NUTRITION 101: LESSON FOUR
VITAMINS:
In previous lessons we discussed the macronutrients protein, carbohydrate and fat. In lesson four we will begin to look at the role micronutrients play in the creation and maintenance of health.
In order for our bodies to utilize the macronutrients of protein, carbohydrate and fat, a large number of co-factors are necessary. Vitamins, minerals and enzymes are major co-factors in facilitating utilization of the macronutrients. We will begin our discussion of micronutrients by looking at vitamins.
Vitamins are organic compounds and are called micronutrients because they are required in much smaller amounts compared to the macronutrients of protein, carbohydrate and fat. Vitamins, with few exceptions, cannot be manufactured endogenously (in the body) and therefore must be obtained from the diet or through supplementation. Vitamins are divided into two basic types, water soluble and fat soluble. Vitamin C and the B-complex are water soluble and vitamins A, E, D, and K are fat soluble.
Vitamin C
Vitamin C was discovered in relation to its deficiency causing scurvy, a disease that causes the walls of the capillaries to become extremely fragile, leading to excessive bleeding and anemia. Vitamin C prevents scurvy from occurring. Chemically, vitamin C is generally defined as ascorbic acid, and in its pure isolated form, is soluble only in water which means it will not be utilized in the fatty tissue of the body. Some researchers believe vitamin C is more accurately defined as a compound or complex consisting of ascorbic acid, bioflavonoids, the enzyme tyrosinase and other co-factors. Many vitamin C supplements are pure ascorbic acid synthesized from corn sugar or coal tar. Other vitamin C supplements include vitamin C derived from whole food sources which include the bioflavonoids and other co-factors. The research is inconclusive as to whether synthetic vitamin C is as effective as natural vitamin C found in food.
There is an esterfied form of vitamin C that is fat soluble. An ester is a compound produced by a reaction between an acid and an alcohol. Ascorbyl Palmitate is a fat-soluble ester form of vitamin C that consists of 42.8% ascorbic acid bound to 57.2% palmitic acid. Ascorbyl Palmitate is retained within the body for a longer period of time than water-soluble forms of vitamin C.
Ascorbyl Palmitate is more effective than water-soluble Vitamin C for preventing lipid oxidation (breakdown of fatty acids) and for transporting ascorbic acid to the heart, brain and central nervous system. Ascorbyl Palmitate appears to be more effective in preventing some forms of cancer compared to water-soluble forms of vitamin C. Oral Ascorbyl Palmitate works best when used in conjunction with water-soluble vitamin C leading some researchers to recommend vitamin C supplementation in the form of 50% Ascorbyl Palmitate combined with 50% pure ascorbic acid.
Because pure ascorbic acid can be irritating to the intestinal lining, it is best to obtain your vitamin C from food where it is naturally complexed with a variety of other nutrients. Vitamin C is available in a wide variety of fruits, vegetables, grains, legumes and even some animal products. Processing of foods, however, often destroys vitamin C content making it advisable to eat a certain amount of raw food on a daily basis and/or add additional vitamin C to the diet through supplementation.
To avoid possible irritation to the intestinal wall from pure ascorbic acid, you may want to supplement with a buffered from of vitamin C. Buffered forms of Vitamin C are combinations of ascorbic acid and some mineral which acts as the buffering agent. One example of a buffered vitamin C is calcium ascorbate which is 82% ascorbic acid bound to 18% calcium. Other buffered forms of vitamin C include magnesium ascorbate, potassium ascorbate and sodium ascorbate.
Ester-C is a patented form of Vitamin C that consists of several molecules of ascorbic acid linked together to form one large molecule. Ester-C also contains metabolites of Vitamin C such as threonic acid that are claimed by its manufacturer to increase its bioavailability. The research is mixed as to whether ester-C is utilized by the body more efficiently than other forms of this vitamin.
Vitamin C is used by the body for some 300 metabolic functions. This vitamin impacts the immune system by stimulating the movement of neutrophils and macrophages, as well as enhancing T cell formation and participating in the production of interferons which fight viruses. Vitamin C actually transforms oxidized vitamin E, making it again available as an anti-oxidant. Bioflavonoids, which are found with vitamin C in foods, increases the uptake of vitamin C into the liver, kidneys and adrenal glands and protects vitamin C from destruction and conversion to less active forms. When supplementing with vitamin C it is wise to use a supplement that includes the bioflavonoids.
Vitamin C is a major antioxidant and contributes to the prevention of free radical damage in the body. Vitamin C participates in the production of collagen protein which is the major protein found in connective tissue such as tendons, ligaments and cartilage. Vitamin C deficiency impairs the construction of collagen which leads to “leaky” tissue as seen in bleeding gums. Vitamin C is essential in the processing of various amino acids in the body. For example, the conversion of the amino acid lysine to the amino acid carnitine is dependent on vitamin C. Increasing dietary vitamin C has been shown to cause a definite increase in blood and tissue carnitine levels.
Supplemental vitamin C should ideally be taken at four hour intervals as the body excretes most ingested vitamin C within four hours after ingestion. Taking a “time released” vitamin C product will maintain blood levels for an extended period of time.
The average western diet contains 50 mg’s per day of vitamin C. The body needs 20 mg per day to prevent Scurvy. The optimal daily allowance recommended by nutritionists and nutrition orientated doctors is 1000 or more mg’s per day. This is the amount believed to be necessary for the prevention of disease.
The B-Complex:
The B-complex of vitamins are classified as B1 (Thiamine), B2 (Riboflavin), B3 (Niacin), B5 (Pantothenic Acid), B6 (Pyridoxine), B12 (Cyanocobalamin), Folic Acid, Biotin, Choline, and Para- Aminobenzoic Acid (PAPA). The B-complex is important to a wide range of physiological and psychological processes. The health of the nervous, cardiovascular, muscular, immune, hormonal and digestive systems are all dependent on a steady availability of the B vitamins. For example, vitamin B1 facilitates the conversion of dietary Carbohydrates into Energy and is required for the production of hydrochloric acid in the stomach which in turn is necessary for the breakdown of protein. A nervous system disorder called Beriberi, marked by pain, inability to move, and swelling, is caused by a deficiency of this vitamin.
Vitamin B2 is an essential co-factor for the endogenous production of Coenzyme Q10. This vitamin also helps facilitate the metabolism of carbohydrates and is essential for the absorption of the amino acid tryptophan. Vitamin B3 is essential to the body's production of energy due to its role in the manufacture of adenosine triphosphate (ATP), the basic energy molecule. A disease called pellagra, characterized by dermatitis, diarrhea, and disorder of the central nervous system, occurs as a direct result of Vitamin B3 deficiency and can be cured with vitamin B3 supplementation. Vitamin B5 is essential for the production of most adrenal hormones and is required for the manufacture of hemoglobin. Vitamin B6 facilitates the breakdown of dietary proteins into individual amino acids and is essential for the proper metabolism of dietary carbohydrates. This vitamin is also necessary for the proper metabolism and utilization of glucose in the body.
Vitamin B12 is required for the formation of red blood cells. A condition call pernicious anemia may occur as a direct result of Vitamin B12 deficiency. Pernicious anemia is a condition in which there are too few red blood cells or the red blood cells are deficient in hemoglobin resulting in poor oxygen carrying capacity of the blood resulting in low energy and general poor health. Pernicious Anemia can usually be totally rectified with either oral or injected Vitamin B12 supplementation. Vitamin B12, along with B6 and folic acid, will lower elevated homocysteine levels. Homocysteine is a risk factor for cardiovascular disease.
Folic acid is essential to the formation of a number of amino acids, hemoglobin, Coenzyme Q10, and the brain chemical serotonin. Epidemiological studies have indicated that people with a low daily intake of folic acid have a 69% greater risk of Ischemic Heart Disease than people who consume 400 mcg or more of folic acid per day. Folic Acid (at least 400 mcg per day consumed by women during Pregnancy) is seen to prevent most neural tube defects, especially Spina Bifida.
Biotin, Choline, and Para- Aminobenzoic Acid (PAPA), are essential for a variety of functions including neuron-transmission, health of the hair, skin and nails, and antioxidant activity.
As can be seen, the B-complex is essential to our health. We have touched on just a few of the many needs the body has for the B-complex. B vitamins are present in a broad spectrum of foods including vegetables, grains, legumes, eggs, liver, nuts and seeds, and a variety of herbs. Daily requirements can vary based on individual differences in genetic inheritance, dietary practices and general life style. When supplementing with B vitamins it is best to take them as a complex. Individual B vitamins can be taken therapeutically to deal with specific health problems. As with Vitamin C, many B vitamin supplements are synthetically manufactured from non-food sources such as coal tar and petroleum derivatives. Natural sources for Vitamin B supplements are rice brand, molasses and brewer's yeast.
In our previous lesson we begin to look at the role micronutrients play in the creation and maintenance of health by examining the water soluble vitamins C and the B complex. This month we will continue to explore the micronutrients by looking at the fat soluble vitamins A and E.Fat soluble vitamins are those that require fatty acids to be present in the diet in order to be utilized and also can be stored in fatty tissue for later use as compared to water soluble vitamins which cannot be stored in the body and must be replaced on a daily basis.
Vitamin A:
Vitamin A is the collective name for a group of fat soluble substances having vitamin A activity. Animal products, such as egg yolk, milk, and liver, contain retinyl esters which are hydrolyze to retinol within the human Intestines. Retinol is the common name for vitamin A. Retinyl esters are organic fragrant compounds formed in a reaction between an acid and an alcohol with the elimination of water. When retinol is manufactured within the intestines from retinyl and other substances having vitamin A activity, it is transported within the blood serum to the cells by retinol binding protein. 1 mcg of retinol is equal to 3.33 IU of Vitamin A activity. Dehydroretinol, also known as vitamin A2 is the form of vitamin A found in the Livers of Fish. Dehydroretinol possesses 40% of the biological activity of retinol.
Vitamin A can be derived indirectly from plants. Plant products, such as carrots, tomatoes, squash and beets have compounds called carotenoids of which over seven hundred different ones have been identified in nature. These carotenoids give fruits and vegetables their distinctive orange, yellow and red colors. Beta-carotene is a carotenoid that when ingested can be converted in the liver to retinol as the body needs it. Beta-carotene also acts on its own as an important anti-oxidant in the body. Other carotenoids which have recently gained in popularity are lycopene, lutein, and zeaxanthin. While many carotenoids can be converted to retinol in the liver, some, such as lycopene, cannot.
Vitamin A is very important to the health of the eyes. In the body it is converted to retinoldehyde which serves as a visual pigment facilitator in the eye. Vitamin A also combines with a protein in the eye to form rhodopsin which facilitates night vision. The lack of vitamin A leads to rhodopsin depletion which in turn leads to impaired night vision.
Vitamin A is critical to the health of both the external and internal skin of the body. Many skin problems have been resolved by increasing vitamin A levels in the body. Vitamin A appears to play a role in numerous body functions including the health of the digestive, nervous, musculoskeletal, respiratory, sexual, and immune systems. Research has shown that administering large doses of this vitamin prior to and after surgery has reduced the immune depression caused by the surgery and accelerated the healing process. Research has shown vitamin A to be a key nutrient in the treatment and prevention of a variety of cancers. Protein cannot be utilized without vitamin A being involved.
Because it is fat soluble, vitamin A does not absorbed across the brush boarder cells of the intestinal tract like water soluble vitamin do. Vitamin A must first be emulsified by liver bile and then taken up into the lymphatic system. Individuals who do not have a good flow of bile may have some difficulty absorbing vitamin A, as well as, other fat soluble vitamins and fats in general. Diabetics have difficulty absorbing vitamin A. Overall, dietary vitamin A has been shown to be about 85% absorbed in a healthy person.
The RDA of vitamin A for adults is 10,000 IU per day. This is the total recommended daily intake of vitamin A (including from dietary sources) for adults. Much of this dosage will be derived from the diet. Therefore a suggested range of vitamin A supplementation for healthy people is 5,000 IU per day for men and 2,500 IU per day for women. A therapeutic dosage of 100,000 IU of vitamin A has been used on a daily basis for short periods in clinical trials to treat severe acne and accelerate healing of wounds. Dosage of 100,000 - 200,000 IU of Vitamin A is used by many cancer patients to suppress the further growth of tumors. Some cancers require even higher dosages. Cancer patients using high doses of vitamin A should be tested periodically by a physician for vitamin A toxicity. Many studies have demonstrated that the use of high doses of Vitamin A of up to 300,000 IU for a few months to treat various ailments does not cause toxicity. The risk of Vitamin A toxicity increases if high doses are used for longer than a few months.
Symptoms associated with excessive consumption of vitamin A are nausea, blurred vision, headaches, fatigue, bone pain and dry skin. As these symptoms can also be signs of vitamin A deficiency and other deficiencies/health problems, one needs to be careful in attributing these symptoms to an overdose of vitamin A.
Women should not consume more than 10,000 IU of vitamin A per day during pregnancy as amounts above this level have been shown (especially during the first seven weeks of pregnancy) to cause birth defects in approximately 2% of pregnancies. It may be prudent to ensure that daily vitamin A consumption does not exceed 5,000 IU during pregnancy. It may be advisable for pregnant women to avoid vitamin A supplementation altogether and, if necessary, use beta-carotene supplements instead. Beta-Carotene is incapable of causing vitamin A toxicity as it is only converted to vitamin A (retinal) as The body needs it.
Concerns about vitamin A toxicity, while valid, may need to be viewed in light of the fact that many people use 200,000 IU of supplemental vitamin A every day without ever experiencing Vitamin A toxicity. Some people occasionally take a single dose of 2,000,000 IU of Vitamin A without experiencing Vitamin A toxicity. The human Liver can store up to 500,000 IU of vitamin A. Vitamin A supplements are most effectively utilized when they are taken in divided doses with a fat-containing, low fiber meal. Supplemental vitamin A is available in various dosage levels as is beta-carotene. Cod liver oil is an excellent source of Vitamin A in a food form.
Vitamin E:
In nature, vitamin E occurs as a complex of four tocopherols (alpha, beta, gamma, and delta) and four tocotrienols (alpha, beta, gamma, and delta). Alpha-tocopherol has been studied the most and it is this form of vitamin E most often found in supplements.
Supplemental vitamin E, as d-alpha tocopherol, is generally derived from soy bean oil. A synthetic form of vitamin E is found in some multiple vitamin/mineral supplements and vitamin E supplements and is designed as dl alpha tocopherol as opposed to d alpha-tocopherol. This synthetic product is often made form petroleum derivatives. Research shows synthetically produced vitamin E has a different molecular structure than natural E and is not utilized by the body as well as natural E.
Vitamin E is absorbed through the ileum of the small intestines and passes into the lymph and then into the Blood. It is stored in the liver. On average, 20 to 40 percent of orally consumed vitamin E is absorbed by the body. The ability of an individual person to absorb vitamin E varies according to their ability to absorb lipids fats.
Increasing interest has centered on the role of tocopherols other than d alpha as well as the four tocotrienols. Some research indicates that gamma tocopherol may provide greater protection against cancer and heart disease than d alpha. Research on vitamin E has demonstrated its effectiveness in overall support of the cardiovascular and circulatory systems. It is shown to suppress tumor growth, slow the development of Alzheimer’s and dementia, reduce pain of rheumatoid arthritis, protect vision and support the immune system as a strong anti-oxidant.
In November of 2004, the national press reported on a recent John Hopkins meta-analysis of 19 studies involving vitamin E supplementation by people suffering from heart disease, end-stage renal failure and Alzheimer’s disease. It was reported that those who took 400 international units (IU) or more per day of vitamin E, were 6% more likely to die from any cause than those who did not take vitamin E supplements. The media proclaimed that supplementation of vitamin E above 400 IU per day increased the risk of death.
What the press didn’t report was that further analysis of this study showed increased risk of death statistically significant only for those taking 2000 IU/day, and that the authors of the study readily admitted that their findings might not apply to healthy people. The authors also pointed out that the analyzed studies were often small and were conducted on patients with chronic disease.
What the press also didn’t report was the results of three other meta-analyses multiple studies involving people with cardiovascular disease taking vitamin E. These studies, as reported by the Linus Pauling Institute, showed supplementation up to 800 IU/day had no bearing on death from any cause.
Unfortunately, the John Hopkins report has caused some to discontinue supplementation with vitamin E or greatly reduce the dosage. It must be pointed out that thousands of studies have been done showing the efficacy of vitamin E supplementation. Vitamin E is one of the most researched of all the vitamins.
In the Cambridge Heart Antioxidant Study reported in Lancet (1996), investigators found that 400 to 800 IU/day of vitamin E supplementation significantly reduced cardiovascular disease and improved mortality.
In a study by Boaz reported in Lancet (2000), hemodialysis patients with cardiovascular disease (age 40 to 75 years old) received either 800 IU/day of vitamin E or a placebo for approximately 519 days. The results showed a significant decrease in cardiovascular disease and myocardial infarction among users of vitamin E.
In the Nurses’ Health Study reported in Stampfer (1993), of the 13% of 87,000 nurses who regularly used vitamin E supplements, there was a 31% reduction in relative risk for non-fatal myocardial infarction and death from cardiovascular disease compared with women who did not take vitamin E.
Another study reported in 2000 showed that a combined supplementation of vitamin E and slow-released vitamin C reduced the progression of atherosclerosis in men by 74% over a three-year period.
In a study by Rimm (1993) in which 39,000 male health professionals were studied for four years, 17% of the men took vitamin E supplements. Those who took the highest dose (median of 419 IU/day) had a 40% reduction in the relative risk for non-fatal myocardial infarction or death from coronary heart disease.
Unfortunately, these kinds of studies are never picked up by the national press which leaves people uninformed as to the benefits of vitamin E. Most diets are deficient in E. The average human diet supplies 14.8 IU of vitamin E per day. The National Academy of Sciences has defined the “tolerable upper intake level” as 1,500 IU per day for natural d-alpha tocopherol. Dosages of up to 3,200 IU of Vitamin E have been used daily in a wide variety of subjects for periods of up to two years without any unfavorable side effects occurring. Supplementation with 400 to 800 IU's per day is adequate for most people. Food sources of E are wheat germ, soy, eggs, whole grains and vegetables. We recommend daily supplementation with a mixed tocopherol/tocotreniol formula.Vitamin D is a fat soluble vitamin made in your body as a result of your skin being exposed to ultraviolet (UV) rays from the sun. Vitamin D is also available in some foods. This vitamin exists in several forms with vitamin D3, also known as cholecalciferol, being the form that is made in the skin when 7-dehydrocholesterol a cholesterol compound, reacts with ultraviolet light from the sun. Once made in the skin, cholecalciferol is transported to the liver where it is made into calcidiol (25-hydroxy-vitamin D). It is this form of the vitamin that the body stores for use. Measuring the blood level of calcidiol is the only way to determine vitamin D levels.
The most active form of the vitamin is calcitriol (1, 25 dihydroxy vitamin D3), which is synthesized from calcidiol in the kidneys where it functions as a hormone by sending messages to the intestines to increase the absorption of calcium and phosphorus. A major biologic function of vitamin D is to maintain normal blood levels of these two minerals. By promoting calcium absorption, vitamin D helps to form and maintain strong bones and teeth. Insufficient vitamin D, can lead to thin, brittle bone tissue and dental problems.
Research shows vitamin D is also involved in helping to maintain a healthy immune system, regulate cell growth and differentiation, and facilitate normal cardiovascular function. Studies suggest that higher levels of vitamin D correlates with lower incidence of certain cancers. . Researchers have observed that greater exposure to sun is associated with lower death rates from colon and colorectal cancers. Vitamin D emerged as a protective factor in a study of over 3,000 adults (96% of whom were men) who underwent a colonoscopy between 1994 and 1997 to look for polyps or lesions in the colon. About 10% of the group was found to have at least one advanced cancerous lesion in the colon. There was a significantly lower risk of advanced cancerous lesions among those with the highest vitamin D levels. Others studies have shown vitamin D to be a protective factor against breast cancer. Clinical studies show vitamin D deficiency to be associated with four of the most common cancers: Breast prostate colon and skin
Vitamin D deficiency has been shown to possibly be linked to diseases such as various cancers, chronic pain, weakness, chronic fatigue, autoimmune diseases like multiple sclerosis, Type 1 diabetes, high blood pressure , mental illnesses (depression, seasonal affective disorder and possibly schizophrenia) heart disease, rheumatoid arthritis, psoriasis, tuberculosis, periodontal disease and inflammatory bowel disease. On the other hand, some research indicates that in some chronic diseases where vitamin D levels (25-hydroxy-vitamin D) appear to be low, they are low because the disease causes too much production of the vitamins active hormonal form, (1, 25 dihydroxy vitamin D) which can be harmful in amounts beyond normal range.
Vitamin D and the sun:
Human skin exposed to sunlight can, under the right conditions, produce quantities as large as 20,000 IU in just a few minutes without any apparent toxicity. This is easily enough to avoid deficiency and the vitamin does build up in the body tissue. Exposure to sunlight also destroys vitamin D, so long term exposure to sunlight cannot cause toxicity, as levels are self-adjusting.
On the other hand, merely being exposed to sunlight does not automatically mean that vitamin D is produced as only the UV rays in sunlight trigger vitamin D production. UV rays mainly reach ground level when the sun is high in the sky. This occurs a few hours around solar midday (1 pm summertime). At higher latitudes, the sun is only high enough in the sky in summer. For example, in the United States, those living north of a line from San Francisco to Philadelphia (about 40 degrees of latitude) will not be able to produce vitamin D in significant quantities for 3 to 6 months a year.
Those living in the higher latitudes from the end of summertime to the following spring must rely on stores of this vitamin which gradually deplete. By some estimates 10 to 20% of the population becomes at least mildly deficient by the end of winter. Sunscreens over 8 SPF significantly interfere with production of Vitamin D3. Melanin, the dark pigment found in skin, screens UV light so dark skin is much less efficient at generating vitamin D. People with darker skin experience greater vitamin D deficiencies, especially if they live at higher latitudes or have an urban lifestyle. Research shows. Vitamin D deficiency is known to be endemic in dark-skinned populations in the UK.
Vitamin D from food:
Vitamin D3 (cholecalciferol) is found in egg yolk, animal fat, various fish and cod liver oil. Vitamin D2 (ergocalciferol) is found in plants and is a less biologically active form of this vitamin. The vitamin D that is added to milk and some other foods is D2. Multi-vitamin/mineral supplements will often use Vitamin D2 in their formula. When buying a multiple or a vitamin D supplement, look for vitamin D3 (cholecalciferol) on the label as this is the more biologically active form.
Vitamin D from Cod Liver Oil:
Vitamin D3 can be obtained from cod liver oil. Taking one teaspoon for every 50 pounds of body weight will provide the average 150 pound adult, with 2-3,000 units of vitamin D. Vitamin K is also present in cod liver oil and is an essential co-factor in building strong bones. Natural vitamin A (retinol) is also present in cod liver oil. Vitamin A is essential to immune function, healthy skin and numerous other areas of our physiology. Additionally, vitamin A provides a protective benefit in limiting to high of a calcium level in the body from the action of vitamin D. Vitamin A antagonizes calcium response to vitamin D in humans. Cod liver oil is also a great source for the very beneficial omega three fatty acids EPA and DHA which most Americans are deficient in. We recommend the Carlson brand of cod liver oil. This brand has an excellent track record of quality and comes in a lemon flavored taste that virtually removes the taste of the oil.
Testing for vitamin D in the body:
There are two vitamin D tests that can be performed by your doctor. One is called 1, 25(OH) D and the other is called 25(OH) D, sometimes referred to as 25-hydroxyvitamin D. The 25(OH) D is the better marker of overall D status. It is this marker that is most strongly associated with overall health.
How much Vitamin D do we need?
Current FDA recommendations are between 200 and 400 international units (IU) per day. Recent and ongoing research is finding that this recommendation is far to low. Such research has shown that much higher dosages of vitamin D would reduce the risk of not only osteoporosis but such serious health problems as cancer and cardiovascular disease. In the 2004 October/November issue of “Integrative Medicine,” in an article entitled, “The Clinical Importance of Vitamin D (Cholecalciferol): A Paradigm Shift with Implications for All Healthcare Providers,” the authors provided considerable evidence that there is an epidemic of vitamin D deficiency. These authors recommended intake of up to 4000 IU of Vitamin D per day for adults and several thousand IU for children.
At Milk ‘N Honey we recommend getting plenty of sunlight (minus the sunscreen) during the summer months and supplementing with Vitamin D during late fall through early spring. Cod liver oil and a variety of vitamin D products are available at Milk ‘N Honey.
Vitamin K
Vitamin K is a fat-soluble vitamin. The "K" is derived from the German word "koagulation." Coagulation refers to blood clotting. K is essential for the functioning of several proteins involved in the blood clotting process. Natural vitamin K derived from plants is called phylloquinone or K1. K is also synthesized from bacteria in the colon of both man and animals and is known as a family of substances called menaquinones or K2. Vitamin K1 is converted in the body to Vitamin K2. Vitamin K3 is a synthetic form of Vitamin K that possesses twice the potency of Vitamin K1. Vitamin K is absorbed by the ileum and jejunum of the small intestine. Vitamin K should be consumed with dietary fats to facilitate absorption.
Vitamin K1 is found in green vegetables such as broccoli, spinach, kale, Swiss chard, string beans, Brussels sprouts and leaf lettuce. Vegetable oils derived from soybeans, cottonseeds, rape seed (canola) and olives are major contributors of dietary vitamin K. Hydrogenation of vegetable oils may decrease the absorption and biological effect of dietary vitamin K.
While vitamin K is best known for its role in blood clotting, it also is important to the maintenance of bone tissue and sustaining arterial health. A study which involved more than 72,000 women for 10 years found that women whose vitamin K intake was low had a 30% higher risk of hip fracture than women with higher vitamin K intake. . One study of postmenopausal women found low dietary vitamin K intake to be associated with increased risk of aortic calcification, as visualized by chest x-rays.
Some oral anticoagulants, such as the drug Coumadin (the rat poison warfarin), inhibit coagulation through antagonism of the action of vitamin K. Although vitamin K is a fat-soluble vitamin the body stores very little of it. Its stores are rapidly depleted without regular dietary intake. Perhaps, because of its limited ability to store vitamin K, the body is able to recycle it. Coumadin prevents the recycling of vitamin K by inhibiting two important reactions and thus can create a vitamin K deficiency if there is little replenishment of this vitamin. Some researchers state that high vitamin K intake does not cause excessive blood clotting (overcoagulation) as the proteins involved in coagulation have only a finite number of spaces for vitamin K uptake.
The recommended daily allowance (RDA) of vitamin K is 80 micrograms for men and 65 micrograms for women. Some medical experts believe that the current RDA for vitamin K is too low to exert the therapeutic effects attributed to Vitamin K such as protecting the bones and arteries. These same experts now recommend an optimal daily intake of 10 milligrams of vitamin K per day. Vitamin K is available as a supplement but the recommended way to obtain it is to eat your vegetables on a daily basis.
Lesson Five: Minerals