Are your supplements doing you more harm than good?

Do I need to take supplements? Are they all good? Are there any I should avoid? Can too many supplements be harmful?

The world of dietary supplements is so confusing.

Here in Chile I’ve found it much harder to eat a varied vegan diet than back in the UK, so I’ve been looking into supplements.

I take calcium, vitamin D and a multivitamin complex, but I’m rather clueless when it comes to what supplements are actually good for me. Until now I’ve been choosing what pill I pop by the prettiness of the jar label.

Just over a third of Brits and a half of Americans take health supplements daily, according to a study published in the Journal of the American Medical Association.

But are supplements worth it?

I’d like to know more so I reached out to a couple of experts and I wanted to share their advice. Read this before you pop that pill, drink that shake or mix that smoothie…

food supplements can be harmful

Not always what it says on the label

Sports dietitian Amy Goodson cautions against the potential danger of supplements. ‘Supplements are not regulated by the FDA meaning that there is no required third party testing for safety. No efficacy or safety tests are required before being placed in the market and supplements are considered “safe” until proven otherwise,’ she warns.

Registered dietitian Rebecca Lwin agrees, adding that customers also need to be wary of the quality on offer too. ‘There is no way of really being certain of purity or potency in any supplement’ she tells me.

In the UK last year an otherwise fit and healthy man took green tea capsules in a drive to get healthy in his middle age. After taking them for just a couple of months Jim McCant fell ill and it wasn’t long before he needed a liver transplant.

Pregnancy and breastfeeding

It’s especially worrying for the vulnerable. ‘While all people should want to know what they put in their body, it is of upmost concern for population groups [such as] people taking medication and for women who may be pregnant or looking to become pregnant’, underlines Amy.

Herbal supplements such as blue cohosh has been linked to heart problems and other abnormalities in newborns, while agnus castus, a plant with estrogen-like properties, may increase the risk of miscarriages.

food supplements can be dangerous

Safety checks

For sports based supplements, Amy recommends checking with third party sites such as Informed Choice and NSF Certified for Sport and looking for their seal of approval logos.

Putting into balance, Rebecca adds, ‘Most supplement manufacturers monitor themselves with testing for purity and potency, and are highly reputable. But you could always get the rouge one that’s not what it says it is’.

Pure doesn’t always mean good

But even if a supplement is legit, pure and of the right dosage, it doesn’t mean it’s OK.

Last year an international study led by the University of Toronto concluded that in some cases, supplements could cause actual harm. They found that in some unique cases niacin (vitamin B3) and antioxidants (vitamins A, C and E) could signify an increased risk of death.

“These findings suggest that people should be conscious of the supplements they’re taking and ensure they’re applicable to the specific vitamin or mineral deficiencies they have been advised of by their healthcare provider,” the report’s author, Dr. Jenkins writes.

food supplements can be harmful

Beware of the supplement cocktail

Even the wrong combination can cause issues.

Rebecca explains: ‘If someone takes a multivitamin containing iron, plus their calcium supplement (at the same time), they won’t both be absorbed fully. Zinc and iron also compete for absorption sites’.

And mixing supplements with medication is another no no. ‘There are also many drug-nutrient interactions that can be adverse. For instance, if someone is on a blood thinner and they take a multivitamin with Vitamin K, this can present a problem with over-thinning of the blood. There are many examples like this’, she cautions. 

Are supplements even worth it? 

It’s important to look at ourselves as individuals and only take the supplements we need.

Rebecca explains: ‘Before I would recommend any supplements to a client, I take a hard look at everything else they take. I only recommend supplements on a very individual basis, taking into consideration a client’s lifestyle, exercise routine/intensity, and food intake.’

‘My general philosophy is that we should eat well enough to get most of our nutrients from our food. I know that doesn’t always happen, even for me! Supplements are definitely a reality, and do provide health benefits. But I like to be intentional about it, to keep things on a minimal level, so you don’t have too much going on.’

food supplements are they worth it?

My vitamin cupboard

I’m double and triple checking my vitamin stash now. I’ll be following up soon with another post on which supplements can be beneficial, and which help me personally. And I’m going to be a lot more wary, even when I see a pretty label.


If you liked this post, check out which supplements the above experts use personally and which they recommend.


Amy Goodson, MS, RD, CSSD, LD is an award winning dietitian and spokesperson on health, wellness and sports nutrition. She has worked with top athletes, including the Dallas Cowboys and PGA Tour players, and develops nutrition and wellness programs, presentations and workshops for businesses.

Rebecca Lwin, MS, RD is a nutrition consultant, boot camp trainer, and professional athlete. She is a sought-after speaker on health & wellness in Manila, Philippines, and has clients worldwide. She specializes in nutrition and wellness for expats and offers personalized consultations via Skype.

Experts always advise speaking to a qualified medical professional before taking any supplements. 

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