Nuts/Seeds and oligosaccharides: 34 foods rated

This is the galacto-oligosaccharide axis in its purest form: raffinose, stachyose and verbascose, the sugars the bean stores for germination. No human enzyme splits them - we have no alpha-galactosidase - so this is not a sensitivity some people have. Soaking and discarding the water is the only real remedy. Pulse oligosaccharides are water-soluble, and that is the practical point: the level here follows work on pulses AND on what cooking does to them, because soaking and boiling move part of them into water that is usually thrown away.

• Reddy N. et al., Food Chemistry 13 (1984) 25-68, and Wang N. et al., Food Res Int 43 (2010) 589-594, oligosaccharides of pulses and the effect of cooking

Broad bean: the galacto-oligosaccharides of a pulse are the specific FODMAP at issue here - raffinose, stachyose and verbascose. They are water-soluble, which is the one useful fact: the soaking water carries them off, and throwing it away is worth doing. The pulse galacto-oligosaccharides are the measured part - Tuck's 2018 survey is what that rests on.

• Tuck C et al., J Hum Nutr Diet 31 (2018), FODMAP content - legume galacto-oligosaccharides

Cashews carry GOS, which is unusual for a nut - most nuts carry none worth counting. It puts them with the pulses rather than with the almonds, and blending them into a cream multiplies the serving without feeling like it.

Chickpea: same reason as the FODMAP level, and the mechanism is visible: the GOS dissolve into the canning liquid, which is why a rinsed can measures below the same chickpeas cooked from dried. Aquafaba is that liquid - it holds the oligosaccharides. Pulse oligosaccharides are water-soluble, and that is the practical point: the level here follows work on pulses AND on what cooking does to them, because soaking and boiling move part of them into water that is usually thrown away.

• Reddy N. et al., Food Chemistry 13 (1984) 25-68, and Wang N. et al., Food Res Int 43 (2010) 589-594, oligosaccharides of pulses and the effect of cooking

Lentils carry the same GOS as the other pulses but less of them, and they cook without soaking - which is why the level is set by how the pot was handled. Boiled in plenty of water and drained, they land far below the same lentils simmered into a dal that keeps its liquid. Pulse oligosaccharides are water-soluble, and that is the practical point: the level here follows work on pulses AND on what cooking does to them, because soaking and boiling move part of them into water that is usually thrown away.

• Reddy N. et al., Food Chemistry 13 (1984) 25-68, and Wang N. et al., Food Res Int 43 (2010) 589-594, oligosaccharides of pulses and the effect of cooking

Pistachios are the one nut carrying both chain families at once - GOS and fructans. That is why they sit above every other nut here, and why the threshold is counted in kernels rather than handfuls.

Same reason as the FODMAP level: kidney bean GOS. The hard boil that food safety demands of this bean is also what leaches them - provided the water goes down the sink rather than into the dish. Pulse oligosaccharides are water-soluble, and that is the practical point: the level here follows work on pulses AND on what cooking does to them, because soaking and boiling move part of them into water that is usually thrown away.

• Reddy N. et al., Food Chemistry 13 (1984) 25-68, and Wang N. et al., Food Res Int 43 (2010) 589-594, oligosaccharides of pulses and the effect of cooking

The soya bean carries the raffinose family in quantity, and it explains why its products diverge so far: pressing takes them out with the whey, fermentation lets the mould eat them, and doing neither leaves them all in.

• Švejstil R. et al., Sci Agric Bohem 46:2 (2015) 73-77, raffinose-series oligosaccharides in soybean products

Same reason as the FODMAP level: adzuki GOS. Red bean paste is made by cooking the beans down with sugar rather than draining them, so the chains stay in the sweet. Pulse oligosaccharides are water-soluble, and that is the practical point: the level here follows work on pulses AND on what cooking does to them, because soaking and boiling move part of them into water that is usually thrown away.

• Reddy N. et al., Food Chemistry 13 (1984) 25-68, and Wang N. et al., Food Res Int 43 (2010) 589-594, oligosaccharides of pulses and the effect of cooking

Channa dal carries both oligosaccharide classes in small amounts: Prichard measured 0.36 g of galacto-oligosaccharides and 0.13 g of fructans per 100 g. GOS are what pulses characteristically carry, and they are the larger of the two here. The measurement is on the dal as sold; soaking water that is poured away takes soluble GOS with it.

• Prichard R et al., Int J Food Sci Nutr 67 (2016) 383-390, FODMAP content of foods commonly consumed by ethnic minority groups
• contents per 100 g, not per serve

Green peas carry both GOS and fructans - one of the few foods to bring a chain from each family. That is why they behave in a dose-dependent way rather than being simply avoidable: a spoonful passes, a portion does not. The pea's oligosaccharides are the raffinose family, measured in the seed itself. They are what a legume stores for its own germination, which is why they sit in the seed and not in the pod.

• Jones D. et al., Seed Sci Res 9 (1999), raffinose-family oligosaccharides in pea seed

Same reason as the FODMAP level: split pea GOS, in a dish built on keeping the cooking liquid. Soup is the worst format for a water-soluble oligosaccharide, because nothing is poured away. The pea's oligosaccharides are the raffinose family, measured in the seed itself. They are what a legume stores for its own germination, which is why they sit in the seed and not in the pod.

• Jones D. et al., Seed Sci Res 9 (1999), raffinose-family oligosaccharides in pea seed

Almonds carry a little GOS - enough that the threshold is counted in nuts rather than handfuls, around ten. They are the standard nut on this diet, but they are not unlimited, which surprises people who treat them as free. Pulse oligosaccharides are water-soluble, and that is the practical point: the level here follows work on pulses AND on what cooking does to them, because soaking and boiling move part of them into water that is usually thrown away.

• Reddy N. et al., Food Chemistry 13 (1984) 25-68, and Wang N. et al., Food Res Int 43 (2010) 589-594, oligosaccharides of pulses and the effect of cooking

Red lentils are split and hulled, which means they cook in minutes and give up their water-soluble GOS quickly into the pot. They are the lowest of the pulses on this axis, and the split is why. Pulse oligosaccharides are water-soluble, and that is the practical point: the level here follows work on pulses AND on what cooking does to them, because soaking and boiling move part of them into water that is usually thrown away.

• Reddy N. et al., Food Chemistry 13 (1984) 25-68, and Wang N. et al., Food Res Int 43 (2010) 589-594, oligosaccharides of pulses and the effect of cooking

White beans carry the same GOS as every other pulse; what puts them at this level is the canned and rinsed serving the figure is measured on. Cooked from dried and served in their liquid, they answer like the beans they are. Pulse oligosaccharides are water-soluble, and that is the practical point: the level here follows work on pulses AND on what cooking does to them, because soaking and boiling move part of them into water that is usually thrown away.

• Reddy N. et al., Food Chemistry 13 (1984) 25-68, and Wang N. et al., Food Res Int 43 (2010) 589-594, oligosaccharides of pulses and the effect of cooking