Posted on 3 August 2023
Dietary supplements are naturally derived compounds which, for better and for worse, are not regulated in the same way as pharmaceutical drugs, meaning that anyone can simply buy them in most places. Dietary supplements can compensate for deficiencies in your diet, improve health and wellbeing, and some may even slow the progression of the ageing process itself. Unfortunately, many dietary supplements are overhyped as sellers have an incentive to exaggerate the strength of the evidence. This hype is often based on their effects on known mechanisms of ageing and on a few small clinical trials. This is not to say that these supplements won’t work – it’s just that the extent of their benefits and risks is uncertain and requires more research.
For this reason, we thought it would be a good idea to compile a list of dietary supplements with a strong safety profile and evidence base. These may not be the most exciting supplements we have in terms of modulating the ageing process, but they all have at least a decent amount of clinical trial data behind them and, more importantly, have been shown to be very safe (though you should still consult with a doctor before taking them).
While dietary supplements are great, it’s important to be realistic about the relative benefits. The effects of regular exercise, good sleep and a healthy diet far outweigh the benefits of any dietary supplements for health and longevity, so make sure you get those things in order before jumping on the supplement train. With that preamble out of the way, here are our picks for the top 5 supplements with the best supporting evidence.
While technically two different things, we’ve decided to lump these two together as their purpose is similar – to improve the health of the gut microbiota (the population of gut-dwelling bacteria). Probiotics are live bacteria from strains known to be beneficial, while prebiotics are nutrients that nourish bacteria already present in the gut.
We know that the composition of the gut microbiota changes with age, and that certain changes are correlated with age-related diseases. We now have over a thousand clinical trials suggesting that probiotic and prebiotic supplements benefit various aspects of human health, such as reduced risk of infection and inflammation within the gut. We also have quite a bit of evidence that these benefits extend beyond the gut, particularly to the immune system and to the central nervous system. For example, there’s some evidence that probiotics and prebiotics improve mental health at least in certain situations.
It’s best if you can get both of these from your diet, but this isn’t always possible for all kinds of reasons, so supplements can be helpful.
Collagen is a protein that is found in many parts of the body, including the skin, bones and joints. It’s the main component of the extracellular matrix – the ‘scaffolding’ that holds our cells together. We know that the extracellular matrix deteriorates in older age, and that part of this is due to a reduction in collagen production.
There’s now a good amount of clinical trial data showing that supplementation with hydrolysed collagen (collagen that has been broken down into smaller collagen peptide chains) can improve skin health and reduce signs of ageing. For example, collagen supplementation has been shown to slow wrinkle formation while improving elasticity and hydration relative to a placebo treatment. Though less well studied, collagen supplementation may also improve bone and cartilage health, potentially reducing the risk of osteoporosis. For example, clinical trials have found that supplementing with collagen peptides improved bone density in postmenopausal women who had age-related loss of bone mass.
Creatine is a compound stored primarily in the muscles, and it allows them to work harder for longer by storing phosphate, which can be used to rapidly provide energy for the muscle. If you want to learn more about creatine and how it works, check out our article on the subject.
In short, there is strong evidence that creatine supplementation improves muscle performance in explosive strength exercises like resistance training. It also boosts muscle strength when combined with such exercises, allowing you to get more out of your workout. As discussed many times on this site, building strong muscles is essential for avoiding frailty in old age. In fact, muscle strength is a strong predictor of mortality not just related to falls and fractures, but from all causes. So while the relationship might not seem as direct as some other supplements on this list, resistance training is important for preserving health in old age, and creatine can help you make the most of the hard work you’re already doing.
Omega-3 polyunsaturated fatty acids are chemical compounds found almost exclusively in seafood. They have many applications within the body, such as in the construction of hormones and cell membranes.
Ever since a 1995 study showing that these compounds could reduce the risk of death from cardiovascular disease, there has been a lot of scientific debate over whether they are actually beneficial or not. However, there’s now pretty good evidence that omega-3s are indeed beneficial – the problem is that we’re still not quite sure who benefits and in what ways. While some studies suggest a reduction in mortality for people taking omega-3s, the 25 000 person VITAL randomised trial found that after 5 years of supplementation, omega-3s only reduced risk of heart attack, but didn’t significantly reduce mortality. Some studies even suggest that omega-3s could increase risk(?the incidence) of atrial fibrillation in people who are already at risk of it. Nevertheless, the current evidence leans heavily in favour of taking omega-3s if you are not at risk of cardiovascular disease.
Vitamin D is a nutrient mostly produced in the skin when it is exposed to sunlight. Unfortunately, many of us don’t get enough of it – about 40% of adults in the US have vitamin D insufficiency (suboptimal levels of vitamin D). About 20% have the more serious vitamin D deficiency (sufficiently low vitamin D levels to cause health problems, mostly related to the bones, muscles and joints). Vitamin D deficiency tends to get more common in older adults because production in the skin becomes less efficient, and because their guts are less efficient at absorbing vitamins.
Vitamin D is perhaps best known for its role in bone health. It helps the gut absorb calcium and phosphorus, which are essential for bone formation. Vitamin D supplementation has been extensively studied for its effects on bone health, though the evidence is not as consistent as you might hope. Many clinical trials find that vitamin D reduces the risk of bone fractures in older adults, but many don’t, including the aforementioned VITAL trial. Size and timing of the dose may be a factor. Some studies also suggest that vitamin D should be taken alongside calcium in order for maximum benefits to be achieved.
The other main benefit of vitamin D supplementation may be in immune system function. Vitamin D supplements seem to protect against the common cold, influenza and possibly other respiratory infections. It may also protect against autoimmune disease – in the VITAL trial, 2000 IU/day of vitamin D was associated with a 22% reduction in the occurrence of new autoimmune diseases.
Finally, meta-analyses as well as the VITAL trial suggests that vitamin D supplementation reduces the risk of dying from cancer by somewhere around 15%, though interestingly, VITAL suggests that it only reduces the risk of actually getting cancer in people with normal BMI (<25kg/m2).
Even for supplements that have been extensively studied, the evidence is not always as conclusive as we would like. This is why we chose to omit some supplements that are very promising, but are still in relatively early stages of human research. These include things like resveratrol, NMN and its precursors – if you’d like to learn more about these and how they may slow the ageing process, we have separate articles dedicated to these subjects.
It’s important to realise that a compound being natural doesn’t automatically make it safe – in fact, the safety profile of many dietary supplements is less well established than those of pharmaceutical drugs, since the latter must receive legal approval by health agencies. You should consult with a doctor before taking a dietary supplement, especially if you have a health condition.
Title image by Emma-Jane Hobden, Upslash
Specific Collagen Peptides Improve Bone Mineral Density and Bone Markers in Postmenopausal Women—A Randomized Controlled Study https://doi.org/10.3390%2Fnu10010097
Principal results of the VITamin D and OmegA-3 TriaL (VITAL) and updated meta-analyses of relevant vitamin D trials https://doi.org/10.1016/j.jsbmb.2019.105522
Vitamin D deficiency and insufficiency among US adults: prevalence, predictors and clinical implications https://doi.org/10.1017/S0007114518000491
Association Between Vitamin D and Influenza: Meta-Analysis and Systematic Review of Randomized Controlled Trials https://doi.org/10.3389%2Ffnut.2021.799709
Vitamin D and marine omega 3 fatty acid supplementation and incident autoimmune disease: VITAL randomized controlled trial https://doi.org/10.1136/bmj-2021-066452
Omega-3 Fatty Acid Supplementation and Coronary Heart Disease Risks: A Meta-Analysis of Randomized Controlled Clinical Trials https://doi.org/10.3389%2Ffnut.2022.809311