Steelhead trout: a fatty fish with few trials of its own

The best trout trial is about cholesterol in people who already had too much. In a randomized open-label trial in people with hyperlipidemia, eating trout for 8 weeks lowered LDL cholesterol by 22.75 mg/dL, while the group given fish oil capsules saw it rise by 18.7 mg/dL, with 95 of the 106 people randomized analyzed. Nobody was blinded, and nobody had normal lipids, so it says nothing yet about healthy eaters. The nutrient numbers are clearer. USDA lists baked or broiled trout at 216 calories, 24.8 g protein, 19.8 micrograms of vitamin D and 0.91 g of EPA plus DHA per 3.5 oz (100 g). That is one figure for trout of unnamed species, with wild and farmed fish not separated. A regular 90 g fillet comes to about 22 g protein, 17.8 micrograms of vitamin D and 0.8 g of EPA plus DHA. The NIH Office of Dietary Supplements lists fatty fish such as trout among the best food sources of vitamin D.

The numbers, per 3.5 oz (100 g)

How much is actually in it

• Baked or broiled trout provides 216 calories, 24.8 g protein, 19.8 mcg vitamin D, 4.81 mcg vitamin B12, 29.3 mcg selenium and 0.91 g EPA plus DHA per 3.5 oz (100 g). — — Evidence E source
  Per 100 g: 216 calories; protein 24.78 g; vitamin D 19.8 ug; B12 4.81 ug; selenium 29.3 ug; EPA 0.27 g; DHA 0.641 g
• According to the NIH Office of Dietary Supplements, the flesh of fatty fish such as trout is among the best food sources of vitamin D. — — Evidence E source
  —

What a real portion looks like

• A regular 90 g trout fillet supplies about 22 g protein, 17.8 mcg vitamin D and 0.8 g EPA plus DHA. — — Evidence E source
  Per 90 g fillet: protein 22.3 g; vitamin D 17.8 ug; EPA 0.2 g + DHA 0.6 g; large fillet 135 g

What your body absorbs

• In a stable-isotope RCT in 35 men, selenium from trout was absorbed as well as selenate and retained better, and cooking did not change absorption or retention. — 35 male volunteers aged 18-50 y, four labeled meals over two days (n = 35) Evidence B source
  Apparent absorption fish = selenate; retention fish > selenate (P<0.001); no difference between processing methods

What it does to your health

• In an 8-week crossover RCT in 44 obese adults, a diet built on fruit, avocado, whole grains and trout lowered fasting insulin, VLDL and HOMA-IR versus a high saturated fat diet. — 44 obese Colombians with BMI 30 or above, 8 weeks per diet (n = 44) Evidence B source
  Fasting insulin, VLDL and HOMA-IR reduced (p < 0.05); size not given in abstract
• In the same 8-week crossover RCT in 44 obese adults, the fruit, avocado, whole grain and trout diet reduced postprandial expression of inflammatory genes NFKB1, IL6 and IL1B. — 44 obese Colombians with BMI 30 or above, 8 weeks (n = 44) Evidence B source
  Lower expression of NFKB1, IL6, IL1B and NFE2L2 vs usual diet (size not in abstract)
• In an 8-week RCT in 30 men aged 40-70, a daily trout meal changed 23 of 681 plasma protein spots, whether the trout was marine- or vegetable-fed. — thirty healthy men aged 40 to 70 years, daily meal for 8 weeks (n = 30) Evidence B source
  23/681 spots changed (P < 0.05, q < 0.30); only one spot differed between the two trout groups

Safety, limits and interactions

• A case report describes a 19-year-old who developed a fish tapeworm infection with falling vitamin B12 two months after eating raw trout. — one 19-year-old male in Japan (n = 1) Evidence D source
  Tapeworm excretion at 2 months; B12 decreased, resolved after anthelmintic treatment

Who this works differently for

• In an 8-week RCT in 95 people with hyperlipidemia, LDL fell by 22.75 mg/dL in the trout group and rose by 18.7 mg/dL in the omega-3 capsule group. — patients with hyperlipidemia, 48 in fish oil group (2 g/day omega-3 capsules) and 47 in fish group (about 250 g trout twice weekly) analyzed, 8 weeks (n = 95) Evidence B source
  LDL +18.7 +/- 24.97 (capsules) vs -22.75 +/- 27.28 (trout), P < 0.001; HDL rise larger with trout

The bottom line

The selenium in trout is well used. In a stable-isotope trial in 35 men, selenium from trout was absorbed as well as selenate and retained better, and cooking the fish did not change either, though the abstract gives no percentages. Other trials put trout inside a larger diet, so they cannot single it out. In 44 obese adults in Colombia, 8 weeks of a diet built on fruit, avocado, whole grains and trout lowered fasting insulin, VLDL and insulin resistance compared with a high saturated fat diet, and it also lowered the activity of several inflammation genes after meals. Neither abstract reports how large the changes were. In 30 healthy men aged 40 to 70, a daily trout meal for 8 weeks shifted 23 of 681 plasma protein spots, a lab signal with no clinical outcome attached. Who should be careful. Eat trout cooked. A case report from Japan describes a 19-year-old who passed a fish tapeworm two months after eating raw trout, with vitamin B12 falling until he was treated. It is one case. We have no card on mercury, pregnancy, children or fish allergy for this fish, and no study of steelhead itself, wild or farmed.

Compared with other foods

Sources

1. sthd-daily-r4-01 · food composition dataset
   Fish, trout, baked or broiled, fdc_id 2706303: Energy 216 KCAL, Protein 24.78 G, Vitamin D (D2 + D3) 19.8 UG, Vitamin B-12 4.81 UG, Selenium, Se 29.3 UG, PUFA 20:5 n-3 (EPA) 0.27 G, PUFA 22:6 n-3 (DHA) 0.641 G per 100 g
   USDA FoodData Central survey (FNDDS) 2024-10-31, Fish, trout, baked or broiled, fdc_id 2706303 · checked 2026-10-02
2. sthd-daily-r4-03 · agency fact sheet
   The flesh of fatty fish (such as trout, salmon, tuna, and mackerel) and fish liver oils are among the best sources [17,1].
   NIH Office of Dietary Supplements, Vitamin D Fact Sheet for Health Professionals · checked 2026-10-02
3. sthd-daily-r4-02 · food portion dataset
   Fish, trout, baked or broiled, fdc_id 2706303: 1 small/regular fillet 90 g; 1 large fillet 135 g; 1 whole fish, any size 270 g
   USDA FoodData Central survey (FNDDS) 2024-10-31, Fish, trout, baked or broiled, fdc_id 2706303 · checked 2026-10-02
4. sthd-daily-r4-04 · randomized controlled trial
   Fish selenium is a highly bioavailable source of dietary selenium. Cooking did not affect selenium apparent absorption or retention from fish.
   Eur J Clin Nutr, 2004 · checked 2026-10-02
5. sthd-daily-r4-06 · randomized controlled trial
   The FAWGT diet reduced fasting insulin, VLDL, and HOMA-IR after 8 weeks (p < 0.05), while there was a lower postprandial increase in TG, VLDL, and insulin levels after both acute and chronic intake of FAWGT diet (p < 0.05).
   Nutrients, 2021 · checked 2026-10-02
6. sthd-daily-r4-07 · randomized controlled trial
   The intervention with a FAWGT diet decreased the expression of inflammatory (NFKB1, IL6, IL1β) and oxidative stress (NFE2L2) genes compared with the intake of the UD.
   Nutrients, 2023 · checked 2026-10-02
7. sthd-daily-r4-08 · randomized controlled trial
   We found 23/681 abundant plasma protein spots, which were up- or down-regulated by the dietary treatment (P < 0·05, q < 0·30), and eighteen of these were identified.
   Br J Nutr, 2015 · checked 2026-10-02
8. sthd-daily-r4-09 · case report
   The patient presented with tapeworm excretion at 2 months following raw trout fish consumption.
   J Infect Chemother, 2025 · checked 2026-10-02
9. sthd-daily-r4-05 · randomized controlled trial
   LDL level was increased in the supplementation group, while it was significantly reduced in the dietary-fish group (+18.7 ± 24.97 vs. -22.75 ± 27.28, P < 0.001).
   Nutr Diabetes, 2017 · checked 2026-10-02