Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...Tell Me More
As the research continues to pile up against artificial sweeteners, it’s a race to take the lion’s share of the growing alternative sweetener market. While natural sweeteners like stevia and erythritol have become more popular in recent years, it’s still a wide field. One lesser known option is yacon syrup—a natural sweetener with a low calorie count and prebiotic abilities.
Yacon syrup is derived from the large tuberous roots of Smallanthus sonchifolius, a species of daisy that is cultivated in the Andes at altitudes of between 880 and 3500 metres. According to archaeological evidence, yacon was an important cultivated crop in Andean societies even before the rise of the Incas. The roots themselves can be eaten just like any other tuber. They look something like a a sweet potato, with a taste somewhere between that of an apple, a watermelon and a pear…and with a texture likened to that of a water chestnut. But it’s when the liquid is extracted from the flesh and evaporated, similar to the process used to make maple syrup, that things start to get really interesting. It’s at this point that yacon becomes a true natural sweetener, taking on a flavor similar to that of molasses or caramel. Delicious to most, slightly off-putting to others.
Much of that sweetness is due to a high concentration of fructooligosaccharides in yacon syrup. More conveniently referred to as FOS for short, they’re often associated with a “have your cake and eat it too” scenario, whereby tastebuds register the sweetness, while the digestive system can’t actually metabolize it. Those fructooligosaccharides are also a good source of prebiotics, having a similar molecular structure to inulin. This means that while the FOS are indigestible within the stomach, they’re a treat for the bacteria residing in our gut and as a result help to promote the microbiome.
But sadly there’s more to it than that. For starters, those FOS pose a problem for folks on a FODMAP diet or anyone dealing with gut permeability issues. Eating foods like yacon that are high in FOS can exacerbate symptoms and cause general digestive upset. What’s more, while the FOS in yacon syrup comprise around half of the total dry weight, much of the remainder (around 35%) is composed of fructose. For reference, sucrose (aka table sugar) is 50% fructose, while honey averages around 40% fructose.
Let’s look at what the research says….
Much of yacon’s modern-day popularity stems from a single study, published in 2009 in the Journal of Clinical Nutrition. As part of the study, 40 obese women with mild cholesterol problems were asked to consume yacon syrup for 120 days while a similar group of 15 women were told to do the same with a placebo syrup. (Both groups were placed on a low fat diet during the experiment—typical.)
By the end of the experiment, the yacon group had lost an average of 33 pounds while the control group gained an average of 3.5 pounds. Pretty significant stuff. The yacon subjects also experienced reductions in waist size, BMI, fasting insulin and insulin resistance. They also saw a significant average reduction in LDL (aka “bad”) cholesterol.
These impressive results are somewhat hampered by the small study group and even smaller control group, but they’re definitely cause for attention—and more research…of which there has unfortunately been very little of (at least regarding any direct link between yacon consumption and weight loss).
As a potent source of FOS, much of the health benefits associated with yacon can be attributed to processes in the gut. As discussed earlier, FOS reach the gut unscathed by enzymatic digestion and quickly get to work stimulating the growth and health of Bifidobacterium—a group of beneficial bacteria naturally found in the gut. These bacteria ferment the FOS and produce short chain fatty acids, which can further promote beneficial Bifidobacterium and Lactobacillus species and keep pathogenic species in check.
While the prebiotic effects of FOS in general is well researched, studies directly examining the prebiotic potential of yacon are a little thinner. A 2012 study found that guinea pigs fed high levels of yacon experienced significant increases in bifidobacteria and lactobacilli, along with a jump in short chain fatty acids. Beyond that, there isn’t much, but the extensive research on the impact of FOS in the gut is enough to give yacon the big thumbs up as a prebiotic.
Aside from the oft-referenced 2009 study that looked at yacon syrup consumption in 40 obese women, there appears to be just one other trial that looked at the direct link between yacon and insulin resistance.
Over the course of 5 weeks, male rats were fed either 6.5% yacon or a 6.5% control aroid in conjunction with a standard diet. While body weight was comparable between the two groups after the end of the trial, yacon feeding was shown to lower fasting glucose levels along with basal hepatic glucose output compared to the control group. Researchers concluded that “the effect of yacon feeding to reduce blood glucose is likely due to its beneficial effects on hepatic insulin sensitivity in the insulin resistant state.”
Another benefit of yacon consumption that repeatedly pops up in the literature is it’s ability to combat constipation. In a small double-blind crossover study, 16 people were given 20 grams of yacon extract per day for two weeks. Across the board, “transit time” decreased from an average of 59.7 hours to 38.4 hours—a huge drop. Additionally, stool frequency increased from 1.1 to 1.3 times per day, and the average poop was notably softer. Too much information?
A more recent 30 day trial used a yacon-based product, dissolved in orange juice (we know…), to produce “an increased number of evacuations” and “an improvement in the consistency of the feces and a reduction in the constipation score.” Patients in the yacon group also had higher counts of beneficial Bifidobacterium and lower counts of parasitic Clostridium and enterobacteria.
Research in this area doesn’t focus on the syrup derivative, but leaves and roots of the yacon plant contain compounds that may be useful in the fight against cancer. In a 2017 study, extracts taken from yacon leaves exhibited significant reductions in viability of breast cancer cells, along with significant cytotoxic effects against colon cancer cells.
A 13 week trial using dried yacon root extract on rats with induced colon cancer showed that 1% yacon extract significantly lowered cancer cell proliferation and adenocarcinomas. Interestingly, combining yacon consumption with L. casei appeared to further increase the protective effect of yacon against colon cancer.
As far as side effects go, yacon has a long history of safe use and doesn’t appear to present any major health problems. Research indicates that daily consumption of 0.14 g FOS per 1 kg of body weight is the cut-off for preventing digestive upset. On average, this means the average person could consume at least 6 teaspoons of yacon per day without any noticeable effect. (Of course, you really shouldn’t be eating more than that anyway.)
In most trials, yacon consumption didn’t produce any adverse symptoms, however one study did report mild bloating—a standard response to high doses of FOS. Keep in mind that those who have IBS or other digestive issues may be more likely to experience adverse symptoms than others.
According to foodies, yacon syrup can be used as an alternative to syrup sweeteners like honey, agave, maple syrup or molasses. While it may not taste good on its own (unless you’re a major fan of straight molasses), it’s in its element in baked goods like cookies and cakes.
While yacon syrup’s consistency has a high resistance to heat, high temperatures can tend to denature FOS, so keep that in mind if your primary reason for using yacon is the FOS-induced health benefits.
Due to its rich maltiness, it can also be used for savory applications like meat and fish marinades or salad dressings, but remember that it can easily overpower mild flavors. Also note that yacon syrup isn’t as sweet tasting as sucrose, so mixing it with other healthy options like stevia may offer the best balance for certain recipes.
Thanks for reading, everyone. Do you use it? Would you give it a shot—or do you stick to other favorite sweeteners in cooking and baking?