Supplements or evidence-based prevention, and where to put your effort

What the evidence shows on supplements

The US Preventive Services Task Force reviewed the evidence in 2022 and recommends against beta carotene or vitamin E supplements to prevent cardiovascular disease or cancer [1]. For multivitamins, and for other single or paired nutrients, it found the evidence insufficient to judge the balance of benefit and harm [1].

Large trials point the same way. In the VITAL trial of 25,871 adults, vitamin D supplements did not lower the rate of invasive cancer or major cardiovascular events compared with placebo [2]. A Cochrane review of 78 trials with 296,707 participants found that antioxidant supplements had no significant effect on mortality overall [3].

Supplements remain popular all the same. In US survey data, 52% of adults had used at least one dietary supplement in the previous 30 days [4].

Where a supplement has a clear role

Some supplements are advised for specific groups. In the UK, the Scientific Advisory Committee on Nutrition recommends a reference intake of 10 micrograms of vitamin D a day for everyone aged 4 years and older [5]. The US task force recommends that anyone planning or capable of pregnancy takes a daily folic acid supplement of 0.4 to 0.8 mg [1].

A measured deficiency, a condition that affects absorption, a restricted diet or a medicine that depletes a nutrient are other good reasons. The task force recommendation itself does not apply to people with a known nutritional deficiency, pregnancy, chronic illness or a hospital stay [1].

Prevention with firmer evidence

The measures with the strongest evidence are less exciting than a capsule. The US task force recommends a statin for adults aged 40 to 75 with at least one cardiovascular risk factor and an estimated 10 year risk of a cardiovascular event of 10% or more [6].

Physical activity matters as much, and the World Health Organization reports that people who are insufficiently active have a 20% to 30% higher risk of death than people who are sufficiently active, and its global recommendation is at least 150 minutes of moderate activity a week [7].

For most people, knowing their blood pressure, cholesterol, blood sugar and weight, stopping smoking and attending the screening they are invited to offer more protection than any supplement.

Risks of supplements

Supplements can also do harm. Beta carotene raised the risk of lung cancer in people who smoke or were exposed to asbestos at work, and excessive doses of vitamins can cause adverse effects [1]. Some supplements interact with prescribed medicines, so tell your doctor everything you take.

The larger cost is often what a supplement replaces. Money and attention spent on a capsule can delay a blood pressure check or a cholesterol test that would change your care.

A checklist before you buy

Answer these for each supplement you take or plan to take.

• What do I expect it to prevent, and is there trial evidence for that outcome?
• Do I have a measured deficiency, or a reason such as planning a pregnancy?
• Could it interact with a medicine I take?
• Is the dose within safe limits, and am I taking the same nutrient twice?
• Have I had the checks with stronger evidence, such as blood pressure, cholesterol and HbA1c?

Who should review supplements with a doctor first

A review suits anyone who takes several supplements, anyone planning a pregnancy, anyone recovering from illness and anyone with a long term condition or regular medicines. If you take a blood thinner, have kidney or liver disease, or are pregnant, speak to a doctor before starting anything new.

If you have chest pain, sudden weakness, palpitations or trouble breathing, call 999 in the UK or the local emergency number elsewhere.

How The Wellness can help

A GP appointment gives you time to go through what you take and why, with a doctor who checks for interactions and orders tests where they would change your care. The Core Wellness blood test includes vitamin D, ferritin, HbA1c and lipids, so a supplement can follow a measured need.

For a wider plan, a free longevity consultation by video covers the prevention with the strongest evidence for you. Our GMC registered doctors see patients on Baker Street in Marylebone and Eccleston Street in Belgravia, and in 12 other cities through partners.