One of the most persuasive aspects of contemporary Paleo Diets is that you will not have to waste your hard earned dollars on supplements (1, 2). Once you get going on this lifetime program of eating, except for Vitamin D and possibly fish oil, you will achieve all of the DRI’s recommended by governmental agencies from just the food you eat (1, 2). Previously, I have extensively covered the calcium issue in a number of scientific publications (2-4), so in this blog, I want to re-emphasize the importance of vitamin D supplementation for health and well being. As we come out of wintertime and into early spring, the possibility exists that many of us may be vitamin D compromised or even Vitamin D deficient (5-11).
Why is this? When we eat the foods that mother nature intended, why should we be deficient in any nutritional element? Vitamin D is actually not a vitamin, but rather is a hormone naturally formed in our skins when we expose ourselves to the ultraviolet radiation of the sun. In North America and in Europe, we receive scant little sunshine in the dead of winter, and consequently our body stores of this essential hormone become depleted as we go from fall to winter to early spring (5-11).
Table 1 below lists the content of the 40 most concentrated sources of vitamin D in real, non-fortified foods. Careful examination of this table makes it clear that, except for salmon or fresh tuna (12), it is difficult or even impossible to achieve recommended vitamin D intakes (600 I.U. or greater per day) (10, 11) with real, non-fortified foods.
Table 1. The 40 most concentrated sources of Vitamin D in real, non-fortified foods in the western diet.
Food | 100 grams food | Vit D I.U. | kcal | Vit D IU/kcal | Vit D IU/100 kcal |
Cod liver oil | 100 | 10,000 | 902 | 11.09 | 1109 |
Catfish, Channel, Wild, Dry Heat | 100 | 568 | 105 | 5.41 | 541 |
Tuna (bluefin), Fresh, wild, baked/broiled | 100 | 920 | 184 | 5.00 | 500 |
Salmon, Coho (Silver), Wild, Baked/Broiled | 100 | 676 | 139 | 4.86 | 486 |
Salmon, Chinook (King), Wild, Baked | 100 | 904 | 231 | 3.91 | 391 |
Fish eggs (roe), mixed species | 100 | 484 | 143 | 3.38 | 338 |
Salmon, Sockeye, Wild Cooked Dry Heat | 100 | 526 | 169 | 3.11 | 311 |
Oysters, Pacific, Steamed | 100 | 320 | 163 | 1.96 | 196 |
Salmon, Atlantic Wild Baked | 100 | 328 | 182 | 1.80 | 180 |
Halibut, Atlantic/Paciific, Baked | 100 | 192 | 140 | 1.37 | 137 |
Salmon, Atlantic Farmed Baked | 100 | 272 | 206 | 1.32 | 132 |
Mushrooms, Oyster raw | 100 | 36 | 33 | 1.09 | 109 |
Herring | 100 | 216 | 203 | 1.06 | 106 |
Tuna, (yellow fin/albacore), baked/broiled | 100 | 140 | 139 | 1.01 | 101 |
Sardines in oil | 100 | 193 | 208 | 0.93 | 93 |
Tuna, Canned in water | 100 | 80 | 128 | 0.63 | 63 |
Mushrooms, Potabella raw | 100 | 12 | 22 | 0.55 | 55 |
Mushrooms, Shiitake raw | 100 | 18 | 34 | 0.53 | 53 |
egg yolks | 100 | 187 | 351 | 0.53 | 53 |
Cod, Atlantic, Cooking dry heat | 100 | 46 | 105 | 0.44 | 44 |
Beef, Kidney | 100 | 68 | 159 | 0.43 | 43 |
Mackerel | 100 | 104 | 262 | 0.40 | 40 |
Pork liver | 100 | 52 | 134 | 0.39 | 39 |
Mushrooms, white | 100 | 7 | 22 | 0.32 | 32 |
Beef liver | 100 | 49 | 175 | 0.28 | 28 |
Cod, Pacific, Cooking dry heat | 100 | 24 | 85 | 0.28 | 28 |
Turkey liver | 100 | 72 | 273 | 0.26 | 26 |
Salmon oil | 100 | 177 | 902 | 0.20 | 20 |
Beef, Filet Mignon | 100 | 36 | 211 | 0.17 | 17 |
Chicken liver | 100 | 16 | 119 | 0.13 | 13 |
Pork loin | 100 | 34 | 273 | 0.12 | 12 |
Lamb liver | 100 | 16 | 139 | 0.12 | 12 |
Lamb, rib roast lean | 100 | 24 | 232 | 0.10 | 10 |
Mushrooms, Enoki raw | 100 | 4 | 44 | 0.09 | 9 |
Bacon | 100 | 42 | 541 | 0.08 | 8 |
Catfish, Channel, Farmed, Dry Heat | 100 | 10 | 144 | 0.07 | 7 |
Mussels | 100 | 11.2 | 172 | 0.07 | 7 |
Pork kidney | 100 | 8 | 151 | 0.05 | 5 |
At the top of the list for natural foods is cod liver oil, which at first appears to be a great source of vitamin D. It is, but unfortunately it also contains high levels of vitamin A which competes with our bodies’ metabolism for vitamin D and may impair vitamin D metabolism (13). A better choice is fish oil from the body of fish, rather than the liver. It also contains vitamin D and the healthful long chain omega 3 fatty acids (EPA and DHA) without the higher concentrations of vitamin A which may impair vitamin D metabolism (13).
But from an evolutionary perspective, fish oil whether derived from cod liver oil or only the body of fish, was known to have been consumed by the Vikings (circa 700s to 1100 AD) but was not commercially manufactured until relatively recent (200 – 300 years) times.
Accordingly, the Paleo Diet paradigm suggests that (as a species) if we consumed vitamin D from food, it must have come from other sources. Table1 indicates that salmon is a concentrated source of vitamin D, and if we consume roughly ¼ pound of salmon or more per day (12), we may be able to achieve low level vitamin D balance. But who do you know who eats a quarter pound or more of salmon a day (day in and day out) in the 21st century?
As you move on down the list of foods in Table 1 from salmon, it becomes increasingly obvious that with our modern tastes and diets, few people could achieve vitamin D balance on any normal diets before modern, fortified foods (milk, margarine and processed foods) were introduced in about the 1930’s and 1940’s. Organ meats won’t do it, eggs won’t do it, shellfish won’t do it and meat won’t do it. The obvious implications of Table 1 is that food never was or never could have been the primary source of the hormone, vitamin D, which is essential for optimal human health. Before I leave this topic, let’s examine milk and dairy products.