coralloid roots. BMAA is mainly concentrated in proteins and was consumed by Chamorro through multiple dietary sources, including cycad flour, flying foxes, and other animals that fed on cycad seeds.

Given that the typical onset of ALS/PDC does not occur until an individual is in their 40s, these results suggest a probable mechanism in which chronic low-concentration exposure to non-excitotoxic doses of BMAA slowly drives neurodegeneration in ALS/PDC patients over several decades.

The implication of the cyanotoxin BMAA in long-lasting neurodegenerative disorders is still a matter of controversy. While an animal model for BMAA-induced ALS is lacking, there is substantial evidence to support a link between this toxin and ALS.

8.4 Animal Toxicity (Cycas revoluta)

Cycas revoluta is poisonous to almost all types of animals. All parts of the plant, including the leaves, seeds, and roots, contain cycasin, a toxin that can cause severe gastrointestinal distress, liver failure, and even death if ingested by dogs, cats, and other pets. Cycad toxicosis has been described in people and many animals, including dogs, sheep, and cattle.

8.5 Genotoxicity and Carcinogenicity (Cycas revoluta)

Seed compounds include the principal cycad toxin cycasin, its active metabolite methylazoxymethanol (MAM), and the non-protein amino acid L-BMAA; each reproduces components of ALS/PDC neuropathology when individually administered to laboratory species. Human exposure to MAM, a potent DNA-alkylating mutagen, also has potential relevance to the high incidence of diverse mutations found among Guamanians with or without ALS/PDC.

References

Health Conditions

Health conditions that Sago palm may help support.

No conditions available.

Body Systems

Body systems that Sago palm may help support.

No body systems available.