The evidence on adzuki is about unsweetened pulses. Leave out the sugar, and discard only the first boiling water.
3 servings70 min
Rinse the beans and bring them to the boil in plenty of water. Once boiling, give them 5 minutes, then throw that water away entirely.
Separately, soak the barley for 30 minutes.
Put the beans and 1.2 L of water in a pot, bring to the boil, then simmer 40 minutes — they are done when they crush between your fingers.
Add the soaked barley and cook 20 minutes more, adding a little water if it thickens too far.
Toast the walnuts in a dry pan over low heat for 3–4 minutes and break them up coarsely.
Season the porridge with 1/2 tsp of salt and nothing else. No sugar.
Serve topped with the walnuts and a pinch of cinnamon.
Leaving out the sugar is the whole dish.
The clinical evidence on adzuki comes from the pulse category. Meta-analyses of randomised trials found pulse intake lowering LDL — and what those trials fed was boiled beans, beans in soups and salads.
That is not how adzuki is usually eaten.
| Form | What comes with the beans |
|---|---|
| Sweet red bean paste | Sugar at 40–50% of the beans' weight |
| Patbingsu | Paste + condensed milk + syrup |
| Sweet red bean bun | Paste + the sugar in the bread |
| This porridge | Half a teaspoon of salt |
Expecting the pulse benefit while eating a paste that is 40% sugar does not add up.
The first water goes out because of adzuki's saponins and tannins, the source of its astringency. Some water-soluble compounds leave with them, so it is a trade — if the astringency does not bother you, skip the step.
Adzuki does not need soaking. Unlike soybeans, its hard coat takes up water slowly. Soaking shortens the cooking but is not required. The barley does need it — it breaks down faster than the beans, which is why it goes in later.
The salt is not there to make it salty. A small amount of salt makes sweetness more noticeable. The sweetness already in the beans and barley comes forward, so it does not taste flat without sugar.
The numbers. For three servings, from 120 g of beans, 60 g of barley and 30 g of walnuts:
The walnuts go on last for texture. Porridge is soft all the way through, with nothing to chew; toasted walnuts fill that gap. Never high heat — walnuts are 65% fat and scorch fast.
Take care if you restrict potassium for kidney disease. Dry adzuki holds 1,250 mg per 100 g, and this recipe uses 120 g.
Grains & legumes
Moderate evidenceMeta-analyses of trials feeding people around 130 g of pulses a day found LDL falling. But in Korea adzuki mostly arrives with sugar — shaved ice, sweet buns, porridge. The 622 µg of folate and 12.7 g of fibre per 100 g dry are real; sweetened paste is a different food.
Grains & legumes
Strong evidenceBeta-glucan lowers LDL by 0.25 mmol/L. The glucose effect, though, fades by two hours and HbA1c did not move at all.
Nuts & seeds
Moderate evidenceWalnuts carry 9.1 g of ALA per 100 g, an order of magnitude beyond other nuts. But the rate at which ALA converts to EPA and DHA is very low.