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Vitamin and mineral supplements

Sorting fact from fiction

 

Table of Contents

Introduction Do I need vitamin supplements?
What are vitamins and minerals? At risk persons
Specific vitamins and what they do Unfounded health claims
Vitamin deficiencies Dangers from excessive vitamins
Minerals the body needs Conclusion / recommendations
How much vitamins do I need? Resources

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Introduction

Vitamins and nutritional supplements represent at least a $6 billion-a-year business that continues to grow as people search for a fast and easy ways to stay healthy and feel better. One-quarter to one-third of Americans now take daily vitamin supplements. Seventy percent take nutritional supplements at least occasionally, and one in three people with chronic disease looks to herbal remedies for help.

Although outrageous claims for vitamin supplements have been around for many years, there has been an explosion of "health-enhancing" megavitamins, magic pills and potions since Congress changed Food and Drug Administration (FDA) regulation of "nutritional" supplements in 1994. Virtually every mall in America has a health food store, shelves lined with products that promise to relieve pain, help you sleep better and give your health, vitality and virility a boost.

Now, more than ever, people are focusing on nutrition to help them remain healthy and active. That's good. But do you need vitamin supplements and are they safe?

The answers to these questions are not always clear-cut. There's disagreement within the medical community, as researchers continue to uncover new information about how nutrition affects your health. Further clouding the issue is an almost daily barrage of media reports on new studies — some suggesting benefits from supplements, others indicating harm. Then there are those advertisements, promising health in a capsule or in a herbal brew.


What are vitamins and minerals?

Vitamins and essential minerals, also called micronutrients, are needed in tiny amounts to promote essential biochemical reactions in your cells. They are essential for normal growth, digestion, mental alertness and resistance to infection, enabling your body to use carbohydrates, fats and proteins. They also act as catalysts in your body, initiating or speeding up a chemical reaction. However, you don't "burn" vitamins, so you can't get energy (calories) directly from them.

Since your body can't make most vitamins and minerals they must come from food or supplements. Deficiency of a micronutrient for a prolonged period causes a specific disease or condition, which can usually be reversed when the micronutrient is resupplied.


There are 13 vitamins; four are fat soluble and nine are water soluble. Fat soluble vitamins are stored in your body fat and may be stored in certain organs, such as the liver. Most water soluble vitamins are not stored in your body in significant amounts, typically lasting several weeks to several months. (An exception is B12 which may be stored upto 4 years.)

Fat soluble vitamins include A,D,E and K

General information
1. Dissolve in lipids
2. Require bile for absorption
3. Are stored in tissues
4. May be toxic in excess

Water soluble vitamins include C and eight B vitamins: thiamine (B1), riboflavin (B2), niacin, pyridoxine (B6), pantothenic acid (B5), vitamin B12, biotin and folic acid (folate)

General information
1. Dissolve in water so cooking and washing water may leach them out
2. Easily absorbed and excreted

3. Not stored extensively in tissues
(except B12)
4.
Seldom reach toxic levels

 



When vitamin supply is adequate your body automatically regulates circulating vitamin levels. Excess water-soluble vitamins are excreted in urine. Surplus fat-soluble vitamins are stored in body tissue. Because they're stored, excess fat-soluble vitamins can accumulate in your body and become toxic. Your body is especially sensitive to too much vitamin A and vitamin D.


Specific vitamins and what they do

 
     Vitamins
A & Beta carotene    
B-Vitamins (Complex)
   B1 (thiamine)
   B2 (riboflavin)
   Niacin
   B6 (pyridoxine)
   Pantothenic acid
   B9 (folic acid)
   Biotin
   B12 (cobalamin)
C (ascorbic acid)
D (ergo/cholecalciferol)
E (tocopherol)
K(quinones)


Vitamin deficiencies (see above section for specific details)

Vitamin deficiencies result from either: (1) Inadequate consumption or (2) Biological malfunction in which the body cannot absorb or use the vitamin properly. Either way, not enough is present to carry on body processes. Deficiencies are a three step process:

  1. decrease in serum and tissue level of the vitamin
  2. related decrease in biological function tied to the vitamin
  3. development of a clinical deficiency

For example, scurvy is a disease due to vitamin C deficiency that plagued sailors on long voyages for many centuries. The disease, due to inability of connective tissue to form, caused brittle bones and bleeding into the muscles, joints and gums- severe cases lead to death.

Although a relationship between the lack of fresh food and the development of scurvy had been suspected for a long time, it wasn't until 1747 that a carefully planned trial showed that lemons and oranges would prevent the disease. Many sailing fleets subsequently used limes to prevent scurvy; hence sailors became known as "Limeys". It took until 1928, when the science of chemistry was more advanced, for a researcher to identify the substance in citrus fruits and other vegetables. The substance was given the name "vitamin C."

Most vitamins and minerals were discovered this way — scientists identifying substances you need because a shortage causes a health problem.


What minerals does the body need?

Your body also needs 15 minerals that help regulate cell function and provide structure for cells. Major minerals include calcium, phosphorus and magnesium. In addition, your body needs smaller amounts of chromium, copper, fluoride, iodine, iron, manganese, molybdenum, selenium, zinc, chloride, potassium and sodium. Amounts needed for most of these minerals is quite small and excessive amounts can be toxic to your body.

Select information link icon to learn more about minerals

How much vitamins do I need?

The answer to this question depends upon your age, health and nutritional status. The question of how much of a vitamin is enough is still debated among scientists and health care professionals.

Initially the FDA published MDA's (minimum daily allowances) for vitamins and minerals. These amounts were needed to avoid diseases seen with specific vitamin deficiencies

In the 1980's this was revised to RDA's (recommended daily allowances). Generally the requirements were increased above the MDA's. RDA's took into account that low levels of certain nutrients, although not low enough to cause a deficiency related disease, might nevertheless interfere with optimal health.

Most recently terminology has again changed to "Percent of Daily Values" or "% DV". This is for an assumed 2000 calorie a day diet. DV's are generally much higher than "minimum requirements".

Recommendations have recently been made to increase the RDA (or DV) for certain nutrients based on recent scientific evidence. Included are:

  • Vitamin C for most individuals- Studies have shown that people who eat diets high in vitamin C have lower rates of cancer and cardiovascular (heart and blood vessel) disease. However, it is not known whether taking vitamin C supplements produces similar benefits.

    Adequate levels of vitamin C may help strengthen resistance to viral infections and help decrease cold symptoms. But vitamin C can't "cure" colds.

    Doses above 250 mg appear to have lessening benefit, and above 500 mg most additional vitamin C is excreted in urine.

    A recent National Institutes of Health (NIH) study has proposed raising the current RDA of 60 mg to 200 mg, and the National Cancer Institute agrees. Only a third of Americans consume more than 200 mg a day while about one-third consume less than 60 mg. Still, the 200 mg recommendation can be achieved with just five servings a day of fruits and vegetables.

  • Vitamin D and calcium for older persons and darkly pigmented persons- This vitamin-mineral combination may be an exception to the no-need-for-supplements advice because some people may not get enough through their diets.

    In 1994 scientists at NIH reviewed new information about calcium's role in preventing osteoporosis- studies showed that people who supplement their diets with calcium and vitamin D slow bone loss and reduce the number of fractures. They recommended increasing the RDA of calcium from 800 mg to 1,500 mg for people older than age 65. That's the equivalent of five 8-ounce glasses of milk a day. Most women consume only about 600 mg a day. The new recommendation stems from studies showing that age affects your ability to use vitamin D and calcium.

    In addition to getting vitamin D from dietary sources, your body makes it when sunlight converts a chemical in your skin into a usable form of the vitamin. Vitamin D then helps your body absorb dietary calcium and deposit the mineral in your bones. With age your intestine absorbs less dietary calcium.

    Many older people don't get enough vitamin D due to lack of exposure to sunlight (15 minutes a day is enough for most people), less efficient conversion of the vitamin in their skin, and reduced liver or kidney function.

    Thus
    , supplements may be appropriate for people who don't get enough calcium and vitamin D in food, or who live in cloudy environments or rarely go outside.

  • Folic acid for pregnant women.   Folic acid (folate), a B-vitamin, may help prevent spinal cord birth defects during pregnancy. Folic acid is needed in increased amounts during pregnancy or any other condition of rapid cell growth. It is important in very early pregnancy. For this reason, the RDA for folic acid has been recently increased. In addition, the FDA is requires manufacturers of breads, cereal, pasta and other grain products to fortify their products with folic acid since January 1998.

    Folic acid has been linked to possible cardiovascular benefits, but it also carries a small risk of masking a vitamin B-12 deficiency. However, most scientists believe masking is unlikely if folic acid intake is below 1,000 micrograms (1 mg) a day. Fortification is designed to keep intake below this level.


Do I need vitamin supplements?

Vitamin hucksters spend millions promoting fear that you are not getting enough vitamins and minerals. They recommend vitamin, mineral and nutritional supplements as "vitamin insurance." The American Dietetic Association, the National Academy of Sciences, the National Research Council and other major medical societies all agree that you should get the vitamins and minerals you need through a well-balanced diet.

An exception is certain high-risk groups that may benefit from a vitamin-mineral supplement. Persons at risk and current recommendations will be discussed below.

Experts favor food, rather than supplements, because food contains hundreds of additional nutrients, including phytochemicals. Phytochemicals are compounds that occur naturally in foods and may contain important health benefits. Scientists have yet to learn exactly what role phytochemicals play in nutrition, and there's no RDA established for them. However, if you depend on supplements rather than trying to eat a variety of whole foods, you miss out on possible health benefits from phytochemicals.

Vitamin-mineral supplements shouldn't substitute for a healthful diet. However, there's probably no harm in taking a multiple vitamin-mineral supplement with dose levels no higher than 100 percent of the Daily Value. Doses above that don't give extra protection, but do increase your risk of encountering toxic side effects.

There is no need to pay more than four to seven dollars for an inexpensive multivitamin supplement. If manufactured using good quality control a vitamin is a vitamin- it does not matter who makes it. However, it should matter what they charge the consumer. If someone claims to provide custom designed vitamins (usually at a very high price) mad just for you DON"T BUY IT!


At risk persons
  • Elderly — Lack of appetite, loss of taste and smell, and denture problems can all contribute to a poor diet. Persons who live alone or are depressed may not eat enough to get all the nutrients you need from food.

    In addition, if you're age 65 or older, you may need to increase your intake of vitamin B-6, vitamin B-12 and vitamin D because your body may not be able to absorb these as well.

    Older women, especially those not taking estrogen, may need to increase their intake of calcium and vitamin D to protect against osteoporosis.

    There's also evidence that a multivitamin may improve your immune function and decrease your risk for some infections if you're older.

  • Persons on a severe diet - Persons eating less than 1,000 calories a day or having limited variety due to intolerance or allergy may benefit from a vitamin-mineral supplement.

  • Digestive tract disease - Diseases of the liver, gallbladder, intestine and pancreas, or previous surgery on your digestive tract may interfere with normal digestion and absorption of nutrients. If you have one of these conditions, your doctor may advise you to supplement your diet with vitamins and minerals.

  • Smokers - Smoking reduces vitamin C levels and causes production of harmful free radicals. The RDA for vitamin C for smokers is higher- 100 milligrams (mg) compared to 60 mg for nonsmokers. Still, this much vitamin C is easy to get by proper eating.

  • Heavy drinkers & alcoholics - may not get enough vitamins due to poor nutrition and alcohol's effect on the absorption, metabolism and excretion of vitamins. Obviously the alcohol is the most important problem!

  • Pregnant or breastfeeding women— If you're pregnant or breastfeeding, you need more of certain nutrients, especially folic acid, iron and calcium. Your doctor can recommend a supplement.

  • Other high-risk groups - Vegetarians who eliminate all animal products from their diets may need additional vitamin B-12. If you have limited milk intake and limited exposure to the sun, calcium and vitamin D supplements may be needed

Unfounded health claims for vitamins
Most exaggerated or unfounded health claims occur with megadose supplements. Although knowledge of the toxicities of certain nutrients, such as vitamin A, vitamin D, niacin, and metallic minerals is more common, very high doses of "safe" vitamins are not helpful and sometimes not even safe. Just because a nutrient has beneficial properties in a test tube does not mean it will work in the same way in the body.

The following are examples:

Beta carotene - This nutrient, widely found in plants, is converted in your body into vitamin A. Unlike vitamin A, Beta carotene is not toxic in high doses. Beta carotene (and vitamins C and E) are antioxidants. Antioxidants neutralize harmful substances called free radicals that result from your cells' ordinary metabolism. Scientists think damage from free radicals may contribute to cardiovascular disease and cancer.

Based on its' antioxidant properties, high doses of Beta carotene were advocated for health protective effects. However, several well-designed studies have found that beta carotene supplements offer no protection against cardiovascular disease. And two studies found an increased risk of lung cancer in smokers who took beta carotene supplements.

Vitamin C- In adequate amounts vitamin C is clearly necessary for good health. However, many proponents (including Nobel laureate Linus Pauling) advocated megadoses as a prevention or treatment for a wide variety of conditions including cancer, aging, and respiratory infection. Further well designed studies have shown such claims to be wrong. Virtually all vitamin C in excess of 500 milligrams a day (from any source) is excreted in the urine.

Although subsequent studies have shown that people who eat diets high in vitamin C have lower rates of cancer and cardiovascular disease (modest effect) it is not known whether taking vitamin C supplements produces similar benefits.

Chromium - Chromium works with insulin to help your body use blood sugar; however, preliminary studies assessing the effect of chromium in the treatment of diabetes are controversial, and there's no proof chromium can prevent the disease.

Despite claims by those hawking chromium picolinate supplements there is no proof that taking chromium supplements can increase your muscle mass, help you lose weight, reduce cholesterol and prevent osteoporosis.


Dangers from excessive vitamins and minerals

  • large amounts of vitamin D can indirectly cause kidney damage
  • large amounts of vitamin A can cause liver damage
  • Modest doses of niacin can cause flushing and stinging of the skin; very high doses can cause heart and liver problems.
Even modest increases in some minerals can lead to imbalances that limit your body's ability to use other minerals. And supplements of iron, zinc, chromium and selenium can be toxic at just five times the RDA. Virtually all nutrient toxicities stem from high-dose supplements.

Conclusion- Recommendations

Vitamins and minerals are essential micronutrients needed for health and life. They are not miracle cures for aging, poor diet, lack of physical exercise, or lack of motivation to take responsibility for one's physical and emotional well being.

Extra vitamins will not treat anxiety, depression, lack of adequate rest, bad interpersonal relationships or unhappiness on the job.

Modern society is stressful in its own way as less and less of our day is center around meal time and food preparation than it has in the past. However, opportunities for excellent health have never been greater due to increased access to information about healthy habits and increased availability of healthy foods.

Most persons can do their part by eating well and exercising regularly. Certain at risk persons may require an additional supplement; however, it does not have to be expensive nor should it exceed recommended daily values.

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Resources

Dr Ardith Brundt: "HEC 131 - Introduction to Nutrition " Chapters 7 & 8 @: http://iweb.tntech.edu/abrunt/homework.htm

Mosbey's Medical & Nursing Dictionary, 1983:pp1140-1145.

"Vitamin and nutritional supplements- Sorting out fact from fiction amid a storm of controversy." From Mayo Clinic Health Letter @ http://www.mayohealth.org/mayo/9707/htm/me_jun97.htm

Special Thanks to Stephen Barrett, M.D. for his review and constructive input to this page

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