Introduction

Apricot seeds are surrounded by major controversy. Essentially, there are two diametrically opposed camps.

People who passionately believe that apricot seeds have health benefits and should be freely available and especially to help people with cancer.

Equally passionate folks on the other side, believe that apricot seeds are poisonous and should be banned.

I am all in favor of passion but I like my passion to be guided by actual science. When I read the science, I did become passionate too.  Here is what the science says.

What Is Vitamin B17?

Technically, there is no such thing as vitamin B17. ‘Vitamin’ B17 is the incorrect name given to laetrile which is a discredited cancer drug. It is not a vitamin – which is by definition ‘an essential micronutrient’. Therefore, it does not matter whether you want to choose the number 17 or any other number you want, it still does not classify as a vitamin. End of story.

Amygdalin (nitriloside, purasin) is the natural substance from which laetrile is made. Amygdalin is found in the seeds of rosaceous fruits such as apricots, apples, peaches, plums, red cherries and almonds.

Amygdalin is broken down in the intestine to form cyanide. The small problem here is that this is the very same cyanide that can kill a person (think of old cold-war spy movies).

Laetrile has been banned by the FDA  and EMA (European Medicines Agency) due to serious concerns about lack of efficacy and risks of toxicity (the worst profile possible for any therapeutic agent). Undeterred by science, the manufacturers of laetrile decided to re-market the compound as vitamin B17. (It’s still not a vitamin).

There are over 1000 apricot seed products available for sale on Amazon. The average cost of an ounce of apricot seeds is somewhere between $1 and $2.

Is There Any Research

There are just over 100 publications on apricot seeds which includes just 2 clinical trials. Changing the search to publications on vitamin B17 gets us 741 publications and 21 clinical trials.

To put this into context, there are almost 150,000 publications on vitamin B which includes almost 1,000 clinical trials.

Do Apricot Seeds Treat Cancer?

cancerIn 1987, the National Cancer Institute made a decision to respond to the widespread public interest in laetrile by undertaking a comprehensive review (1). Requests were sent to 385,000 physicians and 70,000 other health professionals and by direct contact with pro-laetrile groups who were asked to submit cases of successful treatment of cancer with laetrile.

It was thought at the time that at least 70,000 Americans had used laetrile but only 93 cases were submitted for evaluation and only 68 cases provided enough data for meaningful evaluation.

A panel of oncologists then reviewed these 68 cases along with 68 cases of conventional chemotherapy but they were blinded to the treatment used in each case. They concluded that there had been 6 patients out of 68 who had responded to laetrile (two complete and four partial responses).

Four years later, 178 patients with cancer were treated with amygdalin plus dietary recommendations (2).The study was carried out by the National Cancer Institute and included patients with cancer of the lung, colon or breast.  The study reported a short-term improvement in stomach cancer in a single patient.

Overall there was no cancer cure, stabilization of cancer, improvement in cancer symptoms or improved mortality noted. On the downside, a number of patients experienced symptoms of cyanide toxicity. The authors concluded with this pretty unequivocal statement ‘Amygdalin (laetrile) is a toxic drug that is not effective as a cancer treatment’. Game over.

Just to make sure that we are left with no doubt, a 2015 Cochrane review of amygdalin for cancer concluded with the line ‘The risk-benefit balance of laetrile or amygdalin as a treatment for cancer is therefore unambiguously negative’ (3). Game totally over.

A very direct paper entitled ‘The case against laetrile: the fraudulent cancer remedy’ criticised what they called ‘the propaganda for the doctrine of “freedom of choice in cancer treatment” (4). Propoganda is never a good thing in medical sceince.

In 1991, a paper entitled ‘Questionable cancer practices in Tijuana and other Mexican border clinics described the use of ‘unconventional, unproved, and disproved’ methods offered in the border clinics (5).

Listed among these questionable practices was laetrile infusions. The paper finishes with the line ‘The American Cancer Society, therefore, strongly urges individuals with cancer not to seek treatment with metabolic therapies in the Mexican border clinics’.

Bottom Line

Laetrile does not treat cancer but does have the potential to cause serious side-effects. I don’t think that I have ever seen such overtly negative and critical commentary in the literature on any other topic before.

Does Apricot Seeds Boost Immunity?

A component of the immune system called Treg-cells plays a role in the prevention of atherosclerosis (hardening of the arteries). A study in mice showed that amygdalin can boost Treg activity and thereby protect against atherosclerosis (6).

The purpose of the study was to examine the effects of amygdalin in heart disease but is quoted here as one of the only studies looking at amygdalin and immunity.

While this study does show a beneficial effect of amygdalin on Tregs in mice, it has to be said that Tregs are a very specific and niche part of the immune system and this study cannot be taken as evidence that amygdalin boosts the immune system to protect you from colds and flus.

A paper in Future Medicinal Chemistry lists new chemical compounds called amygdalin analogues or lookalikes as possible future treatments for psoriasis based on their immunosuppressing potential (7). Just to state the obvious, immunosuppression is the opposite of boosting immunity.

Bottom Line

There is no human evidence to suggest that amygdalin can boost immunity.

Does Apricot Seeds Lowers High Blood Pressure?

Possibly. There is a case report of a 65 year of a 65 year old lady with liver cancer who became critically unwell which included low blood pressure following laetrile ingestion (8). This is hardly definitive, by any means. Lots of critical illnesses result in drops in blood pressure.

Bottom Line

A single case report mentions apricot seeds and low blood pressure which is hardly conclusive of anything. If we suspend our disbelief for a moment and use the data from this case report, we would still have to say that this is a pretty extreme way to lower blood pressure.

Does Apricot Seeds Relieves Pain?

Relieves PainIn a study in rats, formalin was injected into the right hind-paw plantar surface subcutaneously using a 30-gauge syringe (9). This is known as the formalin test and is used to cause pain in the rats. Amygdalin was injected intramuscularly to right biceps femoris and the behaviour of the rats was observed.

Response to pain was gauged by behaviours such as licking, biting and shaking in addition to measurements of inflammatory cytokines in the paw skin. Ugh. Amygdalin worked and significant decreases were noted in all the above pain measures as compared to a placebo arm.

A year previously, the same research group showed that amygdalin can exert anti-inflammatory and analgesic effects by inhibiting prostaglandin E2 and cyclooxygenase-2 (COX-2) (10).

A very disturbing paper from a Military Medical University looked at ‘hot plate and acetic acid-induced writhing tests’ in mice (11). Ugh, ugh. That sounds very painful indeed. They found that amygdalin was analgesic but not anti-inflammatory.

Amygdalin did not result in addiction but could not replace morphine in morphine addicted rats. I can hear the propoganda brigade selling the anti-addictive effects of amygdalin already. 

A paper published this year looked at a Traditional Chinese Medicine called Guizhi Fuling which contains gallic acid ,amygdalin, albiflorin , prunasin and cinnamic acid (12). Here is where things get super weird. The investigators were studying primary dysmenorrhea (painful periods) in rats.

They found that the ingredients in Guizhi Fuling and particularly amygdalin could relieve period pain. The paper came from the New-tech For Chinese Medicine Pharmaceutic Process in China which is interesting.

Western medicine is usually criticised for being reductionist ie trying to reduce things done to the lowest common denominator and we are told that there synergies in Traditional Chinese herbal blends that cannot and should not be deconstructed. Yet here we have a Chinese company doing exactly that.

Bottom Line

There is evidence from rats and mice, but not humans, that amygdalin has analgesic properties.

Is Eating Apricot Seeds Safe?

Ten dogs fed laetrile with sweet almonds did not do well (13). All dogs showed signs of cyanide poisoning and six of the ten dogs died.

The researchers who studied laetrile in cancer published a companion paper on laetrile toxicity (2). Significant increases in blood cyanide levels were noted but the patients remained asymptomatic. One patient was challenged with raw almonds and developed symptoms of cyanide poisoning.

Symptoms of cyanide toxicity include liver damage, neurological damage, fever, coma and sometimes even death (13). The risk of cyanide toxicity can be increased by co-administration of vitamin C, raw almonds and eat fruits and vegetables that contain the enzyme beta-glucosidase (found in celery, peaches, bean sprouts, and carrots) with laetrile.

Because of the way that amygdalin is broken down by the intestine, symptoms of cyanide poisoning are more likely to occur when amygdalin is taken orally as opposed to intravenously (14).

There is a case report of a 65 year old lady with liver cancer who died of liver failure following ingestion of amygdalin (8).

Laetrile also resulted in congenital skeletal malformations in pregnant hamsters.

Conclusions

I don’t consider myself totally naive and I do like a good conspiracy theory. I am well aware that the possibility exists that large-scale financial interests could systematically trump the humanitarian agenda and of course, this would be wrong. People usually accuse government agencies and big pharma companies for such sins.

Having read the science,I just don’t believe that laetrile is one of those casualties.

The science does not support the use of laetrile. It makes cyanide and can kill you.

What we see here is not government and/or big pharma collusion. What we see here is failure to accept science and deliberate false marketing of a toxic compound which I can only assume is for financial gain.

My sincere advice is avoid this one.