The Washington Post: Pills popping up on your social feed? Verdict on viral vitamins may be hard to swallow

I get why supplements are popular: Taking a pill feels easier than addressing lifestyle factors, such as poor diet or sleep.

But in many cases, the claims behind supplements aren’t backed by strong data. And you can’t redeem an unbalanced diet by popping a pill to fill in the nutrient gaps.

As a doctor, I tend to be wary of most supplements without a medical reason. Run any new supplements by your doctor to ensure you’re not at a higher risk of a bad outcome.

So what should you know about specific supplements? Here are nine popular ones, and what the science says about them.

1. Multivitamins

Many people purchase the supplement because they think it can affect broad health outcomes — help them live longer, decrease cancer risk and reduce cardiovascular disease. Otherwise-healthy people also take it to fill gaps in their diets.

I wish it was that straightforward. Though there’s some encouraging data on the benefits of multivitamins for healthy adults, the supplement isn’t a cure-all: A study published last year in JAMA Network Open of nearly 400,000 adults who were followed for almost 30 years found that multivitamins did not confer any longevity benefit.

My advice? Follow a healthy diet. This has been well established in multiple large studies to improve numerous health outcomes, from reversing coronary heart disease to reducing cancer risk.

2. Psyllium

Most supplements aren’t worth your money. But this one is.

Robust studies have consistently shown psyllium husk — or psyllium, for short — may lower our cholesterol, dampen glucose spikes, help us stay full longer, and even aid in treating constipation and diarrhoea — all while serving our microbiome a sweet, sweet feast.

Psyllium comes from the mainly soluble fibre outer shell of the Plantago ovata plant. It’s the primary ingredient in many over-the-counter fibre supplements, but what sets psyllium apart from other fibres are two properties:

1. It’s rich in arabinoxylan, a molecule that forms a gel when it contacts water, allowing psyllium to promote special reactions, including the conversion of cholesterol into bile acids, as it makes its way through the digestive tract.

2. When psyllium reaches the colon, it becomes a prebiotic for your microbiome, spurring the production of beneficial metabolites such as short-chain fatty acids.

These properties result in numerous health benefits that are backed by decades of research.

3. Collagen

Supplementing with collagen has become increasingly popular in recent years, with brands claiming it can boost nail, skin and hair health. But there isn’t strong evidence behind these claims.

Collagen is a protein found in many parts of the body — in cartilage, bone, tendons and skin. It helps build a structural framework to preserve the skin’s integrity. But as we get old, we produce less collagen. This contributes to skin appearing less elastic (even saggy) and wrinkles forming more easily.

Though several studies on collagen supplementation point to increased elasticity and improvement in wrinkles in skin, the data is often muddied by confounding study design, lack of objective microscopic evidence or funding straight from the people selling the products.

4. Ashwagandha

Ashwagandha has become popular among high profile celebrities such as Meghan Markle, Gwyneth Paltrow and Jennifer Aniston. It is trending on TikTok with claims it improves sleep, anxiety, memory and even muscle mass..

Those who use ashwagandha to help with sleep are probably availing themselves of its known sedating qualities (its Latin name, Withania somnifera, references this). But while ashwagandha may adequately induce sleep, it shouldn’t be viewed as a long-term solution. Before trying it, I’d recommend seeing your doctor to understand what’s causing your sleep issues. There are many reasons for insomnia, such as depression and sleep apnoea, for which ashwagandha is not the first choice of treatment.

Last year the TGA warned Australians that the medicinal herb may cause severe gastrointestinal side effects in some people. People with liver problems should avoid entirely.

5. Magnesium

The data on taking a magnesium supplement is underwhelming for some of the purported benefits popularized on social media, including taking magnesium for sleep and mood symptoms. There are a few clearer circumstances where magnesium supplementation could be warranted, such as for constipation, but it’s hard for a doctor to give magnesium supplementation an unconditional stamp of approval.

Although too much magnesium can be toxic to your body, taking low levels — less than 350 mg daily — probably won’t cause any harm unless you have kidney disease. But it may not do any good, either.

Here is an alternative I can gladly endorse: Eat more magnesium-rich foods. That way, you’ll get the boost of magnesium as well as the other natural benefits of these foods.

6. Iron

People with an iron deficiency often feel exhausted. If that sounds like you, you should ask your doctor about getting tested for iron-deficiency anaemia.

Young children, women who have heavy cycles or are pregnant and older people should be particularly vigilant. A study published in the Annals of Internal Medicine in 2023 found that about one in four healthy adults, 70 and older, developed anaemia within five years of enrolling in the study and that taking a low-dose daily aspirin increased that risk by 20 per cent.

If you have iron-deficiency anaemia, you should take an iron supplement. But here’s an interesting tip I share with my patients: Don’t take it every day. A study found that taking an iron supplement every other day can optimize iron absorption — and may mitigate side effects such as nausea and constipation.

7. Greens powders

Greens powders, made with greens such as kale and algae, are hugely popular on social media. They’re also expensive. I appreciate that fresh vegetables are often not cheap, but your money is better spent on interventions with proven benefit.

Many of these formulas are proprietary, meaning we don’t fully know what’s in them. What we do know is that they’re heavily processed: Greens powders are at the very least freeze-dried, powdered and often mixed with additives and sweeteners.

Ask yourself this: Does your greens powder taste good mixed in water? You probably couldn’t stomach fresh broccoli and water. So what was added to that powder to make it tolerable to you?

Eating fresh vegetables is always going to be more beneficial than taking greens powders.

8. Vitamin B12

Some people think that vitamin B12 can help with fatigue and boost energy levels. But there’s no proven benefit to taking vitamin B12 for fatigue unless you have a deficiency that causes anaemia.

Start by asking your doctor for a simple set of blood tests for vitamin B12 and related biomarkers. Adults above 65 and vegans are particularly at risk of a deficiency. If you’re deficient in the vitamin, you should take a supplement.

For everyone else looking for an energy boost, my advice is to talk to your physician about other ways to help with energy levels, including making lifestyle changes or getting tested to rule out potential medical issues such as thyroid disease.

9. Probiotics

While health professional may recommend probiotic supplements in specific circumstances, this is a for-profit industry. Most people who take them are wasting their money.

Proponents claim probiotic supplements can boost your microbiome — the organisms that live inside your gut — and help with digestive issues, immune function and even mental health.

But there’s not a lot of evidence backing up these claims. As a gastroenterologist, I rarely advise my patients to start a probiotic — much to their surprise.

Instead, here’s what I do recommend: Eat a fibre-rich diet. This time-tested recommendation remains one of the strongest-studied ways to promote and preserve a healthy microbiome and improve your overall health.

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