High-dose supplements and cancer risk

A common line of argument among supporters of alternative medicine is that "natural" products, such as herbal remedies or vitamin supplements, are superior to the drugs peddled by a profit-obsessed pharmaceutical industry. Ignore the fact that plenty of modern drugs have natural origins, and that the multi-billion dollar alternative medicine industry needs profits to stay afloat in much the same way as drug companies. A simple objection to the "natural is best" mantra is that it's simply not true. Anything producing a chemical change can have side effects. Your body doesn't care whether it's natural or not.

A new study bears this out. Over a period of around three years, more than 6,000 people were given a daily high-dose folic acid supplement or an inactive placebo. Followed up in another three years or so, more people taking the folic acid had been diagnosed with cancer, with a particular increase in lung cancer.

The increase in risk was small: 10 percent of people got cancer while taking folic acid, compared with 8.4 percent of people in the placebo group. But the researchers calculated that the difference was unlikely to have happened by chance.

There are also proven benefits to folic acid supplements. For women planning a pregnancy, they cut the risk that the baby will be born with serious spine or brain malformations, like spina bifida.
The dose of folic acid linked to cancer was much higher than the amount recommended for pregnant women. If you're thinking of having a baby or are already pregnant, it's recommended that you take 400 micrograms of folic acid every day, until week 12 of your pregnancy. In the study, people who developed cancer had been taking double this dose for several years.

In the US, flour has been fortified with folic acid since 1998, a move that was followed by a 27 percent fall in the number of babies born with spine and brain defects. The study dose of 800 milligrams per day is four to six times the amount of folic acid a typical American gets from fortified foods, and is double the recommended daily allowance.

Even so, the researchers point out that the supplements being used were within the supposedly safe limit of 1,000 micrograms of folic acid per day.

What you need to know

Try not to assume any medicine, natural or not, is safe and effective without good evidence. For women, taking 400 micrograms of folic acid in early pregnancy can protect the baby from conditions like spina bifida. Anyone else probably gets enough folic acid from food to stay healthy.

--Philip Wilson, patient editor, BMJ Group

ConsumerReportsHealth.org has partnered with The BMJ Group to monitor the latest medical research and assess the evidence to help you decide which news you should use.

Comments

[js]

Please decide if it's milli- or micro- grams, I'd really like to get this sorted out.

[Alene]

". . . it's recommended that you take 400 micrograms . . . "

"The study dose of 800 milligrams per day . . . "

"the supposedly safe limit of 1,000 micrograms of folic acid per day . . . "

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Okay, are we talking MICROgrams or MILLIgrams? They aren't interchangeable. This use of two different measurements is very confusing!

[Kok Siong Chen]

I totally agree with you that "anything producing a chemical change can have side effects". I'm not going to take any chemical drug or medicine when i was sick unless the condition become serious and uncontrolable. I believe that our body is the best doctor. Sickness is just a sign for us about our body system condition and remind us to take care of it.

However, using proper dose of some medicine may not harm us much.

Thanks for sharing!