Most healthy adults don’t need a multivitamin if they eat a varied, balanced diet. The NHS says most people should get all the nutrients they need from food, although some people need particular supplements. The US Preventive Services Task Force concluded in 2022 that there isn’t enough evidence that multivitamins prevent heart disease or cancer. The supplements most people should actually consider are specific ones: vitamin D in autumn and winter, folic acid before and during early pregnancy, vitamin B12 for vegans, and vitamins A, C and D for young children.
What the evidence says about multivitamins
The USPSTF recommendation, which reviewed the evidence for adults who aren’t pregnant, found:
- Multivitamins: not enough evidence to judge whether they prevent cardiovascular disease or cancer.
- Single or paired nutrients, other than the two below: also not enough evidence.
- Beta carotene and vitamin E supplements: the task force recommends against them for preventing heart disease or cancer.
In other words, a multivitamin is unlikely to do harm at normal doses, but it’s not a substitute for a healthy diet, and it hasn’t been shown to prevent major diseases in well-nourished people.
Who may benefit from supplements
| Who | What | Advice |
|---|---|---|
| Everyone, especially in autumn and winter | Vitamin D, 10 mcg a day | The NHS suggests everyone consider this, as sunlight is weak in winter in many countries |
| Trying to conceive and up to 12 weeks pregnant | Folic acid, 400 mcg a day | Reduces the risk of neural tube defects such as spina bifida, according to the NHS |
| Pregnant and breastfeeding | Vitamin D, 10 mcg a day | Also recommended by the NHS |
| Children aged 6 months to 5 years | Vitamins A, C and D | Recommended daily in the UK unless they drink more than 500 ml of formula a day, according to the NHS |
| Vegans | Vitamin B12 | B12 isn’t found naturally in plant foods |
| Some older adults | Vitamin B12, vitamin D | Absorbing B12 becomes harder with age; ask your doctor about a blood test |
| People with a diagnosed deficiency | As prescribed | For example, iron for iron deficiency anaemia |
Recommendations differ between countries, so follow your local health service’s advice.
When a multivitamin can make sense
A standard multivitamin may help fill gaps if you:
- Eat a very limited diet, for example because of a food allergy, an eating disorder in recovery, or very small appetite.
- Are recovering from surgery or illness and not eating well.
- Have had weight loss surgery, in which case your team will prescribe specific supplements.
- Follow a restrictive diet such as strict keto. Our guide to whether keto is safe long term covers the nutrients that can run low.
In these situations, it’s still better to talk to a doctor or dietitian, who can check which nutrients you actually need.
Can you take too much?
Yes. More isn’t better, and some vitamins and minerals are harmful in high doses:
- Vitamin A: the NHS says some research suggests more than 1.5 mg (1,500 mcg) a day over many years may weaken bones, and that your intake from food and supplements combined shouldn’t exceed this. Avoid vitamin A supplements and fish liver oil in pregnancy, as well as liver.
- Vitamin D: large doses can raise calcium levels too high. The NHS sets an upper limit of 100 mcg a day for adults.
- Iron: high doses can cause stomach pain and constipation, and iron supplements are dangerous if young children swallow them. Keep them out of reach.
- Selenium: easy to overdo if you also eat Brazil nuts. Our guide on how many Brazil nuts a day explains the limit.
Interactions with medicines
Some supplements interact with medicines. Vitamin K affects warfarin, and the NIH Office of Dietary Supplements advises people taking warfarin to keep their vitamin K intake steady. Calcium and iron can reduce the absorption of some antibiotics and thyroid medicines. Always tell your doctor or pharmacist what supplements you take.
How to choose a multivitamin
- Choose one with about 100% of daily values, not “mega-doses.”
- Pick a formula for your life stage, such as one for pregnancy, which contains folic acid and no vitamin A in retinol form, or one for over-50s.
- Look for quality marks, such as independent testing, where available.
- Be wary of big claims. Supplements that promise more energy, better immunity or protection from disease are making claims that usually aren’t backed up.
- Check the cost. A basic, inexpensive multivitamin is usually as good as a premium one.
Food first
Nutrients from food come with fiber and many other compounds that tablets don’t provide. A diet with plenty of vegetables, fruit, whole grains, beans, nuts, dairy or fortified alternatives, fish and lean protein covers most people’s needs. Our healthy grocery list and guide to building a balanced meal are good places to start.
Common questions
Do multivitamins give you energy?
Only if you’re deficient in something. If you’re often tired, see your doctor, because tiredness has many possible causes, including iron or vitamin B12 deficiency.
Is it better to take vitamins with food?
Usually, yes. Taking a multivitamin with a meal can reduce stomach upset and helps absorb the fat-soluble vitamins A, D, E and K.
Are gummy vitamins as good?
They can be, but many contain sugar and some have lower amounts of certain nutrients. Keep them out of children’s reach, as they look like sweets.
Should I take a multivitamin if I’m vegan?
You’ll need a reliable source of vitamin B12, from fortified foods or a supplement. Some vegans also take iodine, vitamin D and an algae-based omega-3. A multivitamin designed for vegans can cover several of these. Our guide to vitamin B12 explains why it matters.
Are expensive vitamins better?
Not usually. Price often reflects branding rather than quality. A basic multivitamin with around 100% of daily values is enough for most people who need one.
Can supplements replace a healthy diet?
No. Food provides fiber, protein and thousands of plant compounds that supplements don’t. Use supplements to fill specific gaps, not as a substitute for vegetables, fruit, whole grains and other healthy foods.
This article is general information, not medical advice. Talk to your doctor or a registered dietitian before making big changes to how you eat, especially if you have a health condition, take regular medication, or are pregnant or breastfeeding.
