Salt and diet
A vegetable ferment carries 2.5% salt, and miso a lot more. How much that is per serving against official limits, and how to eat less salt without taking it out of the jar.
5 min read First steps Reviewed October 26, 2026 16 facts, each with its source
How much salt a day
WHO recommends adults have less than 5 g of salt a day, which is 2,000 mg of sodium: just under a teaspoon1. The two figures say the same thing, because 5 g of salt carries 2,000 mg of sodium2. To go from salt to sodium, multiply by 0.4; from sodium to salt, by 2.5.
In the U.S., the Dietary Guidelines set the limit at under 2,300 mg of sodium a day, about 5.75 g of salt3. For children, the limits are lower4. And nearly everyone goes over: in 2021, adults averaged 4,278 mg of sodium a day, about 11 g of salt5.
Why it matters
The main effect of eating a lot of sodium is raised blood pressure, and with it a higher risk of cardiovascular disease, stomach cancer, osteoporosis or kidney disease6.
Most sodium, over 70%, comes from packaged and prepared foods, not the salt shaker7. Some taste salty, like pickles or soy sauce8, but taste isn't a good guide to how much sodium something has9. A homemade ferment has one advantage: you know exactly how much salt went in.
How much salt a serving carries
The salt in a ferment doesn't disappear as it ferments. It spreads between the vegetables and their juice, so each bite carries roughly the percentage you put in. With the salt in Fervida's recipes, here's the math:
| Serving | Salt | Sodium | Of WHO's daily maximum |
|---|---|---|---|
| 50 g of sauerkraut, at 2.5%10 | 1.25 g | 500 mg | 25% |
| 100 g of sauerkraut, at 2.5% | 2.5 g | 1,000 mg | 50% |
| 50 g of kimchi, at 2.5% of the vegetables | About 1.2 g | About 490 mg | 24% |
| 15 g of white miso, at 8% | 1.2 g | 480 mg | 24% |
| 15 g of red miso, at 12% | 1.8 g | 720 mg | 36% |
The math is Fervida's, from each recipe's salt. Other people's can be saltier. Kimchi ends up with between 2 and 5% salt11, and miso carries 5 to 13%, usually 11 to 13%12. If yours has more salt, so does the serving.
Why you don't take salt out of the jar
If you want less salt, the temptation is to put less in the ferment. Don't: cutting the salt in fermented vegetables isn't safe13. Low-sodium substitutes don't work either, because fermentation needs sodium chloride14. Miso is the same: with 25% less salt or more, it spoils15.
The salt in the jar is part of what makes a ferment turn out well. The salt that counts for your diet is what reaches your plate, and that one you can change.
Less salt on the plate
It's a house rule: salt is adjusted when you serve, not in the jar.
- Use it as a condiment. A spoonful of sauerkraut or kimchi next to a dish gives plenty of flavor with little salt. Count that serving in the day's salt.
- Drain it. The juice carries the same salt as the vegetables. Leave it in the jar, where it also protects what's left.
- Rinse it if you're going to cook with it or mix it in. With preserved lemons, for example, the guides say to rinse the peel to remove excess salt16.
- Weigh the miso. Weigh it instead of eyeballing it, and start with less: you can always add more.
- Don't add more salt. If the dish has a ferment in it, don't add salt or soy sauce without tasting first.
If you have high blood pressure
If you have high blood pressure, kidney disease, or have been told to eat less salt, talk to your doctor before eating ferments often. With the sodium figure they give you and the table above, you can work out what serving fits your day.
For children, who have lower limits4, servings need to be smaller too.
Where every number comes from
Every number in the text leads to its figure: the exact sentence from the official guide it comes from, in its own language.
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1
WHO recommends under 5 g of salt a day, 2,000 mg of sodium
“For adults, WHO recommends less than 2000 mg/day of sodium (equivalent to less than 5 g/day salt), or just under a teaspoon.”
World Health Organization · Sodium reduction (fact sheet) · read on October 26, 2026
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2
5 g of salt is 2,000 mg of sodium
“5 grams of salt is equivalent to 2000 mg of sodium”
World Health Organization · Sodium reduction (fact sheet) · read on October 26, 2026
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3
In the U.S., under 2,300 mg of sodium a day
“the Dietary Guidelines for Americans recommends adults limit sodium intake to less than 2,300 mg per day”
U.S. Food and Drug Administration · Sodium in your diet · read on October 26, 2026
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4
For children, limits are lower
“For children under age 14, recommended limits are even lower.”
U.S. Food and Drug Administration · Sodium in your diet · read on October 26, 2026
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5
In 2021, adults averaged 11 g of salt a day
“The global mean intake of adults was 4278 mg/day sodium (equivalent to 11 g/day salt) in 2021”
World Health Organization · Sodium reduction (fact sheet) · read on October 26, 2026
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6
Too much sodium raises blood pressure and cardiovascular risk, among others
“The primary health effect associated with diets high in sodium is raised blood pressure which increases the risk of cardiovascular diseases, gastric cancer, obesity, osteoporosis, Meniere’s disease, and kidney disease.”
World Health Organization · Sodium reduction (fact sheet) · read on October 26, 2026
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7
Over 70% of sodium comes from packaged and prepared foods
“most dietary sodium (over 70%) comes from eating packaged and prepared foods—not from table salt added to food when cooking or eating.”
U.S. Food and Drug Administration · Sodium in your diet · read on October 26, 2026
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8
Pickles and soy sauce taste salty
“some foods that are high in sodium (like pickles and soy sauce) taste salty”
U.S. Food and Drug Administration · Sodium in your diet · read on October 26, 2026
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9
Taste isn't a good guide to how much sodium something has
“using taste alone is not an accurate way to judge a food’s sodium content.”
U.S. Food and Drug Administration · Sodium in your diet · read on October 26, 2026
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10
25 g of salt per kilo, 2.5%
“2.5% 25 g / kg food”
UC Master Food Preservers, Inyo-Mono · Brine Math Made Easy · read on October 20, 2026
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11
Kimchi ends up with 2–5% salt
“the final salt concentration ranges from 2-5%.”
Colorado State University Extension · Understanding and Making Kimchi (2025) · read on October 20, 2026
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12
Miso carries 5 to 13% salt, usually 11–13%
“The salt content varies widely from 5 to 13%, but typically it is in the 11 to 13% range.”
Journal of Fungi (MDPI), Kusumoto K.-I. et al. · Japanese Traditional Miso and Koji Making (2021) · read on October 25, 2026
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13
It isn't safe to cut the salt in fermented vegetables
“It is unsafe to reduce salt in lactofermented vegetables.”
UC Master Food Preservers, Inyo-Mono · Brine Math Made Easy · read on October 20, 2026
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14
Low-sodium substitutes don't work for fermenting
“Reduced sodium salt substitutes should not be used in making fermented pickles or sauerkraut, because the specific properties of sodium chloride are required to achieve the desired fermentation.”
UC Master Food Preservers, Mariposa County (UC ANR) · Pickling versus Fermenting around the World: Key Ingredients (Mariposa MFP, 12-nov-2022) · read on October 26, 2026
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15
In miso, cutting salt by 25% or more spoils it
“○みそには、発酵に適切な塩分と水分の範囲が存在し、２５％以上の低減では変敗が生じ、安全”
Consumer Commission, Cabinet Office of Japan (消費者委員会), with an annex prepared by MAFF (農林水産省) · 資料3-2: ナトリウムに係る低減された旨の表示（25％以上の相対差）の特例を設けることについて (15-oct-2014) · read on October 25, 2026
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16
Preserved lemons are rinsed to remove excess salt
“Rinse under water to remove excess salt.”
Clemson Cooperative Extension, Home & Garden Information Center (Jessica Hardiman) · Traditional Preserved Lemons: How to Make and Use Preserved Lemons at Home (January 2026) · read on October 25, 2026