yacón

What is yacón?

Yacón is a root vegetable from the Andes. It looks like a sweet potato but tastes crisp and juicy, closer to a pear. Most of its sweetness comes from sugars your body cannot digest.

The root is eaten raw, cooked, or boiled down into a dark syrup. Yacón syrup is sold as a low-sugar sweetener and as a weight-loss aid. The dried leaves are also brewed as a tea in parts of South America.

Here is the honest verdict on the evidence. Human research is thin: one small trial and a few others hint at mild effects on weight, stools and blood sugar. Long use of the root as a food does not prove it works as a remedy, and it does not prove it is safe in large or concentrated doses.

How does yacón work?

The leading idea is simple. Yacón is rich in fructooligosaccharides (FOS), which are sugar chains your gut cannot break down.

These chains pass through to the colon. Gut bacteria feed on them there. Foods that feed gut bacteria this way are called prebiotics.

Prebiotics of this type pull water into the bowel and bulk up stools. That part is fairly well accepted for FOS and inulin in general. It is the most likely reason yacón can loosen the bowels.

The weight idea is less settled. FOS tastes sweet but gives few calories, so syrup may replace sugar in the diet. In one small trial, women taking yacón syrup also reported feeling full sooner.

In animal and cell studies, yacón extracts appear to change how the body handles blood sugar and insulin. Whether that happens in people is not established. Treat the blood sugar claim as unproven.

What forms does yacón come in?

Yacón is sold in several forms, and they do not act alike.

- Fresh root: peeled and eaten raw, or added to salads. - Yacón syrup: a dark, treacle-like sweetener, and the usual supplement form. - Dried slices or chips: eaten as a snack.

- Root powder or flour: stirred into drinks or used in baking. - Capsules: made from root or leaf extract. - Leaf tea: brewed from dried leaves, mostly in Peru and Bolivia.

Syrup is the form used in most human studies. Leaf teas and leaf extracts have far less human safety data behind them.

Labels vary widely in strength. Some syrups are little more than sugar. Check the fibre or FOS content on the pack if that is what you are buying it for.

Where it comes from:

Andean farmers grew yacón for centuries before the Spanish arrived. It shows up in pre-Inca pottery and was planted from Colombia down to Argentina.

It was treated as fruit rather than as medicine. Workers ate the juicy root to quench thirst in the fields. It also had a place in harvest festivals and religious days.

Folk practice in Peru and Bolivia did use the leaf tea. Healers gave it for high blood sugar and for kidney complaints. These uses were recorded by travellers and later by plant researchers.

Japan took up the crop in the 1980s and helped spread it to new countries. Sales of yacón syrup in Europe and North America grew sharply after television coverage around 2013.

What does yacón help with?

• Constipation and slow bowels: This is the use with the firmest support. Prebiotic fibres like FOS hold water in the bowel and add bulk. Small human studies of yacón syrup report softer stools and more frequent bowel movements. The studies were short and had few people in them. The trade-off is wind and bloating, which are common. Starting small and going slowly tends to reduce this.
• Feeding gut bacteria (prebiotic use): Yacón does feed gut bacteria; that part is well supported for FOS as a class. Human and animal studies show rises in bifidobacteria, a group of friendly gut microbes. What that means for your health is a separate question. A change in gut bacteria is not the same as feeling better or getting well. No human trial has shown that yacón treats a gut disease.
• Replacing sugar as a sweetener: As a kitchen swap, yacón syrup is reasonable. It tastes sweet and carries fewer usable calories than table sugar or honey. It is not calorie-free, and it still contains some fructose and glucose. If you have diabetes, it will still affect blood sugar to some degree. Check the label. Some syrups sold as yacón are heavily diluted with other sugars.
• Weight management: The weight claim rests on one small trial, so treat it with care. In that study, obese women taking yacón syrup for about four months lost weight and waist size; the placebo group did not. That result has not been repeated in larger trials. The women were also given diet advice, which muddies the picture. No product takes the place of food changes and movement. Yacón may do nothing for your weight.
• Blood sugar support: Traditional healers used the leaf tea for high blood sugar. This use is old and widespread in the Andes. Most supporting work is in animals and cell studies, where leaf extracts appear to lower blood glucose. Human data is scarce and mixed, and the syrup is not the same as the leaf. One rat study found kidney damage with high doses of leaf extract. Do not use yacón in place of diabetes medicine.

Which foods are rich in yacón?

1. Yacón root, fresh
2. Yacón syrup
3. Chicory root
4. Jerusalem artichoke
5. Onion
6. Garlic
7. Leek
8. Asparagus
9. Slightly green banana

Practical Tips:

The active fibre in yacón, FOS, is in many ordinary foods. Onions, garlic, leeks and chicory root are good sources.

If you eat plenty of these already, yacón adds little that is new. Whole foods also bring other nutrients that syrup does not.

What are the side effects of yacón?

• Wind and gut rumbling
• Bloating and a full feeling
• Belly cramps
• Loose stools or diarrhoea
• Nausea
• Allergic rash or itching, mainly in people allergic to the daisy family
• Worse symptoms in people with irritable bowel syndrome (a long-term gut disorder)

Good to know:

Gut effects are common, not rare. They are the main reason people stop using yacón.

They depend on the dose. Small amounts cause less trouble than large ones, and they often fade over a week or two.

Serious harm has not been reported in the short human trials. Allergic reactions are uncommon but can be serious in people sensitive to ragweed, daisies or sunflowers.

How much yacón should you take?

• Recommended daily: Labels on yacón syrup often list 1 to 2 teaspoons a day, sometimes up to 3. That is roughly 5 to 15 grams. This is what the market carries, not advice for you. Human trials used amounts in a similar range. Larger amounts mainly raise the chance of wind and loose stools. Leaf tea and leaf capsules have no agreed amount. Their human safety data is thin. A doctor or a dietitian can judge what fits your gut and your medicines.
• Best time of day: Timing does not matter much. Your gut bacteria work on the fibre whenever it arrives. Spreading it across two or three smaller amounts often causes less wind than one large dose. Some people prefer it earlier in the day so any rumbling settles before bed.
• With or without food: Take it with food. Spreading it through a meal usually means less bloating and cramping. Many people simply use the syrup in place of sugar, on porridge or in drinks. That counts as taking it with food. If you take tablets or capsules by mouth, leave an hour or two between them and a large fibre dose.
• Time to effect: Bowel effects come first. Many people notice softer or more frequent stools within 2 to 7 days. Wind and rumbling can start on day one. These often ease over a week or two as gut bacteria adjust. Any effect on weight or blood sugar would take months, if it happens at all. In the main trial, changes were measured after about four months. It may do nothing for you.
• How long to take it: No clear limit has been set. The longest human trial ran about four months with no serious problems reported. As a food, the root has been eaten for generations. That does not tell us much about daily concentrated syrup over years. If you are using it for constipation and nothing changes in two to three weeks, it is reasonable to stop and ask a doctor why.