10. Hemp seed oil
The ideal 3:1 omega-3:omega-6 — cannabidiol-free nutritional oil and gamma-linolenic acid source.
Hemp seed oil in 1 minute
What does it provide? One of the most favorable omega-6:3 ratios (~3:1)[1950] among plant oils, plus rare GLA and SDA. SDA converts to EPA more efficiently (~30%) than ALA (~5–8%) — placing hemp seed oil among the "intermediate" omega-3 sources.
How much? 1 tablespoon (15 mL) raw per day — drizzled on salad, into smoothies, on cottage cheese, on roasted vegetables.
When to avoid? Hemp allergy, acute pancreatitis, anticoagulant therapy (large doses), occupational drug-testing requirements (trace THC < 10 µg/g). DO NOT CONFUSE with CBD oil or marijuana oil — this is FOOD, not a cannabinoid extract.
Hemp (Cannabis sativa) is one of humanity's oldest useful plants: ceramics of the Chinese Yangshao culture (4000 BCE) preserve hemp seed traces, and the Shennong Bencao Jing (100 CE) mentions hemp seed oil under the name "má-zi" as a medicine — mainly against constipation. In Europe, hemp has been a millennial textile plant: a base material of Central European peasant farms in the Árpádian age (linen-hemp + flax) — rope, canvas, sail, paper.
In Hungary, the Szeged Hemp Mill (1877) is one of the oldest industrial hemp plants. The seeds were traditionally fed to animals (mainly birds) and pressed for oil — mainly in peasant farms in winter, for both lamp oil and food. From the mid-20th century the marijuana ban (1937 Marihuana Tax Act USA, 1961 UN Single Convention) pushed industrial hemp into the background; since the 1990s, more and more countries (Canada 1998, EU continuously) have re-authorized THC-free (< 0.2–0.3%) industrial hemp cultivation for food, industrial, and cosmetic use.[1953] Finnish-Canadian research in the 2000s (Callaway 2005, Journal of Dermatological Treatment) documented the benefit of hemp seed oil consumption for atopic dermatitis. The vegan-paleo-Mediterranean trend of the 2010s brought new demand — today hemp seed oil is one of the premium categories of high-omega-3 plant oils.
Scientific Background
The most robust clinical signal is for atopic dermatitis. Callaway et al. (2005) studied 20 atopic dermatitis patients for 20 weeks in a crossover design: 30 mL/day hemp seed oil consumption (vs. flaxseed oil control) significantly reduced skin dryness, itching, and lowered corticosteroid needs.[1947] The proposed mechanism is the GLA → dihomo-GLA → PGE1 pathway — PGE1 is an anti-inflammatory prostaglandin that improves skin barrier function.
Lipid-profile evidence comes from Schwab et al. (2006): 14 participants, 4+4 weeks crossover, 30 mL/day hemp seed oil → LDL and apoB decreased, HDL rose.[1948] Whelan (2009, J Nutr) discusses SDA (stearidonic acid) → EPA conversion in detail: ~30%, vs. ALA's ~5–8% conversion.[1949] This makes hemp seed oil a more effective EPA source than ALA-dominant flaxseed oil (and ordinary dietary omega-3 plant oils) — although it does not compete with fish oil and algae oil. GLA content is valuable, similar to blackcurrant oil and borage oil; there is evidence on premenstrual symptoms and atopic skin.[1951]
At the microbiome level there is no dedicated human RCT yet. Indirect evidence: the favorable omega-3/6 ratio reduces systemic inflammation (CRP, IL-6 markers), which can be indirectly microbiome-positive — chronic low-grade inflammation and dysbiosis are bidirectionally linked. Chlorophyll content gives in vitro antioxidant activity, but human significance is limited.
- + Salad dressing: hemp seed oil + balsamic vinegar + Dijon mustard + a pinch of salt → for green salad, tomato, cucumber.
- + Smoothie: 1 teaspoon into a spinach-banana-berry blend — chlorophyll and fat together aid absorption.
- + Cottage cheese, yogurt, kefir: hemp seed oil + fermented dairy = omega-3 + probiotic combination.
- + Cold-cooked pasta: hemp seed oil + grated Parmesan + parsley + garlic.
- + Roasted vegetables (drizzled on the plate, NOT in the oven): winter squash, broccoli, cauliflower.
- + Ground hemp seed + hemp seed oil: full package, complete seed matrix in flavor and nutrients.
- + Hemp pesto: basil + hemp seed oil + hemp seed + Parmesan + garlic.
- High-heat frying, cooking: categorical ban — smoke point ~165 °C, omega-3 (ALA, SDA) oxidize rapidly, like flaxseed oil.
- Opened bottle stored in light: rapid rancidity — hemp seed oil should be kept in the refrigerator, in dark glass, consumed within 3–4 weeks.
- As a CBD-oil / marijuana-oil substitute: categorically different product — hemp seed oil is food, CBD oil is a cannabinoid extract (drug-like). Always check that you're buying a "food grade" / "edible" labeled product.
- Stacked with other omega-6-rich oils (sunflower, sesame): hemp seed oil comes with a good ratio, but combined with sunflower the omega-6/3 advantage disappears.
- Hemp allergy (rare): absolute contraindication.
- Acute pancreatitis: avoid in the fat-restriction phase.
- Anticoagulant therapy (warfarin, DOACs): due to omega-3 effect, mild additive bleeding risk — high doses (> 30 mL/day) with medical consultation.
- Occupational drug-testing requirements (police, sport, security work): edible hemp seed oil may contain trace THC (< 10 µg/g); large quantities (multiple tbsp/day) could theoretically cause a positive test (rare but documented). Check employer policy.
- 2 weeks before planned surgery: stop high doses (omega-3 bleeding risk).
- Severe biliary obstruction: fat malabsorption issue.
Daily serving: 1 tablespoon (≈ 15 mL) raw — half of the clinically used 30 mL Callaway dose, matching daily dietary level.
Preparation pattern:
- Never heat directly — always drizzle on cold food or on the warm finished dish.
- For salad dressing: 1 tbsp hemp seed oil + 1 tbsp balsamic vinegar + ½ tsp Dijon mustard + a pinch of salt → shake together.
- Into smoothies: 1 teaspoon at the end of blending so chlorophyll and omega-3 don't emulsify apart.
Classic patterns:
- Green salad dressing: hemp seed oil + balsamic vinegar + mustard
- Cottage cheese + hemp seed oil + herbs: Austrian-Central European peasant breakfast with an omega-3 plus
- Hemp pesto: basil + hemp seed oil + hemp seed + Parmesan + garlic
- Hummus + hemp seed oil: drizzled on top
- Winter squash bowl + hemp seed oil: roasted squash + oil + garlic + pumpkin seeds
- Smoothie: spinach + banana + berries + 1 tsp hemp seed oil
Storage: in the refrigerator, in dark glass, sealed. Consume within 3–4 weeks of opening. Rancid taste (fish-like, sharp) means discard.
Buying: "edible" / "food grade" / "cold-pressed" / organic / dark glass / small package (250 mL) / pressing date on the label. Reliable sources: Canadian, Dutch, French, Central European organic producers.
What not to do: don't fry, don't cook, don't store in light. Don't choose a CBD-oil-labeled product if you're looking for an edible fat. With occupational drug testing, check policy in advance.
References
[1947] Callaway J, et al. J Dermatolog Treat. 2005;16(2):87–94. Efficacy of dietary hempseed oil in patients with atopic dermatitis. 2005. Link
BACKGROUND: Hempseed oil is a rich and balanced source of omega-6 and omega-3 polyunsaturated fatty acids (PUFAs). Anecdotal evidence indicated that dietary hempseed oil might be useful in treating symptoms of atopic dermatitis. PATIENTS AND METHODS: Dietary hempseed oil and olive oil were compared in a 20-week randomized, single-blind crossover study with atopic patients. Fatty acid profiles were measured in plasma triglyceride, cholesteryl and phospholipid fractions. A patient questionnaire provided additional information on skin dryness, itchiness and usage of dermal medications. Skin transepidermal water loss (TEWL) was also measured.
[1948] Schwab US, et al. Eur J Clin Nutr. 2006;60(11):1320–1328. Effects of hempseed and flaxseed oils on the profile of serum lipids, serum total and lipoprotein lipid concentrations and haemostatic factors. 2006. Link
BACKGROUND: Both hempseed oil (HO) and flaxseed oil (FO) contain high amounts of essential fatty acids (FAs); i.e. linoleic acid (LA, 18:2n-6) and alpha-linolenic acid (ALA, 18:3n-3), but almost in opposite ratios. An excessive intake of one essential FA over the other may interfere with the metabolism of the other while the metabolisms of LA and ALA compete for the same enzymes. It is not known whether there is a difference between n-3 and n-6 FA of plant origin in the effects on serum lipid profile. AIM OF THE STUDY: To compare the effects of HO and FO on the profile of serum lipids and fasting concentrations of serum total and lipoprotein lipids, plasma glucose and insulin, and haemostatic factors in healthy humans. METHODS: Fourteen healthy volunteers participated in the study. A randomised, double-blind crossover design was used.
[1949] Whelan J J Nutr. 2009;139(1):5–10. Dietary stearidonic acid is a long chain (n-3) polyunsaturated fatty acid with potential health benefits. 2009.
A review of dietary stearidonic acid as a long-chain (n-3) polyunsaturated fatty acid with potential health benefits.
[1950] Da Porto C, et al. Eur J Lipid Sci Technol. 2014. Hempseed oil: chemical composition and functional properties. 2014.
An article on the chemical composition and functional properties of hempseed oil.
[1951] Leizer C, et al. J Nutraceuticals Funct Med Foods. 2000;2:35–53. The composition of hemp seed oil and its potential as an important source of nutrition. 2000.
An article on the composition of hemp seed oil and its potential as a source of nutrition.
[1952] Crescente G, et al. Phytochem Rev. 2018;17:733–749. Chemical composition and nutraceutical properties of hempseed. 2018.
A review of the chemical composition and nutraceutical properties of hempseed.
[1953] . Health Canada 1998. Industrial Hemp Regulations. 1998.
Health Canada's Industrial Hemp Regulations.