Facts You May Not Know About Fat Soluble Vitamins
By Pamela Avery M.D.
Vitamins are vital in human nutrition but for the most part cannot be manufactured by your body. Therefore, you have to get vitamins from a healthy diet. Vitamins actually work as essential co-factors for properly regulating your body’s metabolic reactions and biochemical processes.
When your diet is deficient in vitamins, many biological functions are disrupted, resulting in sub-optimal health as well as a wide variety of disease conditions specifically related to nutrient imbalances. Vitamins are classified as fat soluble and water soluble. This means they are dissolved and stored in either the fatty tissues of your body or the water tissues.
Water soluble vitamins, vitamin C and B complexes, are easily excreted by your body through the urine. They cannot be stored in your body for future use and require daily intake for maximal health.
Fat Soluble Vitamins
Fat soluble vitamins are stored in the reserves of fatty body tissues and can therefore be drawn upon when they are not obtained daily from the diet. This makes them very available for a period of time even if your diet becomes extremely deficient. Ultimately, however, the reserve of fat soluble vitamins can be depleted and will need to be replenished from your diet. Because these fat soluble vitamins are not easily excreted by your body, excessive intake of fat soluble vitamins can cause toxicity. The fat soluble vitamins are vitamins A, D, E, and K.
Vitamin A was the first vitamin to be discovered and officially named, hence its letter A. Vitamin A is actually a group of nutrients that include retinol, retinal, and the carotenoids. Retinol and retinal are both known as preformed vitamin A and are found in a variety of animal foods, especially liver. Butter, cream, egg yolk, fish oils, and whole and fortified nonfat milk are all good sources of preformed vitamin A.
Carotenoids refer to over 500 substances which naturally occur in fruits and vegetables. Some 50 carotenoids act as precursors to vitamin A, with beta-carotene being the most well-known and most prevalent in foods. Lycopene is another well-studied carotenoid now known for its important role in healing. It is found in abundant levels in tomatoes.
The best food sources of carotenoids are yellow and dark green vegetables, orange fruits, tomatoes, watermelons, and cherries. Orange fruits and green, leafy, and yellow vegetables are all loaded with various precursor carotenoids, particularly beta-carotene, which the body converts to vitamin A.
Vitamin A is important for a wide variety of functions in your body. It supports eyesight, healthy teeth and skin, bone growth, cell differentiation, and tissue repair. Vitamin A also plays an important role in maintaining proper function of the cornea, lungs, mucus membranes, the lining of the gastrointestinal tract, and the bladder and urinary tract. It also acts as an antioxidant which in turn helps prevent inflammation and regulates infectious disease. In addition, it is needed for the production of various anti-tumor compounds in your body, making it a powerful nutrient in the prevention of cancer.
Vitamin A can be depleted in the body by stress and illness as well as alcohol consumption. Alcohol can interfere with vitamin A absorption. A common symptom of vitamin A deficiency is night blindness but can also include sub-optimum bone and tooth formation, eye inflammation, impaired immune response and even weight loss. An unusual condition, keratinosis (hardened pigmented deposits around hair follicles on the body’s upper and lower extremities) is another symptom of vitamin A deficiency.
Carotenoids, those precursor molecules to vitamin A, also act as antioxidants in the body. They are also capable of minimizing the formation of abnormal and precancerous cells, those cells that can over time turn into full-blown cancers. They also prevent age-related vision problems like cataracts and macular degeneration. Some researchers also speculate that carotenoids can improve immune function by stimulating antibodies, lymphocytes, and natural killer as well as T-helper cells – all part of the immune system. Symptoms of carotenoid deficiency can include diminished immune function, increased free radical damage, and increased susceptibility to some cancers and cardiovascular illness.
Vitamin D occurs in your body in ten different forms, D1- D10. The two most vital forms are D2 and D3. While the best food sources of vitamin D are cod liver and fish liver oils, butter, egg yolk, liver, vitamin D-fortified milk, and oily fish such as herring, mackerel, sardines, and salmon, your body can also manufacture vitamin D in the skin when it comes in contact with the sun’s ultraviolet rays. However, if you live in areas riddled with smog, located in high latitudes with less sunlight year round, are indoors a lot, you may not get adequate exposure to sunlight for optimal vitamin D production. As well, strict vegetarians and vegans may not get adequate vitamin D through the diet. If you fall into any of these categories, you should consider supplementing with at least 2000 IUs of vitamin D.
Vitamin D is intimately intertwined with calcium absorption and regulation in your body. Vitamin D is essential for the absorption of calcium from the food you eat as it moves through the GI tract. In addition, it is necessary for the utilization of calcium and phosphorous once it is absorbed, both of which are integral components of healthy bones and teeth. It supports proper function of the nervous system including the regulation of mood. Vitamin D also maintains cardiovascular health as well as normal blood clotting. Of course, it plays a prominent role in childhood growth.
The symptoms of vitamin D deficiency were initially noted in children. Children with specific skeletal abnormalities (rickets) were found to respond to increased levels of vitamin D. Adults signs of Vitamin D deficiency often manifest as a softening of the bones (osteomalacia) or osteoporosis. Vitamin D deficiency has also been linked to inflammatory conditions, some tumors and even mood disorders like depression. Vitamin D levels can now be detected in the blood. Low levels may require large doses to restore the body’s stores. 5,000 to 10,000 IU per day may be necessary to replenish a deficiency.
Vitamin E is not a single substance, but actually refers to a group of substances known as tocopherols. The most active form of vitamin E in your body is d-alpha tocopherol, which is also the form that is most prevalent in nature. We get vitamin E in our diet from seed and vegetable oils, especially saffower oil. Wheat germ, wheat germ oil, nuts, green leafy vegetables, whole grains, butter, and egg yolk all contain natural sources of vitamin E.
Vitamin E is a potent antioxidant and works in combination with other antioxidants like vitamin C and selenium to minimize the effects of free radical damage as well as an anti-tumor agent. In addition, it is an important nutrient for the nervous, reproductive, and skeletal systems, as well as for muscle tissue and red blood cells and corpuscles. It’s useful for skin health and can be applied topically for treating burns, wounds, abrasions, lesions and dry skin.
Vitamin K also occurs in different forms: K1 (phylloquinone) and K2 (menaquinone), both of which occur naturally, and K3 (menadione), a synthetic version. K3, menadione, is twice as active biologically than the natural forms but is only administered to people who have difficulty utilizing the natural forms. Amazingly, in addition to being available from your diet, approximately half of the body’s vitamin K needs are met by the biosynthesis of various bacteria in the intestines. Antibiotics in our food chain or your medical care can deplete the gut of normal levels of healthy bacteria. The lack of healthy bacteria in turn decreases vitamin K. You can restore these healthy bacteria to your GI tract using probiotics (healthy bacteria) which in turn can help restore vitamin K levels. Food rich in vitamin K include dark green leafy vegetables, kelp, alfalfa, egg yolk, yogurt, fish liver oils, and legumes, as well as safflower oil and blackstrap molasses.
Vitamin K’s principle function in the body is to create normal blood clotting, especially in the formation of various proteins involved in the coagulation process. Vitamin K is the one fat soluble vitamin your body is capable of manufacturing. Since the body is able to manufacture its own supply of vitamin K, deficiencies are rare. However, difficulty in absorption in the GI tract, overuse of antibiotics (which destroy healthy intestinal bacteria), and poor liver function or liver disease can create a deficiency state. This can lead to abnormal bleeding or hemorrhaging.
While vitamin K1 and K3 can interfere with the anti-coagulant effect of blood thinners such as coumadin, one form of vitamin K, vitamin K2, doesn’t. This may be due to the active effect of vitamin K1 and K3 in the liver to impact metabolism of these drugs. K2 on the other hand, has a very specific targeted effect on the bones, directing vitamin D into the bone structure for maximal effect.
Vitamins A,E, D and K, the fat soluble vitamins, as well as the carotenoids are important vitamins for your body’s overall health. Eating a diet rich in green leafy vegetables as well as colorful vegetables of the orange variety (sweet potatoes, squash, tomatoes, watermelons and cherries)will supply a lot of your body’s needs. Adding smart supplements will make sure that your body gets all it needs to function at its best.
Dr. Pamela Avery, the Natural MD, is a board-certified physician and specialist of over 30 years in the management of chronic disease through natural methods. She offers free articles, weekly newsletters and online chronic disease management lifestyle coaching. She has developed a lifestyle system for chronic pain entitled “Live Pain Free! 6 Steps to a Pain Free Life.” It can be accessed at drpamavery.com.