In the US, flax, or linseed, is generally regarded as a beneficial supplement to add into a hamsters diet, whereas in other parts of the world it is considered completely unsafe or something to be limited. In this post I attempt to look into the validity of all these claims. Mainly it will be a variety of sources (parenthetically cited in terms of link number at the end of this post) and my thoughts on them, so if that peaks yours interest keep reading! If you want the general conclusion and not all my thoughts, research, and calculations, skip to the bold portion at the end.
Popular Northern American hamster forums and youtubers have recommended flax for nutritional benefits, but in other parts of the world flax is considered something to be limited, or something not to include at all (1). One article I found mentioned that flax should not be purposely given to hamsters because of high acidic and phosphorus content, but I am not sure what the validity of this statement is. I have never heard anyone mention concerns about phosphorus content (2). In terms of benefits of flax, there was a study I located (and that I assume was a contribution to the claim that flax is healthy an essential for hamsters made by popular forums) on the effects of flax on syrian hamsters (15% of a 15g of food per day diet). It concluded that “The flaxseed-enriched diet may regulate the generation of reactive oxygen species and the metabolism of glucose and lipids, and could consequently play a role in the prevention of major cardiovascular complications in diabetic states.” Which in short - this aspect of flax = good (3).
Let's take a look at flax sprays. Each “bulb” should contain 10 seeds, but on a limited sampling the average is about 7 per bulb. According to some German hamster care forums (specifically das-hamsterforum.de), only 1% of a hamster's main diet (ex seed mix) should be flax (this is based off of the concern of the high cyanide concentrations in flax seeds). If a syrian hamster eats about 8 grams of main seed mix per day, and a dwarf hamster eats about 8 grams of food every other day, this means that if you follow their recommendation, per day/every other day only 0.08 grams of flax should be provided. On a larger scale this is 2.4 grams per month/every other month. Based on a rough estimate (aka using my kitchen scale to weigh some flax) this is equal to 324 seeds. 324/7 = 46 or 46 flax bulbs. 46/30*7 = 11 per week for syrians or 5-6 per week for dwarfs. In conclusion, based on suggestions from German forums, less than 11 flax bulbs per week for Syrians or 5-6 per week for dwarfs would be safe for consumption. This of course would be even less if you have flax in your hamsters diet/seed mix. But this brings up the question, why would they put this limitation in place anyways? And why could flax be unsafe?
Now it’s time to talk about cyanide :) This is, I think, the main concern surrounding flax, (that and the high acidity, but based off of link 3 above this shouldn’t be of concern). This is why I believe some forums have come up with the “one percent rule”, but I can’t seem to find where this rule came from (if someone knows please let me know in a comment). Link 4 is a toxicological profile on hydrogen cyanide that has a really useful graph showing the lowest dose of cyanide at which harmful effects were found in animals. Unfortunately hamsters were not used in this study but rats, humans, mice, monkeys, and rabbits were. The dose for mice appeared to be about 85ppm which are likely the most similar to hamsters of all the animals used. Flax has a cyanide concentration of around 200 ppm (only about double the concentration, and much much less when considered in conjunction with a seed mix and fresh veg and other things in a hamsters diet), (5) meaning going by this study, a low concentration of flax sprays probably won’t harm your hamster. At least that’s my opinion (that may be lacking anyways because of the minimal amount of studies done for hamsters).
Right so now we have another issue. Not only are people in the hamster community concerned with the cyanide concentration already in flax, they are also concerned with the cyanogenic glycosides that could release more cyanide overtime (6). (The article I use in the next section notes that whole flaxseed, or what is found in flax sprays, has a much lower cyanide concentration that has virtually no effect on animals, which is certainly something to note).
If you aren’t interested in reading that whole article under link 7, this quote is quite interesting, and relates to how companies may reduce not just the cyanide but the cyanogenic glycosides mentioned above (7): “Scientists have developed ways of treating flaxseed to prevent cyanide production, with the ability to conserve all of the nutritive and nutraceutical benefits. Using fresh, crushed flaxseed Yamashita et al. (2007) developed a commercial-scale method to enzymatically release cyanide and effectively remove the cyanide by steam-evaporation… This method lowered the residual cyanide content below the detection limit without affecting the protein, fat, fibre and lignan content of the linseed. More recently, Wu et al. (2012) developed a fermentation technique that can be performed on a commercial scale with the benefit of lower energy consumption and no environmental pollution compared to steam evaporation…
Other forms of heat-treatment to detoxify crushed flaxseed (boiling, roasting, autoclaving, microwave) may not result in appreciable cyanide production in the body because the heat destroys the enzymes responsible for cyanide production… Such heat-treated products would, however, certainly be safer as far as the cyanide issue is concerned.” This also implies that if you are still concerned about the cyanide concentration, one option would be to boil them before use. This is a well known fact for human cooking as well, that heat-treating flax before use makes it safer for consumption. But if you would like to read into this more, check out link 8.
Link 7 also mentioned that for MOST animals, 1g of flax per kg of body weight would be safe per day. You know what this means - more calculations! Let’s say the average Syrian hamster is 125g, and the average dwarf is a third of that (in the US - in areas where hamsters are healthier this will be a larger number). 125g is equal to 0.125kg, which means according to this 0.125g of flax PER DAY would be safe. Now that is certainly a lot more than what I earlier, but take this all with a grain of salt because I doubt this person wrote this article with hamsters in mind. It’s just another perspective to consider. I still believe the original calculations are more accurate for hamsters.
Alright - and with that I think I just about covered it all. What’s my conclusion? There isn’t that much research done on this topic. But I think I resonate most with the 11 bulbs per week for Syrians and 5-6 bulbs per week for dwarfs maximum (or a scale of that per month, every other month, per day, etc) which I mentioned at the beginning of this. This is by no means a definite recommendation, this entire document is more of a jumble of my thoughts and research, and trying to make sense of them. That is just one suggestion to go by if limiting flax intake is something that has been concerning you. I also think that treating the flax in some way, be it baking, heating, boiling, or any other method you’ve looked into more (that is an area I briefly touched on but didn’t go in depth, so do your own research please) would be a decent idea. I’m also genuinely interested to see if flax companies treat their flax in any way. I know that farmers and gardeners are not treating the flax, but would pet companies know better? It’s definitely a question, and I may see if I can reach out and ask a few of them in the near future! All of this being said - a lot of seeds have a relatively high cyanide concentration, it doesn’t just come from flax. This means there may be a higher concentration in their diet overall than expected. Flax is not the only source. However, I encourage you not to freak out about this. I truly believe that in moderation not many things will inherently harm your hamster (emphasis on not many - this is NOT a universal rule and there are some things NEVER to give a ham). They are foraging creatures that eat all sorts of things in the wild without humans picking over them (though of course we should do our best to give them what is safe and best for them). All of this information is really just a starting point for you to begin research if this is a topic that interests you. I really hope this was a useful post in some way, even though much of it was just a jumble of thoughts and guesses.
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This is a very interesting post and I really enjoyed reading it! FABULOUS!!😁