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Onion vs Kale: Which Is Better for Kidneys?

For a kidney-friendly diet the question is mineral load: Onion is Kidney-friendly, Kale is Moderate. Onion carries the lighter mineral load overall, driven mainly by Potassium (7% vs 17% of the limit).

Onion
Kidney-friendly Kale
Moderate
Phosphorus
29 mg
3%
55 mg
6%
Sodium
4 mg
<1%
53 mg
3%
Potassium
146 mg
7%
348 mg
17%

About Onion

How to think about Vegetables: Onion is worth a closer look - Vegetables are a key source of fiber and vitamins and are beneficial in CKD. Some are high in potassium, but slicing, boiling and discarding the water can remove about 30-50% of the potassium - a practical step.

About Kale

Kale sits in the Vegetables group. Vegetables are a key source of fiber and vitamins and are beneficial in CKD. Some are high in potassium, but slicing, boiling and discarding the water can remove about 30-50% of the potassium - a practical step.

Practical tips

Practical tip: Slice, boil and discard the water to remove roughly 30-50% of the potassium - a practical method for high-potassium vegetables. How to eat it more safely: Slice, boil and discard the water to remove roughly 30-50% of the potassium - a practical method for high-potassium vegetables.

See Onion details See Kale details

Frequently asked questions

Which has more potassium, onion or kale?

For Potassium, the per-100 g values are 146 mg in Onion and 348 mg in Kale — the rest of the mineral profile is on each food page.

Is onion or kale better for kidney disease?

Based on CKD stage 3-4 daily limits, Onion is rated Kidney-friendly and Kale is rated Moderate. Ratings reflect mineral load per 100 g only; individual advice should come from your healthcare team.

What is the difference between onion and kale for a CKD diet?

The largest difference is Potassium: Onion sits at 7% of the daily limit versus 17% for Kale. Portion size changes both numbers, so compare per 100 g values on the food pages.