Lasted Updated May 28, 2026
The Bottom Line
For most healthy adults who eat a balanced diet, vitamin and mineral supplements are not necessary and have not been proven to prevent heart disease, cancer, dementia, or help people live longer. Most vitamins are best obtained through a healthy diet rather than supplements.
Who May Benefit from Supplements?
Vitamin supplementation may be appropriate for people who:
- Are pregnant or planning pregnancy
- Follow a vegan diet
- Have poor dietary intake
- Have certain digestive disorders causing poor absorption
- Have had bariatric (weight loss) surgery
- Are on dialysis
- Have alcohol use disorder
- Take certain medications that affect vitamin absorption
Always discuss supplementation with your healthcare provider.
Vitamin D
May Help:
- Maintain bone health
- Reduce fracture risk in people with deficiency
- Reduce falls in some older adults
Not Proven To:
- Prevent cancer
- Prevent heart disease
- Prevent dementia
- Prevent autoimmune diseases
Typical Supplement Dose
- Most healthy adults: 1,000–2,000 IU daily
- Older adults or those at risk of deficiency: 1,000–2,000 IU daily
- Higher doses may be prescribed if a deficiency is confirmed by blood testing
Vitamin D supplementation is most useful for people who are deficient or at higher risk of deficiency.
Calcium
May Help:
- Maintain bone health
- Reduce osteoporosis risk when combined with adequate vitamin D
Recommended Daily Intake (Diet + Supplements Combined)
- Adults 19–50 years: 1,000 mg daily
- Women over 50 years: 1,200 mg daily
- Men over 70 years: 1,200 mg daily
Supplementation
- Ideally obtained through food sources
- If supplementation is needed, calcium is best absorbed in doses of 500–600 mg at a time
- Most people should not exceed 2,000 mg daily from all sources unless specifically advised
Good dietary sources include dairy products, fortified plant milks, tofu, sardines, and leafy green vegetables.
Antioxidants (Vitamins A, C, and E)
Although diets rich in fruits and vegetables are associated with better health, studies have not shown benefits from antioxidant supplements.
Vitamin A
- Not recommended for routine supplementation
- Excess vitamin A may increase fracture risk
- High doses during pregnancy can cause birth defects
- Beta-carotene supplements may increase lung cancer risk in smokers
Vitamin C
- Does not prevent cancer or heart disease
- May slightly shorten the duration of a common cold
- High doses may increase the risk of kidney stones
Vitamin E
- Does not prevent cancer, heart disease, dementia, or infections
- High doses may increase the risk of bleeding and possibly increase mortality
B Vitamins
Vitamin B12
Vitamin B12 supplementation may be helpful for:
- Vegans
- Older adults
- People taking metformin
- People with poor diets
- People with absorption problems
Vitamin B12 deficiency can cause:
- Anemia
- Numbness or tingling
- Memory and nerve problems
Typical Supplement Dose
- General supplementation: 250–500 mcg daily
- Vegans: 250–500 mcg daily or 1,000 mcg 2–3 times per week
- Confirmed deficiency: often 1,000–2,000 mcg daily initially, as directed by a healthcare provider
Vitamin B12 supplements are very safe and excess amounts are generally excreted in the urine.
Folic Acid (Vitamin B9)
Folic acid is strongly recommended for people who may become pregnant.
Benefits
- Helps prevent neural tube defects (such as spina bifida) in babies
Recommended Dose
- 400 mcg daily beginning at least 1 month before conception and continuing through early pregnancy
- Higher doses may be recommended for patients with specific risk factors
Vitamin B2 (Riboflavin)
- May help prevent migraines in some people
- No proven benefit for most healthy adults
Typical Migraine Prevention Dose
- 400 mg daily
Vitamin B6
- No proven benefit for preventing cancer or heart disease
- Usually obtained adequately through diet
Multivitamins
For Most Healthy Adults
Routine multivitamin use has not been shown to:
- Prevent heart disease
- Prevent cancer
- Prevent dementia
- Increase lifespan
When They May Be Helpful
People with:
- Poor nutrition
- Restricted diets
- Malabsorption conditions
- Certain medical conditions
Multivitamins are generally safe when taken at standard doses.
Can Vitamins Be Harmful?
Yes. More is not always better.
High doses of certain vitamins can cause harm:
- Vitamin A: birth defects, fractures
- Vitamin C: kidney stones
- Vitamin E: bleeding risk
- Vitamin D: high calcium levels
- Some supplements contain much more than the recommended daily amount
Always follow recommended doses and discuss supplements with your healthcare provider.
Practical Advice
✔ Eat a balanced diet rich in fruits, vegetables, whole grains, legumes, nuts, and lean proteins.
✔ Consider vitamin D supplementation (1,000–2,000 IU daily) if recommended by your healthcare provider.
✔ Aim for 1,000–1,200 mg of calcium daily, preferably from food.
✔ Take folic acid if you are pregnant or planning pregnancy.
✔ Take vitamin B12 if you follow a vegan diet or are at risk of deficiency.
✔ Avoid high-dose vitamin supplements unless specifically recommended by your healthcare provider.
Remember: A healthy diet provides far more benefits than vitamin supplements alone.
What About Other Supplements?
Many other supplements are marketed for general health, longevity, immunity, energy, brain function, heart health, or cancer prevention. Examples include fish oil, magnesium, zinc, probiotics, collagen, turmeric, CoQ10, herbal supplements, and various antioxidant blends.
While some of these supplements may be helpful for specific medical conditions or in people with documented deficiencies, there is generally little high-quality evidence that routine supplementation improves overall health, prevents chronic disease, or helps healthy people live longer.
For most individuals, the greatest health benefits come from:
- Eating a balanced diet rich in fruits and vegetables
- Regular physical activity
- Maintaining a healthy weight
- Getting adequate sleep
- Avoiding smoking
- Limiting alcohol consumption
- Managing stress
If you are considering a supplement not discussed in this handout, speak with your healthcare provider to determine whether it is appropriate for your specific health needs.
