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Vitamins and Minerals: A User’s Guide

Worst Pills, Best Pills Newsletter article August, 2010

One promotional strategy of supplement suppliers is to make people worry about whether they are getting enough nutrients. But do most people really need to take vitamins and minerals to supple­ment their diets? Or are they a waste of money? Are there better alterna­tives to taking supplements to ensure adequate nutrition? In this article, the editors of Worst Pills, Best Pills News sort through the fact and fiction sur­rounding nutritional supplements.

Causes of and solutions to...

One promotional strategy of supplement suppliers is to make people worry about whether they are getting enough nutrients. But do most people really need to take vitamins and minerals to supple­ment their diets? Or are they a waste of money? Are there better alterna­tives to taking supplements to ensure adequate nutrition? In this article, the editors of Worst Pills, Best Pills News sort through the fact and fiction sur­rounding nutritional supplements.

Causes of and solutions to vitamin and mineral deficiencies

It is a fact that some people actu­ally do have vitamin and mineral deficiencies — usually older adults. They fall into three categories:

  1. People who do not eat enough food — fewer than 1,500 calories a day.
  2. People who eat enough food but have an unbalanced, low-quality diet, often deficient in fruits and vegetables.
  3. People who have medical problems or take drugs that contribute to vitamin and mineral deficiencies.

Should people who have vitamin or mineral deficiencies take vitamin or mineral supplements? There is no simple answer to this question because of the various causes of such deficiencies. Sometimes, taking a supplement will help. But supple­ments are never the complete answer to anyone’s nutritional problems. It is far better to address the situation that could cause the deficiency and adjust the diet than to take a supple­ment and do nothing more.

Having said that eating good food is the best and only sure way to improve your nutritional health, it should be added that for particular groups of older adults, taking vita­min and mineral supplements may be entirely reasonable and, at times, necessary, especially for:

  1. People who eat fewer than 1,500 calories a day.
  2. People who are institutionalized.
  3. People with certain chronic diseases, including alcoholism, as well as liver, kidney and intestinal diseases.
  4. People who take drugs that inter­fere with absorption of or increase the excretion of nutrients.
  5. People with a specific diagnosed nutritional deficiency or those who are in a high-risk group for devel­oping a deficiency.

People who fit into these categories may require either a supplement of a specific nutrient or a multivitamin supplement with or without miner­als. Either way, supplementation should be started only after discus­sion with and approval by your doctor and consideration of a dietary solution to the problem.

Recommended dietary allowances (RDA)

There is no need to take vitamin or mineral doses above the RDA (see the Table for a list of RDAs). The National Academy of Sciences sets the RDA for each vitamin and mineral, and this allow­ance varies for males, females and different age groups. Because they are designed to account for differences between older and younger adults, the RDAs are the most appropriate ones for an older adult to use.

There is a prevailing myth that the RDA is no more than the amount of a vitamin or mineral that is needed to prevent deficiencies. This is not the case.

An RDA is set to cover the needs of 98 percent of the healthy popula­tion. This number is then set at a level that is often two to three times higher than people’s needs, resulting in a significant safety margin — the government’s own “insurance” for your health.

Because of this built-in safety mar­gin, the vast majority of people do not even need to get 100 percent of the RDA, as it is defined by the RDA committee. Thus, there is no need to take vitamin or mineral supplements with amounts higher than the RDA.

Mega doses of vitamins or minerals

To understand what vitamins or minerals can or cannot do, one must first understand their function in the human body. For the most part, a vitamin works along with an enzyme (protein) and thereby helps the enzyme perform certain chemical functions in the body. For example, many B vitamins help enzymes convert food into energy. Minerals act similarly. Calcium builds bones and also helps enzymes perform their functions. Iron is an essential element of red blood cells and helps them carry oxygen from the lungs to the tissues.

Vitamin functions were originally determined through vitamin defi­ciency diseases in people who were deprived of certain kinds of food for long periods of time. For instance, sailors often developed scurvy, a dis­ease with symptoms such as bleeding into joints, poor healing of wounds and emotional changes. It was de­termined that scurvy resulted from vitamin C deficiency when it was discovered that the sailors’ symptoms dramatically disappeared once they ate citrus fruits.

But many vitamin manufacturers take the process of deficiency diseases and vitamins one step further. For example, claims are made that large doses of vitamin C will help cure skin or emotional problems, colds or cancer. The overwhelming majority of these problems are not caused by vitamin C deficiency, so they will not improve in the average person taking vitamin C.

The flaw in this logic can be demonstrated by substituting “food” for “vitamin” in an example of a deficiency. If you fast for a long time, you will begin to develop certain symptoms, such as muscle aches, headaches, nausea and dizziness. These symptoms of “food” deficiency will disappear dramatically once you begin to eat again. It does not follow that if you have symptoms of nausea, headaches and dizziness while eat­ing normally, more food will cause them to go away. But this is the kind of logic most manufacturers use to make claims for the benefits of megadoses of supplements: If some is good, then more must be better, and much more must be much better.

No extravagant claims made by manufacturers for megadoses of any vitamins have stood up to these tests.

There are a few instances where vitamins have been determined to have specific additional benefits that have been demonstrated by rigor­ous scientific studies. Most of these therapeutic uses occur at doses not much greater than the RDA. They are discussed in individual profiles on WorstPills.org.

In addition to a lack of effective­ness, there are serious dangers associ­ated with taking megadoses of many vitamins. People who take a multivi­tamin supplement in low doses, for example at the RDA, have few risks; however, people who take high doses of certain vitamins have a risk of developing serious medical problems. Dangerous, toxic and occasionally fatal effects have been associated with high doses of the fat-soluble vitamins A, D, E and K. Even the water-soluble vitamin C and the B vitamins, which normally pass out of the body in your urine, can have adverse effects at high doses. Vitamin B6 has been associated with nerve damage, for example. Too much vitamin C can cause stomach cramps or diarrhea.

Some vitamins should not be taken — even in normal doses — if you use certain drugs or have certain medical problems.

If you are going to take any type of vitamin or dietary supplement, be sure to discuss it with your doctor before you start.

What You Can Do

Vitamin and mineral supplements are a booming business in this coun­try. Many people are misled by ad­vertising into thinking that taking a supplement will help get rid of many of their health problems. But this is not the case. The most important step that you can take to maintain your nutritional well-being is to eat a healthy and well-balanced diet.

Certain older adults may need specific vitamin and mineral supple­mentation and should talk to their doctors about this. If you do not fall into one of these categories and still wish to take a supplement, you should follow a few rules of thumb.

First, realize that supplements are by no means the complete answer to good nutrition. Taking a supple­ment is not an adequate replacement for eating healthy food. If you do buy supplements, there is no need to buy anything more than a regular multivitamin or a mineral supple­ment. Take supplements containing amounts less than or equal to the recommended dietary allowance for older adults. Finally, avoid megados­es of any supplement. They will give you no additional benefits from the supplement but will greatly increase your chances of toxic adverse effects.

Be rational about selecting a supple­ment. If you are not at risk for a specific vitamin or mineral deficiency, choose a basic multivitamin plus min­eral supplement. Taking specific pills for specific vitamins is a marketing tactic designed to make supplements more expensive. The average multivi­tamin pill with close to 100 percent of the RDA of each of the vitamins is less expensive.

Read the mineral contents on the label if you are concerned about increasing your intake of minerals. Most multivitamin supplements with minerals contain close to 100 percent of the RDA for vitamins but not for minerals. Mineral deficiency is actually more common than vitamin deficiency, despite what advertising might say.

Buy the least expensive supple­ments. Many products are horren­dously overpriced, being marked up to 1,000 percent over cost! Money that you overspend on supplements is money taken away from buying wholesome food. There is no benefit to be gained from a “natural” supple­ment versus a synthetic supplement. Brand-name vitamins are no better than generic versions. Buy the gener­ics, which will work exactly the same as the more expensive name brands.

National Academy of Sciences Recommended Dietary Allowances for Adults Over 50 Years*








A (Retinol)

900 mcg or 2,970 i.u.

700 mcg or 2,310 i.u.


400 i.u.

600 i.u.


15 mg

15 mg


90 mg

75 mg

Thiamine (B1)

1.2 mg

1.1 mg

Riboflavin (B2)

1.3 mg

1.1 mg

Niacin (B3)

16 mg

14 mg

Pyridoxine (B6)

1.7 mg

1.5 mg

Cyanocobalamin (B12)

2.4 mcg

2.4 mcg

Folic Acid (folate)

400 mcg

400 mcg





1,200 mg

1,200 mg


700 mg

700 mg


420 mg

320 mg


8 mg

8 mg


11 mg

8 mg


150 mcg

150 mcg

mcg = micrograms
mg = milligrams
* From DRI (dietary reference intake) charts taken from the National Academy of Sciences website (www.nas.edu). All intakes are the new recommended daily allowances (RDA) except for those with double asterisks (**), which are Adequate Intakes (AI).