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Best of Hemp Seed Questions

January 17, 2011 Written by JP    [Font too small?]

The history of hemp products in the natural health industry has been one largely dominated by uncertainty. So it didn’t surprise me when a client recently asked me about them. I offered a brief summary and my best opinion. Needless to say, it differed from what he had previously been told. This is a common occurrence in my chosen field. For every health topic, there are numerous opinions. Some are generated by the conventional medical establishment. Others are promoted by the makers of hemp products, the media and health food store employees. The likelihood that all of these disparate sources will agree on anything is infinitesimal.

Simply adding another opinion to the hemp product debate is rather pointless. That is unless it is backed by transparent reasoning. Today I’ll offer my two cents about hempseed oil and protein. But what will differentiate it from most other commentary is that I’ll use published scientific studies to inform my point of view.

The controversy about hemp being the same as marijuana is mostly a relic of the past. Hemp and marijuana are sourced from different members of Cannibis genus – hemp (Sativa) and marijuana (Indica). Hemp is now widely available as a dietary supplement because of its nutrient density. Hemp seeds, which are technically nuts, contain approximately 30% fat and 25% protein. Its fatty acid composition is considered highly desirable because it’s comprised of over 80% polyunsaturated fats. But what really sets hemp seeds apart from most other nuts and seeds is that they present an omega-3/omega-6 ratio of approximately 1:3. This is believed to be more in line with the fatty acid make up of many traditional diets. The seeds of hemp also possess a fairly rare fatty acid known as GLA or gamma-linolenic acid which is documented as having anti-inflammatory properties. (1)

The unique components of hemp seeds have compelled some researchers to investigate their health potential in both animal and human models. The most recent scientific intervention trial involved New Zealand white rabbits. The test animals were fed one of 6 diets: 1) a regular control diet; 2) control diet + 10% hemp seeds; 3) control diet + defatted hemp seeds; 4) control diet + .5% cholesterol; 5) control diet + .5% cholesterol + 10% hemp seeds; 6) control diet + 5% coconut oil. Over the course of 8 weeks, blood tests were performed which measured cholesterol, platelet aggregation (a measure of blood clotting) and triglycerides. It was noted that the cholesterol-enriched diets lead to increased platelet aggregation. However, the addition of hemp seeds to the cholesterol-rich diet nullified this effect. This is relevant because excessive platelet aggregation can increase the risk of heart attacks and strokes. (2)

I wish I could tell you that all of the studies inspire the same level of confidence about hemp seeds. Unfortunately, they do not. A case in point is a human study from the February 2008 issue of the Journal of the American College of Nutrition. A total of 86 men and women took part in a 12 week double-blinded, placebo controlled trial testing the effects of fish oil, flaxseed oil and hempseed oil. Researchers from Manitoba, Canada verified that each oil was absorbed based on changes in blood levels of fatty acids in all of the study volunteers. The surprising finding was that none of the oils provoked any significant changes in circulatory factors, inflammatory markers or lipid levels. However, in fairness, it’s possible that the low dosage used (2 grams/day) was insufficient. (3)

Another human study from December 2006 compared the relative effects of flaxseed and hempseed oil on blood sugar, cholesterol, insulin and triglyceride levels in a group of 14 healthy men and women. This was a crossover trial wherein the subjects were given flax oil for 4 weeks, followed by a 4 break or washout period and then a 4 week trial with hemp oil. This time, the dosage used was considerably higher 30 ml or 30 grams/day. The hempseed oil “resulted in a lower total-to-HDL cholesterol ratio” compared to flax oil. A lower total/HDL cholesterol ratio is thought to reduce the risk of heart disease. (4)

Two animal studies from 2006 and 2007 also yielded mixed results while examining the effects of hempseed intake on “cardiac ischemia-reperfusion injury” – heart damage caused by an absence of blood flow. One of the experiments found that the addition of 10% hempseeds to the diets of rats provided significant cardioprotective effects. But, the authors of the 2006 trial came to a decidedly different conclusion: “The present study does not support the use of dietary hempseed to protect the heart during ischemic insult”. (5,6)

As far as clinical studies are concerned, the only remaining trial to review comes courtesy of the April 2005 issue of the Journal of Dermatological Treatment. In it, hempseed oil was compared to olive oil in 20-week randomized, single-blind crossover study in patients with atopic dermatitis. Those using hemp oil showed evidence of a reduction in dermal medication use, itchiness and skin dryness. The scientists conducting the study also documented a dramatic gain in select plasma fatty acids (alpha-linolenic acid, gamma-linolenic acid and lenoleic acid). They theorized that the hempseed oil corrected a pre-existing imbalance relating to polyunsaturated fatty acids. (7)

Omega-3 & Omega-6 Fatty Acids in Fish, Flax and Hemp Oil

Subject group DHA n-3 (mg) EPA n-3 (mg) ALA n-3 (mg) LA n-6 (mg) GLA n-6 (mg) n-6 (mg) n-3 (mg) n-6:n-3
Fish oil 121 176 6 13 2 15 303 0.05:1
Flaxseed oil 0 0 511 140 9 149 511 0.3:1
Hempseed oil 0 0 186 572 26 598 186 3:1
Source: J Am Coll Nutr. 2008 Feb;27(1):51-8. (link)

The sometimes hyperbolic claims made about hempseed oil far out distance the number of studies available to support them. The same is even more true in the case of hempseed protein. There has yet to be a published trial in humans utilizing hemp protein isolate (HPI). The best data we have to go on comes from a laboratory analysis published in the November 2006 edition of the Journal of Agricultural Food Chemistry. The primary conclusions found were: a) HPI has a comparable amino acid profile as soy protein isolate (SPI); b) it’s lacking in lysine and sulfur-containing amino acids, but is an otherwise sufficient protein source; c) it “can be used as a valuable source of nutrition for infants and children, but has poor functional properties when compared to SPI”. (8)

Animal studies have generally found hemp seeds to be a fine source of nutrition. If these results are translatable to humans, then it’s possible that hemp seeds could be relied upon to alleviate fatigue, promote healthy immune function and support overall health safely. But only further trials in humans can adequately answer that question. At present, I’m unaware of any major studies in this category that are planned or in progress. (9,10)

One pertinent issue that appears to be resolved is the likelihood of testing positive for marijuana while using hempseed supplements. This was a real concern in the 1990s. At that time, several scientific inquiries did indeed find unacceptably high levels of cannabinoids in commercially available products. However, recent changes in the manufacturing process and quality control measures have long since overcome this major hurdle. A newer set of published studies attest to this fact. This is also a major selling point that virtually all hemp products distributors now stand behind. No company wants to be sued as a result of an undeserved positive result during a workplace drug screening. (11,12,13,14,15,16,17,18,19)

So what’s my overall verdict on hempseed oil and protein? I wouldn’t discourage most people from trying either of them out. You see, I’m not at all convinced that they’re bad products. But I wouldn’t recommend them unless there was a good reason to do so. For example, if someone was looking for a good source of GLA or omega-3 fatty acids, I’d prefer to point them in the direction of blackcurrant seed oil, evening primrose oil, fish oil or krill oil first. The same goes for protein sources. I feel more confident recommending organic brown rice protein, egg white protein or whey protein as opposed to hemp protein isolate. The bottom line is that I’m not yet sold on the rather scant amount of research on hemp as a food source. I feel justified in this position knowing that a current summary in the April 2010 issue of the journal Nutrition and Metabolism came to a similar conclusion. Having said that, if you’ve tried hempseed oil and/or hempseed protein isolate and you think my P.O.V. is off base or “on point”, please let me know. I’m always hungry for more knowledge and I’d love to hear what you have to say. (20)

Update: January 2011 – Studies pertaining to niche foods and products such as hemp seeds are generally few and far between. But there are exceptions to every rule. Of late, there have been three published studies pertaining to the medicinal and nutritional value of Cannabis sativa seeds. The latest appears in the January 2011 issue of the American Journal of Gastroenterology. In it, a group of researchers from the School of Chinese Medicine in Hong Kong reports that a hemp seed-based “medicine” is capable of improving symptoms in those with functional constipation safely. The November 2010 edition of the Journal of Agricultural and Food Chemistry provides some much needed data on the quality of protein contained in hemp seeds. Using a model known as the “protein digestibility-corrected amino acid score” or PDCAAS, Canadian scientists concluded that “The current results provided reference data in support of protein claims for hemp seeds and provide evidence that hemp protein has a PDCAAS equal to or greater than certain grains, nuts, and some pulses”. Finally, a recent experiment in an animal model of menopause revealed that adding hemp seeds to the diet of the test animals modified many of the adverse effects of this hormonal change including calcium loss, cholesterol elevation and mood changes. All of these findings should be considered as preliminary in nature, however they do add a bit more substance when making the case for hemp seeds as part of healthy diet. (21,22,23)

Be well!


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Posted in Alternative Therapies, Nutrition, Nutritional Supplements

6 Comments & Updates to “Best of Hemp Seed Questions”

  1. anne h Says:

    Interesting indeed!
    We never think about hemp seeds as food!

  2. John Connor Says:

    Excellent summary of current state of knowledge re Hemp seed nutrition. Thanks to following your info and having experienced a quad heart bypass 2 years ago, I am now a voracious consumer of Krill oil, cinamon and turmeric with the ocassional addition of pycnogenol.

    Many thanks for your lucid and bias free analysis.



  3. JP Says:

    Thank you, Anne.

    That’s part of what makes life great: we can reconsider things … like hemp seeds. 🙂

    Be well!


  4. JP Says:

    You’re most welcome, John. To your good health! 🙂

    Be well!


  5. JP Says:

    Update 05/06/15:


    Complement Ther Med. 2014 Dec;22(6):986-93.

    Activity of liver enzymes in multiple sclerosis patients with Hot-nature diet and co-supplemented hemp seed, evening primrose oils intervention.

    BACKGROUND: It is unknown whether diets with a high dietary total antioxidant capacity (TAC) can modify oxidative stress, low-grade inflammation, or liver dysfunction, all of which are risk factors for multiple sclerosis disease. This study assesses alanine amino-transferase (ALT), aspartate-aminotransferase (AST) and gamma-glutamyl transferase (GGT) activities in MS patients treated with co-supplemented hemp seed and evening primrose oils as well as Hot-nature diet and the therapeutic potential this intervention.

    METHODS AND MATERIALS: In this double blind, randomized trial, 100 MS patients with EDSS<6 were allocated into 3 groups: "group A", who received co-supplemented hemp seed and evening primrose oils with advised Hot-nature diet; "group B",who received olive oil; and "group C", who received the co-supplemented oils. Clinically, EDSS as well as serum level of liver enzymes (GGT, AST, and ALT) were assessed at baseline and after 6 months.

    RESULTS: Mean follow-up was 180±2.9 SD days (N=65, 23 M and 42 F aged 34.25±8.07 years with disease duration of 6.80±4.33 years). There was no significant difference in the study parameters at baseline. Serum levels of liver enzymes (GGT, AST, and ALT) were serially monitored. Intervention was associated with liver function alteration in three groups. Significance decreased in EDSS score and the levels of liver enzymes were found in groups A and C, whereas elevated serum liver enzymes and EDSS score were observed in group B after the intervention.

    CONCLUSION: Selecting foods according to their Total antioxidant capacity such as co-supplemented hemp seed and evening primrose oils with Hot-nature diet affects antioxidant intake and can have beneficial effects on improving EDSS score and activity of liver enzymes in RRMS patients.

    Be well!


  6. JP Says:

    Update 05/06/15:


    Afr J Tradit Complement Altern Med. 2013 Oct 3;10(6):519-27.

    Erythrocyte membrane fatty acids in multiple sclerosis patients and hot-nature dietary intervention with co-supplemented hemp-seed and evening-primrose oils.

    The risk of developing multiple sclerosis (MS) is associated with increased dietary intake of saturated fatty acids. For many years it has been suspected that this disease might be associated with an imbalance between unsaturated and saturated fatty acids. We determined erythrocyte membrane fatty acids levels in Hot nature dietary intervention with co-supplemented hemp seed and evening primrose oils in multiple sclerosis patients. To determine the erythrocyte membrane fatty acids levels and correlate it with expanded disability status scale (EDSS) at baseline after 6 months intervention in MS patients by gas chromatography, in this double blind, randomized trial, 100 RRMS patients with EDSS<6 were allocated into three groups: "Group A" that received co-supplemented hemp seed and evening primrose oils with advised Hot nature diet. "Group B" received olive oil and "Group C" received the co-supplemented oils. The results showed that the mean follow-up was 180 ± 2.9SD days (N=65, 23 M and 42 F aged 34.25 ± 8.07 years with disease duration of 6.80 ± 4.33 years). There was no significant difference in the study parameters at baseline. After 6 months, EDSS, Immunological parameters and the erythrocyte cell membrane with regard to specific fatty acids showed improvement in the group A and C, whereas there was worsening condition for the group B after the intervention. We concluded that Hot-nature dietary intervention with co-supplemented hemp seed and evening primrose oils caused an increase PUFAs in MS patients and improvement in the erythrocyte membrane fatty acids composition. This could be an indication of restored plasma stores, and a reflection of disease severity reduction.

    Be well!


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