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.