1. What are vitamins?
Vitamins are naturally occurring compounds present in most foods. The human body cannot produce vitamins and therefore has to acquire them from external sources: diet or supplements. They are essential for all body functions including growth, repair of tissues, and the maintenance of health.
2. Where does the word "vitamin" come from?
A Polish scientist, Casimir Funk (1884-1967), coined the term "vitamin" after he discovered that certain ingredients in food are essential for maintaining health. The word "vitamin" comes from the Latin word vita (life) and the biochemical term amine (nitrogen-containing)—although we now know that not all vitamins contain nitrogen.
3. Why are vitamins important?
Our bodies use vitamins every day during the normal biochemical processes that maintain life. Taken as recommended, vitamins help release energy from our food, and support growth, healing, and repair. An ongoing shortage of vitamins will lead to failed health, weakness, susceptibility to disease, and may ultimately result in death.
4. How many vitamins are there?
Thirteen vitamins have been identified: A, C, D, E, K, and eight in the B group. The "B complex" vitamins are thiamin (B1), riboflavin (B2), pantothenic acid (B5), pyridoxine (B6), cyanocobalamin (B12), niacin (B3), folic acid (folacin, folate) and biotin (H).
5. What is the difference between water-soluble and fat-soluble vitamins?
Vitamins are divided into two groups: water-soluble and fat-soluble. The water-soluble vitamins (C and B-complex) dissolve in water. They are easily taken up and released by body tissues. Because the body cannot store water-soluble vitamins, a daily supply is necessary. Vitamin B12 is an exception to this rule: if intake has been adequate, the liver maintains stores for several months.
Fat-soluble vitamins (A, D, E and K) dissolve in dietary and body fat. They are absorbed from food along with the fat in the food we eat. Excess fat-soluble vitamins may be stored in the liver and body fat, so several weeks' supply may be consumed in a single dose or meal.
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6. What is meant by "B-complex vitamin"?
This umbrella title covers a group of 8 vitamins: thiamin (B1), riboflavin (B2), pyridoxine (B6), cyanocobalamin (B12), niacin (B3), pantothenic acid (B5), folic acid (folate) and biotin (H). Originally, if a vitamin had a similar structure to one already identified and was found in the same foods, it was given the same letter, but with a distinguishing number. Scientists have since learned each B-vitamin has a unique function.
7. What is beta-carotene?
Beta-carotene belongs to a family of compounds called "carotenoids", which give orange and yellow fruits and vegetables their characteristic colour. Beta-carotene is also found in dark green leafy vegetables. This vitamin is sometimes called "provitamin A" because it can be converted to vitamin A (retinol) inside the body.
Some manufacturers use beta-carotene as a source of vitamin A in multivitamins because, unlike vitamin A, beta-carotene is non-toxic. Research is currently underway to determine other non-vitamin roles for beta-carotene such as preventing cancer and other chronic diseases.
8. Why is beta-carotene considered a safe form of vitamin A?
It is considered a "safe" form of vitamin A because the body converts only as much of it to vitamin A as it needs. Taking excessive amounts of beta-carotene can, however, give an orange/yellowish tint to the skin (hypercarotenosis). It is not dangerous and disappears when intake is reduced or stopped.
9. Can vitamins be made in our bodies?
In a few cases, yes. Vitamin K is produced in the necessary amount by the friendly bacteria (microflora) which live in the adult gut. Newborn infants, however, have immature guts and do not have this normal bacteria. Therefore, they require additional vitamin K until the bacteria become established.
Vitamin D and niacin can also be made in our bodies. However, neither are made in the amounts required for health. For this reason, these vitamins must be obtained from food or supplements.
10. Do vitamins give you "pep" or energy?
No. Vitamins help convert food into energy which your body needs to stay warm, active, and healthy. However, well-nourished individuals cannot increase their physical capacity by simply taking extra vitamins.
People who consume an unbalanced daily diet may suffer from fatigue. In this case, taking vitamin supplements may help restore energy.
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11. Are vitamins fattening?
No. Vitamins have no caloric value, and are not sources of energy. However, vitamins do help your body use or release energy present in food. Some vitamin supplements may have a sugar coating, which may represent a calorie or two.
12. Why do you often find vitamins in cosmetics?
Vitamins A, E, and panthenol are important for healthy skin. Vitamin A enhances the regeneration of skin cells; vitamin E helps to protect against the negative effects of ultra-violet light, reduces redness from exposure to the elements, and retains moisture in the skin. Panthenol, a derivative of pantothenic acid, keeps the skin from drying out, reduces inflammation, and adds lustre and thickness to hair. Biotin has been shown to strengthen fingernails.
13. Can vitamins be replaced by other food components such as minerals or bioflavonoids?
No. Vitamins cannot be replaced by any other food components.
14. What are the Dietary Reference Intakes?
The Dietary Reference Intakes (DRIs) have been developed by the Food and Nutrition Board, Institute of Medicine, National Academy of Sciences, with active involvement of Health Canada. The DRIs are reference values that are quantitative estimates of nutrient intakes to be used for planning and assessing diets of healthy Americans and Canadians. They include the Recommended Dietary Allowance (RDA), Tolerable Upper Intake Level (UL) and Adequate Intake (AI), which is used when and RDA can not be established.
The current Canadian nutrient intake recommendations are called the Recommended Nutrient Intakes (RNIs). The DRIs will officially replace the RNIs once the final reports are published and accepted by Health Canada. However, many health professionals are already referring to the DRIs since they are the most up to date nutrition recommendations.
15. What is the difference between a herb and a vitamin?
Vitamins are naturally occurring compounds present in most foods, which are essential for all body functions. Herbs are also natural products consisting of plant material or plant extract. However, herbs are not essential to the human body. Vitamins have a substantial body of research exploring their function in the human body, intake requirements and safety of intake. Herbs have limited research in these areas and do not have recommended intake levels since they are not essential to human life. Vitamins have strict government regulations ensuring their quality and safety. Herbs lack any legal standards for processing, harvesting or packaging and consequently may not consist of pure products and may vary in potency.
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16. Can food supply all of your vitamin requirements?
Yes, provided your diet is adequate and well-balanced. Canada's Food Guide recommends a daily intake of:
5-10 servings of fruits and vegetables.
(1 serving = 1 medium fruit or vegetable or ?? cup juice
5-12 servings of whole grain or enriched breads and cereals.
(1 serving = 1 slice bread or 30g cereal)
2-4 servings of milk and milk products (depending on your age).
(1 serving = 1 cup milk or ?? cup yogourt or 50g cheese)
2-3 servings of protein-rich meat, fish, poultry, or alternative sources of protein.
(1 serving = 50-100g meat, poultry, fish or 1-2 eggs or 2 tbsp peanut butter)
The USDA Food Guide Pyramid recommends the following daily intake:
Use sparingly -- Fats, oils and sweets,
2-3 servings -- Milk, Yogurt, and Cheese
(1 cup of milk or yogurt, 1.5 ounces of natural cheese, 2 ounces of processed cheese)
2-3 servings -- Meat, Poultry, Fish, Dry Beans, Eggs, and Nuts
(2-3 ounces of cooked lean meat, poultry, or fish -- .5 cup of cooked dry beans, 1 egg, or 2 tablespoons of peanut butter count as 1 ounce of lean meat)
3-5 servings -- Vegetables
(1 cup of raw leafy vegetables 1/2 cup of other vegetables, cooked or chopped raw 3/4 cup of vegetable juice)
2-4 servings -- Fruit
(1 medium apple, banana, orange, etc., .5 cup of chopped, cooked, or canned fruit, .75 cup of fruit juice)
6-11 servings -- Bread, Cereal, Rice, and Pasta
(1 slice of bread, 1 ounce of ready-to-eat cereal, .5 cup of cooked cereal, rice, or pasta)
If your diet is consistently lacking in foods from any of the major groups, if you eat fewer servings than suggested, or very small portions, then food alone cannot meet your vitamin needs.
17. Is it possible to have poor vitamin status and not know it?
Yes. It is possible because poor status usually develops slowly, and in the early stages, there are no classic symptoms. The non-specific characteristics of low vitamin status include fatigue and lethargy, insomnia, irritability, loss of appetite, and poor concentration.
18. What will happen if vitamin intake is very low for a day or two?
If you normally take enough vitamins and are in good health, low vitamin intake for even a week or two would not be harmful. But if your diet is short of vitamins for an extended period, you could experience a vitamin deficiency.
19. Is it possible to be overweight and still have poor vitamin status?
Yes. It is possible to be overfed and undernourished. Foods that are high in calories are often low in vitamins.
20. What are vitamin deficiencies?
"Clinical" vitamin deficiencies result in specific diseases. For example, a lack of vitamin C eventually produces scurvy, characterized by swollen joints, bleeding gums, and aching bones. Scurvy is treatable by increasing vitamin C intake with supplements or citrus fruits. Other disease states associated with classic vitamin deficiency include beriberi (thiamin deficiency), rickets (vitamin D deficiency), pellagra (niacin deficiency), and eye lesions (vitamin A deficiency).
It takes several months to reach a state of clinical vitamin deficiency. Before a deficiency can be diagnosed, the body will have gone through three stages:
- preliminary stage: low vitamin reserves are eventually used up.
- biochemical stage: some interference with normal body functions occurs.
- physiological stage: deficiency symptoms begin to appear.
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21. What can cause vitamin deficiencies?
Causes of vitamin deficiencies can be summarized as follows:
Cause
- Inadequate food intake
- Unbalanced food consumption.
- Increased vitamin needs due to "life cycle".
- Increased vitamin needs due to "life-style" or other factors
- Poor absorption and digestion
People affected
- Individuals living at or close to the "poverty" line.
- Dieters consuming less than 1,800 Calories.
- Strict vegetarians.
- People with denture problems.
- People who choose food unwisely due to ignorance, apathy or depression.
- Others who work or study where nutritious meals are not available.
- Newborn and premature infants.
- Children and adolescents in periods of rapid growth.
- Women who plan to become pregnant
- Women who are pregnant or breastfeeding their infant.
- The elderly.
- Smokers (who need to increase vitamin C by 50%).
- Women taking oral contraceptives or hormone replacement therapy.
- People recovering from surgery or a long illness.
- Many older people, drinkers, and long-term users of some medications.
22. Do fresh fruits and vegetables vary in vitamin content?
Yes. Climate, soil, crop maturity, harvesting methods, transportation, and storage all affect the vitamin content of fresh foods.
23. Does food lose some of its vitamin content when stored?
Yes. Vitamin loss depends on the type of food being stored and on the length and conditions of storage. For instance, potatoes can lose as much as one third of their vitamin C content after being stored for three months. It is best to eat the freshest foods available, and as quickly as possible after buying them.
24. Is deep freezing a good method of conserving vitamins in food?
Yes. Generally, deep freezing is a good way of preserving the vitamin content of foods. However, this is not true in the case of vitamin E, which is degraded by cold temperatures. It is also important to wrap foods well to protect against dehydration, and to freeze each food.. Be sure to label foods with the date of freezing, and observe the guidelines for length of storage of particular foods. Quick thawing deep frozen food, such as in a microwave oven, can also lead to vitamin losses.
25. Can vitamins be unknowingly destroyed in the preparation of food?
Yes. Vitamins are sensitive to heat, air, humidity, and light. As a result, cooking foods or even just exposing them to the kitchen environment may actually destroy vitamins. To avoid vitamin loss, do not soak or overcook your food; trim and chop sparingly; add as little water as possible; re-use the water in which you cooked your vegetables for soups, stews or sauces; do not keep food on a warming plate, but re-heat quickly just before eating.
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26. Does processing destroy the vitamins in food?
Yes. Processing, like cooking, exposes vitamins to heat, humidity, air and light. As a result, some vitamins are destroyed during processing. Most of the losses are due to heat generated during the canning and freezing steps (i.e., blanching, pasteurization, and sterilization). However, care is taken by the food industry to prevent the destruction of vitamins. When vitamin loss is inevitable, vitamins are added to replace those lost in processing.
27. Why do food manufacturers often add vitamins to their products?
- to replace vitamins lost during food processing or storage.
- to avoid possible widespread deficiencies in the population.
- to ensure new processed foods are nutritious, as well as attractive to consumers.
- for technological reasons.
28. What are some technological reasons for using vitamins in food processing?
Vitamin C (ascorbic acid) acts as an antioxidant in products such as cured meats, vegetable oils, margarine, beer; it also improves bread dough.
Vitamin E works as an "antioxidant" to prevent margarines and oils from becoming rancid.
Beta-carotene produces yellow to orange colours, to enhance margarine, butter, salad dressings and beverages.
29. Why do adolescents need more vitamins than adults?
The adolescent growth spurt marks a time when the body requires both more energy (Calories) and a greater quantity of essential vitamins and minerals. However, erratic eating habits, snacking, meal-skipping, eating an excessive amount of "junk" food, unsupervised dieting, or developing an eating disorder may prevent some teens from reaching this nutritional goal.
30. Could adolescents benefit from vitamin supplements?
If an adolescent eats a balanced diet, vitamin supplements are not needed. However, if the teenager is a selective eater, diets for extended periods, is extremely active in sports, is growing rapidly, or eats away from home, then a vitamin supplement may be advisable.
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31. Why do adults over 55 years of age have difficulty fulfilling their vitamin requirements?
Elderly people often have little interest in food and eat less food than they require. Some reasons for this include dental problems, lack of money, or even loneliness. The aging process may also impair the ability of the intestine to absorb vitamins. For these reasons, vitamin-enriched food or vitamin supplements are often recommended for seniors to maintain good health.
32. Do the elderly have increased vitamin D needs?
Older people often have low vitamin D levels because many avoid vitamin D-rich foods such as milk, eggs and liver and, as the body ages, the ability to produce vitamin D decreases. Because sunshine is essential to this process, elderly people who do not spend enough time in sunlight or use heavy sunscreens may have inadequate vitamin D levelsA supplement containing the approximate DRI or RNI of vitamin D would be beneficial in this case. Because vitamin D is toxic in high amounts, 400 IU/day should not be exceeded.
33. Are extra vitamins needed during pregnancy or breast-feeding?
Yes. Because the baby makes extra demands on the mother's body before and after birth, pregnant and nursing women have an increased need for vitamins A, C, B1, B6, B12, and folic acid. They also need extra minerals, such as calcium, phosphorus, magnesium, iodine, zinc and (except when nursing) iron.
The Society of Obstetricians and Gynecologists recommends all women of childbearing age consider taking a supplement, which contains 0.4 mg of folic acid daily. Women at high risk for an NTD affected pregnancy should consider a 4.0 mg folic acid supplement daily. Risk factors include having had an NTD affected pregnancy, or having a close relative who is afflicted, being diabetic or taking folic acid antagonists such as trimethoprim. Recent research indicates that folic acid is especially important to the development of fetus during the first 30-60 days after conception. It may help reduce the risk of neural tube defects (NTDs), which include spina bifida (open spine) and anencephaly (lack of brain). Experts also recommend women take a multivitamin supplement at least three months prior to conception to reduce the risk of having a baby with one of these birth defects.
34. Do vegetarians receive adequate vitamins through their diet?
Strict vegetarians—that is, those who avoid meat, milk and eggs—will experience a nutritional deficiency if vitamin B12 supplements are not supplied. Pregnant women and infants are particularly at risk. Studies of "vegan" mothers show that both mother and baby often suffer from anemia and bone marrow abnormalities if vitamin B12 has not been taken during pregnancy.
35. Does an exclusively breast-fed infant receive all the necessary nutrients?
Yes. An adequate amount of human milk from a well-nourished mother meets the recommended intakes for all nutrients at this age. However, physicians recommend a vitamin K injection at birth, and possibly vitamin D and/or fluoride in the first 4-6 months of life.
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36. Is it true oral contraceptives increase a woman's vitamin needs?
Yes, if the oral contraceptive taken contains high estrogen content. It is known that estrogen in the "pill" can affect the metabolism of nutrients, particularly B6 and folic acid. If pregnancy follows quickly after discontinuing the "pill", a folic acid deficiency may develop.
37. If you are dieting to lose weight, will you still obtain all necessary vitamins?
That depends on the number of calories consumed each day. Scientists have shown that the risk of obtaining an insufficient quantity of vitamins and minerals increases when the diet is less than 1,800 calories.
38. Are "fad" diets wise providing they are only followed for short periods?
No. Popular or "fad" diets are generally nutritionally unbalanced. They are designed to promote quick weight loss, not good health. Usually weight loss is short-lived. Such diets cannot supply adequate nutrition, so supplementary vitamins are advisable if the dieter insists on losing weight in this fashion.
39. Do you need extra vitamin C if you smoke cigarettes?
Yes. The vitamin C intake needed to maintain an adequate vitamin C status is up to 50% higher in heavy smokers (at least 20 cigarettes/day) compared with non-smokers. According to the new Dietary Reference Intakes and Canadian Guidelines, adult male non-smokers require 90 mg/day of vitamin C and female non-smokers need 75 mg/day. These new guidelines indicate that smokers require an additional 35 mg/day above the new RDA. Passive smoke has been shown to increase vitamin C requirements by about 25%.
40. Do alcoholic beverages affect vitamin requirements?
Yes. Regular heavy consumption of alcohol impairs the absorption and utilization of vitamins, particularly vitamins C, pyridoxine (B6), thiamin (B1), and folic acid. Heavy drinkers often experience a lack of appetite; hence their reduced food consumption results in lower vitamin intake. Although vitamin supplements cannot solve the problems caused by heavy drinking, they play a role in the rehabilitative process.
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41. Is extra vitamin E needed by those on a diet high in polyunsaturated fatty acids (PUFAs)?
Research indicates that animals need more vitamin E when they are given higher amounts of polyunsaturated fatty acids. In human diets, foods which are particularly high in PUFAs are usually enriched with vitamin E.
42. Are extra vitamins recommended in times of physical stress?
Yes. The body undergoes a variety of physical stresses at various times, such as when recovering from an acute infection, an extensive skin burn, or major surgery. In the case of a serious infection, additional vitamin C may be prescribed by a doctor. Vitamin E has been shown to reduce damage which occurs to the heart during surgery due to interrupted blood flow.
Vigorous exercise has been shown to increase the production of free radicals. There is some evidence vitamins C, E and beta-carotene may protect against such damage.
43. Are extra vitamins needed during emotional stress?
It is not known whether vitamins play a role in coping with emotional stress because little research exists in this area.
44. Does medication affect vitamin requirements?
Yes. Regular use of some medications may upset the vitamin balance by changing our ability to absorb, use, store, or excrete vitamins. Some examples are: oral contraceptives reducing folic acid and B6 levels; aspirin (ASA) and anticonvulsants affecting folic acid; neomycin and cholestryamine affecting B12; isoniazid affecting niacin; laxatives such as mineral oil impairing the status of vitamins A, E, and D. Ask your pharmacist about the potential of your medication to interact with vitamins and other nutrients if you are concerned.
45. Do vitamin supplements affect appetite?
No. Supplemental vitamins do not affect the appetite. However, vitamin deficiencies may contribute to a loss of appetite. By restoring vitamin balance, the appetite might improve.
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46. There are so many multivitamin supplements on the market; what criteria should be used in making an appropriate choice?
Check the label to be sure:
- the product contains 12 vitamins and beta-carotene (in Canada vitamin K is restricted in vitamin supplements)
- the amount of each vitamin is approximately equivalent to 1-3 times the Recommended Nutrient Intake (RNI) or Dietary Reference Intakes (DRI)
- the expiry date has not passed.
If an iron supplement is also needed, choose a multivitamin with iron rather than using a separate supplement.
47. Are vitamin supplements helpful when you feel weak and lack energy?
If your fatigue and lethargy is the result of a lack of vitamins due, for example, to poor dietary habits, a multivitamin supplement may improve your condition. See your doctor to rule out other causes of these non-specific symptoms.
48. Is the time of day that you take vitamin supplements important?
No. However, it's easier to remember to take vitamin supplements at the same time each day--at breakfast, for example. That way, taking your supplement becomes part of your routine.
You should also be aware that certain nutrients enhance the absorption of others. For example, vitamin D is essential for calcium absorption (hence vitamin D fortification of milk) and vitamin C aids non-heme iron absorption. For this reason, it is best to take an iron supplement with a source of vitamin C (fruit, fortified drink, or supplement).
49. Are slow-release or timed-release preparations superior to regular vitamin supplements?
No, but they may be preferable to use in some cases. If very high doses of a particular water-soluble vitamin are to be taken, then slow/or timed-release preparations are often preferred. Experimental research has not confirmed whether water-soluble vitamins are better absorbed when released gradually.
50. Are vitamin C supplements which contain bioflavonoids more easily digested?
Research suggests that vitamin C may be used more efficiently when certain bioflavonoids are present. Bioflavonoids are being investigated as a possible preventive against heart disease.
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51. How should vitamin supplements be stored?
Because vitamins are vulnerable to light, air, heat, and moisture, they should be stored in a cool, dry place. Do not store vitamins in the refrigerator because they will collect moisture. Keep them out of the reach of children.
52. Can vitamin supplements deteriorate or lose their potency?
Yes. However, if vitamin supplements are correctly stored, they will keep for two or three years. Choose a supplement with an expiry date on the packaging, and discard the product when the expiry date has passed.
53. What other ingredients are used to prepare a vitamin tablet?
Vitamin tablets contain ingredients other than vitamins. For example, starch may be used as a binder, lactose as a stabilizer, and sugar and food colour as a coating. All ingredients in vitamin supplements must comply with Canadian food and/or drug regulations, and can be regarded as safe. If you experience an allergic reaction to a supplement, it may be due to these "excipients" or dyes rather than to the vitamin itself. If you have special requirements due to dietary or religious reasons, consult your pharmacist.
54. Is there any difference between "natural or organic" vitamins versus synthetic?
No. Synthetic vitamins are identical in chemical structure to those found in food. A difference between natural and synthetic vitamins has not been demonstrated for any vitamins, except vitamin E. The form of vitamin E derived from "natural" products is more biologically active than its synthetic form. However, both commercially available types usually contain identical amounts in biological activity
55. Why do many multivitamin supplements contain more than the RDI or Canadian Recommended Nutrient Intake (RNI)?
The RDI's and RNI's apply to healthy individuals in specific age groups or periods of the lifecycle. They are based on certain assumptions so they can be applied to a large population. Many supplements, on the other hand, are formulated to meet the increased needs of people in "risk groups". These groups require a greater-than-average level of vitamins.
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56. Are the best supplements the ones that contain the most ingredients?
It is wise to choose a supplement containing a broad range of vitamins and minerals. However, some products contain substances for which no human nutritional need has been established. Examples are: PABA, inositol, pangamic acid, and RNA.
57. Who decides what goes into a vitamin supplement?
Most manufacturers develop products which contain the approximate vitamin requirements of the consumers targeted; for example, children, teens, pregnant women, etc.
The Canadian Government regulations state maximum allowable vitamin amounts and must approve any other ingredients in the product. Vitamin supplements are manufactured and marketed under very strict regulations in Canada.
58. Are chewable vitamins harmful to children's teeth?
Probably not, unless the child is taking more than the recommended amount. Most chewable children's formulations contain sugar substitutes, instead of sugar, and sodium ascorbate, the least acidic form of vitamin C.
59. Can multivitamin supplements be taken regularly over a long period?
Yes. The amounts contained in multivitamins and prenatal supplements are considered safe. However, continued use of high amounts of vitamin A or D—that is, more than 10 times the DRI or RNI for vitamin A, or 5 times the DRI or RNI for vitamin D can have a negative impact on your health
60. Are vitamins safe if taken in large amounts?
Yes and no. Given the vast differences in individual vitamin requirements and tolerances, there is no absolute rule. As a general guide, water-soluble vitamins (vitamin C and the B complex) can be taken in amounts up to 100 times the DRI or RNI. Surplus amounts are excreted in the urine.
The fat-soluble vitamins A and D have a much lower safety margin. Vitamin A is generally considered safe in amounts up to 10 times the normal daily recommendation, and vitamin D up to 5 times the DRI or RNI recommendation. High doses of A or D should only be taken under the direction of a doctor.
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61. What can happen if too much vitamin A is consumed?
"Hypervitaminosis A" (from the Greek "hyper"—too much) causes symptoms such as loss of appetite, blurred vision, headache, muscle soreness, loss of hair, redness and peeling of the skin. A healthy non-pregnant adult may safely consume up to 10 times the RNI for this vitamin. Pregnant women should limit supplementation to 8,000 IU/day. The recommended amounts of vitamin A from a mixed diet together with supplements of 8,000 IU/day are considered well within the safety margin for this vitamin.
62. People taking high doses of vitamins often feel that "if a little is good, more is better". Are they right?
No. It is possible to maintain a good nutritional status with relatively small doses. If you eat a balanced diet and do not require extra vitamins for a specific reason (for example, you are not pregnant, nursing, on a strict-diet, smoking, drinking heavily, on the "pill", or under severe physical stress), your food should give you all the vitamins you need.
By exceeding the general guide for safe use of supplements, a person increases his or her risk of developing vitamin toxicity.
63. Should vitamins be regarded as "drugs"?
In some cases, yes. Vitamin supplements taken at high dosages may produce therapeutic or drug-like effects. An example is niacin, which is sometimes prescribed in very high doses to reduce cholesterol levels in the blood. Vitamin therapy of this nature should always proceed under the supervision of a physician.
As with drugs, vitamin supplements should be used as directed and keep out of the reach of children. An accidental overdose must be brought to the attention of trained medical personnel.
64. Why does urine often turn bright yellow when vitamin B-complex or a multivitamin supplement is used?
This is caused by the riboflavin (vitamin B2), which has an intense yellow colour. If you are taking more vitamins than you need, you get rid of the excess (water soluble only) through the urine. This is a natural process and no cause for alarm.
65. Can overexposure to the sun cause vitamin D toxicity?
No. There is no risk of vitamin D toxicity from prolonged sun exposure. Production of vitamin D in the skin from sunlight is automatically regulated by the body. In fact, the skin protects itself against overexposure through tanning!
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66. Are vitamin E supplements safe?
It is very hard to take too much vitamin E, even though it is one of the fat-soluble vitamins that can be stored in the body.
According to well-documented studies, adults have taken 800-900 IU daily of vitamin E for extended periods of time without any side effects. Most vitamin E supplements contain 100 to 400 IU, well below the level at which minor complaints such as stomach discomfort have been reported. People who are taking medication should check with their doctor before taking high doses of vitamin E because, in rare cases, negative drug/nutrient interactions may occur.
67. Is there a risk of vitamin poisoning among young children?
Vitamin supplements should be kept well out of the reach of children since swallowing several pills could be harmful, depending on the child's age. Iron supplements can cause toxicity in children.
68. If you eat fortified foods and also take a daily multi-vitamin supplement, is there a risk of getting excessive amounts of vitamins?
No. The levels of vitamins in fortified and enriched foods are carefully monitored and meet government standards. Multivitamins are formulated to meet or exceed the DRI or RNI but are also safe. There is no danger posed by consuming both fortified foods and a well-balanced vitamin/mineral supplement as long as you are consuming a reasonable amount.
69. Does a high dose of vitamin C—3 grams per day, for example—cause any side effects?
Few side effects occur even with large doses of vitamin C. However, one side effect of large doses of vitamin C (ascorbic acid) is a mild laxative effect. This can often be avoided by taking vitamin C in several smaller doses over the day. As a matter of fact, the body can use four 250 mg doses of vitamin C more efficiently than one single dose of 1,000 mg. The new Dietary Reference Intakes has set a Tolerable Upper Limit of 2,000 mg/day of vitamin C for all adults.
70. Is there a danger of getting kidney stones from regular use of vitamin C supplements?
Studies have shown that there is no increased risk. However, people with a history of kidney stones should not take more than the daily recommendation (DRI) for vitamin C. Higher doses (several grams) do not pose a risk to other individuals.
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71. Is there a risk of "rebound scurvy" if high doses of vitamin C supplements are abruptly stopped?
No. Many investigations have been carried out, both in humans and animals, which demonstrate that the body does not increase its requirement for vitamin C when large doses are taken. So if you take a large amount of vitamin C, and then stop abruptly, you will not be at risk for a vitamin C deficiency.
72. Should supplementary vitamin C be avoided by people who have stomach ulcers and need to avoid acidic foods?
In its usual form, yes. However, vitamin C also exists in the form of sodium or calcium ascorbate, which is non-acidic, but just as effective as ascorbic acid. A pharmacist, physician or dietitian can advise you on the preparation best suited to your needs.
73. Is it safe to take beta-carotene supplements?
Beta-carotene has a well established safety record, it has been used in many studies with no reported side effects other than yellowing of the skin. Physicians have been using beta-carotene to treat patients suffering from photosensitivity diseases without complications with doses of up to 180 mg/day.
In light of the CARET study in which participants (all smokers) had a slight increase in incidence of cancer and mortality the U.S. National Cancer Institute and other health authorities advise that the best prevention against lung cancer is to quit smoking and to consume a diet rich in fruits and vegetables. The NCI notes that results of the CARET study suggest smokers should not take beta-carotene supplements.
74. Is vitamin B6 effective in preventing or curing a hangover?
No. While many people believe that B6 cures the after-effects of drinking, this has not been scientifically proven.
75. Is there an advantage in consuming extra vitamin C if you have an iron deficiency?
Yes. Iron deficiency anemia results not only from an insufficient intake of iron, but also from poor absorption of iron from the diet. When foods high in vitamin C or vitamin C supplements are taken together with meals containing non-heme iron (iron from vegetable sources), the absorption of iron is dramatically improved.
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76. Can vitamin C improve physical performance?
Possibly. If blood levels of vitamin C are normal, physical performance will not improve by taking more vitamin C. However, if vitamin C levels are below the normal range, physical performance may be impaired.
77. Can vitamin C supplements prevent or reduce the severity of fever blisters or cold sores?
Scientific data are not yet available to provide an answer to this question.
78. Can vitamin B6 relieve the symptoms of premenstrual syndrome (PMS)?
Studies have shown vitamin B6 to be effective in alleviating some symptoms of "PMS" in some women, such as breast tenderness, headache, tension, irritability, and bloating. A general dosage range of 50-100 mg/day is recommended and considered safe.
79. Does vitamin E help to heal skin burns?
Yes. When applied as a liquid or ointment directly to burns or cuts, vitamin E is believed to speed healing. Although there is no conclusive scientific evidence to support this observation, experiments have confirmed that vitamin E often reduces redness and inflammation.
80. Can vitamin supplements enhance human fertility?
We don't know since research has just begun in this area. One study on male infertility found an association between a low level of vitamin C in the body and sperm "clotting", a condition that inhibits the ability of sperm to move.
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81. Can you protect yourself from mosquito bites by taking large amounts of B1?
Perhaps. Vitamin B1 has a distinct smell. Taken in large doses, it emits an odour through the pores and is said to keep mosquitoes away. Some people find it effective, but it is safer to rely on insect repellents, especially in countries where malaria is a problem.
82. Does vitamin E stimulate sex drive?
No. This belief is based on misinterpreted animal research: rats stopped reproducing after consuming a vitamin E-free diet, and resumed reproduction when the diet was restored to normal. A mistaken conclusion was drawn that vitamin E was therefore able to strengthen the sex drive.
83. Is vitamin C helpful in treating colds?
Studies show that 250-2,000 mg/day of vitamin C—taken as food or a food supplement (250 mg is the equivalent of 18 oz. of orange juice)—decreases the duration of colds as well as certain symptoms. Research is ongoing to determine whether there are other benefits associated with taking vitamin C for colds.
84. Is vitamin B6 effective in treating carpal tunnel syndrome (CTS)?
Researchers have discovered that 100-200 mg/day for three months effectively relieves the symptoms of "CTS" for many people. Because high doses of B6 can cause neurological complications in some individuals, such treatment should be supervised by a physician.
85. To what extent can extra vitamin E slow the aging process or extend life?
In animals, vitamin E has been shown to protect certain tissue components from being oxidized (damaged by oxygen), a process that contributes to tissue aging. As an antioxidant, vitamin E may also help delay the development of certain degenerative diseases that commonly affect the elderly.
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86. Is it true that vitamin E can protect our lungs from cigarette smoke and air pollution?
Yes. Experiments on animals and humans indicate that vitamin E reacts in the lungs with major toxic air pollutants such as nitrogen dioxide and ozone, guarding against their harmful effects. Vitamin E levels in humans are lowered by cigarette smoking.
87. Does beta-carotene have other actions, other than as pro-vitamin A?
Beta-carotene and other members of the family of carotenoids are being investigated in the treatment of cancer. The research studies have not yet been concluded, but the data strongly support a protective role for beta-carotene against cancers, particularly lung cancer.
88. Can the risk of cancer be reduced by taking extra vitamins?
Perhaps. Research from over 200 studies has shown a relationship between low vitamin A (and beta-carotene) intake and the occurrence of cancers of the lung and stomach. And, studies have shown vitamins C and E can prevent the formation of nitrosamines, especially in the stomach. (Nitrosamines are substances formed in the body, in foods, and in cigarette smoke which can be cancer-causing.)
In intervention studies, that is studies where participants received supplements to determine whether cancer incidence could be reduced, have produced mixed results. In a study of 30,000 Chinese men and women, those who took a daily supplement of beta-carotene, vitamin E and selenium had a 13% lower risk of death from cancer and a 10% lower incidence of overall mortality. However, unexpected results from a recent study of male middle-aged, heavy smokers in Finland showed no reduction in lung cancer or mortality among those who took beta-carotene or vitamin E, but did report a much lower incidence of prostate cancer. Men who took beta-carotene actually had a higher incidence of lung cancer. This may have been because these men already were developing precancerous conditions when they entered the study.
Researchers believe antioxidant vitamins play an important role in cancer prevention and will continue to conduct studies throughout the world.
89. Can vitamin D help prevent osteoporosis?
Not directly. Vitamin D does, however promote the absorption of dietary calcium and the mineralization of bones. When vitamin D is absent, these processes are impaired. Serious deficiency diseases may result, such as rickets in children and the softening of the bones in adults.
Inadequate vitamin D and calcium intakes may contribute to the development of osteoporosis. Studies have shown that vitamin D supplementation reduces bone loss in older women. Vitamin D is a fat-soluble vitamin and therefore can be toxic in large amounts. The upper daily limit for adults is 50 mcg or 2,000 IU. It is best to use the DRI guideline for daily intake. Exercise has been shown to be a significant contributor to maintaining healthy bones.
90. Do vitamins strengthen the immune system?
Yes. Good nutritional status is an important defense against illness. Vitamins A, C, E, B6 and beta-carotene, have been shown to be essential to maintaining the immune system.
A Canadian study conducted in 1992 demonstrated that the immune status of the elderly could be improved significantly by taking a multivitamin. Participants who took a supplement once a day had 25 fewer days of illness and required less antibiotics than those who did not.
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91. Can vitamins play a role in the fight against AIDS?
Yes. Because malnutrition often results from AIDS, vitamin supplements help patients meet nutrient requirements when nausea, diarrhea and poor digestion affect food intake. In addition, good vitamin status enhances the body's immune system and has been shown to delay the onset of AIDS in HIV positive individuals. Multivitamins have also been shown to be beneficial to AIDS patients. Consult a physician as to which single entity supplements should be taken to avoid possible negative interactions with drugs.
92. Can supplements help the management of diabetes?
Some studies have shown B6 supplementation reduces the painful neuropathy experienced by some diabetics. Vitamin E has been shown to improve natural insulin action in non-insulin dependent diabetics by increasing glucose metabolism. Vitamin E may also provide protection against oxidative damage, which occurs more frequently in diabetics, due to their high rate of lipolysis in their metabolism. Studies have also shown diabetics have lower levels of vitamin C blood levels than non-diabetics, even when both groups consumed the same amounts of vitamin C. More research is needed to determine how diabetes affects vitamin status, and how supplementation can benefit this group.
93. One hears more and more about the role of vitamins neutralizing "free radicals" in the body. What does that mean?
Free radicals are highly reactive compounds produced spontaneously in the body or because of exposure to certain pollutants. They can be dangerous, since they cause damage to body cells and tissues, including genetic material. Recent studies indicate that vitamins C, E, and beta-carotene protect against free radical damage.
94. Does vitamin E cure fibrocystic breast disease?
At present it is uncertain. In some research trials, vitamin E appeared to be helpful in treating this condition; however, the results are inconclusive. A woman with fibrocystic breast disease should consult her physician about currently accepted methods of treatment.
95. Is it true vitamins can help prevent cataracts?
Possibly. Cataracts are the leading cause of blindness worldwide, and affect about 20% of people between the ages of 60-75. Research to date indicates that people with low levels of vitamins C and E have a greater risk of developing cataracts than people with higher levels. In one study, those who supplemented with 300-600 mg/day of vitamin C and 400 IU/day of vitamin E reduced their risk of cataracts by 50%. Scientists believe these vitamins play an important role in protecting tissues in the lens of the eye.
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96. Do vitamins help prevent heart attacks?
There is a strong association between vitamin intake and incidence of heart attack. Various studies have recently established that people with low levels of vitamins A, E, C, and beta-carotene are more likely to develop heart disease. Recently, one large scale study conducted with 87,000 nurses and another with nearly 40,000 male health professionals found that those who took 100—200 IU of vitamin E daily for at least two years had a lower incidence of cardiovascular disease than the control groups (for women, a 34% reduction in risk and for men a 40% reduction). In another study, male physicians who took beta-carotene supplements had a significantly lower incidence of cardiovascular illness than those who took no supplements. However, more research is needed to explain the role of vitamins in the area of cardiovascular disease.
97. What are nutraceuticals?
Nutraceuticals, sometimes called designer foods, contain phytochemicals, biologically active compounds that help protect the body against certain chronic diseases such as cardiovascular disease, arthritis and cancer.
98. What are some examples of these phytochemicals?
Carotenoids are one of the fourteen compound groups currently under investigation. Beta-carotene is the best known carotenoid and has attracted attention as a possible cancer preventive. Lycopene, Lutein and zeaxanthin are other carotenoids being studied. Other phytochemicals include:
- vitamins, especially vitamins C and E
- allylic sulfides (found in onions and garlic)
- sulforaphane (found in broccoli and cauliflower)
- saponin (found in soybeans, chickpeas, alfalfa sprouts and ginseng)
- capsaicin (found in hot peppers)
- flavonoids
Although no long term study has proven phytochemicals prevent cancer growth, over 200 studies link diets rich in fruits and vegetables with a lower risk of cancer.
Not too far into the future scientists hope to be able to design new products which effectively combine phytochemicals. In fact, the first nutraceuticals are now appearing on the market.
99. What are carotenoids?
Carotenoids are a family of compounds abundantly found in fruits, vegetables and green plants. They provide the bright yellow, orange and red colours to the fruits and vegetables we eat. Of more than 600 known carotenoids in nature, only about 20 are found in human plasma and tissues. The principal carotenoids found in humans are alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein, lycopene and zeaxanthin. A lot of research effort is being put into identifying the health benefits of these compounds.
100. What is Lutein?
Lutein along with Zeaxanthin are the only two carotenoids concentrated in the macula of the human eye. The macula is a collection of sensitive cells in the back of the eye that turn light into sharp image signals the brain can understand. Primary food sources of Lutein and Zeaxanthin include dark green leafy vegetables and other colourful fruits and vegetables, such as corn, brussels sprouts and peppers. Savoy cabbage, watercress and cooked spinach are also sources of Lutein. Oranges, orange juice, corn, orange peppers are sources of Zeaxanthin. Clinical and animal data indicate that these carotenoids could protect the macula from oxidative or light damage. Epidemiological data has shown that high levels of dietary Lutein and Zeaxanthin intake have been associated with a reduced risk of Age-Related Macular Degeneration (the number one cause of blindness in North America).
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101. What is Lycopene?
Lycopene is the most prevalent carotenoid in the Western Diet and the most abundant in human serum. Tomatoes and tomato-based products account for more than 85% of the dietary lycopene in North American. Other food sources include Pink Guava, Pink Grapefruit, Watermelon and Papaya. In recent years Lycopene has attracted much attention due to reports that have associated high intakes of this carotenoid with reduced risk of certain cancers. Lycopene is particularly concentrated in the prostate and several studies have shown a reduced risk of prostate cancer with high intakes of tomatoes or tomato-based products. Other research efforts are looking at its possible beneficial role in lung cancer and cardiovascular disease.
102. Can vitamin C help lower your blood pressure?
Some studies have shown a blood pressure reducing effect from vitamin C. A recent study (Lancet 1999 Dec. 11; 354(9195): 2048-9) demonstrated that Vitamin C can reduce high blood pressure. This double-blind study examined otherwise healthy patients with hypertension (a history of antihypertensive treatment or untreated diastolic blood pressure >90mm Hg). Measurements were taken after an acute 2g dose and after continuation of 500mg/day for 30 days of Ascorbic Acid. The acute treatment did not show significant results however after the 30-day treatment the mean blood pressure was decreased from 155 to 142 mm Hg (approximately 8.4%) and the effect was significant compared to the placebo group. Interestingly, this blood pressure lowering effect is comparable to much more expensive prescription drugs.
103. Is homocysteine related to cardiovascular disease and how can vitamins help?
Homocysteine is an amino acid formed during the metabolism of protein. The association between elevated plasma levels of the amino acid homocysteine and the risk of cardiovascular disease was first postulated decades ago and was dismissed as an obscure hypothesis. However, since then, there are many studies published suggesting a close link between high levels of homocysteine and an increased risk of several forms of cardiovascular disease. The three B vitamins: folic acid, B6 and B12 tightly regulate the amount of circulating homocysteine. These vitamins can effectively lower homocysteine levels and it is thought to be a safe and inexpensive treatment of hyperhomocysteinemia.
104. Can a high intake of vitamin supplements improve intelligence?
There is no evidence that vitamin supplements can improve the mental performance of normally intelligent persons irrespective of their nutritional status. However, nutritional deficiencies in children may affect the normal development of the brain or their ability to concentrate and perform other mental tasks. Vitamin supplementation has been shown to improve 'cognitive function' in older people who were deficient in B vitamins.
105. Should I take vitamins if I feel depressed?
Depression is associated with deficiencies of the B vitamins. However, depression can be caused by many different factors. Vitamin supplements should not be used in place of medical treatment.
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