Today’s post is about Vitamin E, an essential micronutrient that can be too low in home prepared diets, but can often be over-supplemented in other cases. Like all the essentials, getting the amount in the diet optimized is key to a truly gold standard nutrition strategy for your dog. Let’s start with what Vitamin E does in the body and which foods it can be found it, then I’ll show you how to calculate your dog’s actual requirement, discuss when adding more might be appropriate, when it is not indicated, and how to evaluate and choose a supplement.
To start, then – Vitamin E is an umbrella term that is generally thought of as one compound – d-alpha-tocopherol – but in fact, covers 4 tocopherols and 4 tocotrienols; d-Alpha is the most biologically active, and so the one most recommendations refer to. Vitamin E is a fat-soluble vitamin, meaning that it is digested, absorbed and excreted by the same mechanisms as dietary fat, and any excess is stored in the liver. What THAT means is, over time, feeding excess amounts can result in toxicity (water soluble vitamins, like the Bs and Vitamin C, are passively absorbed in the small intestine, and excesses are eliminated via urine) Vitamin E is considered essential, because an absence of it creates an identifiable pathology, that can be diagnosed and treated. (NOTE there is a difference between overt deficiency of any essential, and marginal intake, which is not ideal for health but not as severe as an actual deficiency, which will cause disease). The canine requirement is actually pretty low, but a few things:
- home made diets, cooked or raw, may not be providing adequate, much less optimal, levels
- extra E can be beneficial under some circumstances, but too much may not be a good thing
- supplements are fine, but get the right type and use the right amount
Functions of Vitamin E
Here’s what E does in the body: first and most importantly, Vitamin E is an antioxidant, which means it helps prevent oxidation of dietary PUFAs, or polyunsaturated fatty acids, found in vegetable and fish oils as well as poultry and meat. Further to that, E functions to maintain the health of cell membranes all through the body, which are also vulnerable to oxidative damage. Vitamin E also protects Vitamin A as well as the sulfur-containing amino acids (you will recall that methionine and cysteine, both sulfur containing amino acids, are the precursors for taurine in the canine diet). Lastly, a complex relationship exists between selenium and vitamin E – the short version is, dietary E spares selenium so the mineral can perform other functions (we can’t just load up on selenium, as it has a safe upper limit that we don’t want to reach, so ensuring the diet has adequate Vitamin E means selenium can perform more effectively in the body).
Chronic low levels of dietary Vitamin E can lead to reproductive failure, dermatosis, immunodeficiency and anorexia.
That’s the quick and easy version -but it covers the basics – more detail in the nutrition course. So now that we have an idea how important Vitamin E is, let’s look at which foods provide it, and how much does your dog actually need?
The foods that provide Vitamin E are:
- Various vegetable oils, with sunflower usually the healthiest choice, but corn, grape-seed, and soy also are rich sources, often recommended by DVM nutritionists (I prefer sunflower or safflower)
- Wheat germ – very rich, if your dog can tolerate wheat
- Broccoli, spinach, other greens ( provide a little, but rarely meet the RA with veggies)
- Rainbow trout is a rich source and likely more bioavailable than the greens but not a food most owners can easily access
- Almonds and peanut butter are fairly good sources, but high in oxalate and not suitable to feed in quantity all the time
- Eggs and liver have a small amount
So how much do you need to shoot for in the diet? (this assumes you’re doing a home made diet – raw or cooked – and auditing using the National Research Guidelines, which remain our best source of nutrition information for dogs).
Figuring out amounts of vitamin E can be confusing, as it’s expressed in either IU or mg. The conversions are calculated as follows:
- To convert from mg to IU: 1 mg of alpha-tocopherol is equivalent to 1.49 IU of the natural form or 2.22 IU of the synthetic form. We’re only using natural here but this is good to know.
- To convert from IU to mg: 1 IU of the natural form is equivalent to 0.67 mg of α-tocopherol. 1 IU of the synthetic form is equivalent to 0.45 mg of alpha-tocopherol.
If you are using the Calculator Tool provided to the Group, it will simply send you the amount you need.
To calculate on your own, you: start by taking your dog’s weight in kilograms to the power of 0.75, and then the RA for E (in IUs) is that number, the MW, times 1.0!
So if your dog’s MW is 14, then so is his daily RA for Vitamin E…14 IUs. And this is very often NOT met through food..even if you do manage to get it to 14, we know that not all of that is absorbed. So here is where we need to take a calm and detached look at the use of supplements. I am all too aware of the current trend to rely, or try to rely, solely on foods to provide every nutrient a dog requires, and I support that goal but only to the extent it is feasible – working. Some dogs can’t tolerate many of the foods we need, in the quantities required. Some owners can’t spend half their lives tracking down grass-fed buffalo brains. And some dogs actually need a therapeutic dose of Vitamin E – more on that below. So, let’s look at supplements – what you should look for and how much to add. Bearing in mind, I am neither pro nor con supplement use, I use as needed, and seek the best forms, which is what I am sharing with you today.
How Much to Supplement?
Back when I first started this work, under the guidance of a few holistic vets at that time, I generally used the following formula for supplementing Vitamin E – and I did it across the board, unless something like a bleeding disorder indicated I shouldn’t use any (more on that later).
- Toy to small dog – 100 IUs daily
- Small to medium dog – 200 IUs daily
- Large dog – 2- 400 IUs daily
- And Giant breeds, up to 800 IUs
Today, I find this very vague, and excessive at the higher end – and gear what I suggest adding to the individual dog; their history, what other blood thinning herbs and supplements they’re on, what’s already in the diet, and how much PUFA (polyunsaturated fatty acid, of any type, not *just* fish oil) they get. I am more conservative, overall. The higher doses for large dogs are something I never use, since we have studies that suggest Vitamin E can act as a PRO-oxidant, rather than antioxidant, at high intake. (1) Generally speaking, I look to bring the total amount I supplement, in line with both the overall RA (Recommended Allowance) and the fat content of the individual dog’s diet. The exception to this is therapeutic use, and that is generally higher dose and short term.
Mary Straus (of Dogaware.com) posted that her own Guideline for Vitamin E is 1-2 IU’s per pound of body weight, and I concur with that as a reasonable level. So if your dog weighs 50 lbs, 50 – 100IU’s added on top of whatever is in the diet – assuming it is minimal as it usually is – seems reasonable to me. That 150 pound Dane would be getting 300IUs max, instead of 800. Which seems a much safer bet to me, given what we still don’t know about high doses/longterm.
While we like to be precise and cautious with regular dietary supplementation of E, there are a few conditions wherein it is helpful for use higher doses, short term. I often use higher doses for my clients with atopic dermatitis or variety of other skin conditions (2) and in some cases, with orthopaedic issues such as hip dysplasia (3) with the qualifier, I almost always use supplemental fish body oil with arthritis, hip dysplasia and similar conditions, so I’d be using *some* extra E already, but following the research linked to below and others, I may use higher levels for a period of up to 6 months, and monitor. Any supplemental use that goes above the 1-2 IU’s per pound of bodyweight guideline needs supervision by a nutritionist and or a veterinarian. (Much more detail on therapeutic use in the Practical Herbalism Course).
Vitamin E is a powerful anti-coagulant (blood thinner) and therefore should never be sued with any dog who has a bleeding disorder such as von Willebrand’s disease, or thrombocytopenia. It’s also important to discontinue supplementation at least a week, and preferably two, prior to surgery of any type. It’s worthwhile to consider all additional supplements, too, if a great number of herbs with anti coagulant actions – garlic and turmeric to start – are used, the cumulative effect should be watched. We also want to consider medications and of course, dogs undergoing chemotherapy, wherein the oncologist may not want any extra antioxidants added. All of these are important considerations before adding Vitamin E above the RA.
What Type of Supplement?
I emphasize the use of natural Vitamin E – identified on the label as d-tocopherol, never dl-tocopherol – and if the product contains the other tocopherols and tocotrienols (usually in small amounts) all the better. There are a couple of other things to watch for; first, if your dog has a sensitivity to beef, avoid gelatin capsules derived from beef… as many are. Also, very important to note that much commercial Vitamin E is soy-based, and while I have only a couple of times in my whole career seen dogs so sensitive to soy they reacted, it can happen. In these cases, the focus needs to be on dietary sources, and always check the quality of the company – I recommend using www.consumerlab.org, a small annual fee will provide the interested person with so much information.
I most often use this product as it contains no soy or beef, and also provides mixed tocopherols as well as the alpha.
The Takeaway Points for understanding Vitamin E are:
- E is an essential nutrient which must be met at adequate levels in the diet, or health consequences are likely
- E is not needed at high concentrations, but it is still often difficult to reach the RA in home made diets
- It’s important to boost dietary E when adding supplemental fats, such as fish oil
- Supplements may be the easiest way to achieve goals, but look for natural sources, no soy/beef if your dog is sensitive, and preferably the four tocopherols as well
- Never add E if your dog has a clotting disorder, and discontinue supplements at least a week prior to surgery
- Too much is not necessarily better, so boost a little but not excessively
- E may be helpful with some skin conditions, but use under the supervision of your vet or natural health practitioner/nutritionist
I hope this has been helpful for you in sorting through the many “opinions” on supplementing dogs with VitaminE. Knowledge is power, and safety first..as always.
Courses through The Possible Canine: https://thepossiblecanine.com/courses
1. Meta Analysis – and a human study, but worthwhile: https://pubmed.ncbi.nlm.nih.gov/15537682/