Summary (All Essential Benefits/Effects/Facts & Information)

Yacon is a name used to refer to the plant Smallanthus sonchifolius, which is a

tuber vegetable (similar to a potato) and a common food product in South America.

It looks like a sweet potato and tastes like a pear. While the tuber itself is used in

cooking, a syrup derived from the tuber (called yacon syrup) is used as an

alternative sweetener.

This vegetable is also sometimes called the 'diet potato,' which is thought to be

related to its fructooligosaccharide (FOS) content. The FOS benefits gut health and

has a prebiotic effect, and they may also have a minor appetite suppressing effect

in the obese, which reduces food intake. It is thought to be a good dietary

supplement, since its production costs are low and yield is high, so it may be one

of the most financially feasible sources of dietary FOS while possibly deter sugar

consumption, as yacon syrup itself is sweet.

Human studies on yacon are currently limited. One study supports a weight loss

effect, which may be due to a reduction in consumed calories, while the other study

noted that yacon possesses an anti-motility property (slowing intestinal transit time

down) which is known to reduce appetite somewhat. These properties are thought

to be related to the FOS content, and are similar to the benefits of FOS from other

sources.

Rodent studies suggest proliferation of the 'good' bacteria in the colon in

accordance with yacon's prebiotic effects, as well as an increase in mineral uptake

from the colon, the latter of which is beneficial for bone health. These properties

are not yet proven in humans with, but thought to occur since they have been

noted to occur in humans with any other source of FOS.

There is a tea product made from the leaves of yacon, which is said to be anti-

diabetic. There is no human evidence for this claim and due to at least one study

noting kidney damage associated with the tea (kidney damage tends to reduce

glucose levels in the blood), it is thought that this underlies the supposed anti-

diabetic effects and consumption of the tea is not recommended.

Things to Know

Also Known As

Smallanthus sonchifolius, Yacon Syrup, Aicama, Jicama, Diet potato, yacon

potato, yacon strawberry

Things to Note

Limited evidence suggests that water extracts of the leaves (sold as an anti-diabetic tea)

are harmful to the kidneys, due to a group of molecules not known to exist in the tuber

(where syrup is derived from). At this moment in time, it would be prudent to avoid

drinking tea made from yacon leaves.

Although it is thought to be very rare, it may be possible to be allergic to yacon tubers.

Is a Form of

Biotic Supplement

Dietary Fiber

Goes Well With

Soy Isoflavones (The fructooligosaccharides in yacon syrup may enhance the

absorption of isoflavones)

Calcium and Magnesium (Their absorption in the colon may be enhanced by the

aforementioned FOS)

Caution Notice

Yacon leaves (tea product) are thought to be toxic to the kidneys

Examine.com Medical Disclaimer

Human Effect Matrix The Human Effect Matrix looks at human studies (excluding animal/petri-dish studies) to

tell you what effect Yacon has in your body, and how strong these effects are.

GRADE LEVEL OF EVIDENCE

A Robust research conducted with repeated double blind clinical trials

B Multiple studies where at least two are double-blind and placebo controlled

C Single double blind study or multiple cohort studies

D Uncontrolled or observational studies only

LEVEL OF EVIDENCE

EFFECT CHANGE

MAGNITUDE OF EFFECT SIZE

SCIENTIFIC

CONSENSUS COMMENTS

C Intestinal Motility Notable

100% See study The one study to assess intestinal motility (speed of food transit from

stomach to anus) has noted a near halving of time, suggesting a

relatively notable anti-motility ... show

C Fecal Moisture Minor

100% See study A mild increase in fecal moisture and consistency has been reported with

consumption of yacon syrup, thought to be related to prebiotic effects and

a reduction in intestinal ... show

C Insulin Minor

100% See study A minor reduction in fasting insulin levels has been noted in obese

women given supplementation, but this is confounded with weight loss.

C Insulin Sensitivity Minor

100% See study A minor increase in insulin sensitivity has been noted in a lone study in

obese women that is also confounded with weight loss (ie. the weight

LEVEL OF EVIDENCE

EFFECT CHANGE

MAGNITUDE OF EFFECT SIZE

SCIENTIFIC

CONSENSUS COMMENTS

loss could explain the increase ... show

C LDL-C Minor

100% See study A respectable decrease in LDL has been reported once, although this

reduction in LDL is confounded with weight loss that occurred with yacon

syrup.

C Weight Minor

100% See study A decrease in weight has been noted in obese women given Yacon,

although this study could potentially be explained by a reduction in food

intake (due to an increase in ... show

C Blood Glucose 100% See study No significant influence on fasting blood glucose in nondiabetic obese

women who consume Yacon relative to placebo, despite weight loss.

C HDL-C 100% See study No significant influence on HDL cholesterol has been noted with Yacon

syrup, despite weight loss occurring.

C Total Cholesterol 100% See study No significant influence on total cholesterol has been noted despite

changes in LDL and accompanying weight loss.

C Triglycerides 100% See study Despite a triglcyeride reducing effect of fructooligosaccharides in rats, the

limited evidence in humans (with mildly elevated triglcyerides) failed to

find any appreciable ... show

Scientific Research Table of Contents:

1. Sources and Composition

1. Sources

2. Composition

3. Physicochemical Properties

2. Cardiovascular Health

1. Absorption

2. Cholesterol

3. Triglycerides

3. Interactions with Glucose Metabolism

1. Blood Glucose

4. Fat Mass and Obesity

1. Interventions

5. Bone and Joint Health

1. Bone Mass

6. Inflammation and Immunology

1. Interferons and Immunoglobulins

7. Interactions with Hormones

1. Testosterone

8. Peripheral Organ Systems

1. Intestines

2. Kidneys

9. Sexuality and Pregnancy

1. Seminal Parameters

10. Nutrient-Nutrient Interactions

1. Minerals

2. Soy Isoflavones

11. Safety and Toxicology

1. General

2. Case Studies

1. Sources and Composition

1.1. Sources

Yacon refers to the plant Smallanthus sonchifolius (of the family Asteraceae) which

is also synonymous with polymnia edulis and polymnia sonchifolius. It is native to

South America, and is cultivated in countries such as Colombia and Ecuador for

both nutritive and medicinal uses.[1] It is sometimes paired alongside Maca due to

their similar places of origin and both being tuber vegetables used as dietary

supplements.[2][3]

Yacon is a plant which has usage as a nutritive functional food (mostly due to its

syrup) and the name 'Yacon' is thought to originate from yakku (tasteless)

and unu (water) from the Quechua Indian language.[1] Other names for this plant

include 'Yacon strawberry' (US), 'Yacon Potato' or 'Diet Potato' (Brazil), or the

names of aricoma and jicama (Ecuador and Peru, no botanical relation to the

mexican tuber pachyrhizus erosus which is more commonly called Jicama)[1] and

despite the aforementioned 'tasteless' origin of its name the syrup derived from

Yacon is said to have physical and sensorial characteristics are similar to those of

honey or sugar cane syrup.[4]

It is sought after as a dietary supplement due to its fructooligosaccharide (FOS)

content, mainly because it has a low production cost and high yield per hectare

whereas other supplemental sources of FOS (Jerusalem artichoke, Chicory) tend

to be more expensive to produce.

Yacon is a nutritive vegetable (a tuber vegetable resembling a Jerusalem artichoke or

variant of potato) grown mostly in South America, and is used as a functional food for

general health and weight loss. It is also a common dietary staple

It appears that the leaves are also used medicinally at times, as an infusion of the

leaves of Yacon are traditionally used for the treatment of diabetes and disorders

related to glucose metabolism[3][5][1] as well as kidney impairments.[6]

1.2. Composition

Yacon (as a whole plant product, water weight inclusive) tends to contain:

85-90% moisture content[7]

Carbohydrates (9-13g/100g[8]) and dietary fiber (3.1–4.1mg/100g[8]) of which 40-70% of

the root's dry mass is said to consist of fructooligosaccharides (FOS)[7] while 15-40% of

the dry mass is simple sugars[7]

Proteins (2.7–4.9g/100g[8] or less[7])

With lesser noncaloric components of (tubers unless otherwise specified):

Diterpenes Smallanthaditerpenic acids A and C (leaves[2]) and acyclic diterpenes

smaditerpenic acid E and F[9]

A sesquiterpene lactone known as enhydrin (leaves[2][10] at 0.97% dry weight[11]) as well as

sonchifolin, uvedalin, and uvedalin (Melampolides)[12][13]

Phenolic compounds (203mg/100g[1]) based off of caffeic acid,[14][15] most

notably Chlorogenic Acid (48.5+/-12.9μg/g[16]) and caffeic esters of octulosonic acid (a

carboxylated sugar)[17]

Quercetin[15]

Ferulic acid[15]

Potassium (1.80-2.95mcg/g[8][18])

Calcium (0.56–1.31mcg/g[8] or less[19])

Phosphorus (1.82–3.09mcg/g[8]

Iron (3mcg/g[1])

Zinc (6.74mcg/g[1])

Vitamin C (13110mcg/g[1])

The total antioxidant capacity due to the aforementioned phenolics is moderate to

low, but comparable with other tuber vegetables grown in the same region (Olluco,

Oca, Mashua) and potato as well as being similar to another FOS rich tuber known

as Chicuru.[20]

The short chain fructooligosaccharides appear to be the bioactive component of yacon,

since there does not appear to be much else in this plant's tubers (the commercial product

from where the syrup is derived). There are some phenolic compounds in yacon based off

of caffeic acid, but they appear in low levels

The fructooliogosaccharides (FOS) in yacon are predominantly short chain FOS

between 2-10 fructose molecules, in contrast to the 60+ fructose molecules in an

inulin molecules chain which are referred to fructopolysaccharides (Yacon is

sometimes thought to be a major source of inulin due to its similarities to

Jerusalem Artichoke,[1] a major inulin bearing plant); regardless, FOS from yacon is

structured in a similar manner as inulin, having the fructose being configured as

β(2→1)fructofuranosylsaccharose molecules[1][21] and is similarly indigestible in

humans, as humans cannot digest the β(2→1) bond between sugars due to a lack

of enzymes in the small intestines.

Due to the lack of human digestion yet microbial ingestion in the colon, FOS from

yacon are classified as prebiotics[1][22]particularly

for Bifidobacterium and Lactobacillus species.[23]

The short chain FOS in yacon are structurally different from inulin in regards to their size

(inulin being much larger), but the bonds between the fructose molecules are quite similar

and they appear to work in a similar way

When processed into a syrup, the overall composition of the syrup is

approximately:

67.04-75% carbohydrate, of which 40-60% is fructooligosaccharides (FOS)[4][24]

2.16% protein[4]

0.14% lipids[4]

Potassium (936mg/100g[4])

Sodium (84mg/100g[4])

When breaking the fructooligosaccharides into chain length via degrees of

polymerization (DPs; a way of explaining how many sugar molecules are in a

chain) the FOS in yacon syrup tend to be:

3 DPs at 7.4% total carbohydrates[24]

4 DPs at 11.2% total carbohydrates[24]

5 DPs at 10.2% total carbohydrates[24]

6 DPs at 8.1% total carbohydrates[24]

7 DPs at 5.9% total carbohydrates[24]

8 DPs at 4.9% total carbohydrates[24]

9-12 DPs at 10.7% total carbohydrates[24]

Inulin (60+ DPs) at 13.5+/-0.4mg/g (1.3%) dry weight[1]

FOS that are lower than 12 fructose molecules in length predominate almost exclusively in

yacon, they are relatively balanced, meaning a 4 fructose chain is not favored over an 8

fructose chain, and so on

1.3. Physicochemical Properties

Yacon appears to have a high heat tolerability (up to 140°C; anything further

breaks down the FOS into free fructose and greatly enhances sweetness[4]) and

stability in solutions with a pH greater than 3, with the only limiting factor for

production being a short shelf-life due to the high water content of yacon;[24] this is

circumvented a bit with production of yacon syrup which reduces the 85-90% water

content and promotes shelf-life and which is stable at room temperature and

standard conditions for up to a year.[4]

Yacon syrup has a slightly acidic pH (5.4) and a Brix of around 73° when

standardized for 40-50% FOS.[4]

Yacon tends to have high heat tolerance until the FOS breaks down, which suggests that

the tubers and the syrup derived from it can be used in cooking. The only limiting factor of

its short shelf life is the high water content of the tuber itself. Water content is reduced with

the syrup however, thus extending shelf life

2. Cardiovascular Health

2.1. Absorption

In rats, when ingestion of Yacon syrup (340mg/kg or 6,800mg/kg) alongside fatty

acids was compared to fatty-acid only controls, serum triglycerides were reduced

39.6-41.6% with no apparent dose-dependence;[24] dietary cholesterol absorption

was unaffected.[24]

One study has noted a reduced overall exposure (absorption) of triglycerides when yacon

was consumed alongside dietary fatty acids. The mechanisms underlying this are not

known at this time

2.2. Cholesterol

In obese and slightly dyslipidemic adults given 140mg/kg FOS (via Yacon syrup)

daily for 120 days, there was a reduction in LDL cholesterol (although this was

confounded with weight loss) and no significant alteration in total cholesterol nor

HDL cholesterol.[4]

The lone study assessing cholesterol levels in humans noted a reduction in LDL cholesterol

that occurred alongside weight loss. It is not known if yacon has an inherent influence on

cholesterol levels in humans

2.3. Triglycerides

Fructooligosaccharides (FOS) in general are thought to have hypolipidemic

(triglyceride reducing) properties secondary to producing GLP-1 in the colon

(prebiotic effect)[25][26] and to produce short chain fatty acids (SCFAs) such as

propionate;[26] both of which have hypolipidemic (triglyceride reducing) properties.

This hypolipidemic property, in rats, appears to be secondary to suppressing

triglyceride synthesis in the liver[27] resulting in less production and efflux of vLDL

cholesterol[28] (known to mediate efflux of triglycerides from the liver to serum) as

most lipogenic enzymes in the liver have been noted to be suppressed with rat

diets consisting of up to 10% dietary FOS.[27][28] Despite reducing efflux of

triglycerides from the liver, dietary FOS appears to reduce liver fat buildup from

excesses of dietary fructose in rats.[29]

Propionate is known to be increased in the liver following ingestion of fermentable

carbohydrates[30] and is a known inhibitor of fatty acid synthase (FAS,[31][32] a highly

nutrient responsive enzyme that produces fatty acids[33]), although this enzyme is

significantly less responsive to propionate in humans relative to rats.[34]

Dietary fructooligosaccharides (FOS) are known to have triglyceride-reducing properties

in rats, secondary to the suppression of triglyceride synthesis in the liver. Triglyceride

synthesis pathways in rats are more sensitive to inhibition than in humans however, so it is

not currently known if these effects extend to humans

In obese adults with minor dyslipidemia (high blood triglycerides), consumption of

yacon syrup providing 140mg/kg FOS daily (10g per 70kg bodyweight) failed to

significantly alter fasting triglycerides.[4]

The one study in humans to assess triglycerides failed to find any benefit with yacon syrup,

despite weight loss

3. Interactions with Glucose Metabolism

3.1. Blood Glucose

Although a large number of studies have investigated the effects of yacon on

diabetes, most of these studies use yaconleaf extracts as that is a traditional

medicine for diabetes[5][6][2] probably due to the 0.97% enhydrin content[11] which is

bioactive on its own.[35][10] The roots and tubers (from which the syrup is derived) are

not commonly utilized for this purpose.

Yacon leaves are known to have hypoglycemic (glucose reducing) properties, but this may

not apply to the tubers/roots of the plant, nor the syrup derived from the tubers. These

properties may also be accompanied by deleterious effects on the kidneys (see kidney

section for more detail)

In rats fed an acute dose of either 340mg/kg or 6,800mg/kg fructooligosaccharides

(FOS) from yacon flour, there was a minor reduction in the spike of blood glucose

following an oral glucose tolerance test at 60-120 minutes yet not prior to the test.

This efect only occurred with the low dose,[24] and ingestion of yacon flour did not

modify the overall exposure (AUC) of glucose after a meal.[24]

When not consumed in the presence of a tolerance test, yacon itself showed a

similar increase in blood glucose as glucose itself when measured at 60-120

minutes, but the spike seen at 20 minutes (with glucose) was not present.[24]

In rats, consumption of yacon tuber/syrup FOS alongside dietary sugars does not appear to

significantly prevent an increase in glucose levels in the blood from the sugars.

Consumption of yacon alone will cause an increase in blood sugar, but without the spike

seen with pure sugar

In a study of Zucker rats fed 6.5% yacon for five weeks, compared to an isocaloric

control diet, yacon significantly reduced fasting glucose. Euglycemic-

hyperinsulinemic clamp showed an improvement in insulin sensitivity in the rats fed

yacon, and comparable glucose disposal rate in yacon and control groups paired

with tracer data indicating stabilized hepatic glucose output suggests that yacon

improves hepatic insulin sensitivity but does not affect skeletal muscle insulin

resistance.[36] One study with diabetic Wistar rats fed aqueous extract of yacon root

(at 60 mg/kg body weight) for seven days showed a significant reduction in blood

glucose levels, which may have been mediated by a reduction in food intake and

increase in water intake (causing loss of glucose via urine).[37]

4. Fat Mass and Obesity

4.1. Interventions

When obese and dyslipidemic consumed two divided doses of Yacon an hour prior

to both the morning and evening meal (conferring 140mg/kg yacon FOS daily, or

10g per 70kg) over the course of 120 days, there were increases in self-reported

satiety and weight loss relative to placebo.[4] This study did not track caloric intake,

but a reduction in food intake secondary to satiety can be inferred from weight loss.

While a doubling of the dose (280mg/kg FOS) was also effective, it was associated

with adverse intestinal side-effects such as bloating and flatulence.[4]

One study has noted weight loss in obese women given yacon syrup, and although calories

were not tracked in the study, a reduction of food intake can be inferred due to an increase

in satiety and weight loss occuring. This suggess yacon is an appetite suppressant when

taken with meals

5. Bone and Joint Health

5.1. Bone Mass

Fructooligosaccharides (FOS) in general are known to promote absorption of

minerals from the colon into serum, which is thought to preserve bone mass via

providing more exposure to dietary minerals involved in regulating bone mass

(calcium, magnesium, and phosphorus mostly).

This increased absorption is due to bacterial production of short chain fatty acid

(SCFA) binding to minerals and facilitating their absorption[38] and may promote

increased expression of proteins regulating calcium uptake in the colon;[39][40][41] while

this effect is primarily seen in the distal colon, it may not extend to the proximal

colon[38] or the small intestines, as bacteria are not present in high levels in the

small intestine.

Fructooligosaccharides are known to promote calcium/magnesium/phosphorus reuptake

from the colon,secondary to producing SCFAs. This increased mineral uptake is thought to

promote bone health

In otherwise normal Wistar rats, yacon flour (from the tubers) at 15.6% of the diet

by weight for four weeks failed to significantly increase the mineral content of the

tibia relative to control;[42] in the same study, rats given Bifidobacterium

longum culture (probiotic at 0.1mL, 109 CFU/mL) noted a significant improvement

whereas the combination of treatments was similar in potency to culture alone and

no group experienced an increase in femur thickness nor fracture resistance.[42] In

another study, a lower dose of yacon (conferring 5-7.5% total FOS in the diet) in

growing Wistar rats was associated with increased mineral status of bones as well

as increased femur stiffness and peak load capacity.[43]

There is mixed evidence as to the efficacy of yacon FOS promoting bone health in rats.

Although it has a possible role in promoting bone growth in immature rats, there are no

studies conducted in osteoporotic rats

6. Inflammation and Immunology

6.1. Interferons and Immunoglobulins

Consumption of yacon-derived fructooligosaccharides (FOS) in rats has failed to

alter serum immunoglobulin concentrations (IgA, IgM, IgG)[44] although an increase

in IgA fecal elimination was noted relative to control, suggesting localized effects in

the colon.[44] This increase in intestinal IgA is thought to underlie prevention of

intestinal infections by the Salmonella enteritidis serovar Typhimurium bacteria in

mice fed these pathogens with a diet containing yacon-derived FOS.[45]

Yacon FOS are thought to promote immune defenses in the intestines, but this may not be

associated with any systemic increase in immune parameters

7. Interactions with Hormones

7.1. Testosterone

Oral ingestion of 200mg/kg of a yacon tuber extract (50% ethanolic; 73.1% yield)

for six weeks in otherwise normal rats appears to increase circulating testosterone

approximately three-fold (5.09+/-2.53ng/mL) relative to control (1.66+/-1.08ng/mL);

while 50-100mg/kg were also tested, their influence on testosterone was not

stated.[46] This is thought to be due to yacon extract (40-60mg/mL in vitro)

suppressing the degradation of testosterone, possibly related to a concentration-

dependent reduction in testosterone degradation by Chlorogenic Acid at 4-

10mg/mL.[46]

Limited evidence suggests a relative increase in testosterone, secondary to a reduction in

degradation. While definite effects on testosterone degradation were noted, the specific

enzyme responsible for this was not identified

8. Peripheral Organ Systems

8.1. Intestines

Yacon fructooligosaccharides (FOS) are not digestible in the upper (small)

intestines, resulting in them being partially metabolized in the colon and conferring

prebiotic properties. There may be a small caloric content associated with these

carbohydrates due to short chain fatty acid (SCFA) production, a normal

occurrence with fermentable fibers.[30] Up to 55% of ingested carbon from FOS may

be converted to SCFAs (being detected as exhaled carbon dioxide 48 hours after

ingestion) of which 90% is used within 24 hours,[47] suggesting about 2kcal energy

per gram of FOS ingested.

Yacon FOS have been noted to be preferentially fermented by the bacterial strains

of bifidobacteria and lactobacilli when tested in vitro_[23] and these prebiotic

properties have been confirmed in a rodent trial where yacon promoted the

proliferation of these bacterial species with a potency comparable to inulin.[20] The

production of SCFAs was noted to be nonsignificantly greater with Yacon FOS

than inulin in regards to acetate (51% vs. 21%), propionate (41% vs. 33%), and

butyrate (1,293% vs. 1,090%) as well as total SCFAs (78.5% vs. 40%) when the

oral doses were similar.[20]

FOS are fermentable in the colon. Due to this fermentation, FOS can exert prebiotic effects

on certain bacterial strains. The bacteria that respond to FOS are those that are generally

seen as beneficial. This prebiotic effect has been confirmed in rats (with yacon) with a

potency comparable to inulin and is known to occur in humans with FOS in general

Fructooligosaccharides in general are able to produce GLP-1 locally in colonic

tissue[25] which may underlie the hypertrophy seen with very high doses

(6,400mg/kg FOS in rats) in this tissue with yacon syrup[24] and FOS in

general.[48]This enhancement of colonic tissue size is associated with an increase in

absorptive area and bifurcated crypts,[20][43] and is thought to contribute to increased

feed efficiency in rats[20] and improved mineral absorption from the colon into

serum.[43]

A local increase in GLP-1 in the colon is known to promote colonic tissue hypertrophy,

which is thought to contribute to increased colonic nutrient reuptake. This includes dietary

minerals (calcium and magnesium) as well as short chain fatty acids

Yacon syrup at the dose of 20g (6.4g Fructooligosaccharides) in otherwise healthy

adults was able to reduce colonic transit time to 64% of baseline (from 59.7+/-4.3

hours down to 38.4+/-4.2 hours) associated with a mild increase in stool frequency

and moisture content but without any notable bloating.[49]

8.2. Kidneys

A water leaf extract of yacon has failed to show acute toxicity to the kidneys when

fed to diabetic rats[10][5] but one study using an oral water extract (9% yield) oral

ingestion for 90 days noted that the lower two doses (10 and 50mg/kg) were not

associated with any toxic signs but 100mg/kg was associated with renal toxicity

(inflammation and loss of glomeruli);[50] it should be noted that the petroleum ether

extract also tested in this study (lacking any sequesterpene compounds) was fully

nontoxic and a sequesterpene rich leaf-rinse extract also tested was highly toxic.[50]

Yacon leaf extract in water, which is commonly consumed as tea, is potentially toxic to the

kidneys. The toxicity appears to be associated with the sequesterpene content. This is not

thought to extend to the tubers (where syrup is derived from) due to a lack of

sequesterpenes in this part of the plant

9. Sexuality and Pregnancy

9.1. Seminal Parameters

Supplementation of Yacon leaves (ethanolic extract of 7.8% yield; 5mg/mL in the

water) appears to preserve seminal parameters such as seminal count and daily

sperm production in diabetic rats, with a potency comparable to Maca (same dose

of 5mg/mL) and mixtures of them either in even amounts of in a 9:1 ratio all

performing statistically comparable to one another.[2] This spermatogenic property

has been noted elsewhere with the leaves[46] and this was replicated by Yacon

tubers (50% ethanolic extract giving a 73.1% yield, ingested at 50-200mg/kg for six

weeks) as well as the isolated molecules ferulic acid (5mg/kg) and Chlorogenic

Acid (5mg/kg).[46]

Limited and nonreplicated evidence in diabetic mice suggests an increase in

spermatogenesis associated with yacon tuber ingestion, although the mechanism is

currently not known or replicated

10. Nutrient-Nutrient Interactions

10.1. Minerals

Fructooligosaccharides tend to have differential influences on mineral absorption,

as some direct binding to minerals in the small intestine may reduce absorption

(this is usually mediated by a phytic acid content) while any increase in colonic pH

may be met with increased mineral uptake from the colon into serum, usually

demonstrated with Calcium andMagnesium.[51][52]

Absorption of calcium, magnesium, and phosphorus from the colon into the blood is

enhanced when fructooligosaccharides (FOS) from any source are ingested, and this also

applies to yacon

The relative bioavailability of iron (as ferric pyrophosphate at 12mg/kg) appears to

be reduced when coingested with a diet containing 7.5% fructooligosaccharides

from yacon, with the bioavailability being 63.1% less than iron control without

FOS.[53]

Iron, which is one of the minerals not easily taken up by colonic tissue, may have its

bioavailability reduced when ingested alongside yacon

10.2. Soy Isoflavones

Fructooligosaccharides have been implicated in promoting the overall absorption

of Soy Isoflavones[54] as circulating isoflavones are dependent on colonic

metabolism, since Yacon may slow intestinal transportation[49] it may allow more

time for this metabolic process to occur.

Bioavailability of soy isoflavones, which depend on colonic exposure, may be increased

when rats are also given yacon FOS alongside the isoflavones

11. Safety and Toxicology

11.1. General

In rats fed Yacon flour (up to 6,800mg/kg fructooligosaccharides daily) for four

months, there was an increase in cecal hypertrophy seen that did not occur at

lower tested doses (340mg/kg; human equivalent of 55mg/kg) and no alterations in

other biomarkers of toxicity were noted at either dose.[24]

Yacon syrup up to 140mg/g fructooligosaccharides (FOS) which is around 10g per

70kg bodyweight appears to be well tolerated,[49][4] although double this dose (20g

FOS per a 70kg human) is associated with intestinal pain and diarrhea over the

course of 120 days.[4]

Limited studies in humans have found no adverse effects with moderate usage of yacon,

although taking higher than normal doses results in intestinal side-effects, likely related to

excessive fermentation of the FOS in the colon, producing gas and loose stool

As mentioned more in depth in the kidney section, the leaves of yacon contain

sequesterpene compounds which may be harmful to renal tissue.[50]

The leaves of yacon may be harmful to the kidneys based on preliminary evidence, and

should be avoided for the time being

11.2. Case Studies

There has been one reported case study of anaphylaxis following consumption of

Yacon root, of which an allergic reaction was confirmed with a skin prick

test.[55] This woman reported numbness of the oral cavity and chest tightness

following the tolerance test with an oral dose of yacon root.[55]

One case study suggests that it is possible to be allergic to yacon, although due to the

prominent usage of yacon as a food product and limited reported cases of allergies, this

condition is inferred to be quite rare

Scientific Support & Reference Citations

References

1. Valentová K, Ulrichová J Smallanthus sonchifolius and Lepidium meyenii - prospective Andean crops for the prevention of chronic

diseases . Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. (2003)

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