How Vitamins A, D, E, and K Interact - Part 3: Where To Find Them
Posted Nov 21 2008 10:02am
So we’ve looked at the four fat-soluble vitamins - A, D, E, and K - and discussed their roles within the body as well as looked at few ways that they interact to keep your health in check. Now let’s rise above the science and dive into the buffet. It’s time to have a look at all of the delicious foods that contain these incredibly important vitamins.
First, I want to give you one more interesting anecdote from Stephan:
In my opinion, vitamins A, D and K2 are among the very few micronutrients worth worrying about in your diet. Hunter-gatherers didn’t have multivitamins, they had nutrient-dense animal foods. As long as you eat a natural diet containing some vegetables and some animal products, and lay off the processed grains, sugar and vegetable oil, the other vitamins and minerals will take care of themselves.
Food for thought…
What Are Some Good Food Sources Of These Vitamins?
Vitamin A Here are some excellent food sources of vitamin A (per 100g (3.5 oz) with a bit of conversion work to get from “micrograms of retinol equivalent” to IU and account for beta-carotene [number in italics is IU divided by 12 for plant-sources]):
Liver, beef, cooked 3 oz (30,325IU)
Liver, chicken, cooked, 3 oz (13,920IU)
Carrots (8350IU - 695 )
Broccoli leaves (8000IU - 666 )
Sweet potatoes (7090IU - 590 )
Kale (6810IU - 567 )
Spinach (4690IU - 390 )
Pumpkin (3690IU - 307 )
Milk, whole, 3.25% fat, 1 cup (305IU)
Whole egg, 1 medium (280IU)
Collard greens (3330IU - 278 )
Cantaloupe melon (1690IU - 141 )
But let’s remember one thing: only animal foods provide retinyl palmitate, which is readily converted to retinol in the small intestine. Plant sources of vitamin A actually provide beta-carotene, which is not efficiently converted to retinol in humans, somewhere around the order of 12-to-1 is the assumption. These two studies found marked variation in beta-carotene absorption for men and women:
The vitamin A activity of beta-carotene, even when measured under controlled conditions, can be surprisingly low and variable.
Variable absorption and conversion of beta-carotene to vitamin A both contribute to the variable response to consumption of beta-carotene.
That means only the animal foods above are “guaranteed” to provide that amount of vitamin A. The plant sources are going to depend very much on the individual. (And of course, the animal foods may vary, though not as markedly as the plant sources.)
Vitamin D We’ve already discussed where to get your vitamin D from food, so I’m just going to scavenge the previous list of foods:
Cod liver oil - 1tsp, 450IU
Salmon, cooked, 3 1/2 oz: 360 IU
Mackerel, cooked, 3 1/2 oz: 345 IU
Sardines, canned in oil, drained, 3 1/2 oz: 270 IU
Pork lard, 1 tbsp - 140IU
Beef Liver, cooked, 3.5oz - 30IU
Whole Egg - 25IU
But remember that vitamin D is preferentially created by the body in the skin via interaction with UVB radiation from sunlight. While food can provide moderate amounts and supplements can provide hefty doses of the D 3 the body needs, neither compares to the ability of the skin to create this vitamin. Thirty minutes of full body exposure can drop up to 20,000 IU of vitamin D (depending on latitude, skin color, time of day, pollution, etc). That’s a lot of cod liver oil.
Vitamin K The two main sources of vitamin K 2 in the diet are MK-4 and MK-7. There are other forms of this vitamin, like MK-8, 9, and 10, but the two predominant forms are the -4 and -7 forms.
MK-4 Sources (mcg/100g)
Egg Yolk (Netherlands) - 32.1 (Egg White contains 0.4)
Goose Leg - 31.0
Egg Yolk (United States) - 15.5
Butter - 15.0
Chicken Liver - 14.1
Chicken Leg - 8.5
Ground Beef (Medium Fat) - 8.1
Calf Liver - 5.0
Milk - (Whole: 1.0, 2%: 0.5, Skim: 0.0)
Salmon - 0.5
MK-7 Sources (mcg/100g)
Natto - 1103.4 (0% MK-4)
Hard Cheeses - 76.3 (6% MK-4)
Soft Cheeses - 56.5 (6.5% MK-4)
Curd Cheeses - 24.8 (1.6% MK-4)
Sauerkraut - 4.8
Plenty of vegetable foods are high in vitamin K 1, such as avocados, spinach, chard, and the cruiferous vegetables. Remember that MK-7 is produced by bacterial fermentation, hence why the foods in that list are all fermented foods. MK-4 is produced directly in animal tissues. But there isn’t much K 2 in fish.
Notably absent from the main text body is a discussion of where the K2 is coming from. It’s tucked away in one sentence of the methods section: “cheese contributed 54%, milk products 22% and meat 15% of menaquinone intake.” Oops! These are the foods that are supposed to cause heart disease! And do you remember where the K2 is? In the fat– double oops! Yet another important nutrient that’s found in animal fat.
Since the amount of vitamin K1 in typical diets is ten times greater than that of vitamin K2, researchers have tended to dismiss the contribution of K2 to nutritional status as insignificant. Yet over the last few years, a growing body of research is demonstrating that these two substances are not simply different forms of the same vitamin, but are better seen as two different vitamins: whereas K1 is preferentially used by the liver to activate blood clotting proteins, K2 is preferentially used by the other tissues to place calcium where it belongs, in the bones and teeth, and keep it out of where it does not belong, in the soft tissues.
Vitamin E Now vitamin E is a bit of a different beast than the other three vitamins, and that’s why I put it last. You’ll notice that the main sources of vitamin E are not animal foods.
Almonds, dry roasted, 1 ounce - 5mg
Spinach, frozen, chopped, boiled, ½ cup - 1.1mg
Red Palm Oil, 2 tbsp - 0.9mg
Broccoli, frozen, chopped, boiled, ½ cup - 0.8mg
Kiwi, 1 medium fruit without skin - 0.7mg
Mango, raw, without refuse, ½ cup sliced - 0.3mg
Spinach, raw, 1 cup - 0.2mg
These are all foods that fit perfectly into my way of eating. I don’t cook with palm oil as I used to, though it is still in my kitchen (and I’m not sure that vitamin E number is correct as it was very hard to find information on palm oil other than “it’s bad because of the saturated fat”). Palm oil is notable however because it contains all 8 forms of vitamin E, the 4 tocotrienols and the 4 tocopherols. Especially at this time of year, I eat tons of broccoli and I always toss a few almonds in my salads. Note that the RDA is 10mg for men and 8mg for women.
Stepping Onto My Soapbox Ahem! Does anyone notice anything revolutionary? I see one very important thing: the very animal foods that we’re told to reduce our consumption of or avoid altogether are also the richest sources of the oh-so-important fat-soluble vitamins (vitamin E excepted). We are told to reduce our consumption of real foods like liver, eggs, and butter, and to increase our consumption of foods that have had these vitamins added back into them, like fat-free vitamin A & D fortified milk.
How can we ever expect to be healthy when we’re shunning the foods our bodies are built for? These foods come with the vitamins our body needs, but we’re told to avoid them. Instead, we are told to increase our consumption of processed foods that are enriched or fortified with vitamins, invariably vitamins that are in their least-usable state (such as D 2 rather than D 3 or beta-carotene rather than retinyl palmitate). And then there’s a little thing of importance that these are FAT -soluble vitamins. How much of that added vitamin A & D do you think you get from fat-free or reduced-fat milk? Did you see how much vitamin K is left in skim milk? (I’ll wait while you go look again.)
Is it any wonder we see such ill-health throughout the population, from the elderly who expect declining health as part of “aging” to the youth, those who should be in the prime of their lives, full of energy and vigor? Does it seem right that 1-in-4 school-age children are wearing glasses or contacts? We have children aged 6-19 with the arteries of 45-year-olds. Something isn’t right here! Yet we keep taking this vitamin or that and adding it to some new Frankenfood and putting a big label on it that says “Look how good for you I am! I have the vitamin-du-jour in me!” Worse yet, there are companies being paid (PAID!) to endorse this stuff as healthful (see: American Heart Association).
In trying to find how much vitamin E is in palm oil, I happened to look at the standard nutrition label on the foods in the supermarket. Anyone notice anything? Not a single of these four vitamins are listed, only the water-soluble vitamins. There’s no way to even know what your intake of A, D, E, and K are from processed foods.
So I ask again, how can we ever expect to be healthy when we’re shunning the foods our bodies are built for?