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Walnuts benefits start with their unusual fat profile. English walnuts are the only common tree nut with a large amount of alpha-linolenic acid (ALA), the plant omega-3 fat: about 2.57 grams per ounce, more than the official Adequate Intake for adults in a single serving. They also supply copper, manganese, fiber and protein. In controlled trials, diets that include walnuts lowered LDL cholesterol modestly compared with diets without them, while a large two-year trial in older adults found no overall effect on memory and thinking. Here is the USDA nutrition data, how walnuts compare with other nuts and seeds, and what the research does and does not show.
Peptide Labs does not sell walnuts. The black walnut hull supplements in our store are a different product made from the outer hull, not the nut. This article is general nutrition information, not medical advice.
Key Takeaways
- A 1-ounce serving of English walnuts (about 14 halves) has about 185 calories and 2.57 grams of ALA.
- No other common nut comes close on ALA; pecans, the runner-up, have about a tenth as much.
- Your body converts only a small share of ALA into EPA and DHA, the omega-3s found in fish.
- A 2018 meta-analysis of 26 trials found walnut diets lowered LDL cholesterol by about 3.7% versus control.
- Walnuts are a tree nut allergen, and their calories add up quickly if they are added on top of a diet.
Walnut nutrition facts: USDA chart
The values below are from the USDA FoodData Central SR Legacy entry for English walnuts (FDC ID 170187), converted to the 1-ounce serving USDA lists as about 14 halves. The percent Daily Value (%DV) uses the FDA Daily Values for food labels.
| Nutrient | Per 1 oz (28 g, about 14 halves) | % Daily Value |
|---|---|---|
| Calories | 185 | n/a |
| Protein | 4.3 g | 9% |
| Total fat | 18.5 g | 24% |
| Saturated fat | 1.7 g | 9% |
| Polyunsaturated fat | 13.4 g | n/a |
| ALA (plant omega-3) | 2.57 g | no DV |
| Carbohydrate | 3.9 g | n/a |
| Fiber | 1.9 g | 7% |
| Copper | 0.45 milligrams | 50% |
| Manganese | 0.97 milligrams | 42% |
| Magnesium | 45 milligrams | 11% |
| Phosphorus | 98 milligrams | 8% |
| Zinc | 0.9 milligrams | 8% |
| Iron | 0.8 milligrams | 5% |
Walnut calories are similar to other nuts: about 185 per ounce. What sets English walnuts apart is that most of their fat is polyunsaturated, about 13.4 of the 18.5 grams, and a large share of that is ALA. They are also low in carbohydrate and sugar, and they provide half the Daily Value for copper per serving.
ALA in walnuts compared with other nuts and seeds
The NIH Office of Dietary Supplements (ODS) explains that ALA is the only omega-3 fat that is essential, meaning the body cannot make it, which is why the Adequate Intake (AI) is set for ALA: 1.6 grams a day for men and 1.1 grams for women. The USDA figures below show why walnuts appear on every list of plant omega-3 sources.
| Food (USDA description, shortened) | Serving | ALA, grams |
|---|---|---|
| Chia seeds, dried | 1 oz (28 g) | 5.05 |
| Walnuts, English | 1 oz (28 g) | 2.57 |
| Flaxseed, whole | 1 tbsp (10 g) | 2.35 |
| Walnuts, black, dried | 1 oz (28 g) | 0.76 |
| Pecans | 1 oz (28 g) | 0.28 |
| Pistachios, raw | 1 oz (28 g) | 0.08 |
| Macadamia nuts, raw | 1 oz (28 g) | 0.06 |
| Hazelnuts | 1 oz (28 g) | 0.02 |
| Cashews, raw | 1 oz (28 g) | 0.02 |
| Brazil nuts, dried | 1 oz (28 g) | 0.01 |
| Almonds | 1 oz (28 g) | 0.00 |
One caveat matters. ODS says the body converts ALA into EPA and then DHA only to a very limited extent, with reported rates below 15%, so walnuts are not a stand-in for fish when it comes to those two fats. Our omega-3 guide covers EPA and DHA, and our comparison of krill oil and fish oil covers supplement forms. For other plant sources, see our guides to chia seeds and flaxseed.
Walnuts benefits: what the research shows
Most studies of the health benefits of walnuts look at blood lipids, and the results are consistent but modest. A 2018 meta-analysis in the American Journal of Clinical Nutrition pooled 26 controlled trials with 1,059 participants. Compared with control diets, walnut-enriched diets lowered total cholesterol by about 3.3% more and LDL cholesterol by about 3.7% more, and also reduced triglycerides and apolipoprotein B. Walnut diets did not lead to a significant difference in body weight or blood pressure.
The largest single trial is the Walnuts and Healthy Aging (WAHA) study, which randomly assigned 708 healthy adults aged 63 to 79 in Spain and California to a diet with walnuts making up about 15% of calories or a diet without walnuts for two years. In the 2021 lipid report in Circulation, LDL cholesterol was about 3.6% lower and the number of LDL particles about 4.3% lower in the walnut group. The 2020 cognition report found no difference between groups in overall memory and thinking scores; the authors called some subgroup findings encouraging but inconclusive. WAHA was funded in part by the California Walnut Commission, which is worth knowing when you read headlines about it.
FDA has allowed a qualified health claim for walnuts and heart disease since 2004. The required wording begins “Supportive but not conclusive research shows” and ties the claim to a diet low in saturated fat and cholesterol that does not increase total calories. In other words, the agency regards the evidence as promising, not proven, and assumes walnuts replace other calories rather than adding to them.
English walnuts vs other walnuts
Nearly all walnuts sold for snacking and baking are English, or Persian, walnuts (Juglans regia). Eastern black walnuts are a separate North American species with a stronger flavor. USDA lists them with more protein, about 6.8 grams per ounce, but far less ALA, about 0.76 grams. The supplements sold as black walnut hull capsules or tinctures are made from the green outer hull, not the nut you eat, and the evidence and safety questions are different; our black walnut guide covers them. Curious how walnuts compare with a very different nut? Our Brazil nuts guide explains why that one is all about selenium.
Calories, allergies and other cautions
- Tree nut allergy: FDA lists English walnut, black walnut and several other walnut species among the tree nuts it considers major food allergens, so they must be declared on packaged food labels. Anyone with a known nut allergy should follow their allergist’s advice.
- Calories: about 185 per ounce. The trials above swapped walnuts in for other foods; adding them on top of an unchanged diet is a different experiment.
- Small children: whole nuts are a choking hazard for young kids, so chopped or ground walnuts are the safer way to include them.
- Supplements are not walnuts: walnut oil, walnut extracts and black walnut hull products have their own labels and their own evidence. Check for an independent seal with our third-party testing guide.
If you follow a plant-based diet or eat very little on a GLP-1 medicine, nuts are an easy way to add protein, fiber and healthy fats in a small volume; see our list of high protein foods for more options.
Frequently Asked Questions
What are the main walnuts benefits?
Walnuts supply ALA, the plant omega-3, plus copper, manganese, fiber and protein. Controlled trials show walnut diets modestly lower LDL cholesterol compared with control diets.
How many calories are in walnuts?
About 185 calories per ounce, or roughly 14 halves, in USDA data, similar to most other nuts.
Are walnuts a good source of omega-3?
They are the richest common nut source of ALA, at about 2.57 grams per ounce. The body converts only a small share of ALA into EPA and DHA, the omega-3s in fish.
Do walnuts help memory or brain health?
The two-year WAHA trial in 708 older adults found no overall difference in cognition between the walnut and control groups. Some subgroup results were called inconclusive by the authors.
What is the difference between English walnuts and black walnuts?
They are different species. English walnuts are the common grocery nut and are much higher in ALA; black walnuts have more protein and a stronger flavor. Black walnut hull supplements are a separate product.
Do walnuts cause weight gain?
In a 2018 meta-analysis of controlled trials, walnut diets did not lead to a significant difference in body weight, but those trials generally replaced other foods rather than adding walnuts on top.
Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or are shopping for a child. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Omega-3: Benefits, Foods, Side Effects and Heart Research, Brazil Nuts: Selenium per Nut, Nutrition Facts and the Upper Limit, Almonds Benefits: USDA Nutrition per Ounce, Calories and Research.