The more D the better, right? Not always...

"Double the dose, double the benefits" is a common rookie error. Too often people think that more is better. But this isn't always the case, especially with supplements.

But it's not always our own bright idea to mega-dose. Some companies market their products as being completely safe at doses far higher than the recommended daily amount, with reasons like "they're water soluble so your body will eliminate the excess through urine."

While this may be true for most foods, supplements are usually a single isolated nutrient, making them more akin to a drug than food. In the absence of the accompanying organic nutrients usually present in food sources of any nutrient, the body cannot properly regulate the supplements action or concentration in our body.

So let's take a look at some of the most commonly double-dosed supplements, and what the dangers are.

Vitamin D

You can't get too much vitamin D from eating mushrooms or too much time outdoors. But in a study, athletes were given either a 30,000 IU dose or a 70,000 IU dose of vitamin D, and what they found was interesting. Not only did those who had the higher dose of vitamin D show lower levels of the active form of vitamin D in the body, but these low levels persisted for weeks after having stopped taking the vitamin D supplement.

Vitamin C

Vitamin C is one of the most commonly consumed supplements, despite being one of the most abundant nutrients in most fruits and vegetables. It is commonly believed that mega-dosing vitamin C will provide a higher resistance to illness, but this isn't always the case, especially with supplements. Vitamin C metabolises into an oxalate, something we don't want too much of in our body. A clinical study showed that exceedingly high doses of vitamin C can lead to oxalate nephropathy, a potentially devastating condition.


Too much magnesium from food is not a concern for healthy adults, but the same cannot be said for supplements. Magnesium is a vital nutrient for protein synthesis, healthy bone formation, energy, and more, and deficiency can lead to serious problems. But too much magnesium can cause lethargy, weakness, nausea, and even heart and respiratory issues in more serious cases.


Zinc supplements have grown in popularity recently as more posts of Facebook are shared detailing its role in supporting immunity and testosterone levels. But too much zinc supplements, even a little too much, can cause nausea and vomiting. It can also cause flu like symptoms. In more serious cases, too much zinc can increase our vulnerability to infections, lower 'good' cholesterol levels, lower testosterone levels, and cause copper deficiency which has its own serious effects. There is a well known case of a man who caused himself serious physiological damage by consuming huge amounts of 'vitamin C + zinc' jellies. It's interesting to note that despite some foods providing well over the daily allowance of zinc, there are no reported cases of poisoning from naturally occurring zinc in food.

Vitamin E

You can get all the vitamin E you need from 30 almonds. But many vitamin E supplements contain more than 50 times this amount, and too much vitamin E supplements have been found to increase risk of prostate cancer.

The list goes on, and likely includes any supplement you can think of or have in your cabinet.

But it's not all bad, supplements are a great modern innovation and can actually save lives.

But they don't replace natural foods, and they won't work better at higher-than-recommended doses. Try to get as much of your nutrients from food as possible, and you'll find less goes further, and a little over the top won't hurt either.

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