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Folly of Mega-Dose Supplements
Part One

By Gary F. Zeolla

For years I took a mega-dose vitamin/ mineral supplement. This was done at the recommendation of the naturopathic-type doctors I was seeing at the time. Both agreed that I needed to take such high dose supplements since I have fibromyalgia. The idea was that people with fibromyalgia have much higher nutrient needs than "normal" people.

Experience with Mega-dose Supplements

I first took Jarrow Formulas Multi 1-3, then their Multi-Easy. Initially these supplements seemed to be benefiting me. But after a while, my health deteriorated. Most especially, my fibromyalgia fatigue worsened.

At the time, I thought that could be from the vitamin C being in the form of calcium ascorbate. That was because taking a separate calcium ascorbate supplement left me drowsy and even light-headed. It might also have been due to the zinc being in the form of zinc monomethionate, as again, a separate zinc monomethionate supplement (Jarrow's Zinc Balance), made me drowsy.

In any case, I then switched to Twinlab's Daily Two Caps. And once again, initially, the supplement seemed to be benefiting me. After a while, I switched to Twinlab's Daily One Caps, since it was much less expensive and the amounts of nutrients were not that much less. But after a while, my health again deteriorated. So thinking I needed the extra nutrients in the Daily Two Caps, I tried it again, but after just a few days, my health really took a downturn.

It was at that point that I began to think that maybe all these mega-dose supplements were actually making me worse. So I stopped taking them altogether. When I did, initially, I felt much worse, but then I seemed to improve some.

Problems with Mega-Doses of Nutrients

The four different supplements I took all contained much higher levels of nutrients than the Daily Values (DV) or the Recommended Dietary Allowances (RDA). But first, a clarification of the differences between these two values would be helpful.

The RDAs are actually several sets of values of the recommended levels of intake for a wide variety of vitamins and minerals. There are different values for male and females and for different age categories. There are also separate values for pregnant and breast-feeding women. They are revised every five years by the Food and Nutrition Board.

The DVs are the values seen on food and supplement labels. They were based on the highest level of recommended nutrients in the RDAs, not including the levels for pregnant and breast-feeding woman. However, they have not been updated since 1968. So they are very out of date. Some RDAs have been raised since then, while others have been lowered.

But whether the RDA or the DVs, these, "are the amounts of selected nutrients that are considered adequate to meet the nutrient needs of most healthy people" (Yahoo Health).

However, some believe, "the best dose is often far beyond the government's recommended levels (RDA/ DV), which are woefully low in most cases" (Josephs, p.22). This claim is based on the idea that the RDAs are just the bare minimums to prevent deficiency symptoms, but they are not adequate to provide optimal health.

It is also commonly claimed that the RDAs are for "couch potatoes," but that athletes or even anyone who works out regularly needs far greater amounts. Some even go so far as to claim, "Exercise without complete and optimal supplementation is self destructive, and suicide" (Crain, p. 89). So they recommend supplemental intakes that far exceed the RDAs. But these claims are just not true.

The RDA for each nutrient is designed to meet or exceed most people's requirements for that nutrient, and in most cases, the RDA contains a margin of safety. What does this margin of safety mean? It means the "R" in RDA stands for recommendation, not requirement, and that the RDAs are not minimum requirements, but meet the nutrient requirements and contain an extra allowance for most people (Somer, p.11, emphasis added).

For instance, the DV for thiamin is 1.5 mg. One of thiamin's functions is to help the body convert food into energy. For this reason, it is said that athletes need far more thiamin than this since they are far more active than the average person.

However, "The RDAs [for thiamin] are based on 0.5 mg/ 1,000 calories" (Somer, p. 39). So the DV is based on a 3,000 calorie diet. And 3,000 calories is more than the average person consumes, so the DV value is more than adequate.

Now it is true that some athletes will consume more than 3,000 calories a day, in some cases much more. Long distance endurance athletes like triathlon athletes and large athletes like heavyweight powerlifters and bodybuilders might consume as much as 5,000 – 10,000 calories a day. So they would need 2.5 – 5.0 mg of thiamin. However, with consuming more food, that level can easily be reached.

This writer, for instance, consumes an average of 2,500 calories a day, while I consume an average of 1.55 mg a day. So I am consuming more than enough for that caloric intake.

However, all four of the above supplements contain levels of thiamin (vitamin B1) that far exceed the RDA or DV. The Multi-Easy and Daily One and Daily Two Caps contain 25 mg, while the Multi-1-3 contains 50 mg. But some will recommend as much as 100 mg (Crain, p.92) or even 200 mg (Josephs, p.76).

Based on the RDA, these levels would be sufficient for someone consuming 50,000 – 400,000 calories a day. Those levels are of course ridiculous. No one, but not one, comes even close to consuming that much food. Moreover, "There are no known benefits to taking megadoses of thiamine, including the popular belief that it will help boost energy" (Family Education).

Now it will be conceded that there might be some specific health situations where higher doses of thiamin might be warranted. "Those taking medications such as diuretics, birth control pills, antibiotics, sulfa drugs, and drugs used to treat cancer also need more thiamin, as do those suffering from chronic stress, diarrhea, fever, diabetes, or kidney disease."

But even in such cases, by "higher doses" is meant 5-10 mg of thiamin. And even then, "Treatments involving large megadoses of thiamin or any other vitamin should be undertaken only under doctor supervision" (

So why put the ridiculously high 25 – 200 mg of thiamin in a supplement? The answer is simply so a manufacturer can claim its brand of supplements contains more than a competitor's. That's it, simply an advertising ploy not based on any sound science.

Moreover, those who claim you need such large doses of nutrients often benefit financially from the sales of mega-dose supplements. For instance, the above quote about the RDAs/ DVs being "woefully low" comes from a book written by the president of a company that manufactures mega-dose supplements (Josephs, p.42).

In the case of thiamin, at least the ridiculously large dose is safe. It is water soluble, so the body will simply excrete the excess. This makes for expensive urine, but nothing more. However, in some cases, large doses can be dangerous, even for some B vitamins. "Vitamin B6 is one of the few water-soluble vitamins that can cause harm if taken in megadoses. Large doses taken over a long period can damage the nervous system" (Family Education).

In the case of the antioxidant nutrients Beta Carotene (pro-vitamin A), vitamin C, vitamin E, and selenium, at one time it was thought that mega-doses would be beneficial in the prevention of chronic diseases like heart disease and cancer. However, almost all recent research has shown that this is not the cases. In fact, the opposite is proving to be true.

New research suggests that people who try to prevent heart disease by taking antioxidants in pill form may be throwing their money away. A study in the Archives of Internal Medicine found that supplements containing Vitamins C and E, and beta carotene, offer no heart benefit to women at risk of cardiovascular disease. Foods containing those antioxidants, on the other hand, have been found to reduce heart risk (KDKA, Taking Vitamins).

Antioxidant vitamins, including A, E and C, don't help you live longer, according to an analysis of dozens of studies of these popular supplements. The new review showing no long-life benefit from those vitamins, plus beta carotene and selenium, adds to growing evidence questioning the value of these supplements….

When they eliminated the lower-quality studies and looked only at the most trustworthy ones, they actually found a higher risk of death for people taking vitamins: 4 percent for those taking vitamin E, 7 percent for beta carotene and 16 percent for vitamin A (KDKA, antioxidants).

If anything, people in trial groups given the antioxidants beta-carotene, vitamin A, and vitamin E showed increased rates of mortality (Devlin).

When it comes to antioxidants, Prof Tony Segal of University College London has for years questioned the basic scientific rationale for how these vitamins work and says the new study comes as no surprise. "More and more evidence is accumulating to show that not only do they have no benefit, they are detrimental," he said (Highfield).

In regards to other nutrients, consider the following from Dr. Mia Parsonnet:

Potassium excess has serious consequences. Irregular heart rhythms and abnormal heart activity are the most ominous effects and require emergency treatment (p.64).

Excess [magnesium] leads to nauseas, vomiting, diarrhea, and drop in blood pressure (p.68).

On the down side, excessive iron supplementation interferes with the absorption of zinc…. High iron levels in the body, sometimes seen in men and postmenopausal women, have been reported to increase the risk of heart attack and intestinal polyps (p.69).

… too much zinc is not harmless. It interferes with the availability of copper and iron and may cause anemia. It also changes the lipid profile unfavorably and may produce gastrointestinal side effects such as vomiting and diarrhea. The immune system can possibly be interfered with by too much as well as too little zinc (pp.70, 71).

Interference with copper utilization can be brought about by large supplemental doses of zinc or megadoses of vitamin C (p.71).

When selenium intake is excessive over a prolonged period or with occupational exposure, toxic effects may be seen. These include hair loss, nail deformities, skin eruptions, nervousness, nausea, and offensive body odor (p.75).

Excessive amounts of molybdenum reduce copper levels and interfere with its function. Very large doses can cause swelling of joints similar to gout (p.76).

The page "Dangers of Supplementation" listed in the Bibliography summarizes potential problems with large doses of many other nutrients.

What Did God/ Nature Intend?

In my book God-given Goods Eating Plan, I write, "God did not intend for us to get our nourishment from pills. He put all that we need in the foods He provided for us. But we need to eat a variety of these God-given foods" (p.15). If this is true, then it would make no sense for there to be benefit from mega-dose supplements.

Going back to thiamin, there is no conceivable way that a person could consume 25 let alone 200 mg of thiamin from normal foods. The best non-fortified, non processed food source of thiamin on a per calorie basis would be bean sprouts. Half a cup contains 0.341 mg. So to get 25 mg, you would have to eat over 36 cups of bean sprouts! To get the 200 mg mentioned above would require 288 cups. That's 72 quarts!

Looking at a more common high-thiamin food, 3 ounces of pork tenderloin, lean only, contains 0.799 mg of thiamin. So to get 25 mg, you would have to consume almost six pounds of pork. To get 200 mg, you'd have to consume 48 pounds!

Looking at vitamin E, sunflower seeds would be your best normal food source. They contain 5.77 IUs per tablespoon. The DV is just 15 IUs, so that is over a third of a day's needed intake. But some recommend supplementing with as much as 1200 IUs (Crain, p.92) or even 2,000 IUs (Josephs, p. 22). To get those amounts, you would have to consume 13-22 cups of sunflower seeds. That's up to 5 quarts.

These amounts of food are ridiculous, and they are using the best single food sources. On a more varied diet, things get even more ridiculous.

My diet provides on average 2,551 calories, 1.55 mg of thiamine, and 33.9 IUs of vitamin E. To get 25 mg of thiamin from the same foods, I would have to consume over 40,000 calories. To get 200 mg, make that 320,000 calories! To get 1200 – 2000 IUs of vitamin E would take 90,000 – 150,000 calories. Needless to say, there is no way neither I nor anyone else could eat that much.

My point is this, God would not have created our bodies in such a way so as to require levels of nutrients that are impossible for us to attain from the foods that He created for us to eat. For those who do not believe in God, the argument still holds. The human body would not have evolved to require levels of nutrients that were impossible to attain from the foods human beings were eating throughout their evolution.

Folly of Mega-Dose Supplements: Part Two


Nutrition information for foods taken from: Diet Power 4.0 software. Copyright 1992-2004 by DietPower inc.

Crain, Ricky Dale. Xtreme Squatting. Crain's Muscle World, Limited: Shawnee, OK, 2005.

Dangers of Supplementation.

Devlin, Kate. Vitamin pills increase risk of early death.

Highfield, Roger. Vitamin pills are no substitute for healthy diet.

Family Education. Healthy Eating: Valuable Vitamins.

Josephs, Allen S. Natural Cures. USA, 2006. Study: Taking Vitamins No Boost To Heart Health. Aug 14, 2007. - Study: No Antioxidant Vitamin Long-Life Benefit. Feb 27, 2007.

NutraSanus. Vitamin E Benefits and Dosage Information.

Nutrition Action, "Designed to Sell. October 2006, p. 9.

Somer, Elizabeth, M.A., R.D. The Essential Guide to Vitamins and Minerals. New York: HarperPaperback, 1992. The Health Benefits of Thiamin Supplements.

Yahoo Health. Dietary reference intakes (DRIs), recommended dietary allowances (RDAs), and daily values (DVs).

Zeolla, Gary F. God-given Goods Eating Plan. 2007 by Gary F. Zeolla.

Folly of Mega-Dose Supplements: Part One. Copyright 2008 by Gary F. Zeolla.


Folly of Mega-Dose Supplements: Part Two

The above article first appeared in the free FitTips for One and All newsletter.
It was posted on this site June 21, 2008.


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