Vitamin B12

What is vitamin B12 and what does it do?

 

 

Vitamin B12 is a nutrient that helps keep the body's nerve and blood cells healthy and helps make DNA, the genetic material in all cells. Vitamin B12 also helps prevent a type of anemia called megaloblastic anemia that makes people tired and weak.
Two steps are required for the body to absorb vitamin B12 from food. First, hydrochloric acid in the stomach separates vitamin B12 from the protein to which vitamin B12 is attached in food. After this, vitamin B12 combines with a protein made by the stomach called intrinsic factor and is absorbed by the body. Some people have pernicious anemia, a condition where they cannot make intrinsic factor. As a result, they have trouble absorbing vitamin B12 from all foods and dietary supplements.

How much vitamin B12 do I need?

The amount of vitamin B12 you need each day depends on your age. Average daily recommended amounts for different ages are listed below in micrograms (mcg):

Life Stage	Recommended Amount
Birth to 6 months	0.4 mcg
Infants 7–12 months	0.5 mcg
Children 1–3 years	0.9 mcg
Children 4–8 years	1.2 mcg
Children 9–13 years	1.8 mcg
Teens 14–18 years	2.4 mcg
Adults	2.4 mcg
Pregnant teens and women	2.6 mcg
Breastfeeding teens and women	2.8 mcg

What foods provide vitamin B12?

Vitamin B12 is found naturally in a wide variety of animal foods and is added to some fortified foods. Plant foods have no vitamin B12 unless they are fortified. You can get recommended amounts of vitamin B12 by eating a variety of foods including the following:

• Beef liver and clams, which are the best sources of vitamin B12.
• Fish, meat, poultry, eggs, milk, and other dairy products, which also contain vitamin B12.
• Some breakfast cereals, nutritional yeasts and other food products that are fortified with vitamin B12. To find out if vitamin B12 has been added to a food product, check the product labels.

What kinds of vitamin B12 dietary supplements are available?

Vitamin B12 is found in almost all multivitamins. Dietary supplements that contain only vitamin B12, or vitamin B12 with nutrients such as folic acid and other B vitamins, are also available. Check the Supplement Facts label to determine the amount of vitamin B12 provided.
Vitamin B12 is also available in sublingual forms (which are dissolved under the tongue). There is no evidence that sublingual forms are better absorbed than pills that are swallowed.
A prescription form of vitamin B12 can be administered as a shot. This is usually used to treat vitamin B12 deficiency. Vitamin B12 is also available as a prescription medication in nasal gel form (for use in the nose).

Am I getting enough vitamin B12?

Most people in the United States get enough vitamin B12 from the foods they eat. But some people have trouble absorbing vitamin B12 from food. As a result, vitamin B12 deficiency affects between 1.5% and 15% of the public. Your doctor can test your vitamin B12 level to see if you have a deficiency.
Certain groups may not get enough vitamin B12 or have trouble absorbing it:

• Many older adults, who do not have enough hydrochloric acid in their stomach to absorb the vitamin B12 naturally present in food. People over 50 should get most of their vitamin B12 from fortified foods or dietary supplements because, in most cases, their bodies can absorb vitamin B12 from these sources.
• People with pernicious anemia whose bodies do not make the intrinsic factor needed to absorb vitamin B12. Doctors usually treat pernicious anemia with vitamin B12 shots, although very high oral doses of vitamin B12 might also be effective.
• People who have had gastrointestinal surgery, such as weight loss surgery, or who have digestive disorders, such as celiac disease or Crohn's disease. These conditions can decrease the amount of vitamin B12 that the body can absorb.
• Some people who eat little or no animal foods such as vegetarians and vegans. Only animal foods have vitamin B12 naturally. When pregnant women and women who breastfeed their babies are strict vegetarians or vegans, their babies might also not get enough vitamin B12.

What happens if I don't get enough vitamin B12?

Vitamin B12 deficiency causes tiredness, weakness, constipation, loss of appetite, weight loss, and megaloblastic anemia. Nerve problems, such as numbness and tingling in the hands and feet, can also occur. Other symptoms of vitamin B12 deficiency include problems with balance, depression, confusion, dementia, poor memory, and soreness of the mouth or tongue. Vitamin B12 deficiency can damage the nervous system even in people who don't have anemia, so it is important to treat a deficiency as soon as possible.
In infants, signs of a vitamin B12 deficiency include failure to thrive, problems with movement, delays in reaching the typical developmental milestones, and megaloblastic anemia.
Large amounts of folic acid can hide a vitamin B12 deficiency by correcting megaloblastic anemia, a hallmark of vitamin B12 deficiency. But folic acid does not correct the progressive damage to the nervous system that vitamin B12 deficiency also causes. For this reason, healthy adults should not get more than 1,000 mcg of folic acid a day.

What are some effects of vitamin B12 on health?

Scientists are studying vitamin B12 to understand how it affects health. Here are several examples of what this research has shown:
Heart disease
Vitamin B12 supplements (along with folic acid and vitamin B6) do not reduce the risk of getting heart disease. Scientists had thought that these vitamins might be helpful because they reduce blood levels of homocysteine, a compound linked to an increased risk of having a heart attack or stroke.
Dementia
As they get older, some people develop dementia. These people often have high levels of homocysteine in the blood. Vitamin B12 (with folic acid and vitamin B6) can lower homocysteine levels, but scientists don't know yet whether these vitamins actually help prevent or treat dementia.
Energy and athletic performance
Advertisements often promote vitamin B12 supplements as a way to increase energy or endurance. Except in people with a vitamin B12 deficiency, no evidence shows that vitamin B12 supplements increase energy or improve athletic performance.

Can vitamin B12 be harmful?

Vitamin B12 has not been shown to cause any harm.

Are there any interactions with vitamin B12 that I should know about?

Yes. Vitamin B12 can interact or interfere with medicines that you take, and in some cases, medicines can lower vitamin B12 levels in the body. Here are several examples of medicines that can interfere with the body's absorption or use of vitamin B12:

• Chloramphenicol (Chloromycetin®), an antibiotic that is used to treat certain infections.
• Proton pump inhibitors, such as omeprazole (Prilosec®) and lansoprazole (Prevacid®), that are used to treat acid reflux and peptic ulcer disease.
• Histamine H2 receptor antagonists, such as cimetidine (Tagamet®), famotidine (Pepcid®), and ranitidine (Zantac®), that are used to treat peptic ulcer disease.
• Metformin, a drug used to treat diabetes.

Tell your doctor, pharmacist, and other health care providers about any dietary supplements and medicines you take. They can tell you if those dietary supplements might interact or interfere with your prescription or over-the-counter medicines or if the medicines might interfere with how your body absorbs, uses, or breaks down nutrients.

Disclaimer

This fact sheet by the Office of Dietary Supplements provides information that should not take the place of medical advice. We encourage you to talk to your health care providers (doctor, registered dietitian, pharmacist, etc.) about your interest in, questions about, or use of dietary supplements and what may be best for your overall health. Any mention in this publication of a specific brand name is not an endorsement of the product.

Vitamin C

 

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Vitamin C is a water-soluble vitamin that is necessary for normal growth and development.
Water-soluble vitamins dissolve in water. Leftover amounts of the vitamin leave the body through the urine. That means you need a continuous supply of such vitamins in your diet.

Function

Vitamin C is needed for the growth and repair of tissues in all parts of your body. It is used to:

• Form an important protein used to make skin, tendons, ligaments, and blood vessels
• Heal wounds and form scar tissue
• Repair and maintain cartilage, bones, and teeth

Vitamin C is one of many antioxidants. Antioxidants are nutrients that block some of the damage caused by free radicals.

• Free radicals are made when your body breaks down food or when you are exposed to tobacco smoke or radiation.
• The buildup of free radicals over time is largely responsible for the aging process.
• Free radicals may play a role in cancer, heart disease, and conditions like arthritis.

The body is not able to make vitamin C on its own, and it does not store vitamin C. It is therefore important to include plenty of vitamin C-containing foods in your daily diet.
For many years, vitamin C has been a popular remedy for the common cold.

• Research shows that for most people, vitamin C supplements or vitamin C-rich foods do not reduce the risk of getting the common cold.
• However, people who take vitamin C supplements regularly might have slightly shorter colds or somewhat milder symptoms.
• Taking a vitamin C supplement after a cold starts does not appear to be helpful.

Food Sources

All fruits and vegetables contain some amount of vitamin C.
Fruits with the highest sources of vitamin C include:

• Cantaloupe
• Citrus fruits and juices, such as orange and grapefruit
• Kiwi fruit
• Mango
• Papaya
• Pineapple
• Strawberries, raspberries, blueberries, cranberries
• Watermelon

Vegetables with the highest sources of vitamin C include:

• Broccoli, Brussels sprouts, cauliflower
• Green and red peppers
• Spinach, cabbage, turnip greens, and other leafy greens
• Sweet and white potatoes
• Tomatoes and tomato juice
• Winter squash

Some cereals and other foods and beverages are fortified with vitamin C. Fortified means a vitamin or mineral has been added to the food. Check the product labels to see how much vitamin C is in the product.
Cooking vitamin C-rich foods or storing them for a long period of time can reduce the vitamin C content. Microwaving and steaming vitamin C-rich foods may reduce cooking losses. The best food sources of vitamin C are uncooked or raw fruits and vegetables.

Side Effects

Serious side effects from too much vitamin C are very rare, because the body cannot store the vitamin. However, amounts greater than 2,000 mg/day are not recommended because such high doses can lead to stomach upset and diarrhea.
Too little vitamin C can lead to signs and symptoms of deficiency, including:

• Anemia
• Bleeding gums
• Decreased ability to fight infection
• Decreased wound-healing rate
• Dry and splitting hair
• Easy bruising
• Gingivitis (inflammation of the gums)
• Nosebleeds
• Possible weight gain because of slowed metabolism
• Rough, dry, scaly skin
• Swollen and painful joints
• Weakened tooth enamel

A severe form of vitamin C deficiency is known as scurvy, which mainly affects older, malnourished adults.

Recommendations

The Recommended Dietary Allowance (RDA) for vitamins reflects how much of each vitamin most people should get each day. The RDA for vitamins may be used as goals for each person.
How much of each vitamin you need depends on your age and gender. Other factors, such as pregnancy and illnesses, are also important.
The best way to get the daily requirement of essential vitamins, including vitamin C, is to eat a balanced diet that contains a variety of foods.
Dietary Reference Intakes for vitamin C:
Infants

• 0 - 6 months: 40* milligrams/day (mg/day)
• 7 - 12 months: 50* mg/day

*Adequate Intake (AI)
Children

• 1 - 3 years: 15 mg/day
• 4 - 8 years: 25 mg/day
• 9 - 13 years: 45 mg/day

Adolescents

• Girls 14 - 18 years: 65 mg/day
• Boys 14 - 18 years: 75 mg/day

Adults

• Men age 19 and older: 90 mg/day
• Women age 19 year and older: 75 mg/day

Smokers or those who are around secondhand smoke at any age should increase their daily amount of vitamin C an additional 35 mg per day.
Women who are pregnant or breastfeeding and those who smoke need higher amounts of vitamin C. Ask your doctor what amount is best for you.

Alternative Names

Ascorbic acid; Dehydroascorbic acid

References

Escott-Stump S, ed. Nutrition and Diagnosis-Related Care. 6th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2008.
Sarubin Fragaakis A, Thomson C. The Health Professional's Guide to Popular Dietary Supplements. 3rd ed. Chicago, Il: American Dietetic Association; 2007.
Institute of Medicine. Food and Nutrition Board. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. National Academy Press, Washington, DC, 2000.
Douglas RM, Hemila H, Chalker E, Treacy B. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev; 2007(3):CD000980.

Update Date: 8/30/2011

Updated by: A.D.A.M. Editorial Team: David Zieve, MD, MHA, and David R. Eltz. Previously reviewed by Alison Evert, MS, RD, CDE, Nutritionist, University of Washington Medical Center Diabetes Care Center, Seattle, Washington (2/15/2011).

Khasiat Peria

Peria pahit tapi berkhasiat

Peria merupakan sejenis sayuran yang agak pahit rasanya. Kebanyakan orang tidak menggemarinya.

Namun ia mempunyai khasiat yang tinggi. Peria mempunyai pelbagai khasiat termasuk protein, lemak, mineral, serat, karbohidrat, vitamin dan kalsium.

Peria digunakan untuk merawat penyakit kencing manis. Caranya minum perahan daripada empat atau lima biji peria setiap pagi. Bijinya yg dihancurkan boleh dicampur ke dalam makanan. Selain itu, ia boleh dijadikan air rebusan atau serbuk.

Daunnya pula boleh merawat buasir. Caranya, campurkan perahan daun peria ke dalam segelas susu dan minum setiap pagi selama sebulan. Akar yang dihancurkan boleh disapu pada tempat buasir.



Peria juga boleh mengatasi masalah darah kotor yang menyebabkan bisul, kudis buta dan rasa gatal. Yang perlu dilakukan, campur segelas perahan peria dan secamca teh perahan limau. Ia perlu diminum sedikit demi sedikit setiap hari selama empat hingga enam bulan.

Masalah ketagihan alkohol juga boleh diatasi dengan meminum air daun peria. Ia juga boleh mengatasi masalah hati disebabkan pengambilan alkohol berlebihan.

Walaupun kurang digemari, peria mempunyai nilai perubatannya sendiri. Ia mengandungi tonik bertindak sebagai julap dan mampu meningkatkan selera makan.

Untuk mengurangkan rasa pahit, rendam ia ke dalam air garam sebelum dimasak.

Khasiat makanan

* Buahnya yang belum masak dijadikan sebagai sayur yang digoreng, dibuat sup, dikukus, direbus, masak kari dan sebagainya.

* Buah, pucuk dan bunganya dijadikan sebagai perisa dalam masakan.

* Buahnya boleh dijadikan sebagai jeruk, dikeringkan dan ditinkan.

* Mengandungi khasiat makanan kerana mengandungi banyak mineral dan vitamin.

* Isi yang meliputi biji peria boleh dibuat manisan.

Khasiat ubat-ubatan

* Semua bahagiannya boleh dijadikan sebagai jus sebagai ubat luaran untuk penyakit kulit, serta dimakan bagi mengubati penyakit artritis, demam panas, masalah hati, reumatisme, asma, membunuh cacing dalam perut dan urus serta masalah kaum wanita.

* Sebahagian bahagian tumbuhan boleh membantu melawaskan buang air besar.

* Buahnya dimakan atau direbus sebagai ubat harba antimikrob, antitumor, membunuh cacing dalam perut dan usus, cirit-birit, mengecutkan otot, minuman tonik, tonik perut, ubat kencing manis, merawat kulit terbakat, luka-luka, sampu dan sakit perut.

* Buah yang dimasak sebagai lauk boleh mengubati batuk, bengkak sistem penafasan dan banyak kahak.

* Jus buah hijaunya diminum bagi mengubati cirit-birit dan bengkak usus besa