Cabbage water, the liquid left over after boiling cabbage, contains a modest amount of nutrients that leach out during cooking. It’s not a miracle drink, but it does carry some of the same beneficial plant compounds found in cabbage itself, making it a reasonable addition to your diet rather than something to pour down the drain.
What Actually Ends Up in the Water
When you boil cabbage, water-soluble compounds migrate from the vegetable into the cooking liquid. Polyphenolic acids, a group of antioxidants naturally present in cruciferous vegetables, are reduced in the cooked cabbage precisely because they leach into the water. Flavonol glycosides, another class of beneficial plant compounds, are especially prone to this transfer because they sit in the outer, water-friendly layers of plant tissue. So the liquid you’d normally discard actually becomes a dilute carrier of some of cabbage’s most valuable chemistry.
That said, the concentrations are lower than what you’d get from eating the cabbage itself. Boiling scatters these compounds across a larger volume of water, and heat degrades some of them in the process. Cabbage water is better thought of as a nutritious bonus, not a replacement for eating vegetables.
Anti-Inflammatory Potential
Cruciferous vegetables as a group show a meaningful connection to lower inflammation. A large study of women found that those who ate the most cruciferous vegetables had roughly 13% lower levels of one key inflammatory marker (TNF-alpha), 18% lower levels of another (IL-1 beta), and about 25% lower levels of a third (IL-6) compared to women who ate the least. These are significant differences tied to real dietary patterns, not supplements or extracts.
Whether cabbage water alone delivers enough of these compounds to move the needle on inflammation isn’t established. The studies measured whole vegetable intake, not the cooking liquid. But the anti-inflammatory compounds in cabbage are water-soluble, which means at least some of them transfer into the broth. Using cabbage water as a base for soups or grains is a practical way to recapture what would otherwise be lost.
Weight Loss Claims Are Overstated
Cabbage water is often associated with the “cabbage soup diet,” a short-term crash diet that promises rapid weight loss. The reality is simpler and less exciting: cabbage-based soups are very low in calories and high in fiber, which promotes a feeling of fullness. Any weight loss comes from eating far fewer calories than your body needs, not from a special fat-burning property in cabbage.
There is no scientific evidence that cabbage water boosts your metabolism. Drinking it won’t accelerate fat loss on its own. If you enjoy it as part of a balanced eating pattern, the low calorie count is a genuine advantage. But treating it as a weight loss tool sets up unrealistic expectations.
Cholesterol and Heart Health
Red cabbage in particular contains pigments called anthocyanins that have shown promise for lipid health. Animal studies have found that red cabbage extract can act as a cholesterol-lowering agent, reducing total cholesterol and LDL (“bad” cholesterol) levels in rats exposed to toxic substances that disrupt fat metabolism. Multiple studies have recorded reductions in triglycerides, total cholesterol, and LDL when red cabbage was part of the treatment.
These are animal studies, so translating results directly to humans requires caution. Still, the direction of the evidence is consistent: the compounds in cabbage, many of which dissolve into cooking water, tend to support healthier blood lipid profiles rather than harm them.
Fermented Cabbage Water Is a Different Drink
There’s an important distinction between plain boiled cabbage water and the brine from fermented cabbage (sauerkraut juice or “rejuvelac”). Fermented cabbage liquid is alive with beneficial bacteria. The dominant species include Lactobacillus and Leuconostoc, both well-known probiotic genera. Sauerkraut fermentation establishes a stable microbial community quickly, and the liquid carries a high concentration of these organisms along with organic acids they produce.
If you’re looking for gut health benefits specifically, fermented cabbage water is the better choice. Plain boiled cabbage water has no probiotic content because the heat kills any bacteria present. The two liquids share some of the same plant-derived nutrients, but fermented brine adds a living microbial dimension that boiled water simply can’t offer. Sauerkraut juice can be strong on the stomach if you’re not used to fermented foods, so starting with a few tablespoons and working up is a reasonable approach.
Thyroid Concerns Are Mostly Overblown
Cabbage belongs to the brassica family, which contains compounds called glucosinolates that can theoretically interfere with thyroid function. This concern circulates widely online, but the evidence is reassuring. A comprehensive systematic review concluded that brassica vegetables are safe for thyroid function, especially when iodine intake is adequate. One of the earliest studies on the topic found that cabbage consumption did not cause significant antithyroid activity.
Cooking actually reduces the risk further. Heat deactivates an enzyme called myrosinase that would otherwise convert glucosinolates into their more potent breakdown products. Since cabbage water is made by boiling, the liquid you drink has gone through exactly the process that minimizes any thyroid concern. The only scenario where caution applies is eating very large amounts of raw cruciferous vegetables while also having low iodine intake.
How to Use It
The simplest approach is to save your cabbage cooking water and use it as a base for soups, stews, or cooking grains like rice or quinoa. This captures the leached nutrients without requiring you to drink a warm, mildly flavored liquid on its own. Some people do drink it straight, sometimes with a squeeze of lemon or a pinch of salt, and that’s fine too. It keeps in the refrigerator for about three to four days.
For a more nutrient-dense version, use red cabbage instead of green. The deeper color reflects a higher concentration of anthocyanins, the same pigments linked to cholesterol-lowering effects in animal studies. You’ll end up with a striking purple liquid that works well as a soup base or even a natural food coloring. Just be aware that the flavor is mild and slightly sweet, so it pairs better with savory dishes than you might expect.