Multivitamin · #1 supplement worldwide

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Connected to · 2

cofactor · 1

Testing for Deficiency
Testing should start with a question and then choose the test, not run a batch of tests and go looking for problems. Apply the same approach to supplements and the question becomes: does taking this actually do anything?

regulates · 1

Astaxanthin
Astaxanthin and beta-carotene are both carotenoids. In ATBC and CARET, two large randomized trials in smokers, beta-carotene supplements increased lung cancer. One explanation is that at high doses carotenoids switch from antioxidant to pro-oxidant, but that has not been shown directly. More antioxidant is not better.

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Stop 1/5

Why more stops helping

EVIDENCEGUIDE 1

READ THE ORIGINAL

If your diet is roughly in order, the daily multivitamin mostly has nothing to do. In decades of large randomized trials, it did not give healthy people less heart disease, and for cancer only one trial, in male doctors, saw a very small drop.

It was never designed for people who are already well. When vitamin C runs out, the step in your body that twists collagen into cables stalls: the cables cannot be wound tight, blood-vessel walls and gums lose their support, and so gums bleed and old wounds reopen. Put vitamin C back and the step starts up again, and the person recovers quickly. Repairing the gap from none to enough was the whole battlefield where vitamins first proved themselves.

The key point is that it is a switch, not a dial. From zero to enough, the body changes dramatically; from enough upward, the curve is already flat. So filling a gap and taking more to be healthier are two different things, and most of the large trial results that follow can be read from this.

If there are children in your home, lock up any multivitamin that contains iron. If you suspect a child has swallowed iron-containing tablets, do not wait at home for symptoms: contact poison control or go to the emergency department now.

Educational content, not medical advice — consult a clinician.

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