Vitamin D, a fat-soluble vitamin that has properties of both a vitamin and a hormone, is required for the absorption and utilization of calcium and phosphorus. It is necessary for growth, and is especially important for the normal growth and development of bones and teeth in children. It protects against muscle weakness and is involved in regulation of the heartbeat. It is also important in the prevention and treatment of breast and colon cancer, osteoarthritis, osteoporosis, and hypocalcemia; enhances immunity; and is necessary for thyroid function and normal blood clotting.
There are several forms of vitamin D, including vita-min D2 (ergocalciferol), which comes from food sources; vitamin D (cholecalciferol), which is synthesized in the skin in response to exposure to the sun’s ultraviolet rays; and a synthetic form identified as vitamin D$ , Of the three, vitamin 03 is considered the natural form of vitamin D and is the most active.
The form of vitamin D that we get from food or supplements is not fully active. It requires conversion by the liver, and then by the kidneys, before it becomes fully active. This is why people with liver or kidney disorders are at a higher risk for osteoporosis. When the skin is exposed to the sun’s ultraviolet rays, a cholesterol compound in the skin is transformed into a precursor of vitamin D. Exposing the face and arms to the sun for fifteen minutes three times a week is an effective way to ensure adequate amounts of vitamin D in the body. However, researchers have learned that very dark-skinned people in particular (because the skin pigment blocks the sunlight) and people living in the upper third of the continental United States cannot produce adequate amounts of vitamin D from exposure to the limited available sunlight during the winter months. Adolescents often are also deficient in vitamin D. For many, lack of outdoor exercise and an aversion to drinking milk seem to go hand-in-hand with deficiency.
The benefits of vitamin D include a reduction in the risk of colon polyps and prostate cancer, less coronary artery disease, and a decreased chance of developing type 1 diabetes, plus increased muscle strength and coordination, along with higher bone strength.
Severe deficiency of vitamin D can cause rickets in children and osteomalacia, a similar disorder, in adults. Lesser degrees of deficiency may be characterized by loss of appetite, a burning sensation in the mouth and throat, diarrhea, insomnia, visual problems, and weight loss. In a study reported in The New England Journal of Medicine, there are indications that vitamin D deficiency is much more wide-spread than previously thought, especially in older adults. In a group of people of whom few had risk factors for vitamin D deficiency, 57 percent were found to have below-normal levels of vitamin D. Sixty-seven percent of those reporting a vitamin D intake below the RDI had deficiencies categorized as moderate to severe.
Fish liver oils, fatty saltwater fish (especially mackerel), dairy products, and eggs all contain vitamin D. It is also found in butter, cod liver oil, dandelion greens, egg yolks, halibut, liver, milk, shiitake and chanterelle mushrooms, oatmeal, oysters, salmon, sardines, sweet potatoes, tuna, and vegetable oils. Herbs that contain vitamin D include alfalfa, horsetail, nettle, and parsley.
Vitamin D is also formed by the body in response to the action of sunlight on the skin. Intestinal disorders and liver and gallbladder malfunctions interfere with the absorption of vitamin D. Some cholesterol lowering drugs, antacids, mineral oil, and steroid hormones such as cortisone also interfere with absorption.
Thiazide diuretics such as chlorothiazide (Diuril) and hydrochlorothiazide (Esidrix, HydroDIURIL, Oretic) disturb the body’s calcium/vitamin D ratio. Taking excessive amounts of vitamin D (over 1,000 international units) daily may cause a decrease in bone mass.
Do not take vitamin D without calcium. Toxicity may result from taking excessive amounts of supplemental vitamin D.
Vitamin E is actually a family of eight antioxidant com-pounds. These consist of four tocopherols (alpha, beta, gamma, and delta) and four tocotrienols (also alpha through delta). The alpha-tocopherol form is the one found in the largest quantities in human blood and tissue. Small amounts of the gamma form are also found.
Alpha-tocopherol acts as an antioxidant in the human body. As an antioxidant, vitamin E prevents cell damage by inhibiting the oxidation of lipids (fats) and the formation of free radicals. It protects other fat-soluble vitamins from destruction by oxygen and aids in the utilization of vitamin A. It protects the low-density lipoproteins (LDL cholesterol) from oxidation as well. Oxidized LDL has been implicated in the development of cardiovascular disease. It is also known to inhibit blood platelet aggregation (clotting) and has other functions related to the activity of the immune system.
The most common dietary form of vitamin E is the gamma-tocopherol form. However, this form is not taken up by the body in any quantity because the liver selectively incorporates alpha-tocopherol into blood lipoproteins for de-livery to the tissues. About ten times more alpha-tocopherol than gamma-tocopherol is found in the blood. However, the gamma form may have some unique benefits in suppressing colon cancer, according to recent animal studies, making a sufficient amount of dietary vitamin E even more important to good health.
Vitamin E deficiency may result in damage to red blood cells and destruction of nerves. Signs of deficiency can include infertility (in both men and women), menstrual problems, neuromuscular impairment, shortened red blood cell lifespan, spontaneous abortion (miscarriage), and uterine degeneration. People with impaired balance and coordination and/or damage to the retina (pigmented retinopathy) may also be deficient. Individuals with severe malnutrition, genetic defects affecting a liver protein known as alpha-tocopherol transfer protein (alpha-TTP), or fat malabsorption problems such as those caused by cystic fibrosis, cholestatic liver disease, or Crohn’s disease may have a vitamin E deficiency. True vitamin E deficiency is rare, but low intake (lower than required) is relatively common.
One study showed that 27 to 41 percent of people studied had blood levels of alpha-tocopherol less than 20 micro-moles per liter (L), the level below which there appears to be an increased risk for cardiovascular disease. Low levels of vitamin E in the body has been linked to both bowel cancer and breast cancer.
The d-alpha-tocopherol form of vitamin E is the most potent, and is the one we recommend. Also, natural sources of vitamin E are better than synthetic vitamin E because natural vitamin E is more available for use by the body than the synthetic form. Synthetic vitamin E is only 67 percent as active as the natural form. Read labels closely. The natural form of vitamin E is listed as d-alpha-tocopherol, r-alpha-to-copherol, d-alpha-tocopherol acetate or d-alpha-tocopherol. The synthetic form is listed as dl-alpha-tocopherol or all-roc alpha-tocopherol (watch out for the / after the d). The synthetic form costs only about half as much as the natural form, but it has significantly less activity, or potency. Some vitamin manufacturers have been known to mix 10 percent natural and 90 percent synthetic vitamin E, then label the product natural. Your responsibility is to check the label and make sure it says 100 percent potency or 100 percent natural
If you cannot absorb fat, there is a special water-soluble form of vitamin E available from various suppliers.
What about the “esterified” vitamin E, otherwise known as tocopherol phosphate? This is a relatively new product that is being sold as vitamin E. This product is not actually recognized (by the FDA) as being vitamin E and the phosphate form is not natural, nor are there any studies proving that the body even needs this substance. We recommend using only tested products. There are esterified forms of alpha-tocopherol acetate and succinate available and you should use one of these if you want to try ester-E. Ester-E administered by injection may be beneficial in the treatment of tumors (cancer), and while the ester form has no antioxidant activity, it does appear to influence the death of cancer cells through apoptosis (programmed cell death). With this compound, administration by injection is required because the ester form would be converted to plain alpha-tocopherol in the gut and none would be delivered to the tissues.
Vitamin E is found in the following food sources: avocados, cold-pressed vegetable oils (olive, soybean, corn, canola, safflower, and sunflower), dark green leafy vegetables, legumes, nuts (almonds, hazelnuts, peanuts), seeds, and whole grains. Significant quantities of this vitamin are also found in brown rice, cornmeal, dulse, eggs, kelp, desiccated liver, milk, oatmeal, organ meats, soybeans, sweet potatoes, watercress, wheat, and wheat germ. Herbs that contain vitamin E include alfalfa, bladderwrack, dandelion, dong quai, flaxseed, nettle, oat straw, raspberry leaf, and rose hips.
The body needs zinc in order to maintain the proper level of vitamin E in the blood. Vitamin E that has oxidized a free radical can be revitalized by vitamin C and enabled to battle additional free radicals, according to Lester Packer, Ph.D., noted researcher and professor of molecular and cell biology at the University of California-Berkeley. Adding vitamin E to fats and oils prevents them from becoming rancid. The oxidation of fats is a key factor in the formation of plaque adhering to blood vessel walls.
If you take both vitamin E and iron supplements, take them at different times of the day. Inorganic forms of iron (such as ferrous sulfate) destroy vitamin E. Organic iron (ferrous gluconate or ferrous fumarate) leaves vitamin E intact.
If you are taking an anticoagulant medication (blood thin-ner), do not take more than 200 international units of vitamin E daily. If you suffer from diabetes, rheumatic heart disease, or an overactive thyroid, do not take more than the recommended dose. If you have high blood pressure, start with a small amount, such as 100 international units daily, and increase slowly to the desired amount. If you have retinitis pigmentosa that is not associated with vitamin E deficiency, do not take any supplemental vitamin E.
Vitamin K is needed for the production of prothrombin, which is necessary for blood clotting. It is also essential for bone formation and repair; it is necessary for the synthesis of osteocalcin, the protein in bone tissue on which calcium crystallizes. Consequently, it may help prevent osteoporosis.
Vitamin K plays an important role in the intestines and aids in converting glucose into glycogen for storage in the liver, promoting healthy liver function. It may increase resistance to infection in children and help prevent cancers that target the inner linings of the organs. It aids in promoting longevity. A deficiency of this vitamin can cause abnormal and/or internal bleeding.
There are three forms of vitamin K. The first is vita-min KI (phylloquinone or phytonadione), which comes from plants and makes up your dietary vitamin K. The second is vitamin K/2, a family of substances called menaquinones, which are made by intestinal bacteria and also found in butter, cow liver, chicken, egg yolks, fermented soybean products, and some cheeses. Third, there is vitamin KS (menadione), which is a synthetic, man-made substance.
Vitamin K! is found in some foods, including asparagus, blackstrap molasses, broccoli, Brussels sprouts, cabbage, cauliflower, chicken, dark green leafy vegetables, egg yolks, leaf lettuce, liver, oatmeal, oats, rye, safflower oil, soybeans, wheat, and yogurt. Herbs that can supply vita-min K! include alfalfa, green tea, kelp, nettle, oat straw, and shepherd’s purse. However, the majority of the body’s supply of this vitamin is synthesized by the “friendly” bacteria normally present in the intestines..