Overview
About Yam
True yam, the starchy Dioscorea tuber sold in African, Caribbean and Asian markets, grades high in oxalate.
That is not incidental: raw yam contains needle-shaped calcium oxalate crystals, which is exactly why peeling one bare-handed can leave your skin itching. It is otherwise clean on histamine, gluten, lactose, nickel and nightshades, with a moderate polyol grade that can matter on a low FODMAP plan. It is also graded pro-inflammatory as a dense starchy staple.
Sensitivities
How Yam scores
Watch for
What trips people up
- High in oxalate, driven by the calcium oxalate raphides in the tuber, so it is a food to portion rather than pile on if you form calcium oxalate kidney stones
- Raw yam sap irritates skin, which is why cooks glove up or peel under water. Yam should always be cooked thoroughly, never eaten raw
- Moderate polyol content, the sugar alcohol group behind bloating and osmotic diarrhoea, so a large serve can be an issue even though yam is clean on fructans, GOS and fructose
- Graded pro-inflammatory as a dense starchy staple, which is a dietary pattern note rather than a chemical sensitivity
- Yam and sweet potato are different plants and are often mislabelled in supermarkets, so check what you actually bought before you trust a lookup
Diet fit
Where it fits
Swap ideas
More alternatives
FAQ
Common questions about Yam
Is yam high in oxalate?
Yes. Yam grades high for oxalate, and the reason is structural: Dioscorea tubers store calcium oxalate as microscopic needle crystals called raphides. Cooking and thorough peeling reduce the irritant effect, but they do not remove the oxalate load, so portion size still counts on a low oxalate plan.
Is yam the same as sweet potato?
No, they are unrelated plants, and North American supermarkets confuse the two constantly by labelling orange sweet potatoes as yams. It matters less than you would hope for oxalate, because sweet potato also grades high. If oxalate is your target, swapping one for the other will not get you there. Celeriac or plain rice will.
Why does peeling raw yam make my hands itch?
The sap contains sharp calcium oxalate crystals that lodge in skin and cause an immediate itching or burning sensation. It is mechanical irritation rather than an allergic reaction. Peeling under running water or wearing gloves prevents it, and cooked yam does not cause the same problem.
Is yam low FODMAP?
Yam is clean on fructans, GOS and excess fructose, but carries a moderate polyol grade, so a modest serving generally suits a low FODMAP plan while a large one can bring bloating. Note that this applies to true yam. Sweet potato and taro have their own separate thresholds and are not interchangeable here.
References
Read the background
Ratings reflect the Triggerbites ingredient database and may vary with portion size and preparation.