Post on 07-Oct-2018
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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