Supplements: More is not better

Does it seem to you that when scientists identify a particular substance in food with  disease-fighting power,  it becomes a hot commodity in the form of a supplement?   Consider that we are spending billions on dietary supplements but somehow we keep forgetting what they really are.

Many believe that what’s in a pill  bottle  can  take the place of nutritious eats. But by definition, these supplements are supposed to add to  our nutritional intake or help meet our requirements – not take the place of wholesome food.

In the matter of  dietary supplements, there are two key points we also seem to either forget, ignore or are unaware of.  Firstly, we often mistakenly believe that if a little is good, more is better. Secondly that if a food is rich in a particular compound and has been shown to be associated with a decreased risk of disease, isolating from food and taking it on its own may simply not provide the  expected health benefits.

It, in fact, may do the opposite.

Quercetin is a prime example. It belongs to a family of compounds called flavonoids –  the centre of exciting research as they supply an arsenal of weaponry against a growing list of diseases including  heart disease, cancer and cognitive decline.

Apples, onions and tea have long been linked to heart health benefits, likely in part because of their  quercetin content, which protects the heart in a number of different ways. Among their benefits, quercetin-rich foods offer both antioxidant and anti-inflammatory properties,.

It’s estimated that a daily quercetin intake from food might range from 10 to 100 milligrams. Quercetin supplements, meanwhile, may supply 10 to 100 times as much. These high doses of quercetin appear to reduce statin levels in the blood in those taking the common cholesterol-lowering drugs.  This can wreak havoc in determining proper dosages – and impact the drug’s benefit – which certainly counters quercetin’s healthy-heart advantages.

The latest research on quercetin supplements, published in the journal Food and Chemical Toxicology,  shows that they may interact with certain genes which affect thyroid function.  In some people, high doses of quercetin may inhibit the growth of thyroid cells,  leading to the scientists calling these supplements possible  thyroid disruptors.

As science evolves, we are seeing more and more evidence that our genes may interact with various nutritional components – an area called nutritional genomics or nutrigenomics.  It’s these gene-nutrient interactions that may be responsible for so much conflicting nutrition research.

Another key point about supplements to keep in mind: in amounts we may consume from food,  think of them as supplements. In large doses, though,  they should be considered as drugs and given the respect that pharmaceutical preparations are provided. And in some cases, these doses are used as treatments for illness.

So while it may not seem to be cutting edge science to adopt a wait-and-see  approach to supplements, it may certainly be what’s best for your health.


What’s your take on this issue? Please share in the comment section below.

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Categories: Nutrition News

Author:Rosie Schwartz

Rosie Schwartz is a Toronto-based consulting dietitian and writer.

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