Peanuts and walnuts: protein on one side, omega-3 on the other

A meta-analysis of 25 randomized trials in 2155 adults found walnuts lowered apolipoprotein B by a small amount (weighted mean difference -0.06, 95% CI -0.10 to -0.01) and did not change blood pressure. In a review of trials in adults with prediabetes, 2 oz (56 g) of walnuts a day for 6 months did not change fasting glucose or HbA1c, and that rests on one walnut trial. Peanuts have a single trial of their own here. In 61 older adults with obesity, high oleic peanuts at 15 to 20 percent of energy for 12 weeks left lipids, glucose and CRP unchanged, and weight rose by under 1.1 lb (0.5 kg). We found no trial that put peanuts and walnuts side by side. The tree nut network meta-analysis that ranked walnuts second for lowering triglycerides and total cholesterol left peanuts out, and its evidence was rated low quality. The clear difference is in the nut itself. Per 100 g raw, USDA measured 23.2 g protein and 8.0 g fiber in peanuts against 14.6 g and 5.2 g in walnuts. Walnuts held 69.7 g fat, 49.3 g of it polyunsaturated, and UK tables give them 7.47 g omega-3 per 3.5 oz (100 g) against 0.35 g in peanuts.

How much is actually in it

• USDA analyzed samples show raw peanuts carry more protein (23.2 g) and fiber (8.0 g) per 3.5 oz (100 g), while raw walnuts carry more fat (69.7 g), most of it polyunsaturated (49.3 g). — USDA Foundation Foods, 8 analyzed samples each of raw peanuts and raw English walnut halves (n = 8 samples each) Evidence E source
  Peanuts: protein 23.2 g (21.2-24.5), fat 43.3 g (38.7-48.5), fiber 8.0 g, Mg 179.7 mg; walnuts: protein 14.6 g (12.9-16.3), fat 69.7 g (67.5-71.4), PUFA 49.3 g, fiber 5.2 g, Mg 142.4 mg
• In UK composition tables walnuts give 7.47 g of omega-3 per 3.5 oz (100 g) against 0.35 g in peanuts, while peanuts give more vitamin E (10.1 vs 3.9 mg). — CoFID 2021 codes 14-877 (peanuts, kernel only, plain) and 14-879 (walnuts, kernel only) Evidence E source
  Energy 564 vs 688 calories; fat 46.0 vs 68.5 g; protein 25.8 vs 14.7 g; n-3 0.35 vs 7.47 g; vitamin E 10.09 vs 3.85 mg; Mg 210 vs 160 mg per 3.5 oz (100 g)

What a real portion looks like

• A one-ounce (28 g) serving of walnuts gives about 207 calories, while roasted peanuts give 599 calories per 3.5 oz (100 g), about 168 calories for the same 28 g. — US survey foods, FNDDS 42116000 walnuts and 42111110 roasted unsalted peanuts Evidence E source
  Walnuts 730 calories/100 g, 1 oz 28 g 207 calories; peanuts 599 calories/100 g, 1 cup 146 g 874.5 calories

What your body absorbs

• The plant omega-3 in walnuts (ALA) is poorly converted to DHA: seven intervention studies found no conversion from nut and seed oils. — 10 intervention studies of vegetarian omega-3 sources (n = 10 studies) Evidence C source
  7 of 10 studies: ALA from nut and seed oils not converted to DHA

What cooking and storage change

• Human and lab studies show the body takes up less energy from walnuts and peanuts than label factors predict, and nut butter releases more than roasted, which releases more than raw. — 21 human and in vitro studies of almonds, cashews, hazelnuts, pistachios, walnuts and peanuts (n = 21 studies) Evidence C source
  Metabolizable energy below Atwater prediction for all nut types; release butter > roasted > raw, flour > chopped > whole

What it does to your health

• A meta-analysis of 25 RCTs in 2155 people found walnuts lowered apolipoprotein B slightly (WMD -0.06) but did not change blood pressure. — adults in 25 randomized trials (26 arms), 1997-2020, mostly USA and Spain (n = 2155) Evidence A source
  ApoB WMD -0.06 (95% CI -0.10 to -0.01); SBP -1.20 (-4.02 to 1.61) and DBP -0.44 (-2.55 to 1.67), not significant
• In a 12-week crossover RCT in 61 older adults with obesity, high oleic peanuts at 15-20% of energy did not change blood lipids, glucose or CRP, and weight rose by under 1.1 lb (0.5 kg). — 61 healthy adults, mean age 65, BMI 31, 12-week phases (n = 61) Evidence B source
  No difference in lipids, CRP, glucose, insulin; energy intake +853 kJ/day; weight gain below 1.1 lb (0.5 kg)
• In a systematic review of RCTs in adults with prediabetes, 2 oz (56 g) of walnuts a day for 6 months did not change fasting glucose or HbA1c. — adults with prediabetes or at risk of diabetes, 5 RCTs (n = 371) Evidence B source
  Walnuts 56 g/d for 6 months: no effect on FPG or HbA1c; pistachios 57 g/d and almonds 60 g/d improved FPG

Safety, limits and interactions

• The FDA-approved levothyroxine label names walnuts among foods that may bind the drug and lower its absorption. Peanuts are not named. — people taking levothyroxine Evidence E source
  Possible reduced levothyroxine absorption with walnuts
• Observational data pool shows children first given peanut after 12 months of age had higher odds of food allergy (OR 2.55). — children under 6, 190 studies, 2.8 million participants, 40 countries (n = 2.8 million) Evidence C source
  Delayed peanut introduction after 12 months: OR 2.55, risk difference 6.8% (95% CI 1.9%-14.6%)

What people believe that the data does not support

• The EU rejected the claim that about 1.1 oz (30 g) of peanuts a day helps achieve healthy cholesterol levels and heart health. — EU health claims regulation Evidence E source
  Claim status: non-authorized
• The EU also rejected the general claim that walnuts support cardiovascular health. — EU health claims regulation Evidence E source
  Claim status: non-authorized

Who this works differently for

• A USDA review found no link between eating peanuts in early and mid pregnancy and allergic rhinitis in the child in a US cohort. — US cohort, baseline n=2128, maternal diet in pregnancy (n = 2128) Evidence C source
  No association between maternal peanut intake in trimesters 1-2 and child allergic rhinitis
• In people with chronic kidney disease, a small review found walnuts lowered LDL cholesterol and blood pressure without upsetting electrolyte balance. — 4 studies (3 trials, 1 cohort) in 1270 CKD patients (n = 1270) Evidence C source
  Walnuts: lower LDL-C and blood pressure, no electrolyte risk; effect sizes not given in abstract

What is still unknown

• A network meta-analysis of 34 trials in 1677 people ranked walnut-enriched diets second best among five tree nuts for lowering triglycerides and total cholesterol, but it did not include peanuts. — adults in 34 randomized trials comparing walnut, pistachio, hazelnut, cashew, almond and control diets (n = 1677) Evidence A source
  Walnut ranked 2nd for TG and TC; pistachio 1st (SUCRA 85% TG, 87% LDL, 96% TC); low quality of evidence

The bottom line

Walnut omega-3 is ALA, the plant form. In seven of ten intervention studies of nut and seed oils, ALA was not converted to DHA at all, and those studies used oils rather than whole walnuts. Peanuts give more vitamin E in UK tables, 10.1 against 3.9 mg per 3.5 oz (100 g). A one-ounce, 0.99 oz (28 g) serving of walnuts gives about 207 calories in the US survey database. The same weight of roasted peanuts comes to about 168 calories, our arithmetic from 599 calories per 3.5 oz (100 g). Across 21 human and lab studies of six nuts, walnuts and peanuts among them, the energy the body took up came in below the label factors. Nut butter released more than roasted nuts, which released more than raw. The EU refused the claim that about 1.1 oz (30 g) of peanuts a day helps achieve healthy cholesterol levels and heart health. It also refused the general claim that walnuts support cardiovascular health. A refusal means the dossier fell short at assessment, and it is not proof of no effect. A narrower walnut claim on blood vessel elasticity is authorized, and we did not pull its conditions of use. Who should be careful. If you take levothyroxine, its FDA-approved label names walnuts among foods that may bind the drug and lower its absorption, with no measured size. Peanuts are not named. For babies, observational data from 190 studies and 2.8 million children link a first taste of peanut after 12 months with higher odds of food allergy (odds ratio 2.55, risk difference 6.8%, 95% CI 1.9% to 14.6%). That is an association from observational studies, and it does not say how, in what form or for which babies a first taste is safe. We have no card on that, and this figure is not a guide to feeding a baby. A US cohort of 2128 found no link between peanuts eaten in the first two trimesters of pregnancy and allergic rhinitis in the child, and breastfeeding was not studied. In chronic kidney disease, a review of four studies in 1270 patients reported that walnuts lowered LDL cholesterol and blood pressure without upsetting electrolytes. It gave no effect sizes, and every study had a moderate to high risk of bias. We have no card on how common peanut or walnut allergy is in adults or how severe the reactions are, and that gap is not reassurance. Walnuts carry the plant omega-3. Peanuts carry more protein and fiber.

Sources

1. pnwl-r5-07 · reference dataset
   Peanuts, raw: Protein 23.205 g, range 21.1848-24.4608 · Total lipid (fat) 43.28 g, range 38.68-48.52, n=8 · Fiber 8.014 g · Magnesium 179.7 mg. Nuts, walnuts, English, halves, raw: Protein 14.5644 g, range 12.932-16.324 · Total lipid (fat) 69.74 g, range 67.49-71.43, n=8 · PUFA 49.331 g · Fiber 5.21 g · Magnesium 142.4 mg
   USDA FoodData Central Foundation Foods, release 2026-04-30 · checked 2026-09-28
2. pnwl-r5-08 · reference dataset
   CoFID 14-877 Peanuts, kernel only, plain, unsalted: Energy 564 kcal, Fat 46.0 g, Protein 25.8 g, n-3 poly 0.35 g, Vitamin E 10.09 mg, Magnesium 210 mg · CoFID 14-879 Walnuts, kernel only: Energy 688 kcal, Fat 68.5 g, Protein 14.7 g, n-3 poly 7.47 g, Vitamin E 3.85 mg, Magnesium 160 mg
   CoFID 2021, Public Health England, OGL v3.0 · checked 2026-09-28
3. pnwl-r5-09 · reference dataset
   FNDDS 2707531 Walnuts, excluding honey roasted: Energy 730 kcal/100 g, 1 oz 28 g 207.0 kcal · FNDDS 2707516 Peanuts, roasted, unsalted: Energy 599 kcal/100 g, 1 cup without shell 146 g 874.5 kcal
   USDA FNDDS 2021-2023 · checked 2026-09-28
4. pnwl-r5-06 · systematic review
   Ten key papers published over the last 10 years were identified with seven intervention studies reporting that ALA from nut and seed oils was not converted to DHA at all.
   Crit Rev Food Sci Nutr, 2014 · checked 2026-09-28
5. pnwl-r5-05 · systematic review
   The ME of nuts was consistently lower than that predicted by Atwater factors for investigated nut types (almonds, cashews, hazelnuts, pistachios, walnuts, and peanuts). ... ME was influenced by nut type (ME = 22.6 kJ/g for pistachios; ME = 18.5 kJ/g for raw almonds), physical form (flour > chopped > whole nuts), heat processing (butter > roasted > raw) and dose of consumption.
   Adv Nutr, 2023 · checked 2026-09-28
6. pnwl-r5-01 · meta-analysis of RCTs
   Twenty-five RCTs comprising 26 intervention arms with 2155 patients were included. Walnut significantly decreased ApoB (WMD = -0.06; 95% CI: -0.10, -0.01, p = 0.002), but did not affect ApoA1 (WMD = -0.50; 95% CI: -1.34, 0.33, p = 0.249), systolic blood pressure (SBP) (WMD = -1.20; 95% CI: -4.02, 1.61, p = 0.401) and diastolic blood pressure (DBP) (WMD = -0.44; 95% CI: -2.55, 1.67, p = 0.682).
   Endocrinol Diabetes Metab, 2026 · checked 2026-09-28
7. pnwl-r5-03 · randomized crossover trial
   In a randomised cross-over design, 61 healthy subjects (65 ± 7 years, body mass index (BMI) 31 ± 4 kg/m²) alternated either high oleic peanuts (15%-20% of energy) or a nut free diet for 12 weeks. ... Consistent with other nut studies, there were no differences in lipids, CRP, glucose and insulin with peanut consumption.
   Nutrients, 2015 · checked 2026-09-28
8. pnwl-r5-04 · systematic review of RCTs
   We included five RCT involving 371 adults with prediabetes or at risk of diabetes; three RCT investigated the effects of whole nut consumption and two the effects of ground flaxseed consumption. ... Consumption of 56 g/d walnuts for 6 months was not found to affect FPG or HbA1c concentrations.
   Br J Nutr, 2019 · checked 2026-09-28
9. pnwl-r5-12 · drug label
   Soybean flour, cottonseed meal, walnuts, and dietary fiber may bind and decrease the absorption of levothyroxine sodium from the gastrointestinal tract.
   Levothyroxine sodium prescribing information, DailyMed, effective 2026-03-24 · checked 2026-09-28
10. pnwl-r5-13 · meta-analysis of observational studies
    delayed solid food introduction (eg, peanut after age 12 months [OR, 2.55; RD, 6.8%; 95% CI, 1.9%-14.6%])
    JAMA Pediatr, 2026 · checked 2026-09-28
11. pnwl-r5-10 · regulatory decision
    POL-HC-7733 Peanuts, Peanut butter, Peanut oil Consuming a small handful, about 30 grams, of peanuts a day as part of a diet low in saturated fat helps to achieve healthy cholesterol levels and promotes heart health. Consuming two tablespoons, about 30g, of peanut butter a day as part of a diet low in saturated fat helps to achieve healthy cholesterol levels and promotes heart health. Consuming two tablespoons, about 30 grams of peanut oil a day as part of a diet low in saturated fat helps to achieve healthy cholesterol levels and promotes heart health. Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-7733, snapshot 2026-09-21 · checked 2026-09-28
12. pnwl-r5-11 · regulatory decision
    POL-HC-8134 Walnuts Walnuts support cardiovascular health. Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-8134, snapshot 2026-09-21 · checked 2026-09-28
13. pnwl-r5-14 · systematic review (agency)
    The U.S.-based cohort study showed no association between maternal peanut consumption during the first and second trimesters and allergic rhinitis risk.
    USDA NESR 2020, Maternal Diet during Pregnancy and Lactation and Risk of Child Food Allergies and Atopic Allergic Diseases · checked 2026-09-28
14. pnwl-r5-15 · systematic review
    Results: The search identified 2,521 records, with four studies (three trials, one cohort) involving 1,270 CKD patients meeting the inclusion criteria. ... walnuts reduced LDL cholesterol and blood pressure while posing no risk regarding electrolytes balance.
    Front Nutr, 2025 · checked 2026-09-28
15. pnwl-r5-02 · network meta-analysis
    Thirty-four trials enrolling 1677 participants were included in this study. The pistachio-enriched diet was ranked best for TG (SUCRA: 85%), LDL cholesterol (SUCRA: 87%), and TC (SUCRA: 96%) reductions. For TG and TC reductions, the walnut-enriched diet was ranked as the second-best diet.
    Am J Clin Nutr, 2020 · checked 2026-09-28