RDA or AI of the Essential Fat Soluble Vitamins
(in micrograms [ug] & milligrams [mg]
|Vitamin A (retinol)|
| Vitamin D|
| Vitamin E|
| Vitamin K|
is a publication that sets long-term national goals for improving the overall health of Americans. Unlike the Dietary Guidelines and MyPyramid, which provides information to individuals, the goals and objectives put forth in Health People 2020 are meant to be used by government agencies, communities, and professional organizations to help develop programs to improve the health of our communities.
Fat Soluble Vitamins
Fat soluble vitamins are organic substances that dissolve in lipids and are vital to health. Fat soluble vitamins include Vitamins A, D, E, & K. Fat soluble vitamins are key players in cell growth, maturation, and gene regulation. They are absorbed in the small intestine. They require that lipids (fats) are also eaten along with them for adequate absorption. They are stored in the body, so toxicity is something to be careful of.
Vitamin A: (Retinoic Acid). Provitamin A Carotenoids (beta-carotene) can be converted to Vitamin A. Functions of Vitamin A include: cell differentiation, maintaining healthy immune system, vision, reproduction, and maintaining immune function. Thus deficiencies lead to increased risk of infections. Vitamin A Deficiency Levels include the following: The first level of deficiency is Night Blindness. The second level of deficiency is Xerophthalmia (Dry Eyes): the white of the eye loses its shine and begins to wrinkle. The third level of vitamin A deficiency is Bitot's Spots Patches: little gray bubbles form on the whites of the eye. The forth level of deficiency is Corneal Ulceration: dullness of damage to the cornea. The fifth level of deficiency is Keratomalcia: soft or bulging cornea. The sixth level of deficiency is increased risk of infection. The 7th level is Hyperkeratosis: skin is rough, bumpy, irritated. The progression of Vitamin A Deficiency is as follows: First: Night Blindness -which is reversible; Second: Degradation of the epithelium of the cornea - also reversible; Third: Xeropthalmia, Hyperjeratosis, drying of the cornea, formation of opaque area - this is irreversible; Finally: Irreversible damage to the cornea leads to blindness. Hypervitaminosis A (excess intake of vitamin A) can cause blurred vision, liver abnormalities, reduced bone strength, and birth defects. Hypercarotenemia (excess intake of carotenoids) can cause elevated serum beta-carotene levels, leading to the formation of orange skin. Acute Toxicity involves single very high does of vitamin A either from food or supplement use (>200,000 IU at one time). Symptoms include: Nausea, vomiting, headache, increased CSF, blurred vision, and loss of coordination. Chronic Toxicity is increasingly common in the developed world and primarily caused by supplement consumption (for instance 25,000 IU for 10-25 yrs). Symptoms are variable, and include: hepatomegaly, anemia, bone pain, irritability, skin lesions. Teratogenic Effects involves excessive intake of dietary vitamin A or through supplemental use (possibly as low as 10,000 IU per day during pregnancy), or as the consequence of the clinical use of all-tans-retinoic acid (Retin-A) or 13-cis-retinoic acid (Accutane). Symptoms include: Craniofacial, heart, kidney.
Vitamin K: Vitamin K is involved in blood coagulation, and artery and bone formation. Vitamin K is required for post-translational modification of proteins that "activates" them. If there is no Vitamin K, then we can't activate thrombin and blood clots can't form. If blood clots cannot form, wounds cannot heal. In addition to blood coagulation, Vitamin K also catalyzes carboxylations of other proteins for bone and tooth development. Vitamin K binds Calcium, so ingesting sufficient vitamin K is very important when it comes to preventing brittle bones. Food sources of Vitamin K includes many dark green vegetables, such as asparagus, broccoli, and brussels sprouts. Fish and legumes also provide Vitamin K. Excessive exposure of foods to light and heat can destroy vitamin K.
Vitamin D: (Ergocalciferol in plants; Cholecalciferol in animals). Vitamin D is a powerful hormone. Synthesis of Vitamin D occurs in the skin and is activated by UV light. ~10-15 minutes of sunlight 3 times each week is enough for the body to produce adequate amounts of cholecalciferol (Vitamin D3). People with darker skin need up to 3 times more sun exposure. This is because darker skin contains more melanin, a pigment that blocks synthesis of precalciferol. Vitamin D functions to help maintain Calcium Homeostasis. Low blood Calcium concentration leads the body to increase vitamin D activation within the kidneys. This in turn leads to increased calcium absorption within the small intestines. Vitamin D up-regulates several genes that code for proteins required of the transport of dietary calcium into the enterocytes. In other words, vitamin D is involved in cell signaling. Without vitamin D, these proteins cannot be made and calcium absorption is severely limited. Calcium in bones is important for their structure. Calcium in the blood also has additional physiological functions. It is needed for muscle contractions, blood pressure regulation, and the conduction of neural impulses. Without vitamin D to help maintain adequate levels of calcium in the blood, these vital functions would be impaired. Vitamin D is also involved in cell differentiation (bone and intestinal cells) and may protect agains colon, breast, skin, and prostate cancer. Vitamin D deficiency leads to: Osteomalacia - inadequate mineralization of bone in adults (more common amongst those with dark skin) causing bones to become soft and weak. Symptoms include diffuse bone pain and muscle weakness; Rickets - in infants and children who are in active stages of growth, vitamin D deficiency can result in inadequate bone mineralization causing bowed legs or knocked knees; and Osteoporosis - demineralization of bone, the ultimate resulting disease from prolonged osteomalacia. Toxicity is uncommon. Supplementation with high doses can cause calcium levels in the blood to rise causing hypercalcemia.Hypercalcemia can result in the deposit of calcium in soft tissue such as the heart and lungs, and can affect the function of the Central Nervous System (CNS). Vitamin D toxicity promotes bone loss and can result in death.
Vitamin E: (alpha tocopherol). Vitamin E reduces free radicals (thus functions as an antioxidant), stabilizing them so that they do not damage the cell membrane. Thus, Vitamin E protects cell membranes. Its ability to act as an antioxidant is enhanced in the presence of other antioxidant micronutrients, such as vitamin C and selenium. Vitamin E protects DNA against free radical damage that can result in cancer. It protects the eye tissue against free radical damage that can result in cataract formation. Vitamin E also prevents free radical reactions ultimately resulting in heart disease by slowing down the rate of plaque formation, and ultimately protecting against the formation of atherosclerosis. Supplements fail to show a significant effect on the body. Vitamin E is abundant in vegetable oils, nuts, and seeds. Some dark green vegetables such as broccoli and spinach contain Vitamin E. But Vitamin E is easily destroyed during food preparation, processing, and storage. Vitamin E deficiency leads to hemolytic anemia (very rare). Those susceptible to Vitamin E deficiency are those who suffer from fat malabsorption (gallbladder disease leads to fat malabsorption because of bile mal-production); and preterm infants. This is characterized by neuromuscular problems, loss of coordination, and muscular pain. Red blood cell membranes weaken and rupture which reduces RBCs ability to transport oxygen, resulting in weakness and fatigue. The more Polyunsaturated Fatty Acid (PUFA) content consumed leads to more susceptibility to free radical damage, and a higher requirement of Vitamin E intake. Vitamin E toxicity is rare even with high intakes of supplements because the supplemental form of vitamin E is less biologically active then naturally occurring vitamin E, so that large doses can be consumed without adverse effects. Although toxicity can cause bleeding or hemorrhage due to genetic differences.
Deficiency of the water-soluble vitamins leads to the 3 D's: Dermatitis, which affects the skin (the cells turn over faster, meaning they die faster); Diarrhea, which affects the intestines (the cells turn over fast, once again meaning that they die fast); Dementia, which affects nerve function and the brain. Deficiency of water-soluble vitamins cause anemia and damage to vessel integrity as well.
B-Vitamins There are 8 B-vitamins. They dissolve very easily in water. They are generally readily excreted and are subject to cooking loss. They participate in energy metabolism. 50-90% of B-vitamins are absorbed in the body. Marginal deficiency is common. You can preserve some of the lost B-vitamins by steaming, stir-frying, microwaving, or simmering in minimal moisture. Typically B-vitamins are not deficient in American diets (a lot due to fortification). Marginal deficiency, however, can increase the risk for cardiovascular disease, cardiac arrest, and cataracts. B-vitamin deficiency can lead to Glossitis (raw swelling of the tongue).
- Thiamin (B1): the "first" B-vitamin. It contains sulfur ("thio") and nitrogen ("amine") groups. Thiamin is destroyed by alkaline and heat environments. Excess thiamin is quickly excreted in the urine. Some great food sources include: white bread, pork, hot dogs, luncheon meat, cold cereal, orange juice, sunflower seeds, green beans, mushrooms, and enriched grains/whole grains. Deficiency of thiamin leads to BeriBeri. Overall symptoms of BeriBeri include: weakness, nerve degeneration (peripheral neuropathy), irritability, poor arm/leg coordination, and loss of nerve transmission.
- Riboflavin (B2): a small amount is stored in the liver and excess is excreted in the urine. Good food sources include: milk products, enriched grains, liver, oyster, and Brewer's yeast. Riboflavin is sensitive to UV radiation (sunlight). Therefore, it is stored in paper, opaque plastic containers. Deficiency of Riboflavin is rare and leads to Ariboflavinosis. Symptoms of Ariboflavinosis includes glossitis, cheilosi, seborrheic dermatitis, stomatitis, eye disorder, throat disorder, and nervous system disorder. Ariboflavinosis occurs within 2 months of Riboflavin deficiency, usually in combination with other deficiencies.
- Niacin (B3): great food sources of niacin includes: mushrooms, enriched grains, beef, chicken, turkey, and fish. Niacin is heat stable, so there is little cooking loss. Deficiency of niacin leads to Pellagra. Pellagra causes the 3 D's. Pellagra occurs within 50-60 days of niacin deficiency. Niacin can cause decreased appetite and weight loss and is commonly accompanied by a red rash (flushing). You can prevent the flushing effect if the niacin intake accompanies an adequate protein diet and acetaminophen (tylenol). Toxicity effects including flushing, burning, tingling, itching, reddening of skin, nausea, and liver abnormalities. Niacin deficiency was the only deficiency disease to reach epidemic proportions in the US (WWI to WWII: ~200.000 to millions were affected). Niacin is used as a medicine today. 1.5-2.0 grams per day of nicotinic acid (nicotinamide doesn't work) can lower total and LDL cholesterol, and increase HDL. Increased HDL can slow/reverse progression of atherosclerosis (along with diet and exercise). 2 grams per day is the mega dose and has been shown to cause toxicity effects. The Tolerable Upper Limit for niacin is 35 mg per day for adults and 10-30 mg of niacin per day for children. Niacin reduces recurrent myocardial infarction and increases long-term survival. Niacin should be monitored carefully because of its side effects.
- Pantothenic Acid (B5): is essential for metabolism of carbohydrates, fats, and proteins. Pantothenic acid was discovered in the 1930s. It cured an experimental deficiency in chicks that caused dermatitis. In 1947, we discovered that the biologically functional form of pantothenic acid is a part of Coenzyme A (CoA) Pantothenic Acid is synthesized by intestinal microbes, and metabolized to two major enzyme cofactors: CoA and Acyl Carrier Protein (ACP).
- Biotin: there are 2 forms of this very important B-vitamin: free biotin and protein bound biotin. Biotinidase is an enzyme founding the small intestines that releases the protein bound to the biotin (from the protein bound biotin) and allows for biotin's absorption. Infants with a genetic defect causing low levels of biotinidase are at an increased risk for biotin deficiency. Biotin functions as a cofactor, in addition to assisting in fat and carbohydrate metabolism. Biotin deficiency is rare. Biotinidase deficiency signs and symptoms include: skin rash, hair loss, convulsion, and neurological disorders.
- Vitamin B6: (Pyridoxal, Pyridoxine, Pyridoaximine). The main coenzyme form of vitamin B6 is pyridoxal phosphate (PLP). PLP is used by many enzymes involved in the metabolism of protein. PLP is also involved in transamination (amino acid carrier [amino transferases]), which is involved in the making of NADH (ENERGY!!). PLP is primarily involved in amino acid metabolism and finally also involved in the synthesis of neurotransmitters.
- Folate: (Folic Acid, Folacin). Folate deficiency has many identical deficiency signs and symptoms as seen in vitamin B12 deficiency. This is because vitamin B12 is needed in order to recycle the folate coenzyme. A function of folate is DNA synthesis. SOme great food sources for folate includes: liver, fortified breakfast cereal, grains, legumes, and leafy vegetables. Deficiency of Folate includes: Megaloblastic Anemia and Neural Tube Defects. Neural Tube Defects include spin bifid a and anencephaly which is an infant born without a brain.
- Vitamin B12: (Cobalamin). Vitamin B12 is called Cobalamin because it contains cobalt. Vitamin B12 regenerates folate in one reaction and is synthesized exclusively by microorganisms (bacteria, fungi, and algae). Food sources of Vitamin B12 include: liver (since Vitamin B12 is stored primarily in the liver), animal products (meats, dairy products), seafood, and eggs. Vegans/vegetarians are often Vitamin B12 deficient. Elderly adults often don't absorb Vitamin B12 because they stop making proteins that help with B12's absorption. R-protein, made in salivary gland, protects B12. Intrinsic Factor, made in the stomach, protects B12 and helps with B12 absorption into intestinal cells. Since elderly adults stop making R-Proteins and Intrinsic Factors, therapy for ineffective absorption of Vitamin B12 is often necessary. Therapy for ineffective absorption includes monthly injections of Vitamin B12, Vitamin B12 nasal gel, and megadoses of Vitamin B12 to allow for passive diffusion. Vitamin B12 is non-toxic so the average intake can exceed the RDA. Deficiency of Vitamin B12 includes Megaloblastic anemia and Pernicious anemia. Pernicious anemia involves: nerve degeneration, muscle weakness, tingling/numbness in the extremities, paralysis and death. B12 Deficiency looks like folate deficiency and is usually due to decreased absorption ability - especially in the elderly.
- Vitamin C: In its reduced form, Vitamin C is called Ascorbic acid. In its oxidized form, Vitamin C is called Dehydroascorbic acid. Vitamin C is synthesized by most animals (but not by humans). Excess is excreted, therefore excess is NOT STORED IN THE BODY. Vitamin C is an electron donor involving proline hydroxyls and collagen formation. Vitamin C is also an antioxidant. It cycles between reduced and oxidized forms. Most importantly, it reduces the Iron and Copper atoms in important enzymes. Functions of Vitamin C includes: functioning as a reducing agent (antioxidant); functioning in iron absorption; functioning in the synthesis of serotonin, thyroxine, corticosteroids, and collagen; and recharges enzymes. Food sources for Vitamin C (which are easily lost through cooking) includes: Citrus Fruits, Potatoes, Green Peppers, Cauliflower, Broccoli, Strawberries, Romaine Lettuce, Spinach. The RDA for Vitamin C is 90 mg per day for male adults; 75 mg per day for female adults; and +35 mg per day for smokers. The average recommended intake is ~75 mg per day. Vitamin C is fairly nontoxic at <1 gm. And the established upper level limit is 2 gm per day. Excess intake has not been proven to cure the common cold. Deficiency of Vitamin C leads to Scurvy. Deficiency develops in 20-40 days of lack of Vitamin C intake. Symptoms of Scurvy include: bleeding gums and joints, hemorrhages, and death. Scurvy is associated with poverty and early sea voyages. Half the passengers on early ships would die sailing to the Cape of Good Hope. On the recommendation of Scottish physician James Lind (1795) sailors in the British navy are given lime juice to prevent scurvy.
Vitaminsare essential for the normal growth and development. Using the genetic blueprint inherited from our parents, a fetus begins to develop, at the moment of conception, from the nutrients it absorbs. We require certain vitamins and minerals to be present at certain times of our life. These nutrients facilitate the chemical reactions that produce among other things, skin, bone, and muscle. If there is serious deficiency in one or more of these nutrients, you can develop a deficiency disease. Even minor deficiencies can cause permanent damage, especially in children.
If you are going to take a vitamin or supplement, it is recommended that you do not take more than 100% of the RDA.
The FDA requires the following info to be on food labels:
- Product name and place of business
- Product net weight
- Product ingredient content (from most abundant to least abundant ingredient)
- Company name and address
- Product dating if applicable
- Religious symbols if applicable
- Safe handling instructions if applicable (such as for raw meats)
- Special handling instructions if applicable (such as for aspartame)
- Nutrition Facts panel outlining specified nutrient information
The FDA also requires several elements on a Nutrition Facts panel. The manufacturer must include info concerning the serving size of the food. Serving size have been standardized so that the nutrient contents of similar foods can be easily compared.
Information concerning total energy (listed as Calories), total carbohydrates (including dietary fiber), sugar, and protein must be provided. Information concerning specific nutrients that the Dietary Guidelines either limit or promote must also be provided.
Nutrients that the Dietary Guidelines suggest we limit include total fat, saturated fat, trans fats, cholesterol, and sodium. Conversely, we are encouraged to increase dietary fiber, vitamins A and C, and the minerals calcium and iron.
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RDA or AI of the Essential Water Soluble Vitamins
(in micrograms [ug] & milligrams [mg])
| Thiamin||1100 ug |
|Riboflavin||1100 ug |
| Niacin||14000 ug |
| Pantothenic Acid||5000 ug |
| Vitamin B6 (pyridoxine)||1300 ug |
| Biotin||30 ug |
| Folate||400 ug |
| Vitamin B12||2.4 ug (.0024 mg)|
| Vitamin C||75000 ug (75 mg)|