According to the journal Food Supplements, the global vitamins and supplements market is worth an astonishing $146 billion. It’s projected to reach $250 billion by 2032.
Nearly half of UK adults take multivitamins or dietary supplements once a week.
It’s easy to see why, because swallowing a promise of a healthier life is much easier, and arguably cheaper, than cooking a rounded, nutritious meal.
Hundreds of journals corroborate the use of vitamin supplements… or do they? Where is the evidence that they work?
Digging deeper
A recent study in the journal Nutrition, Obesity and Exercise found that taking a daily multivitamin doesn’t help you live longer.
The US researchers analysed health records from nearly 400,000 adults with no major long-term diseases to ascertain whether a daily multivitamin reduced their risk of death over a 20-year period from the first study in the late 1990s.
It didn’t.
Worryingly, the research continued, taking vitamins may in fact increase the risk of early death.
One theory as to why is that while natural sources of beta-carotene protect against cancer, there’s evidence that beta-carotene supplements can heighten the risk of lung cancer and heart disease.
A further questioning of that multi-billion-dollar spend came in the form of a 2020 study in The BMJ (British Medical Journal).
It stressed that the people taking these supplements tend to be fitter individuals who care about their wellbeing and that’s why the products are seen as health-promoting.
In other words, they’re healthy by association. It’s not a positive picture.
“It’s true that the benefits of taking a multivitamin supplement aren’t always clear-cut,” says dietitian Claire Pettitt.
“For the average healthy person, the benefits of a daily multivitamin may be minimal. Instead of taking a broad multivitamin, a targeted approach – vitamin D in winter or iron for anaemia, for example – may be more effective.”
“There’s also the risk of taking too high a dose if you’re swallowing several multivitamins or a combination of supplements,” Pettitt adds.
“If you take individual, targeted nutrients, it allows you to adjust dosages according to your specific needs. For cyclists, nutrient needs may vary with intensity, diet and climate.”
So, according to Pettitt, there is potentially a place in a cyclist’s larder for some supplements.
They may not make you live longer, but they could boost performance.
This targeted assessment and then prescription comes at a cost, though. A vitamin and minerals profile blood test from pharmacy chain Boots, for instance, is yours for £85.
Crunching the numbers
If you’ve identified a deficiency that needs a supplement boost beyond your healthy diet, what’s the next step? Nip down to your local bargain store and bag some £1 vitamin D pills?
“The difference between a cheap and an expensive pot of vitamins comes down to factors like bioavailability, formulation quality, additional ingredients and third-party testing,” says Pettitt.
“Bioavailability refers to how well the body absorbs and utilises the nutrients in a supplement. Expensive brands often use more bioavailable forms of vitamins and minerals.
"For example, magnesium citrate is much more bioavailable than magnesium oxide; vitamin D3 is generally more bioavailable than D2; methylcobalamin is a more active form of B12 than cyanocobalamin.”
You can measure bioavailability via another blood test or urinalysis strips, then compare that figure to how much you ingested in supplement form for an idea of how much you absorbed.
As for formulation, higher-quality supplements may use capsules instead of tablets, avoiding binders and fillers that could potentially hinder absorption.
Brands may also include co-factors that enhance absorption, such as vitamin C with iron.
Boost your vitamin ingestion
“This pairing is important, as certain vitamins and minerals become more bioavailable when paired with specific foods or drinks due to interactions that enhance their absorption,” says Pettitt.
At the other end of the absorption spectrum, there are certain vitamins whose bioavailability is hampered by the wrong food or drink.
“Iron absorption is inhibited by tannins and caffeine, which are often found in coffee and tea, so avoid those drinks for one to two hours before or after an iron-rich meal,” says Pettitt.
“Calcium absorption is inhibited by oxalates, which are found in spinach and rhubarb, and phytates, which are found in wholegrains, legumes and nuts. It’s best to cook these foods to reduce the oxalate and phytate levels.”
Interestingly, some vitamins – certainly the fat-soluble ones – are better absorbed with food, while the likes of iron and vitamin C can be taken on an empty stomach.
And as we’ve heard, there’s a strong case for not scrimping on your targeted supplements, especially because cheaper products may also include unnecessary fillers, artificial colours or allergens. More expensive brands often undergo third-party testing for purity, potency and safety, too.
All in, then, there’s a case for cyclists to take vitamin supplements – but always start with a food-first approach.
“Wholefoods offer vitamins, minerals and co-factors that work synergistically for better absorption,” says Pettitt. “They’re naturally proven!”
