COSMOS Study: Do Multivitamins Slow Epigenetic Ageing?

A closer reading of the study, however, paints a far more restrained picture.

Across many health pages, it can suddenly seem like a straightforward answer: take one pill a day and the body will age more slowly. The basis for this claim is a recent study in Nature Medicine that followed adults aged over 70. Called COSMOS, the project examined whether taking a daily multivitamin could slow the body’s so-called “epigenetic clock” - biological ageing processes at DNA level.

What the COSMOS study investigated

The COSMOS study, short for “Cocoa Supplement and Multivitamin Outcomes Study”, was conducted by a respected research team at Brigham and Women’s Hospital in Boston. Rather than studying individual vitamins, the researchers tested an ordinary combined supplement under everyday conditions.

Almost 1,000 people took part, with men and women represented equally; all were at least 70 years old. Participants were randomly allocated to four groups and took capsules every day for two years, without knowing what they actually contained.

Four groups, four different treatments

• A multivitamin plus 500 mg of cocoa powder, containing around 50 mg of epicatechin, an antioxidant
• Cocoa powder only, plus a placebo
• A multivitamin only, plus a placebo
• A placebo containing no active ingredient

The researchers aimed to establish whether cocoa compounds, the multivitamin, or the combination of both could produce measurable changes in biological ageing markers.

How COSMOS measured biological age

Instead of counting wrinkles or carrying out fitness tests, COSMOS centred on a relatively abstract laboratory measure: epigenetic clocks. These refer to patterns of chemical tags on genetic material, chiefly methyl groups that can attach to or detach from DNA. Such patterns shift with age and are regarded as indicators of so-called biological age.

More specifically, the research team measured five epigenetic signatures in every participant. Blood samples were assessed at the start of the study, after 12 months and again after 24 months. Two of these “clocks” are considered particularly closely associated with mortality.

The analysis shows that people taking a multivitamin displayed slightly slower changes across all five epigenetic clocks - particularly those who already appeared to be ageing faster at the outset.

Over the two-year period, the model equated this result with an “advantage” of roughly four months over the placebo group. Put differently, after two calendar years, the cells of those in the multivitamin group appeared on average as though only just under 20 months had passed.

Cocoa showed no measurable anti-ageing effect

The study’s other major candidate, cocoa powder containing epicatechin, did not produce beneficial effects on the epigenetic clocks. No advantage was apparent when it was taken alone or alongside the multivitamin. This puts the focus firmly on the vitamin supplement, although the observed effect was modest.

What the researchers say about the findings

Despite the headlines, the authors themselves stress the need for caution. Their conclusions explicitly describe the effects as “statistically significant but limited”. Whether these differences would be noticeable in everyday life remains unknown.

The researchers stress that further studies are needed to determine whether a slightly altered epigenetic age actually means fewer illnesses and a longer healthy lifespan.

An observation by study lead Howard Sesso in an accompanying article in Nature is also notable: he calls for the relationship between diet, nutrient intake and epigenetic clocks to be examined more broadly. It is an honest point: at present, nobody knows whether a multivitamin delivers effects equal to, or weaker than, consistently healthy eating.

That comparison is precisely what COSMOS lacks. The study never tested “vitamin pill versus Mediterranean diet” or “vitamin pill versus substantially more vegetables, pulses and wholegrains”. Instead, it compared pills with placebo among people eating a fairly typical everyday US diet.

How reliable are epigenetic clocks?

Epigenetic clocks are an exciting area of research. Some models can estimate biological age with striking accuracy and can even statistically predict mortality risk. Even so, the method has not yet become established in routine clinical practice.

• The testing methods are complex and expensive.
• There are numerous clocks based on different algorithms.
• The direct connection with specific diseases remains poorly understood.
• It is still unclear how strongly lifestyle changes can alter these values over the long term.

Sesso also points out that many pieces of the puzzle are still missing. The exact link between epigenetic patterns and chronic diseases of ageing, such as heart attacks, dementia or cancer, has only been broadly outlined. The same is true of the impact of diet, exercise and dietary supplements on these markers.

Who funded the COSMOS study?

To put medical studies into context, it is worth looking at the end of the paper, where funders and possible conflicts of interest are listed. COSMOS reveals a varied mix: public funders alongside major players from the food and supplement industries.

Among those named are:

• The US National Institutes of Health (NIH)
• Mars, including its health division Mars Edge, which is responsible for cocoa products
• Pfizer Consumer Healthcare, now Haleon, a major manufacturer of over-the-counter products
• Foxo Technologies, which specialises in epigenetic testing
• American Pistachio Growers
• The Council for Responsible Nutrition, a trade body for the supplements industry

The authors state that they worked independently and had no financial conflicts of interest. Formally, the study therefore meets standard transparency requirements. Yet, in public perception, such an industry-linked funding mix can still leave an unpleasant aftertaste.

Had exactly the same results emerged without support from large supplement manufacturers, they could be interpreted with considerably more ease. Particularly where effects are relatively small, the question of possible bias naturally arises, even if it cannot be demonstrated.

What does this mean for older people in daily life?

For older adults, the message sounds appealing: buy an inexpensive multivitamin from the chemist and biological age slows down. The reality is more complicated.

For some older people, multivitamin supplements may be useful - for example, where deficiencies have been confirmed, appetite has declined, diets are limited, or certain medication combinations are involved. Many GPs now specifically test vitamin D, B12 or folate levels.

The COSMOS data add one more argument that a daily tablet may offer a small biological benefit to very elderly people whose diets are less than ideal. But they do not provide a free pass to disregard other lifestyle factors.

Vitamins from a pill or from the plate?

Nutrition specialists have emphasised for years that most nutrients should come from food. A wholefood diet offers not only vitamins, but also fibre, phytochemicals and complex combinations that cannot yet be fully reproduced in a tablet.

A realistic anti-ageing package in everyday life typically includes:

• Plenty of vegetables and fruit, ideally in a wide range of colours
• Wholegrain products instead of refined white flour products
• Pulses, nuts and seeds
• High-quality plant oils and oily fish
• Regular exercise, especially strength training and moderate endurance exercise
• Not smoking and eating as few highly processed convenience foods as possible

A multivitamin can fill a gap in certain circumstances, but it cannot replace this broader package. A future study addressing exactly this question would be particularly interesting: how does a multivitamin perform in a direct comparison with a radically improved diet, perhaps combined with structured exercise?

Until then, the Nature paper remains above all an interesting piece of the much larger ageing puzzle. It shows that micronutrients can leave measurable traces in our cells. Research still needs to establish how far those traces actually influence health, illness and lifespan - ideally with independent funding and an honest comparison with a good old plate of vegetables.