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Kelp Seaweed Nutrition Facts: Is Kelp Seaweed Good for You?
Raw kelp seaweed provides several key minerals and vitamins for very few calories. A 100-gram serving is high in folate, vitamin K, and magnesium, and is a good source of iron, calcium, and zinc. It is low in fat and sugar but contains some sodium. Whether it’s a healthy choice depends on your portion size and what the rest of your diet looks like, as with any single food.
Per 100 g · Seaweed, kelp, raw
What stands out in kelp seaweed
- High in folate. A 100-gram serving of raw kelp provides 180 mcg of folate, which is 45% of the Daily Value (DV).
- High in vitamin K. Raw kelp contains 66 mcg of vitamin K per 100 grams. This amount supplies 55% of the Daily Value.
- Source of key minerals. This seaweed is high in magnesium (29% DV) and a good source of iron (16% DV), calcium (13% DV), zinc (11% DV), and copper (14% DV) per 100 grams.
- Low in calories and fat. Per 100 grams, raw kelp has 43 calories, about 1 gram of total fat, and less than 1 gram of sugar.
What to keep in mind
- Raw kelp contains 233 mg of sodium per 100 grams, which is 10% of the Daily Value.
- While it provides some fiber, the 1.3 grams per serving is less than many other vegetables.
Kelp Seaweed nutrition facts per 100 g
| Nutrient | Per 100 g | % DV |
|---|---|---|
| Calories | 43 kcal | – |
| Protein | 1.7 g | 3% |
| Total fat | 0.56 g | 1% |
| Saturated fat | 0.25 g | 1% |
| Monounsaturated fat | 0.1 g | – |
| Polyunsaturated fat | 0.05 g | – |
| Cholesterol | 0 mg | 0% |
| Carbohydrate | 9.6 g | 3% |
| Dietary fiber | 1.3 g | 5% |
| Total sugars | 0.6 g | – |
| Water | 81.6 g | – |
| Sodium | 233 mg | 10% |
| Nutrient | Per 100 g | % DV |
|---|---|---|
| Potassium | 89 mg | 2% |
| Calcium | 168 mg | 13% |
| Iron | 2.9 mg | 16% |
| Magnesium | 121 mg | 29% |
| Phosphorus | 42 mg | 3% |
| Zinc | 1.2 mg | 11% |
| Copper | 0.13 mg | 14% |
| Manganese | 0.2 mg | 9% |
| Selenium | 0.7 mcg | 1% |
| Vitamin A (RAE) | 6 mcg | 1% |
| Vitamin C | 3 mg | 3% |
| Vitamin D | 0 mcg | 0% |
| Vitamin E | 0.87 mg | 6% |
| Vitamin K | 66 mcg | 55% |
| Thiamin (B1) | 0.05 mg | 4% |
| Riboflavin (B2) | 0.15 mg | 12% |
| Niacin (B3) | 0.47 mg | 3% |
| Vitamin B6 | 0 mg | 0% |
| Folate (DFE) | 180 mcg | 45% |
| Vitamin B12 | 0 mcg | 0% |
| Choline | 12.8 mg | 2% |
% Daily Value uses the FDA Daily Values for adults and children 4 years and older. Highlighted rows are 20% DV or more per 100 g. A dash means no Daily Value is set.
Kelp Seaweed by portion
The nutrition data is based on a 100-gram (about 3.5 ounce) serving. A more common portion size listed by the USDA is 2 tablespoons, which weighs 10 grams. This portion of raw kelp has 4 calories, 1 gram of carbohydrate, and less than 1 gram each of protein, fat, fiber, and sugar.
| USDA portion | Weight | Calories | Protein | Carbs | Fiber | Fat |
|---|---|---|---|---|---|---|
| 2 tbsp (1/8 cup) | 10 g | 4 | 0.2 g | 1 g | 0.1 g | 0.1 g |
How kelp seaweed compares with other vegetables
With 43 calories per 100 grams, raw kelp is calorically similar to other vegetables like beets, Brussels sprouts, and carrots. Among the 38 vegetables in its group on this site, kelp ranks first for its content of sodium, iron, magnesium, and zinc. It also ranks very high for folate (second) and calcium (fourth). On the other hand, it ranks last for potassium and is lower in dietary fiber and vitamin C than most other vegetables in the group.
| Per 100 g | Calories | Protein | Carbs | Fiber | Fat |
|---|---|---|---|---|---|
| Kelp Seaweed | 43 | 1.7 g | 9.6 g | 1.3 g | 0.56 g |
| Beets | 43 | 1.6 g | 9.6 g | 2.8 g | 0.17 g |
| Brussels Sprouts | 43 | 3.4 g | 8.9 g | 3.8 g | 0.3 g |
| Butternut Squash | 45 | 1 g | 11.7 g | 2 g | 0.1 g |
| Carrots | 41 | 0.93 g | 9.6 g | 2.8 g | 0.24 g |
Quick answers
How many calories are in kelp?
A 100-gram serving of raw kelp has 43 calories. A smaller 2-tablespoon serving has 4 calories.
How much protein is in kelp?
Raw kelp contains 1.7 grams of protein per 100 grams. A 2-tablespoon serving provides about 0.2 grams of protein.
How many carbs and how much sugar is in kelp?
A 100-gram serving of raw kelp has 9.6 grams of carbohydrates, which includes 1.3 grams of fiber and 0.6 grams of total sugars. A 2-tablespoon serving has 1 gram of carbohydrates and 0.1 grams of sugar.
When to talk to a doctor or dietitian
- It supplies 66 mcg of vitamin K per 100 g. If you take warfarin, the usual advice is to keep vitamin K intake steady rather than avoid these foods, so talk to your care team before making big changes.
- Seaweed and algae products can vary a lot in iodine and other minerals. If you have a thyroid condition, ask your doctor before eating them often.
- This page describes nutrient content, not medical advice. If a health condition, medicine or pregnancy affects what you eat, a doctor or registered dietitian can tell you how kelp seaweed fits your situation.
Last updated October 21, 2026