Common Vitamins and their Explanations

Vitamin A

Vitamin B6

Vitamin B12

Vitamin C

Vitamin D

Vitamin E

Vitamin K

Biotin

Folic Acid

Niacin

Pantothenic Acid

Riboflavin

Thiamin

Vitamin A is a fat-soluble vitamin which means it can be dissolved in fat. Vitamin A is carried through the body by fat. The body can store this type of vitamin in fat tissue. Getting too much can be harmful.

Vitamin A can come from animal sources such as:

• eggs
  
• fortified milk
  
• liver
  
• oils of some fish
  

This form of Vitamin A is called retinal or retinol.

Vitamin A is also found in plants. This form is called carotenoids. Substances such as beta-carotene are converted from carotenoids into vitamin A in the body. Beta-carotene is one of the most common carotenoids. Carotenoids are pigments found in deep orange, red, and yellow fruits and vegetables. They are also found in many dark-green leafy vegetables, such as:

• carrots
  
• pumpkin and other squashes
  
• sweet potatoes
  
• cantaloupe
  
• broccoli
  
• spinach

Vitamin B6 is a vitamin that can be dissolved in water. It is one of the B-complex vitamins.

Vitamin B6 is found in legumes such as:

• peas
• beans
• nuts
• eggs
• meats
• fish
• whole grains
• fortified breads and cereals.
  

Vitamin B6 helps the body:

• build protein
  
• make antibodies, which are key to a strong immune system
  
• make hormones
  
• make red blood cells and keep nerve tissue healthy
  
• process and digest protein
  

The Recommended Dietary Allowance, called RDA, for vitamin B6 for men is 2 milligrams (mcg) per day; for women, it's 1.6 mcg per day. People who eat a well-balanced diet should get enough vitamin B6. Most people do not need to take supplements. Someone with a vitamin B6 deficiency can suffer from:

• mouth sores
  
• nausea
  
• nervousness
  
• fatigue
  
• dizziness
  
• convulsions, which are sudden, uncontrollable muscle spasms
  

A person can get too much vitamin B6. This only happens when high doses, more than 50 to 500 times the RDA, are taken over months or years. This can cause temporary or permanent nerve damage.

Vitamin B12 is a water-soluble vitamin. It can dissolve in water. It is one of the B-complex vitamins. The B complex includes:

• B1
  
• B2
  
• B6
  
• pantothenic acid
  
• folic acid
  
• niacin
  
• biotin
  

Vitamin B12 is found in animal foods, fortified foods, and some fermented foods. Some sources of B12 are:

• eggs
  
• meat
  
• poultry
  
• fish
  
• dairy products
  
• tempeh and miso, which both come from soy
  

The amount of B12 in some foods includes:

• salmon, cooked (3 oz) = 2.6 mcg (micrograms)
  
• beef tenderloin lean, broiled (3 oz) = 2.2 mcg
  
• milk (1 cup) = 0.5 mcg
  

Vitamin B12 helps the body:

• make red blood cells, with folic acid, another B-vitamin
  
• work with many chemicals found in all body cells
  
• copy the genetic code within each cell
  
• form and maintain the nervous system
  
• build and maintain protective coating around nerves
  
• digest and use fats, carbohydrates, and some proteins for energy
  
• form neurotransmitters in the brain, such as serotonin, that help regulate mood, sleep, and appetite
  

The recommended dietary allowance for adults, called RDA, for vitamin B12 is 2 micrograms (mcg) per day. For pregnant women, the RDA is 2.2 mcg; for nursing women, it is 2.6 mcg. A microgram is a very small amount. Since the only dietary sources of B12 are animal products, strict vegetarians may need to take supplements. They may also eat foods that have had the vitamin added.

Not getting enough vitamin B12 can cause:

• anemia
  
• fatigue
  
• nerve damage, with symptoms such as tingling sensations and numbness
  
• smooth tongue
  
• very sensitive skin
  
• muscle and nerve paralysis
  

Some people have trouble absorbing B12. Other people may just have poor dietary intake. Anemia can be treated with injections of B12. Strict vegetarians who eat no animal products, their infants, and older people are at the highest risk for vitamin B12 deficiency. For these people, eating fortified foods and/or taking dietary supplements can help prevent a deficiency. High intakes of folic acid can hide this type of anemia.

Getting too much vitamin B12 has no known symptoms or toxicity. Since it is water-soluble, any extra leaves the body in the urine. There is no proof that taking extra B12 boosts energy. Vitamins do not provide calories or create energy. Vitamins can help break down nutrients that yield energy. These nutrients include carbohydrate, protein, and fat.

Calcium is needed to help the body absorb vitamin B12. A deficiency of either iron or vitamin B6 can decrease the amount of B12 the body is able to absorb.

Vitamin C is a water-soluble vitamin. This means that it can be dissolved in water. Water-soluble vitamins are carried throughout the body in the bloodstream. They are, for the most part, not stored in the body. The body uses what it needs and the rest is passed in the urine.
The best sources of vitamin C are fruits and vegetables. Citrus fruits such as:

• oranges
• orange juice
• grapefruit
• and tangerines
• melons
• kiwi
• strawberries

Vegetables such as:

• broccoli
• sweet green and red peppers
• potatoes (with skin)
• tomatoes
• brussels sprouts

Cabbage and many dark green leafy vegetables are all good sources of vitamin C. Vitamin C can be easily lost in foods when they are cooked or handled improperly.

Fresh and frozen fruits and vegetables are the best choices for getting vitamin C. Canned vegetables lose vitamin C during processing. If the canning water is thrown out, even more is lost. Freezing has little effect on Vitamin C. Cooking vegetables too long at high heats, for example boiling, can destroy vitamin C. Most of the vitamin C is left in the cooking water, which is usually thrown away. Cutting and slicing fruits and vegetables leaves a greater surface exposed to air and light, which will also destroy vitamin C. Raw fruits and vegetables should be eaten shortly after they were cut. They should be cooked only for a short time in a small amount of water or by steaming. Aging and leaving fruits and vegetables at room temperature too long can also destroy vitamin C.
Vitamin C is important to many body functions. It helps the body:

• build and maintain collagen, which are fibers that make up the tissue between tendons, ligaments, bones, and cartilage.
  
• maintain healthy bones, teeth, gums, red blood cells, and blood vessels.
  
• heal wounds, bruises, and fractures.
  
• absorb iron from plant food sources.
  
• protect from infection by keeping the immune system healthy.
  
• reduce some of the risk of certain chronic diseases by acting as an antioxidant.

Antioxidants help the body fight the effects of free radicals, which can damage the body.
Vitamin C has a long history. It was used as a cure for scurvy. Scurvy is a disease that causes open sores in the mouth, loosening of teeth, and soft gums. In the 1700s, it was discovered that sailors who often consumed lime juice did not get scurvy. Sailors who did not consume lime juice had a 50 percent chance of dying from scurvy. It was not until 200 years later that vitamin C was found to prevent the disease.

Severe deficiency, going for a very long time without vitamin C, can lead to scurvy.

Severe deficiency and scurvy are rare in the United States. Poor vitamin C intake is more common. Alcohol intake, stress, smoking, poor intake of fruits and vegetables, and chronic illness can contribute to vitamin C deficiency. Signs of deficiency include:

• inflamed gums.
  
• slow wound healing.
  
• stomach disorders.
  
• reduced resistance to colds and infections.
  
• skin problems.
  

Large doses of vitamin C can cause stomach upset, diarrhea, or kidney stones. The upper levels for vitamin C is 2,000 milligrams (mg) per day for adults. People should not routinely go above the set upper levels for vitamins and minerals. An upper level is not the recommended amount to take. It is the maximum amount of a vitamin or mineral that is likely to cause no health risks. Some scientists think not enough is known about mega dosing, or taking extremely high doses of vitamins, to claim that it has health benefits. There is debate if mega doses of antioxidants, such as vitamin C, can help decrease the risk for chronic diseases. Much of the current information is conflicting, therefore, more research is needed.

The recommended dietary allowances, or RDAs, for vitamin C were recently increased. Levels were increased to provide maximum health benefits. Levels were raised from 60 mg daily to 75 mg per day for women and 90 mg per day for men. Smokers are advised to take an extra 35 mg daily. This is because smoking depletes the body of some vitamin C. Pregnant and nursing women need slightly more, too. Many people do not get enough vitamin C. Thirty-nine percent of men and 43 percent of women fall short of the recommended amount.

Because vitamin C cannot be stored in the body; it is important to eat foods high in vitamin C. Eating a well-balanced diet, including at least five servings of fruit and vegetables every day, should provide all the body needs.

Vitamin D is a fat-soluble vitamin. It can be dissolved in fat. Vitamin D is carried through the body by fat and stored in fat tissue. Getting too much can be harmful. Vitamin D can be produced in the body, as well as, obtained from the diet.
The most reliable source of vitamin D, in the US diet, is fortified milk. All milk sold in the United States is fortified with vitamin D. Vitamin D is also present in:

• cheese
  
• butter
  
• margarine
  
• cream
  
• some soy milks
  
• eggs
  
• liver
  
• fish such as sardines and salmon
  
• cod liver oil
  
• fortified cereals
  

Vitamin D is called the sunshine vitamin. This is because the body can make vitamin D after sunlight, or ultraviolet light, hits the skin. Ten to 15 minutes of sun exposure 3 times a week is all the body needs. Older people are less efficient with this conversion.

Vitamin D helps build strong and healthy bones and teeth. It does this by helping the body to absorb the minerals calcium and phosphorous and to deposit them in bones and teeth.

If the body does not get enough vitamin D and calcium, a person is at higher risk for bone mass loss, which is known as osteoporosis. Low levels of vitamin D also increases the risk of bone softening, known as osteomalacia, in older adults. Children who do not get enough vitamin D over a long period may develop rickets, which is defective bone growth. Fortifying milk with vitamin D has made rickets extremely rare in the US.

Vitamin D is measured as micrograms (mcg) of cholecalciferol (koh-li-kal-sif-ah-rall). The Recommended Dietary Allowance, called RDA, for men and women, 25 to 50 years old, is 5 mcg per day. Children need twice as much daily vitamin D as adults, because their bones are still growing. Pregnant and lactating women also need 10 mcg per day.

Another common measurement for vitamin D is International Units, known as IU. The RDA, in IUs, for vitamin D for adults is 200 IU per day; for children, it is 400 IU per day; and for pregnant and lactating women, it is 400 IU.

In 1997, the recommendations were revised for vitamin D, doubling the amount for adults over age 50, going up to 400 IU or 10 mcg daily. People over age 70 need 600 IU or 15 mcg per day.

No one should have more than 2000 IU or 50 mcg per day of Vitamin D.

Because vitamin D dissolves in fat, it can build up in the fat tissues of the body. This can pose a problem for people taking high doses of vitamin D. While it is almost impossible to get too much vitamin D from foods or sunlight, it is easy to get too much from supplements. High doses of vitamin D can be toxic and cause:

• kidney stones or damage
  
• weak muscles
  
• weak bones
  
• excessive bleeding

Vitamin E is a fat-soluble vitamin. This means that it is dissolved in fat. Vitamin E attaches to fat. This is how it is carried through the body. This is one reason why moderate amounts of fat are needed in the diet. The body can store fat-soluble vitamins. Vitamin E has strong antioxidant properties. The vitamin may protect against heart disease and cancer. Its protective role has been widely studied. Vitamin E is part of a group of substances called tocopherols. Each group has different potencies.

Vitamin E is found in the fatty parts of foods. The best sources of vitamin E are unsaturated fats, such as vegetable oils. These include

• sunflower, safflower, canola, olive, and wheat germ oils.
• avocados, nuts, seeds, wheat germ, and whole grain, or unrefined, products.
• Green leafy vegetables have smaller amounts.
• Soybean oil has a form of vitamin E that has little influence on health. This oil is not a good source of vitamin E. Soybean oil is the most common oil used in products like salad dressing and mayonnaise.

Heating oils to high temperatures, such as in frying, can destroy vitamin E. Storage and freezing foods for a long time can also destroy vitamin E.

Vitamin E is found in the germ of a seed or grain. Most of the nutrients are concentrated there. Whole-wheat flour contains much of the original germ, so it has vitamin E. Refined flour, or white flour, has been stripped of many of its nutrients, including vitamin E.
Vitamin E is an important antioxidant. Antioxidants protect cells from oxidation. Oxidation can lead to cell damage. Cell damage can lead to chronic health problems, such as heart disease and cancer. Vitamin E works closely with other antioxidants, like vitamin C and selenium, to help protect the body. Vitamin E improves the way the body uses vitamin A. It may help protect against ion the toxic effects of some metals, such as lead.

The recommended dietary allowances, or RDAs, for vitamin E were recently changed. They were increased to provide maximum health benefits. Levels were raised from 10 milligrams (mg) daily to 15 mg daily for adult men and women. Pregnancy increases the recommendations slightly. It is difficult to get enough vitamin E from food alone. To get the full benefit of vitamin E, a supplement is recommended. The government estimates that 68 percent of men and 71 percent of women do not get enough vitamin E daily.

An upper level, based only on intake from vitamin supplements has been set at 1,000 mg of alpha-tocopherol. This is the most potent form of vitamin E. The upper level is not the recommended amount to take. The upper level is the maximum intake of a vitamin or mineral that is likely to cause no health risks. People should not routinely go above the set upper levels for vitamins and minerals. Taking too much vitamin E puts people at risk for prolonged bleeding time. This is because large doses can interfere with vitamin K. Vitamin K helps the blood to clot when a person is bleeding. Not enough is known about vitamin E to make positive claims on mega doses, or extremely high doses of the vitamin. The question is if mega doses of antioxidants, such as vitamin E, can decrease the risk for chronic diseases. More research is needed.

Severe vitamin E deficiency is rare. Conditions where it may occur include people who don't absorb fat normally, premature infants, people with red blood cell disorders, and people on kidney dialysis. Symptoms of vitamin E deficiency include nerve damage and anemia in infants.

To maximize vitamin E intake, healthy vegetable oils, nuts, seeds, and unrefined whole-grain products should be a regular part of the diet.

Vitamin K is a fat-soluble vitamin. It can be dissolved in fat. Vitamin K is carried through the body by fat and is stored in fat tissue. There are three forms of Vitamin K:

• phylloquinone, which is found in food
  
• menadione, which is man-made
  
• menaquinone, which is produced by the body
  

Vitamin K can be found in the following foods:

• collards, kale, and other green leafy vegetables
  
• members of the cabbage family including broccoli, cauliflower, and Brussels sprouts
  
• liver
  
• cheese
  
• milk
  
• egg yolk
  
• some fruits
  

Intestinal bacteria produce some vitamin K in the body.

Vitamin K makes several proteins that help blood to clot when bleeding. It also makes other proteins for blood, bones, and kidneys. Along with vitamins A and D, vitamin K is important for strong bone development.

The Recommended Dietary Allowance, called RDA, for vitamin K for adult males, age 25 years and older, is 80 micrograms (mcg) per day. For women, age 25 years and older, it is 65 mcg per day. For pregnant and lactating women, the RDA is also 65 mcg.

Vitamin K deficiency is rare. It is often the result of impaired absorption rather than not getting enough in the diet. Newborns are at risk for vitamin K deficiency. This is because their digestive tracts contain no vitamin K-producing bacteria. For this reason, doctors often give injections of vitamin K to newborns. The main symptom of vitamin K deficiency is blood that's slow to clot. Prolonged use of antibiotics can also cause a low level of this vitamin because they destroy some of the bacteria in the gut that help to produce vitamin K.

No symptoms are known to result from consuming too much vitamin K. Moderation is always the best approach. The most toxic form is supplements. People taking blood thinning medicines, such as aspirin or warfarin, may need to limit their intake of vitamin K-rich foods. This is because the vitamin's pro-clotting actions can work against this type of medicine.

Biotin and pantothenic acid are water-soluble vitamins. They are two of the eight B vitamins. The B vitamin complex includes vitamins B1, niacin, B6, B12, folate, biotin, and pantothenic acid.

Pantothenic acid and biotin are found in many foods.

Good sources of pantothenic acid include:

• egg yolks
  
• organ meat
  
• other meat
  
• poultry
  
• fish
  
• dairy products
  
• whole-grain cereal
  
• broccoli
  
• cauliflower
  
• legumes
  

Good sources of biotin include:

• soybeans
  
• peanuts
  
• egg yolks
  
• meats and liver
  
• milk
  
• yeast
  
• cereal
  

Some biotin is made by bacteria in the body's lower digestive tract.

These two vitamins are important for many functions. Pantothenic acid is changed to a substance called coenzyme A. This coenzyme helps convert fat, carbohydrate, and protein into energy. Pantothenic acid is also needed to make cholesterol, bile, some fats, red blood cells, hormones and nerve regulators. Pantothenic acid is necessary to make Vitamin D. It works closely with biotin, vitamin B1, B2, B6, and niacin.

Biotin also helps the body use protein, fat and carbohydrate from foods for energy. It helps the body produce energy in the cells. Biotin works closely with pantothenic acid, folic acid and vitamin B12.

There are no established recommended daily allowances, or RDAs, for these vitamins. However, a safe and adequate amount for adults for pantothenic acid is 4 to 7 milligrams per day. For biotin the recommendation is 30 to 100 micrograms per day.

There are no toxic effects for pantothenic acid other than diarrhea. There is no known benefit to taking large doses. Because it is so common in food, deficiency is rare for people who eat a healthy diet.

There are no toxic effects for biotin. Although biotin deficiency is rare, consuming a large amount of raw egg whites can cause biotin deficiency. This is due to a protein in egg whites, avidin, that blocks the absorption of biotin. The protein is destroyed in cooking so cooked egg whites are not a problem. Long-term use of antibiotics could also interfere with the production of biotin, and increase the risk of deficiency. Deficiency symptoms include:

• loss of appetite
  
• nausea
  
• depression
  
• muscle pain and weakness
  
• fatigue
  
• hair loss, known as alopecia

Folacin is also known as folic acid and folate. It is a water-soluble vitamin. It is one of the eight members of the B complex. These include vitamins B1, B2, B3, B6, B12, biotin, and pantothenic acid

Foods naturally high in folacin include:

• citrus fruits
  
• beans
  
• peas
  
• liver
  
• yeast breads
  
• wheat germ
  
• peanuts and other legumes
  
• spinach and other dark greens
  
• organ meats
  

Fortified grain products such as commercial breads, cereals and pastas are good sources of folacin. Items made from enriched flour products supply folacin, as well. The US Food and Drug Administration (FDA) enacted a new law in 1998. This law states that enriched grain products must be fortified with folacin. This was done to ensure women of child-bearing age consume enough folacin. This law was also based on the data about other benefits of folacin. It is hoped that this "fortification" program will help all Americans to reach the desired level of 400 micrograms (mcg) of folacin a day. Researchers think that most Americans get between 220 to 280 mcg a day of folacin from their diets

The recommendation or the RDI (Recommended Daily Intake) for folacin is 400 mcg per day for adult men and women. This amount is especially important for women of child-bearing age. Daily intake of folate should not exceed 1,000 mcg. This is because too much folacin can mask the symptoms of vitamin B12 deficiency. The FDA restricts the amount of folacin available in nutritional supplements to 400 mcg for adults and 800 mcg for pregnant women.

Folacin plays many important roles in the body:

• prevention of neural tube defects in fetuses before birth. Neural tube defects are malformations in the fetus that occur during pregnancy, involving defects in the skull and spinal column.
  
• normal growth and maintenance of all cells.
  
• involvement in production of neurotransmitters, such as serotonin, that regulate mood, sleep, and appetite.
  
• works with vitamin B12 to form hemoglobin in red blood cells.
  

Information

Folacin is a B vitamin required for many chemical processes in the body. Folic acid is a man made form of folate. It converts easily into the natural form of the vitamin in the body.

Getting enough folate during pregnancy is key to reducing the risk of neural tube defects in newborns. A neural tube defect arises when tissue does not properly close around the spinal column. This is also called spina bifida. Folate is crucial during the first 18 to 30 days of pregnancy. The baby's brain and spinal column are in a critical stage of development during this period. A woman may not even know that she is pregnant at this early stage. Neural tube defects occur in about one of every 1,000 births in the US and Canada. The Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, estimates that 400 mcg of folate per day could decrease this rate by about two-thirds.

As well as preventing birth defects, folate may have a role in lowering heart disease risk. Scientists are studying the link between folate and a substance called homocysteine. High homocysteine levels in the blood have been connected with a higher heart disease risk. Homocysteine levels seem to be lower in people who get plenty of folate in their diets. Current evidence also suggests that folate may have a role in the prevention of some cancers. This is especially true when it is consumed along with a variety of nutrients found in fruits, vegetables and other foods.

Niacin is a water-soluble vitamin. It is one of the eight B complex vitamins. These include vitamins B1, B2, B6, B12, folate, biotin, and pantothenic acid. Water-soluble vitamins are not stored in the body.

What food source is the nutrient found in?
Good sources of niacin include:

• enriched and fortified grain products
  
• legumes like peas and beans
  
• meats, especially organ meats, like liver
  
• poultry
  
• fish
  
• peanut butter
  

Niacin can be made in the body from the amino acid known as tryptophan. Another B vitamin, Vitamin B6, is needed to convert niacin to tryptophan. Amino acids are the building blocks of proteins. So, protein-rich foods can be good sources of niacin. Examples of these foods are:

• 3 oz turkey = 4.5 mg of niacin
  
• peanut butter 2 Tbsp. = 4 mg of niacin
  
• 3 oz tuna = 11.8 mg of niacin
  
• 1 cup wheat flour = 7.4 mg of niacin
  
• 1 cup cheerios = 5.0 mg of niacin
  

How does the nutrient affect the body?
Niacin works closely with vitamin B1, B2, B6, pantothenic acid, and biotin to break the carbohydrates, fats, and proteins in food down into energy. Without niacin, the body would not be able to convert the food we eat into energy. Niacin also helps enzymes function in the body. Enzymes are used by the body in many reactions. Niacin helps keep the skin, digestive tract, and nerves healthy.

Information
In the early 1900's, a disease called pellagra was common in the southern United States. At this time, corn was a staple of the diet. This diet provided neither niacin-rich foods like meats and certain vegetables, nor protein-rich foods containing tryptophan. Pellagra was caused by this lack of niacin intake. Pellagra is uncommon today. This is due to widespread niacin enrichment of most cereals, flours, pastas, and corn meals.

For people who eat enough protein, niacin deficiency is not common. Niacin deficiency symptoms include:

• weakness
  
• loss of appetite
  
• digestive upsets
  
• insomnia
  
• headaches
  
• irritability
  
• frequently, a sore, swollen, purple-red tongue.
  

More drastic niacin shortfall leads to pellagra, which can result in symptoms such as:

• skin and gastrointestinal lesions
  
• swollen mucous membranes
  
• diarrhea
  
• dementia
  
• death, in extreme cases
  

But, as mentioned above, pellagra is all but a thing of the past in the United States.

In recent years, niacin has been used with some success to treat people with high cholesterol levels. The high dose required to bring about any change in cholesterol, up to 3,000 mg per day, can bring on side effects. Common side effects include flushing of the skin and itching. High doses of niacin may also cause liver damage or stomach ulcers. Because of these potentially dangerous side effects, niacin should only be used to control cholesterol when prescribed by a doctor.

The Recommended Dietary Allowance, called the RDA, for niacin is:

• Adult males, age 19 to 50: 19 milligrams (mg)
  
• Adult males, age 50 and older: 15 mg
  
• Adult females, age 19 to 50: 15 mg
  
• Adult females, age 50 and older: 13 mg
  
• Pregnant women: 17 mg
  
• Lactating or breastfeeding women: 20 mg

Pantothenic Acid and biotin are water-soluble vitamins. They are two of the eight B vitamins. The B vitamin complex includes vitamins B1, niacin, B6, B12, folate, biotin, and pantothenic acid.

Pantothenic acid and biotin are found in many foods.

Good sources of pantothenic acid include:

• egg yolks
  
• organ meat
  
• other meat
  
• poultry
  
• fish
  
• dairy products
  
• whole-grain cereal
  
• broccoli
  
• cauliflower
  
• legumes
  

Good sources of biotin include:

• soybeans
  
• peanuts
  
• egg yolks
  
• meats and liver
  
• milk
  
• yeast
  
• cereal
  

Some biotin is made by bacteria in the body's lower digestive tract.

How does the nutrient affect the body?
These two vitamins are important for many functions. Pantothenic acid is changed to a substance called coenzyme A. This coenzyme helps convert fat, carbohydrate, and protein into energy. Pantothenic acid is also needed to make cholesterol, bile, some fats, red blood cells, hormones and nerve regulators. Pantothenic acid is necessary to make Vitamin D. It works closely with biotin, vitamin B1, B2, B6, and niacin.

Biotin also helps the body use protein, fat and carbohydrate from foods for energy. It helps the body produce energy in the cells. Biotin works closely with pantothenic acid, folic acid and vitamin B12.

Information
There are no established recommended daily allowances, or RDAs, for these vitamins. However, a safe and adequate amount for adults for pantothenic acid is 4 to 7 milligrams per day. For biotin the recommendation is 30 to 100 micrograms per day.

There are no toxic effects for pantothenic acid other than diarrhea. There is no known benefit to taking large doses. Because it is so common in food, deficiency is rare for people who eat a healthy diet.

There are no toxic effects for biotin. Although biotin deficiency is rare, consuming a large amount of raw egg whites can cause biotin deficiency. This is due to a protein in egg whites, avidin, that blocks the absorption of biotin. The protein is destroyed in cooking so cooked egg whites are not a problem. Long-term use of antibiotics could also interfere with the production of biotin, and increase the risk of deficiency. Deficiency symptoms include:

• loss of appetite
  
• nausea
  
• depression
  
• muscle pain and weakness
  
• fatigue
  
• hair loss, known as alopecia

Riboflavin, also called Vitamin B2, is a water-soluble vitamin. It is one of the eight B vitamins. The B vitamin complex includes vitamins B1, niacin, B6, B12, folate, biotin, and pantothenic acid.

Good sources of riboflavin include:

• milk and dairy products
  
• meat and eggs
  
• leafy, dark green vegetables
  
• whole-grain or enriched breads and cereals
  
• organ meats such as liver, kidney, and heart
  

In the United States, milk products supply about half of the riboflavin that people get. Ultraviolet light, such as sunlight, destroys riboflavin. This is why milk is stored in opaque plastic or cardboard containers. Unlike other vitamins, riboflavin is not destroyed by cooking.

However, when grains are milled, or refined, most of the riboflavin and other nutrients are removed. This makes whole-grain foods, such as oatmeal and whole wheat, better choices. Enriched refined foods are also healthy choices because the riboflavin lost in refining has been added back in. Refined - but non-enriched foods, such as white rice, do not supply riboflavin in any significant amount. The content of riboflavin in some common foods is as follows:

• 1 cup of milk = 0.4 milligram (mg)
  
• 1 cup of cottage cheese = 0.37 mg
  
• 1 cup of yogurt = 1.6 mg
  
• 3-ounce pork chop = 0.24 mg
  
• 3 ounces of beef liver, braised = 3.5 mg
  

Riboflavin helps keep the body healthy in a number of ways, including the following:

• It helps to convert food into energy.
  
• It is also needed to convert an amino acid called tryptophan into niacin.
  
• It works closely with other B vitamins.
  
• It helps make red blood cells and it keeps body tissues healthy, especially the skin and eyes.
  
• It is key to healthy growth and development.
  
• It helps the body make and control certain hormones.
  

The recommended daily allowances, called RDAs, for this nutrient are:

• adult men from age 19 to 50: 1.7 milligrams (mg)
  
• men older than age 50: 1.4 mg
  
• adult women from age 19 to 50: 1.3 mg
  
• women older than age 50: 1.2 mg
  
• pregnant women: 1.6 mg
  
• breastfeeding women: 1.8 mg during the first six months and 1.7 mg the next six months after the baby's birth
  

Several servings per day of riboflavin-rich foods are needed to meet requirements. Because riboflavin is found in so many foods, a balanced diet will usually provide enough.

Because riboflavin is so key to health, a shortage in the diet can cause problems. Severe riboflavin deficiency with clinical symptoms is rare. Mild deficiencies are more common, especially with elderly people and individuals with anorexia nervosa.

Strict vegans, who eat no meat or dairy products, may have riboflavin deficiencies. Symptoms can include:

• dry and scaly skin, especially on the face
  
• cracks at the corners of the mouth
  
• eye disorders
  
• swollen tongue or gums
  

Children who do not get enough riboflavin over a long period of time can have poor growth. Vitamin supplements usually reverse symptoms within a few days to a few weeks.

It is not possible to be poisoned by too much riboflavin. Because it is a water-soluble vitamin, any extra is passed in the urine.

Thiamine, also known as Vitamin B1, is a water-soluble vitamin. It was the first vitamin to be discovered. Thiamine is one of eight members of the vitamin B complex. The complex also includes:

• vitamin B2
  
• niacin
  
• vitamin B6
  
• vitamin B12
  
• folate
  
• biotin
  
• pantothenic acid
  

Because thiamine is water-soluble, any extra is passed out of the body in the urine. Thiamine is needed each day to maintain health.

Thiamine is found in foods such as:

• meats (pork and liver)
  
• brewer's yeast
  
• soybeans
  
• peanuts
  
• dried beans
  
• whole or enriched breads, grains, and cereals
  

Enriched products add back the vitamins that are lost when grains are processed. Thiamine is lost in cooking due to heat. The thiamine contents of some foods are:

• beef liver, braised (3 ounces) = 9.2 milligrams (mg)
  
• sunflower seeds (3.5 ounces) = 1.96 mg
  
• pinto beans (3.5 ounces) = 0.84 mg
  
• enriched rice, cooked (1/2 cup) = 0.2 mg
  

How does the nutrient affect the body?
Thiamine works with the other B vitamins to change protein, carbohydrate, and fat to energy. It is especially vital for changing carbohydrates to energy. It is a key factor in the healthy functioning of all the body's cells, especially the nerves.

Information
Daily needs for thiamine are based on the amount of calories taken in each day. The recommended daily allowances, called RDAs, for thiamine are based on 0.5 milligram (mg) for every 1,000 calories consumed. Based on the recommended calorie intake for men and women at certain age levels, the RDAs for thiamine are:

• men from 15 to 50 years = 1.5 mg
  
• men over 50 years = 1.2 mg
  
• women from 11 to 50 years = 1.1 mg
  
• women over 50 years = 1.0 mg
  
• pregnant women = 1.5 mg
  
• breastfeeding women = 1.6 mg
  

Thiamine is common in foods. A balanced diet based on the Food Guide Pyramid should provide enough thiamine daily.

A disease called beriberi, which affects the nerves and heart, is caused by a lack of thiamine in the diet. This is extremely rare in the United States, because enriched grain products are so common. Before grains were enriched, it was much more common.

Mild thiamine deficiencies are more common. Exceptions may be found with chronic alcoholism, fasting, the elderly, and chronic dieting. Symptoms usually show up in the nerves, stomach, and heart. Early warning signs include:

• fatigue and weakness
  
• loss of appetite and weight loss
  
• stomach upset and nausea
  
• confusion and irritability
  
• depression
  
• poor memory
  
• sleep disturbances
  
• chest pain
  
• irritation
  
• abdominal discomfort
  
• constipation
  

If deficiency continues, symptoms can get worse, and some damage can be permanent. This can include damage to the heart, and changes to the nervous system.

There is little chance of getting too much thiamine, even when it is taken at high doses. Because it is water soluble and not stored in the body, it is not likely to build up to toxic levels. In older people with low levels of thiamine, taking vitamin B1 pills has improved their lives by decreasing both blood pressure and weight.

In isolated cases, however, thiamine toxicity has occurred from injections or concentrated formulas used with hospital patients. Toxicity symptoms include nervous irritability, headaches, insomnia, and a rapid pulse.