What are vitamins?
Nutrition textbooks dryly define vitamins as organic compounds that the body needs in small quantities for normal functioning. Here's the translation: Vitamins are nutrients you must get from food because your body can't make them from scratch. You need only small amounts (that's why they are often referred to as micronutrients) because the body uses them without breaking them down, as happens to carbohydrates and other macronutrients.
So far, 13 compounds have been classified as vitamins. Vitamins A, D, E, and K, the four fat-soluble vitamins, tend to accumulate in the body. Vitamin C and the eight B vitamins—biotin, folate, niacin, pantothenic acid, riboflavin, thiamin, vitamin B6, and vitamin B12—dissolve in water, so excess amounts are excreted.
The "letter" vitamins sometimes go by different names. These include:
Vitamin A = retinol, retinaldehyde, retinoic acid
Vitamin B1 = thiamin
Vitamin B2 = riboflavin
Vitamin B6 = pyridoxine, pyridoxal, pyridoxamine
Vitamin B12 = cobalamin
Vitamin C = ascorbic acid
Vitamin D = calciferol
Vitamin E = tocopherol, tocotrienol
Vitamin K = phylloquinone
What are vitamins and how do they work?
If you have read the article How Cells Work, then you know that DNA is a template for different enzymes. Enzymes help cells to carry out chemical reactions. A cell is really just an extremely sophisticated chemical machine.
A vitamin is a small molecule that your body needs to carry out a certain reaction. Your body has no way to create vitamin molecules itself, so the vitamin molecules must come in through food that you eat. The human body is known to need at least 13 different vitamins:
Vitamin A (fat soluble) - Retinol; comes from beta-carotene in plants (When you eat beta-carotene, an enzyme in the stomach turns it into Vitamin A.)
Vitamin B (water soluble):
B1 - Thiamine
B2 - Riboflavin
B3 - Niacin
B6 - Pyridoxine
B12 - Cyanocobalamin
Folic acid
Vitamin C (water soluble) - Ascorbic acid
Vitamin D (fat soluble) - Calciferol
Vitamin E (fat soluble) - Tocopherol
Vitamin K (fat soluble) - Menaquinone
Pantothenic acid (water soluble)
Biotin (water soluble)
Inside the body, vitamins are used in many unique ways. For example, one of vitamin A's main roles is in the production of retinal. Retinal is used within the rods and cones in your eyes to sense light. There is no way for your body to produce retinal without vitamin A, and without retinal you cannot see.
The different B vitamins are often embedded within the structure of different enzymes that a cell produces. For example, aspartate aminotransferase is an enzyme that transfers amines between amino acids. Each copy of the enzyme contains two vitamin B6 molecules, and without these molecules the enzyme cannot do anything.
One use of Vitamin C is in the formation of collagen. Collagen is produced by special ribosomes in certain cells, and then exported from the cells to form collagen networks. During the process of collagen formation, the body must manufacture hydroxylproline from the amino acid proline. Vitamin C is essential to this reaction. Without vitamin C, collagen cannot be produced -- the first signs of this are very weak (and easily broken) blood vessels and loose teeth (which are held in their sockets by collagen).
The body is able to store some vitamins, such as vitamin A (up to a year's supply is stored in your liver). Other vitamins need to be re-supplied frequently.
What's the difference between folate and folic acid?
Folate is the form of the B vitamin found naturally in foods, and it is the generic term for the vitamin. Folic acid is the form of the vitamin that is added to multivitamins and to fortified foods (such as white flour and products made with white flour, breakfast cereals, "energy" or protein bars, and so on).
During digestion, the body converts folate into folic acid, which is then absorbed and used in multiple ways. Since vitamin pills and fortified foods contain folic acid, they can "skip" this conversion step, making folic acid more readily available to the body than folate from food.
To reflect this difference in availability to the body, government recommendations for folate are given in "Dietary Folate Equivalents," or DFEs: One microgram of folate from food equals 1 DFE; 1 microgram of folic acid from fortified foods, or from a vitamin pill taken with food, equals approximately 1.7 DFEs; 1 microgram of folic acid from a vitamin pill taken on an empty stomach equals 2 DFEs.
Are time-release vitamins better for you?
The idea behind time-release vitamins is that they provide a consistent amount of vitamins into your blood stream over the course of a day. However, time-release vitamins, unlike some time-release prescription medications, seem not to be useful and end up costing more.
What type of vitamin D supplement is best?
Two forms of vitamin D are used in supplements: vitamin D2 (“ergocalciferol,” or pre-vitamin D) and vitamin D3 (“cholecalciferol”). Vitamin D3 is chemically indistinguishable from the form of vitamin D produced in the body, and there’s evidence that it may be more effective than vitamin D2 at raising vitamin D levels in the blood. That’s why some scientists recommend looking for vitamin supplements that contain vitamin D3. Other scientists believe that vitamin D2 and vitamin D3 are similarly effective. Indeed, high dose vitamin D2 is available by prescription, and doctors regularly prescribe it to restore vitamin D levels in people who are deficient. As it turns out, the marketplace may answer the vitamin D question for you: More and more supplement makers offer vitamin D3 in their products.
| Nutrient |
Incidence of Deficiency |
Typical Symptoms and
Diseases |
| Biotin |
Uncommon |
Dermatitis, eye inflammation, hair loss, loss
of muscle control, insomnia, muscle weakness |
| Calcium |
Average diet contains 40 to 50% of RDA* |
Brittle nails, cramps, delusions, depression,
insomnia, irritability, osteoporosis, palpitations, peridontal disease, rickets, tooth
decay |
| Chromium |
90% of diets deficient |
Anxiety, fatigue, glucose intolerance,
adult-onset diabetes |
| Copper |
75% of diets deficient; average diet contains 50% of RDA* |
Anemia, arterial damage, depression, diarrhea,
fatigue, fragile bones, hair loss, hyperthyroidism, weakness |
| Essential fatty acids |
Very common |
Diarrhea, dry skin and hair, hair loss, immune
impairment, infertility, poor wound healing, premenstrual syndrome, acne, eczema, gall
stones, liver degeneration |
| Folic acid |
Average diet contains 60% of RDA*; deficient in 100% of
elderly in one study; deficient in 48% of adolescent girls; requirement doubles in
pregnancy |
Anemia, apathy, diarrhea, fatigue, headaches,
insomnia, loss of appetite, neural tube defects in fetus, paranoia, shortness of breath,
weakness |
| Iodine |
Uncommon since the supplementation of salt with iodine |
Cretinism, fatigue, hypothyroidism, weight
gain |
| Iron |
Most common mineral deficiency |
Anemia, brittle nails, confusion,
constipation, depression, dizziness, fatigue, headaches, inflamed tongue, mouth lesions |
| Magnesium |
75 to 85% of diets deficient: average diet contains 50 to
60% of RDA* |
Anxiety, confusion, heart attack,
hyperactivity, insomnia, nervousness, muscular irritability, restlessness, weakness |
| Manganese |
Unknown, may be common in women |
Atherosclerosis, dizziness, elevated
cholesterol, glucose intolerance, hearing loss, loss of muscle control, ringing in ears |
| Niacin |
Commonly deficient in elderly |
Bad breath, canker sores, confusion,
depression, dermatitis, diarrhea, emotional instability, fatigue, irritability, loss of
appetite, memory impairment, muscle weakness, nausea, skin eruptions and inflammation |
| Pantothenic acid (B5) |
Average elderly diet contains 60% of RDA* |
Abdominal pains, burning feet, depression,
eczema, fatigue, hair loss, immune impairment, insomnia, irritability, low blood pressure,
muscle spasms, nausea, poor coordination |
| Potassium |
Commonly deficient in elderly |
Acne, constipation, depression, edema,
excessive water consumption, fatigue, glucose intolerance, high cholesterol levels,
insomnia, mental impairment, muscle weakness, nervousness, poor reflexes |
| Pyridoxine (B6) |
71% of male and 90% of female diets deficient |
Acne, anemia, arthritis, eye inflammation,
depression, dizziness, facial oiliness, fatigue, impaired wound healing, irritability,
loss of appetite, loss of hair, mouth lesions, nausea |
| Riboflavin |
Deficient in 30% of elderly Britons |
Blurred vision, cataracts, depression,
dermatitis, dizziness, hair loss, inflamed eyes, mouth lesions, nervousness, neurological
symptoms (numbness, loss of sensation, "electric shock" sensations), seizures.
sensitivity to light, sleepiness, weakness |
| Selenium |
Average diet contains 50% of RDA |
Growth impairment, high cholesterol levels,
increased incidence of cancer, pancreatic insufficiency (inability to secrete adequate
amounts of digestive enzymes), immune impairment, liver impairment, male sterility |
| Thiamin |
Commonly deficient in elderly |
Confusion, constipation, digestive problems,
irritability, loss of appetite, memory loss, nervousness, numbness of hands and feet, pain
sensitivity, poor coordination, weakness |
| Vitamin A |
20% of diets deficient |
Acne, dry hair, fatigue, growth impairment,
insomnia, hyperkeratosis (thickening and roughness of skin), immune impairment, night
blindness, weight loss |
| Vitamin B-12 |
Serum levels low in 25% of hospital patients |
Anemia, constipation, depression, dizziness,
fatigue, intestinal disturbances, headaches, irritability, loss of vibration sensation,
low stomach acid, mental disturbances, moodiness, mouth lesions, numbness, spinal cord
degeneration |
| Vitamin C |
20 to 50% of diets deficient |
Bleeding gums, depression, easy bruising,
impaired wound healing, irritability, joint pains, loose teeth, malaise, tiredness. |
| Vitamin D |
62% of elderly women's diets deficient |
Burning sensation in mouth, diarrhea,
insomnia, myopia, nervousness, osteomalacia, osteoporosis, rickets, scalp sweating |
| Vitamin E |
23% of male and 15% of female diets deficient |
Gait disturbances, poor reflexes, loss of
position sense, loss of vibration sense, shortened red blood cell life |
| Vitamin K |
Deficiency in pregnant women and newborns common |
Bleeding disorders |
| Zinc |
68% of diets deficient |
Acne, amnesia, apathy, brittle nails, delayed
sexual maturity, depression, diarrhea, eczema, fatigue, growth impairment, hair loss, high
cholesterol levels, immune impairment, impotence, irritability, lethargy, loss of
appetite, loss of sense of taste, low stomach acid, male infertility, memory impairment,
night blindness, paranoia, white spots on nails, wound healing impairment |
The Suggested Optimal Daily Nutritional Allowances (SONA)
| |
Men |
Women |
| Nutrient |
RDA |
SONA |
RDA |
SONA |
| Fat-soluble Vitamins |
| Vitamin A (RE, I RE = I micro gm = 3.33 IU) |
1,000 |
2,000 |
800 |
2,000 |
| Beta-carotene (mg) |
N/A |
100 |
N/A |
80 |
| Vitamin D (micro gm, 1 microgram = 40 IU) |
5 |
24 |
5 |
24 |
| Vitamin E (IU, 1 IU alpha tocopherol equivalent to I mg
alpha tocopherol) |
10 |
800 |
8 |
800 |
| Vitamin K (mg) |
80 |
80 |
65 |
65 |
Water-soluble Vitamins
|
| Vitamin C (mg) |
60 |
800 |
60 |
1000 |
| Vitamin B12 (mg) |
2 |
3 |
2 |
3 |
| Folic acid (micro gm) |
200 |
2000 |
180 |
2000 |
| Niacin (mg) |
15 |
30 |
15 |
25 |
| Pyridoxine (B6) (mg) |
2 |
25 |
1.6 |
20 |
| Riboflavin (B 2) (mg) |
1.4 |
2.5 |
1.2 |
2 |
| Thiamin (B1) (mg) |
1.2 |
9.2 |
1 |
9 |
Minerals
|
| Boron (mg) |
N/A |
2.5 |
N/A |
3 |
| Calcium (mg) |
800 |
700 |
800 |
1200 |
| Chromium (micro gm) |
50-200 |
300 |
50-200 |
300 |
| Copper (mg) |
1.5-3 |
1.5-4 |
1.5-3 |
1.5-4 |
| Iodine (micro gm) |
150 |
150 |
150 |
150 |
| Iron (mg) |
10 |
20 |
15 |
20 |
| Magnesium (mg) |
350 |
600 |
280 |
550 |
| Manganese (mg) |
2-5 |
10 |
2-5 |
10 |
| Phosphorous (mg) |
800 |
800 |
800 |
800 |
| Potassium (mg) |
99 |
200-500 |
99 |
200-500 |
| Selenium (micro gm) |
70 |
250 |
55 |
200 |
| Sodium (mg) |
500 |
400 |
500 |
400 |
| Zinc (mg) |
15 |
20 |
12 |
17 |
Note: While these are for all adults,
they are most accurate
for those aged 51 and above.
RDA - Recommended Daily Allowance
SONA - Suggested Optimum Daily Allowance
|
The nutrients listed below are recommended for good health.
Daily dosages are suggested; however, before using any supplements, you should consult
with your health care provider. The dosages given here are for adults and children
weighing 100 pounds and over. Appropriate dosages for children vary according to age and
weight. A child weighing between 70 and 100 pounds should be given three-fourths the adult
dose; a child weighing under 70 pounds (and over the age of six) should be given
half the adult dose. A child under the age of six years should be given nutritional
formulas designed specifically for young children. Follow the dosage directions on the
product label.
Vitamins
|
Daily Dosages |
| Vitamin A |
10,000 IU |
| Beta-carotene |
15,000 IU |
| Vitamin B1 (thiamine) |
50 mg |
| Vitamin B2 (riboflavin) |
50 mg |
Vitamin B3 (niacin)
(niacinamide) |
100 mg
100 mg |
| Pantothenic acid (vitamin B5) |
100 mg |
| Vitamin B6 (pyridoxine) |
50 mg |
| Vitamin B12 |
300 mcg |
| Biotin |
300 mcg |
| Choline |
100 mg |
| Folic acid |
800 mcg |
| Inositol |
100 mg |
| Para-aminobenzoic acid (PABA) |
50 mg |
| Vitamin C with mineral ascorbates |
3,000 mg |
| Bioflavonoids (mixed) |
500 mg |
| Hesperidin |
100 mg |
| Rutin |
25 mg |
| Vitamin D |
400 IU |
| Vitamin E |
600 IU |
| Vitamin K (use natural sources such as alfalfa, green
leafy vegetables) |
I 00 mcg |
Essential fatty acids (EFAS)
(primrose oil, flaxseed oil, salmon oil, and fish oil are good sources) |
As directed on label |
Minerals
|
Daily Dosages |
| Calcium |
1,500 mg |
| Chromium (GTF) |
150 mcg |
| Copper |
3 mg |
| Iodine (kelp is a good source) |
225 mcg |
| Iron |
18 mg |
| Magnesium |
750-1,000 mg |
| Manganese |
10 mg |
| Molybdenum |
30 mcg |
| Potassium |
99 mg |
| Selenium |
200 mcg |
| Zinc |
50 mg |
Optional
Supplements
|
Daily Dosages |
| Coenzyme Q10 |
30 mg |
| Garlic |
As directed on label. |
| L-Carnitine |
500 mg |
| L-Cysteine |
50 mg |
| L-Lysine |
50 mg |
| L-Methionine |
50 mg |
| L-Tyrosine |
500 mg |
| Lecithin |
200-500 mg |
| Pectin |
50 mg |
| RNA-DNA |
100 mg |
| Silicon |
As directed on label. |
| Superoxide dismutase (SOD) |
As directed on label. |
http://recipes.howstuffworks.com/question129.htm
http://www.medicinenet.com/vitamins_and_calcium_supplements/article.htm | |
