Vitamins are essential nutrients (i.e. nutrients that we need for basic function but cannot produce on our own). There are two classifications of vitamins: Water-soluble and fat-soluble. Water-soluble vitamins include vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B7 (biotin), vitamin B9 (folic acid), vitamin B12 (cobalamin), and vitamin C (ascorbic acid). The fat-soluble vitamins include vitamin A (retinol), vitamin D, vitamin E (tocopherol), and vitamin K.
When something is fat-soluble, it simply means it dissolves in fat. The best way to get these vitamins is consuming them with a little bit of fat, such as butter or olive oil. Not surprisingly, many fat-soluble vitamins are found in foods that are fatty (our Creator is so smart). Most vegetables, however, don’t contain fat, so when people try to be “extra healthy” by not using any oil or fat with their vegetables, they’re actually missing out on the fat-soluble vitamins those vegetables contain.
The interesting thing about fat soluble vitamins is they are not in extremely high demand in terms of quantity. They are actually stored in our tissues, so they do not need to be consumed in massive quantities. For this reason, fat-soluble vitamins (especially vitamin A) can cause toxicity if one is not careful. Toxicity is usually due to a person taking vast amounts of synthetic fat-soluble vitamins. One rarely becomes toxic from vitamins consumed from food sources. So, like in most everything nutrition related, it is best for the body when one consumes, whole, nutrient-dense foods.
Vitamin A (Retinol)
Functions: Absolutely essential for eye health (wards off night blindness and other eye ailments); maintains mucus membranes, skin, and epithelial cells; anti-inflammatory effects; bone and tooth growth; reproduction; immunity.
Dietary Sources: Cod liver oils, sweet potatoes, chicken livers, beef livers, calf livers, lamb livers, eggs, spinach, parsley, paprika, red pepper, cayenne, chili powder , cantaloupe, carrots, lettuce, dried herbs, butternut squash, watercress, mango, tomatoes, butter, beef
Notes: When consuming animal products containing vitamin A, you are actually getting retinol. This is the actual vitamin. Consuming plant-products gives you the precursor (also called the pro-vitamin) beta-carotene. The body turns this into vitamin A.
Functions: Regulation of the minerals calcium and phosphorus
Dietary Sources: Cod liver oil, herring, pink salmon, kippers, mackerel, sardines, tuna, butter, caviar, salami, ham, sausages, eggs, mushrooms
Notes: The main source of this vitamin comes from the sun. It is synthesized in our skin and can be stored for periods of time (like through the winter). Lighter-skinned people synthesized it very effectively, whereas darker-skinned peoples are not able to synthesize it very well. It is interesting to point out that traditionally, darker-skinned people groups are usually found where sunshine is plentiful, like Africa, South America, and so on. Lighter-skinned people groups herald from colder climates, such as Norway, Sweden, Denmark, etc. They need all the vitamin D they can get, and they are more able to make it. Fascinating! Also, stay away from things fortified with vitamin D2. Your body utilizes vitamin D3, and vitamin D2 comes from some sketchy sources.
Vitamin E (Tocopherol)
Functions: A powerful antioxidant, it is actually part of the cell membrane and protects it. Some research suggests it can protect from certain types of cancers as well as heart disease, diabetes, viruses, and neurodegenerative diseases such as Alzheimer’s. A lot of research is still pending on this vitamin.
Dietary Sources: Sunflower seeds, paprika, red chili powder, almonds, egg yolks, pine nuts, fatty meats, wheat germ, liver, dried herbs, dried apricots, spinach, butter, avocado, almonds, raw peanuts (with skins), rye, asparagus, hazelnuts, blackberries
Notes: It really must be taken with food to even be absorbed.
Functions: Synthesis of blood-clotting proteins and bone proteins
Dietary Sources: Gouda cheese, cauliflower, kale, green tea, turnip greens, spinach, tomatoes, parsley, Swiss chard, runner beans, broccoli, scallions, chili powder, curry, paprika, and cayenne, asparagus, Brussels sprouts, pickles, prunes, cabbage
Notes: Vitamin K1 is found and plants and must be converted to vitamin K2. Animal sources are already vitamin K2. Vitamin K is not stored well in the body like other fat-soluble vitamins, but it does recycle itself.
Understanding Nutrition, 12th Edition (Whitney & Rolfes 2010)
Originally posted 2013-09-03 09:51:37.