It’s becoming more and more widely accepted that keto diets can be healthy and also nutritionally complete.1 Meat, fish, eggs, dairy, nuts and vegetables are rich in key nutrients that your body needs on a daily basis. In some cases, however, supplementing with minerals known as electrolytes may be beneficial.

This is because when carb intake is extremely low, levels of electrolytes – especially sodium  – can drop. And if this happens, you may not feel your best.2


Symptoms of electrolyte deficiency and what to do about it

Sodium

Symptoms3
  • Fatigue
  • Weakness
  • Headaches
  • Difficulty concentrating
Course of action

Be more liberal with the salt shaker at mealtimes. If needed, especially the first week, have 1-2 cups of bouillon or broth daily. Learn more

Potassium

Symptoms4
  • Muscle cramps
  • Muscle twitching
  • Heart palpitations / increased awareness of heartbeat
Course of action

Eat an extra avocado or portion of leafy greens or mushrooms per day. Learn more

Magnesium

Symptoms5
  • Muscle cramping or twitching at night or after exercise
Course of action

Eat seeds like hemp, pumpkin and chia or a portion of mackerel, almonds or leafy greens per day. If needed, take a magnesium supplement. Learn more

Interested in learning more about why electrolyte levels can decrease on low carb and other dietary options to replenish them? Keep reading!

The keto flu

When you restrict carbohydrates, your body begins to process electrolytes differently. This is because when insulin levels are low, the kidneys excrete more sodium.6 Since there is a delicate balance between sodium and other electrolytes in the body, the loss of sodium may disrupt levels of other electrolytes as well.

In some cases, this leads to symptoms that are often described as the “keto flu.” These symptoms are usually temporary and resolve after your body adapts to low carb.7

Fortunately, replenishing sodium, magnesium, and potassium may help prevent or greatly diminish symptoms of keto flu and fix some of the side effects you may have long term. Read on to find out more.

Do you need mineral supplementation?

The decision to take mineral supplements should be based on how you feel and whether or not you experience any symptoms. If you already feel well on a keto diet, you may not need to add any supplements or electrolyte-rich food  (although you may feel you want to try upping your intake to see if you feel even better!)8

Bear in mind that if you engage in endurance exercise or any type of rigorous physical activity, you may find it difficult to get enough electrolytes solely from food, and you may choose to take supplements for performance reasons.9

Here are the daily mineral needs for people who follow a keto lifestyle, the best keto-friendly food sources, and supplement recommendations for those who can’t meet their needs through diet alone.

Sodium

According to many health organizations, most of us should be cutting back on sodium in order to prevent high blood pressure and other health problems. For example, The American Heart Association recommends consuming less than 2.3 grams and ideally no more than 1.5 grams of sodium per day.

For people with hypertension who eat high-carb diets, this advice might be warranted. However, some of the supporting trial evidence shows a small blood pressure lowering effect without clear evidence of improved overall health.10 And many observational studies suggest that the optimal sodium intake is between 3 and 6 grams per day.11 In addition, on a keto diet, your sodium needs may actually increase, due to increased losses via the kidneys.12 Therefore, on a keto diet we are usually more concerned with too little sodium rather than too much.

Reasons for possible deficiency

When carb intake is dramatically reduced, blood insulin levels decrease, leading to a loss of salt in the urine.13 If sodium isn’t replaced, you may experience a variety of symptoms.

Symptoms

  • Fatigue
  • Weakness
  • Headaches
  • Difficulty concentrating14

Daily need: Most people on a low-carb diet will feel best with  3–7 grams of sodium (7–17 grams of salt, or about 1-3 teaspoons) per day.15

However, if you have certain medical conditions — such as hypertension, kidney disease, or congestive heart failure — you may need to be more cautious about sodium. Read our complete guide on salt to learn why optimal intake varies from person to person.

Note that salt and sodium are not quite same thing, when you calculate your daily intake. Salt contains only 40% sodium, and the remainder is another mineral, chloride. So although you increase your sodium intake by eating more salt, it’s important to remember that eating one teaspoon (6 grams) of salt provides you with only 2.4 grams of actual sodium.

Add salt to your diet

Most people get at least 2 grams of sodium from the foods they eat. You can add a teaspoon of salt to a liter of water and drink it over the course of the day. Another strategy is to drink broth or bouillon, which contains about 1 gram of sodium per cup.

If you do physical exercise, adding sodium prior to a workout may improve your performance. Drs. Phinney and Volek recommend taking one-half teaspoon of salt within the half hour prior to exercising in their book The Art and Science of Low Carb Performance16

Note: If you have high blood pressure, heart failure, or kidney disease, be sure to speak with your doctor before increasing your sodium intake.


Potassium

When sodium is lost during ketosis, the kidneys may respond by reabsorbing more sodium while excreting more potassium into the urine, in an attempt to maintain biochemical balance.17

Symptoms of deficiency

  • Muscle cramps
  • Muscle twitching
  • Heart palpitations/Increased awareness of heartbeat18

Daily need: 3,000–4,700 mg (3–4.7 g) of potassium

Although most foods contain only low to moderate amounts of potassium, there are several low-carb sources that can help you meet your daily requirement.

High-potassium foods

To get more potassium into your diet, you could take potassium supplements. Or, why not try adding an avocado or a couple of servings of other keto-friendly high-potassium foods to your diet on a daily basis?

  1. Avocado 1,000 mg per medium avocado (200 grams)
  2. Swiss chard, cooked 950 mg per cup (175 grams)
  3. Spinach, cooked 840 mg per cup (180 grams)
  4. Mushrooms, cooked 550 mg per cup (150 grams)
  5. Brussels sprouts: 500 mg per cup (160 grams)
  6. Broccoli, cooked 460 mg per cup (160 grams)
  7. Salmon 430–500 mg per 4 ounces (114 grams)
  8. Meat 400–500 mg per 4 ounces (114 grams)
  9. Flounder 400 mg per 4 ounces (114 grams)
  10. Artichoke 345 mg per medium artichoke (121 grams)
  11. Hemp seeds 335 mg per ounce (30 grams)
  12. Almonds 200 mg per ounce (30 grams)

Supplements

If you’re very active or don’t consume enough potassium-rich food on a regular basis, it might make sense to take supplemental potassium on an as-needed basis.

Potassium supplements are typically available as 99 mg tablets.19 Note that although the front label on a potassium supplement may list 595 mg as the dosage, each tablet only contains 99 mg of pure potassium, which can be verified on the detailed “Supplement Facts” label on the back of the container.

Your blood potassium levels need to remain within a narrow range, and taking too much in concentrated form can be dangerous, especially if you take certain medications or have kidney disease.  For this reason, it’s best to get your potassium through food intake whenever possible.

Recommended supplements

If you do decide to take potassium supplements, here are some good options on Amazon:20

NOW potassium supplements >

Solaray potassium supplements >

Note: If you have high blood pressure, heart disease, kidney disease, or are taking medications for any other condition, be sure to speak with your doctor before you take a potassium supplement.


Magnesium

Although magnesium is found in a wide variety of foods, many people don’t get enough from diet alone. In fact, it’s estimated that almost 50 percent of the US population does not meet the daily dietary requirement for magnesium.21

Deficiency symptoms

Symptoms of magnesium deficiency may include muscle twitching or cramping at night or after exercising. Although muscle cramps can also occur with inadequate potassium, sodium, or fluid intake, getting too little magnesium is a very common cause.22

Daily need: 400 mg magnesium

High-magnesium foods

Most foods don’t provide much magnesium, but there are a few good sources that can be included on a keto diet. What’s more, many of them are high in potassium as well. Eating Swiss chard and other cooked greens on a regular basis is a great strategy for helping to meet your magnesium needs.

  1. Hemp seeds 195 mg per ounce (30 grams)
  2. Swiss chard, cooked 150 mg per cup (175 grams)
  3. Pumpkin seeds, dried 150 mg per ounce (30 grams)
  4. Mackerel 105 mg per 4 ounces (114 grams)
  5. Chia seeds 95 mg per ounce (30 grams)
  6. Dark chocolate (70–85% cacao) 70–90 mg per ounce (30 grams)
  7. Almonds 75 mg per ounce (30 grams)
  8. Spinach, cooked 75 mg per cup (180 grams)
  9. Pine nuts 70 mg per ounce (30 grams)
  10. Avocado 60 mg per medium avocado (200 grams)
  11. Artichoke 50 mg per medium artichoke (120 grams)

Supplements

Taking up to 400 mg of magnesium per day in supplement form is safe for most people with healthy kidneys. Some forms of magnesium can cause digestive issues, however, especially when taken alone. For this reason, it’s best to take a magnesium supplement with a meal.

Forms that are well absorbed include magnesium citrate, magnesium chloride, and magnesium glycinate (also known as magnesium bisglycinate or diglycinate).23 Additionally, magnesium glycinate and Slow-Mag (a slow-digesting form of magnesium chloride) seem least likely to cause loose stools or other digestive issues.24

Recommended supplements

If you decide to take magnesium supplements, here are some good options on Amazon:25

NOW Magnesium citrate supplements >

Slow-Mag (magnesium chloride) >

Solaray magnesium glycinate supplements >

Note: If you have kidney disease, you may not be able to handle a large amount of magnesium. In addition, certain medications may interact negatively with magnesium supplements. Speak with your doctor before taking a magnesium supplement if any of these apply to you.


Related material

The keto flu, other keto side effects, and how to cure them >

How to get into ketosis >

More keto guides

Exogenous ketones: Do they work?
A ketogenic diet for beginners
Ketogenic diet foods – what to eat and what to avoid

Keto videos

How does a keto diets work? Learn more below.
  1. Nutrition & Metabolism 2017: Assessing the nutrient intake of a low-carbohydrate, high-fat (LCHF) diet: a hypothetical case study design [descriptive study; ungraded]

  2. Dr. Steve Phinney, one of the foremost experts in ketogenic diets, has discussed the importance of electrolyte management in several papers, including this one:

    Nutrition & Metabolism 2004: Ketogenic diets and physical performance [overview article; ungraded]

  3. The British Medical Journal 2006: Disorders of sodium balance [overview article; ungraded]

  4. Medical Clinics of North America 1997: Hypokalemia and hyperkalemia [overview article; ungraded]

  5. International Journal of Endocrinology 2018: Magnesium and human health: perspectives and research directions [review article; ungraded]

  6. American Journal of Physiology. Renal Physiology 2007: Insulin’s impact on renal sodium transport and blood pressure in health, obesity, and diabetes [overview article; ungraded]

    Diabetalogia 1981: The effect of insulin on renal sodium metabolism [overview article; ungraded]

  7. In one study, people lost more sodium and potassium in their urine during the initial stage of a low-carb diet, although this effect was no longer seen after 28 days:

    Annals of Nutrition & Metabolism 1981: Loss of weight, sodium and water in obese persons consuming a high- or low-carbohydrate diet [non-randomized trial; weak evidence]

    In addition, this is based on clinical experience of low-carb practitioners and was unanimously agreed upon by our low-carb expert panel. You can learn more about our panel here [weak evidence].

  8. This is based on the consistent clinical experience of doctors who regularly provide patients with low-carb nutrition interventions.[weak evidence]

  9. This is detailed by Dr. Stephen Phinney and Jeff Volek in their book The Art and Science of Low Carbohydrate Living.

    Diet Doctor will not benefit from your purchases. We do not show ads, use any affiliate links, sell products or take money from industry. Instead we’re funded by the people, via our optional membership. Learn more

  10. A Cochrane meta-analysis of RCTs show no clear benefit:

    Cochrane 2014: Reduced dietary salt for the prevention of cardiovascular disease [strong evidence]

  11. The Lancet 2016: Associations of urinary sodium excretion with cardiovascular events in individuals with and without hypertension: a pooled analysis of data from four studies [observational study with HR < 2; very weak evidence]

    The New England Journal of Medicine 2014: Urinary sodium and potassium excretion, mortality, and cardiovascular events [observational study with HR < 2; very weak evidence]

    Journal of the American Medical Association 2011: Urinary sodium and potassium excretion and risk of cardiovascular events [observational study with HR < 2; very weak evidence]

  12. This is based on the consistent clinical experience of doctors who regularly provide patients with low-carb nutrition interventions.[weak evidence]

  13. In a 2007 review, researchers suggested that under conditions of low insulin, the kidneys absorb less sodium and excrete more into the urine:

    American Journal of Physiology. Renal Physiology 2007: Insulin’s impact on renal sodium transport and blood pressure in health, obesity, and diabetes [overview article; ungraded]

  14. Less common symptoms may include nausea, vomiting, or even loss of consciousness if sodium levels drop too low.

  15. This is based on the consistent clinical experience of doctors regularly providing patients with low-carb nutrition interventions.[weak evidence]

  16. Diet Doctor will not benefit from your purchases. We do not show ads, use any affiliate links, sell products or take money from industry. Instead we’re funded by the people, via our optional membership. Learn more

  17. International Journal of Hypertension 2011: Insulin resistance, obesity, hypertension, and renal sodium transport [overview article; ungraded]

    Virta Health blog post 2019: The importance of managing potassium and sodium as part of a well-formulated ketogenic diet [overview article; ungraded]

  18. Less common symptoms may include numbness, dizziness, abdominal cramping, and constipation.

  19. National Institutes of Health Office of Dietary Supplements: Potassium supplement brief [overview article; ungraded]

  20. Diet Doctor will not benefit from your purchases. We do not show ads, use any affiliate links, sell products or take money from industry. Instead we’re funded by the people, via our optional membership. Learn more

  21. USDA: What we eat in America, NHANES 2005-2006, usual nutrient intakes from food and water compared to 1997 Dietary Reference Intakes for vitamin D, calcium, phosphorus, and magnesium [observational study; weak evidence]

    Nutrition Review 2012: Suboptimal magnesium status in the United States: are the health consequences underestimated? [overview article; ungraded]

  22. The mineral is so important to muscle and physiologic functioning that Phinney and Volek devote almost three pages to it in their book, The Art and Science of Low Carbohydrate Living:

    “Cramps during or after exercise or at night are a sign that your body has a major magnesium deficiency,” they write.[book excerpt; ungraded evidence]

  23. Magnesium Research 2003: Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study [randomized trial; moderate evidence]

    Journal of Parenteral and Enteral Nutrition 1994: Bioavailability of magnesium diglycinate vs magnesium oxide in patients with ileal resection [randomized trial; moderate evidence]

    Magnesium Research 2001: Bioavailability of US commercial magnesium preparations [non-controlled study; weak evidence]

  24. This is based on the consistent clinical experience of low-carb practitioners. [weak evidence]

  25. Diet Doctor will not benefit from your purchases. We do not show ads, use any affiliate links, sell products or take money from industry. Instead we’re funded by the people, via our optional membership. Learn more