Potassium and Magnesium on Keto: Food First, Pills via Your Doctor
Summary: Adults need roughly 2,600–3,510 mg of potassium and 310–420 mg of magnesium a day; low-carb vegetables, meat and light salt cover much of it, and pills should go through your doctor because both minerals act on the kidneys and heart.
On this page
- How much you need
- Why potassium is harder on keto
- Low-carb food sources
- Light salt and salt substitutes
- What the research says
- Why pills need your doctor
How much you need
| Mineral | Reference | Adults per day |
|---|---|---|
| Potassium | WHO (2012) | At least 3,510 mg (90 mmol), from food |
| Potassium | NASEM (2019) | Adequate intake 2,600 mg women, 3,400 mg men; no upper limit set |
| Magnesium | NIH Office of Dietary Supplements | RDA 310–320 mg women, 400–420 mg men |
| Magnesium (supplements only) | NIH ODS; IOM 1997 | Upper limit 350 mg from supplements; no limit for magnesium in food |
The magnesium upper limit applies only to pills and powders. Food magnesium has no set limit.
KetoDick on this: He gives 4,700 mg as the potassium RDA (video -dHjt_Bpruk). The NASEM 2019 figures above are lower (2,600 mg for women, 3,400 mg for men), and WHO's is 3,510 mg. Check which reference your doctor or app uses.
Why potassium is harder on keto
The best-known potassium foods are often starchy: potatoes, sweet potatoes, bananas. Cutting carbs cuts many of them.
Potassium also pairs with sodium. As keto lowers insulin, the kidneys pass more sodium, and insulin research shows they pass more potassium too (DeFronzo et al., 1975). That is part of why sodium and potassium are discussed as a pair.
KetoDick on this: He calls potassium the hard one on keto because potatoes and sweet potatoes are high-carb, and says sodium and potassium work as a ratio (video lbRPlGZ3Rvw).
Low-carb food sources
The evidence pages behind this guide do not list mineral amounts per food, so this list gives sources without numbers. Use a nutrition app or label for amounts.
Potassium
- Leafy greens (spinach, kale, lettuce)
- Avocado
- Broccoli, Brussels sprouts, cauliflower
- Meat and fish
- Broth made with light salt
Magnesium
- Leafy greens
- Nuts and seeds
- Avocado
See the keto food list and can you eat vegetables on keto?
KetoDick on this: He points to leafy greens such as baby spinach for calcium and magnesium, and likes pickle juice as a source of all four electrolytes. He warns that avoiding greens on keto, "looking at lettuce like it's the devil" (from the video), can cause keto-flu symptoms (video lbRPlGZ3Rvw).
Light salt and salt substitutes
"Light salt" and salt substitutes replace part of the sodium chloride with potassium chloride. They taste like salt and add potassium.
- WHO suggests potassium-containing lower-sodium salt substitutes in place of regular salt, except for people at risk of high blood potassium (hyperkalaemia) (WHO fact sheet). The year of that guideline is not confirmed.
- The SSaSS trial (n = 20,995, rural China) found a potassium-enriched salt substitute lowered stroke, major heart events and death, with no significant difference in serious hyperkalaemia (Neal et al., 2021).
The exception matters. People with kidney disease, or who take certain blood pressure medicines, can be the ones at risk of high potassium. They should ask before switching.
More on this product type: light salt (potassium chloride).
KetoDick on this: He uses potassium-chloride salt in his bouillon: 1/4 teaspoon per cup, which he puts at about 640 mg potassium, three cups a day (video -dHjt_Bpruk). In 2017 he recommends light salt as a source of potassium (video lbRPlGZ3Rvw), and in his 2018 beginners' video calls it better for keto than pink Himalayan salt (video UygKGoP_BtA). He also shows that 3,000 mg of potassium as potassium chloride is a large pile of salt, and says many pharmacy potassium pills hold about 4% of daily need (video -dHjt_Bpruk).
What the research says
Potassium
| Study | Finding |
|---|---|
| Whelton et al., 1997 | Potassium supplements lowered systolic and diastolic blood pressure in trials, more where sodium intake was higher |
| Aburto et al., 2013 | Higher potassium lowered blood pressure in people with hypertension, with no harm to lipids or kidney function; lower stroke risk in cohorts |
Magnesium
| Study | Finding |
|---|---|
| Rosanoff et al., 2012 | A large share of the US eats less magnesium than the average requirement; blood magnesium is a poor test of status |
| Fang et al., 2016 | In cohorts, each extra 100 mg a day was linked to lower heart failure, stroke, type 2 diabetes and death from any cause, not total heart disease |
The magnesium findings are observational. The potassium blood-pressure findings come from trials. A normal blood magnesium result does not prove your intake is fine, per Rosanoff.
Why pills need your doctor
Food potassium and magnesium are hard to overdo for people with healthy kidneys. Pills are different.
Your kidneys clear extra potassium and magnesium. If they work less well, levels can build up, and potassium in particular affects heart rhythm. That is why the WHO salt-substitute advice carves out people at risk of hyperkalaemia.
Ask your doctor before potassium or magnesium supplements, or before switching to light salt, if you:
- Have kidney disease of any stage.
- Have type 2 diabetes or pre-diabetes. KetoDick notes many people with these have some kidney impairment (video lbRPlGZ3Rvw).
- Have a heart condition or a history of irregular heartbeat. See heart palpitations on keto.
- Take blood pressure medicine or water pills. Ask how they affect your potassium. KetoDick notes some potassium products are themselves diuretic drugs (video -dHjt_Bpruk).
- Are pregnant.
KetoDick on this: He draws this line in several videos: potassium and magnesium supplements can affect the kidneys and then the heart, so involve your doctor before taking them, and that electrolytes can "largely and most safely" (auto-caption) be found in vegetables (video lbRPlGZ3Rvw; video 9r2Y74AnjUQ).
For cramps specifically, see leg cramps on keto and magnesium on keto.
Related
- Guide: Chapter 7: Electrolytes · Sodium · Keto flu · Multivitamins · Medications · Who should talk to a doctor
- Blog: Light salt (potassium chloride) · Magnesium on keto · Leg cramps on keto · Heart palpitations on keto
- Videos: Making sense of electrolytes · Electrolytes are absolutely critical · It's not keto flu
Last verified: 2026-10-31