I admit it, I’ve jumped on the vitamin D “bandwagon.” I’ve been a part of the “vitamin D craze,” recommending larger-than-RDA doses of vitamin D to my friends and family. Why?
- The majority of Americans have low to borderline-low vitamin D levels, due to lack of sun exposure, overuse of sunscreen, overuse of soap (I’ll explain this in a minute), and extremely low consumption of dietary vitamin D.
- Though most of the evidence is low quality (correlative rather than causative), there is still a great deal of evidence that points to lower risks of heart disease, many cancers, and depression when physiological vitamin D levels are on the high side.
So should every adult be taking 5000IU of supplemental D3 every day? Absolutely not.
Some people experience signs of vitamin D toxicity (fatigue, kidney stones, aches and pains) with doses as low as 2000IU a day. Why? Not enough magnesium, and not enough vitamin A. This article by Christopher Masterjohn of the Weston Price Foundation provides an excellent overview. In short, supplementing with vitamin D increases the body’s requirement for magnesium, and many people are magnesium deficient in the first place. Vitamin D also increases the need for vitamin A (see the Masterjohn article for details).
One interesting highlight of the article is a discussion of a 1941 study conducted by Irwin G. Spiesman, in which massive doses of vitamin A and D were given to subjects to see if either substance, or the combination of the two, could prevent the common cold. Only the combination proved effective, and only the combination prevented toxicity from the megadose supplementation levels.
I started taking vitamin D enthusiastically, at a dose of 5000IU a day. I experienced only positive effects (better immunity, better sleep, disappearance of all asthma symptoms), but I was also consuming a fair amount of vitamin A from cod liver oil, as well as large amounts of dietary carotenoids (from carrots, peppers, rainbow chard, etc.). I’ve also been taking a magnesium supplement for years, both as part of my protocol to control asthma symptoms (which I need less since I switched to a more-or-less paleo diet) and also to prevent noise-related hearing loss (an occupational hazard of DJ’ing and electronic music production — I also use musicians earplugs from H.E.A.R.). However I have been recommending to others to take vitamin D without also mentioning the need for vitamin A and magnesium (which I just learned about recently). That’s why I feel compelled to write about this subject.
What’s the Ideal Vitamin A to Vitamin D Ratio?
Nobody knows. However, vitamin A toxicity is more common that vitamin D toxicity, so it probably makes sense to be conservative with how much vitamin A you’re taking. In fact, taking too much vitamin A can nullify the benefits of taking vitamin D! Edit: John Cannell’s conclusions about the dangers of vitamin A may be flawed — see my extended edit below. Cod liver oil, even the high-end fermented stuff from greenpasture.org, has much more A than D, so relying on cod liver oil alone for a vitamin D source is a bad idea.
I recently had my vitamin D levels tested — the result was 63ng/ml. That’s well within the standard range, slightly on the high side. That’s after a year of taking 5000 IU about 5 days a week (except for the time when I was in Costa Rica, and getting some sun).
I’d like to keep my vitamin D levels between 40 and 50 ng/ml, so I’ve backed off somewhat on the supplementation (to 3000-5000 IU of D3 a few times a week). I take one or two grams of cod liver oil a few times a week to make sure I’m getting enough vitamin A. Getting enough vitamin A is important for night vision and testosterone production (the latter point is highlighted in the new Tim Ferriss book The Four Hour Body), but too much can increase the risk of bone fractures and osteoporosis,
deactivate vitamin D, and cause liver damage. Pregnant women and fetuses are particularly vulnerable to excess vitamin A. Extremely large doses are fatal to humans (that’s why you should never eat polar bear liver).
What About Vitamin K and Vitamin E?
Vitamins K and E are the other two fat-soluble vitamins. Regarding vitamin E, food sources (almonds and sunflower seeds, for example) are the best bet. Research into high doses of vitamin E supplementation (400IU+/day) has shown that it might be detrimental to health.
Regarding vitamin K (which I’ve written about here), abundant dietary intake of both K1 (from leafy greens) and K2 (from pastured butter, aged and fermented cheeses, sauerkraut, kimchee, foie gras, and nattō) is probably a good idea. Vitamin D and vitamin A interact with vitamin K in ways that are just beginning to be understood (the Christopher Masterjohn article discusses this). In short, if you supplement with vitamin D, it’s especially important to get enough vitamin K2 from your diet.
The All Natural Route
The body can synthesize vitamin D from sunshine, retinol (vitamin A) from carotenoids (found in yellow, orange, and red fruits and vegetables), and vitamin K2 from vitamin K1 (found in green leafy vegetables and tomatoes). So do we need to eat or supplement any of these fat-soluble vitamins?
You don’t, if and only if you follow all of the actions below:
- Get 15-20 minutes of mid-day sunshine on your bare skin without sunscreen most days during the summer, at a latitude not too far north or too far south.
- Do NOT wash with soap for the next 48 hours, so the vitamin D that formed on your skin can be absorbed into your bloodstream.
- During the winter, eat less (especially carbohydrates) so that you burn fat and provide your body with the vitamin D stored in that fat.
- Eat large amounts of yellow, orange, and red vegetables and fruits with dietary fat (to increase absorption) to get enough carotenoids (especially beta-carotene).
- Do NOT consume alcohol or smoke, as this will destroy carotene and prevent retinol (activated vitamin A) formation.
- Eat large amounts of green leafy vegetables and other source of vitamin K1 (also with fat, to increase absorption).
- Do NOT use antibiotics, which destroy the gut bacteria which convert vitamin K1 to vitamin K2.
That’s quite a list, isn’t it? Personally, I think it’s easier to supplement with vitamin D, and to eat foods that are high in activated vitamin A, and vitamin K2.
I’m not a doctor or a health professional, so I’m not qualified to make any recommendations. If I were, I’d probably recommend the following:
- Get your vitamin D level tested. If it’s below optimum, supplement with vitamin D, starting at 2000-4000IU/day (or 5000IU a few times a week). Increase to a higher dose only if you experience no negative effects, and your blood levels are still below optimum. If you get some sun (without sunscreen) during the summer and don’t mind using less soap, you can probably skip the vitamin D for those months.
- Make sure you’re getting enough dietary magnesium (nuts, greens, legumes, and real cocoa are all good sources), and consider supplementing with a few hundred milligrams of magnesium on most days (take with food, and don’t take too much; most forms of magnesium have a moderate laxative effect).
- Include a rich source of activated vitamin A in your diet, such as a few grams of cod liver oil a week, and/or a few ounces of chicken liver or calf’s liver, or a multivitamin, but don’t overdo it. Many multivitamins provide too much vitamin A as retinoic acid (vitamin A as beta-carotene is generally ok at non mega-dose levels).
- Include rich sources of vitamin K2 in your diet (stinky cheeses, fermented cabbage, pastured butter, foie gras, etc.). Note that foie gras is also a good source of vitamin A.
- Include rich sources of vitamin E in your diet (such as sunflower seeds, almonds, other nuts and seeds, green leafy vegetables, etc.)
- Include high (but not super high) amounts of carotenoids in your diet. Yes to carrots, no to carrot juice (unless you smoke). Carotenoids are better absorbed with fat (butter, olive oil, etc.). For most people this shouldn’t be too much of a hardship.
- Same things goes for food sources of vitamin K1 (green leafy vegetables, cabbage, broccoli, cauliflower, etc.). Consume with fat.
- Maintain a healthy “biotic community” (gut flora) by eating prebiotic foods like onions, asparagus, and leeks. Fermented foods like raw sauerkraut, kimchee, kombucha, and yogurt with live cultures (for those that aren’t sensitive to dairy) are also great for gut flora. The right kinds of bacteria in your intestines will not only help convert K1 into K2, they’re also a huge part of your immune system.
- Don’t take antibiotics unless absolutely necessary. If you have to, rebuild your gut flora with the foods above, and go easy on alcohol and vinegar (which can be hard on the “good” bacteria). “Natural” antibiotics like clove oil or wormwood can be just as hard on gut flora as prescribed antibiotics, so be careful with these potentially toxic “natural” remedies as well.
Understanding exactly how all the fat soluble vitamins interact, and how they are produced and absorbed in the body is complicated. After weeks of reading about this topic I feel I’m just beginning to understand the surface of it. However, in terms of actions we need to take to stay healthy, it’s not that complicated. Most people probably need to take at least 2000IU (and probably 4000-5000IU) of supplemental vitamin D during the winter months. Ingesting some activated vitamin A (from cod liver oil, liver, caviar, eggs, etc.) is probably a good idea while supplementing with vitamin D (but make sure not to take more A than D, and include all food and vitamin sources when you estimate your own intake). If you rely only on carotenoids (vegetable sources) for vitamin A, you’ll need to consume much more, and be liberal with the oil or butter. Make sure to get plenty of magnesium, vitamin E, vitamin K1, and vitamin K2 from food, and keep your gut flora happy so they can produce their own K2 (and provide you with numerous other health benefits as well).
Good health to you!
Edit: After reading more from John Cannell (of the Vitamin D Council) and Christopher Masterjohn (who blogs on the Weston Price Foundation site), I no longer think that vitamin A is “antagonistic” to vitamin D. It would be more accurate to say that high vitamin A intake (from diet and/or supplements) is potentially dangerous (increased risk of hip fracture, possible liver damage) unless accompanied by supplemental vitamin D or a great deal of sunshine on the skin. The inverse — high doses of vitamin D without (roughly) matching amounts of vitamin A from food and/or supplements — may lead to kidney stones and other calcification problems. To get a sense of the debate first read this (from Cannell) and then read this (a rebuttal from Masterjohn) and this (Masterjohn again, on the possibility that we’re pushing D levels too high). There is no consensus regarding the ideal ratio or the ideal blood levels. Cannell is very concerned that Americans are already getting too much A, and goes so far as to call cod liver oil “poison.” He advocates vitamin D from sunshine and/or supplements and vitamin A from dietary beta-carotone (no supplements or CLO). The Weston Price people say cod liver oil is fine — just make sure to use a high quality brand like Carlson’s or Green Pasture/Blue Ice that doesn’t have extra synthetic vitamin A added in, and retains significant amounts of vitamin D (Masterjohn recommends an A to D ratio of between 2-1 and 1-1). Masterjohn’s interpretation of the data makes more sense to me, and the bulk of the data indicate that the two vitamins work together synergistically, along with K2, to protect against osteoporosis, heart disease, cancer, and even diabetes.
A few people have expressed frustration with the complexity of this issue. How much is “enough” and how much is “too much”? The good news is that the exact ratio probably doesn’t matter as long as it’s not skewed too far either way. If you don’t get much sun, shoot for around 3000IU a day (on average) of both vitamin A (either from liver or high quality cod liver oil) and supplemental D3. In addition to this, eat lots of greens (for K1 and magnesium) and pastured butter (such as Kerrygold) and raw sauerkraut or aged/stinky cheeses (for K2). Consuming moderately large amounts of the fat-soluble vitamins, in balance, carries little risk and contributes to vibrant health, a strong libido, and a disease-free body.